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Darkness prediction

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  • Joe
    Say using the near space ventures prediction page is it too late to get a prediction that is all at night anymore/? IE: I m mainly looking for temps aloft but
    Message 1 of 15 , Apr 14, 2012
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      Say using the near space ventures prediction page

      is it too late to get a prediction that is all at night anymore/?

      IE: I'm mainly looking for temps aloft but at night now.

      Joe WB9SBD
      --
      Sig
      The Original Rolling Ball Clock
      Idle Tyme
      Idle-Tyme.com
      http://www.idle-tyme.com
    • Ted
      From the standard atmospheric data referenced on the EOSS page: ftp://nssdcftp.gsfc.nasa.gov/models/atmospheric/cira/cira86ascii/nht.lsn Looks like for January
      Message 2 of 15 , Apr 14, 2012
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        Sig

        From the standard atmospheric data referenced on the EOSS page:

         

        ftp://nssdcftp.gsfc.nasa.gov/models/atmospheric/cira/cira86ascii/nht.lsn

         

        Looks like for January at 100,000 feet it’s 228 K (-45 C).  For July, it’s 235 K, or -38 C. 

         

        If you only had pressure data, you could calculate the temperatures using the hypsometric equation. 

         

        As for the diurnal air temperature variations, it’s not going to be much aloft.  The impact of your object absorbing solar radiation could be different.

         

        Ted

         

        From: GPSL@yahoogroups.com [mailto:GPSL@yahoogroups.com] On Behalf Of Joe
        Sent: Saturday, April 14, 2012 9:06 AM
        To: gpsl
        Subject: [GPSL] Darkness prediction

         

        Say using the near space ventures prediction page

        is it too late to get a prediction that is all at night anymore/?

        IE: I'm mainly looking for temps aloft but at night now.

        Joe WB9SBD

        --

        The Original Rolling Ball Clock
        Idle Tyme
        Idle-Tyme.com
        http://www.idle-tyme.com

      • Joe
        Awesome Data chart! wow! Thats a keeper. Now I wonder where we can learn for sure how much change there is day vs night there really is. Joe WB9SBD The
        Message 3 of 15 , Apr 14, 2012
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          Awesome Data chart!  wow!  Thats a keeper.

          Now I wonder where we can learn for sure how much change there is day vs night there really is.

          Joe WB9SBD
          Sig
          The Original Rolling Ball Clock
          Idle Tyme
          Idle-Tyme.com
          http://www.idle-tyme.com

          On 4/14/2012 5:12 PM, Ted wrote:
          Sig

          From the standard atmospheric data referenced on the EOSS page:

           

          ftp://nssdcftp.gsfc.nasa.gov/models/atmospheric/cira/cira86ascii/nht.lsn

           

          Looks like for January at 100,000 feet it’s 228 K (-45 C).  For July, it’s 235 K, or -38 C. 

           

          If you only had pressure data, you could calculate the temperatures using the hypsometric equation. 

           

          As for the diurnal air temperature variations, it’s not going to be much aloft.  The impact of your object absorbing solar radiation could be different.

           

          Ted

           

          From: GPSL@yahoogroups.com [mailto:GPSL@yahoogroups.com] On Behalf Of Joe
          Sent: Saturday, April 14, 2012 9:06 AM
          To: gpsl
          Subject: [GPSL] Darkness prediction

           

          Say using the near space ventures prediction page

          is it too late to get a prediction that is all at night anymore/?

          IE: I'm mainly looking for temps aloft but at night now.

          Joe WB9SBD

          --

          The Original Rolling Ball Clock
          Idle Tyme
          Idle-Tyme.com
          http://www.idle-tyme.com

        • Joe
          hmmmmmm,,, So saying that if on that chart it is -30 that is the actual air temp, but physically due to solar heating it may feel warmer to the payload. And
          Message 4 of 15 , Apr 14, 2012
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            hmmmmmm,,,

            So saying that if on that chart it is -30 that is the actual air temp, but physically due to solar heating it may feel warmer to the payload. And when the sun sets, it looses this radiation benefit and the payload experiences in reality closer to the real -30 temp that it really is in.

            Joe
            Sig
            The Original Rolling Ball Clock
            Idle Tyme
            Idle-Tyme.com
            http://www.idle-tyme.com

            On 4/14/2012 6:23 PM, Mike Manes wrote:
            Ted's quite right in suggesting that solar flux heating is a far more
            significant factor in payload thermals than is air temp. Since the air
            density is quite low at altitude, it's ability to convect heat out of
            the payload is pretty minimal.  This is why aerospace outfits have solar
            flux vacuum chambers to test their birds.
            
            73 de Mike W5VSI
            
            On 4/14/2012 16:12, Ted wrote:
            
            
             From the standard atmospheric data referenced on the EOSS page:
            
            ftp://nssdcftp.gsfc.nasa.gov/models/atmospheric/cira/cira86ascii/nht.lsn
            
            Looks like for January at 100,000 feet it’s 228 K (-45 C). For July, it’s 235
            K, or -38 C.
            
            If you only had pressure data, you could calculate the temperatures using the
            hypsometric equation.
            
            As for the diurnal air temperature variations, it’s not going to be much
            aloft. The impact of your object absorbing solar radiation could be different.
            
            Ted
            
            *From:*GPSL@yahoogroups.com [mailto:GPSL@yahoogroups.com] *On Behalf Of *Joe
            *Sent:* Saturday, April 14, 2012 9:06 AM
            *To:* gpsl
            *Subject:* [GPSL] Darkness prediction
            
            Say using the near space ventures prediction page
            
            is it too late to get a prediction that is all at night anymore/?
            
            IE: I'm mainly looking for temps aloft but at night now.
            
            Joe WB9SBD
            
            --
            
            The Original Rolling Ball Clock
            Idle Tyme
            Idle-Tyme.com
            http://www.idle-tyme.com
            
            
            
            
            
          • Mike Manes
            Ted s quite right in suggesting that solar flux heating is a far more significant factor in payload thermals than is air temp. Since the air density is quite
            Message 5 of 15 , Apr 14, 2012
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              Ted's quite right in suggesting that solar flux heating is a far more
              significant factor in payload thermals than is air temp. Since the air
              density is quite low at altitude, it's ability to convect heat out of
              the payload is pretty minimal. This is why aerospace outfits have solar
              flux vacuum chambers to test their birds.

              73 de Mike W5VSI

              On 4/14/2012 16:12, Ted wrote:
              >
              >
              > From the standard atmospheric data referenced on the EOSS page:
              >
              > ftp://nssdcftp.gsfc.nasa.gov/models/atmospheric/cira/cira86ascii/nht.lsn
              >
              > Looks like for January at 100,000 feet it’s 228 K (-45 C). For July, it’s 235
              > K, or -38 C.
              >
              > If you only had pressure data, you could calculate the temperatures using the
              > hypsometric equation.
              >
              > As for the diurnal air temperature variations, it’s not going to be much
              > aloft. The impact of your object absorbing solar radiation could be different.
              >
              > Ted
              >
              > *From:*GPSL@yahoogroups.com [mailto:GPSL@yahoogroups.com] *On Behalf Of *Joe
              > *Sent:* Saturday, April 14, 2012 9:06 AM
              > *To:* gpsl
              > *Subject:* [GPSL] Darkness prediction
              >
              > Say using the near space ventures prediction page
              >
              > is it too late to get a prediction that is all at night anymore/?
              >
              > IE: I'm mainly looking for temps aloft but at night now.
              >
              > Joe WB9SBD
              >
              > --
              >
              > The Original Rolling Ball Clock
              > Idle Tyme
              > Idle-Tyme.com
              > http://www.idle-tyme.com
              >
              >
              >
              >

              --
              Mike Manes mrmanes@... Tel: 303-979-4899
              "Things should be made as simple as possible, but not more so."
              A. Einstein
            • Ted
              Good, glad it was of use to you. It s interesting to know the answer. I really doubt day versus night is more than a few degrees. I suppose you could
              Message 6 of 15 , Apr 14, 2012
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                Sig

                Good, glad it was of use to you.  It’s interesting to know the answer.

                 

                I really doubt day versus night is more than a few degrees.  I suppose you could calculate the temperature change in any given layer by knowing the actinic flux through that layer (calculable with the TUV model) and the absorption cross section of that layer.  But most gases are very poor absorbers at the relevant wavelengths, so I just can’t see that it would vary much.  Also, the density of that layer is ~1% of the sea level air density, so there just isn’t that much atmosphere to interact with the incoming solar radiation. 

                 

                As Mike noted, an absorbing payload could experience higher temperatures, although an absorbing payload might also do a good job of reradiating that heat away.  If you don’t mind me asking, what problem are you trying to solve?    

                 

                Ted

                 

                From: GPSL@yahoogroups.com [mailto:GPSL@yahoogroups.com] On Behalf Of Joe
                Sent: Saturday, April 14, 2012 3:41 PM
                To: Ted
                Cc: 'gpsl'
                Subject: Re: [GPSL] Darkness prediction

                 

                Awesome Data chart!  wow!  Thats a keeper.

                Now I wonder where we can learn for sure how much change there is day vs night there really is.

                Joe WB9SBD


                The Original Rolling Ball Clock
                Idle Tyme
                Idle-Tyme.com
                http://www.idle-tyme.com


                On 4/14/2012 5:12 PM, Ted wrote:

                From the standard atmospheric data referenced on the EOSS page:

                 

                ftp://nssdcftp.gsfc.nasa.gov/models/atmospheric/cira/cira86ascii/nht.lsn

                 

                Looks like for January at 100,000 feet it’s 228 K (-45 C).  For July, it’s 235 K, or -38 C. 

                 

                If you only had pressure data, you could calculate the temperatures using the hypsometric equation. 

                 

                As for the diurnal air temperature variations, it’s not going to be much aloft.  The impact of your object absorbing solar radiation could be different.

                 

                Ted

                 

                From: GPSL@yahoogroups.com [mailto:GPSL@yahoogroups.com] On Behalf Of Joe
                Sent: Saturday, April 14, 2012 9:06 AM
                To: gpsl
                Subject: [GPSL] Darkness prediction

                 

                Say using the near space ventures prediction page

                is it too late to get a prediction that is all at night anymore/?

                IE: I'm mainly looking for temps aloft but at night now.

                Joe WB9SBD

                --

                The Original Rolling Ball Clock
                Idle Tyme
                Idle-Tyme.com
                http://www.idle-tyme.com

              • Joe
                Now who out there is good with excel and can convert this mess into a nice graph like the turn around winds are/ Joe The Original Rolling Ball Clock Idle Tyme
                Message 7 of 15 , Apr 14, 2012
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                  Now who out there is good with excel and can convert this mess into a nice graph like the turn around winds are/

                  Joe
                  Sig
                  The Original Rolling Ball Clock
                  Idle Tyme
                  Idle-Tyme.com
                  http://www.idle-tyme.com

                  On 4/14/2012 6:23 PM, Mike Manes wrote:
                  Ted's quite right in suggesting that solar flux heating is a far more
                  significant factor in payload thermals than is air temp. Since the air
                  density is quite low at altitude, it's ability to convect heat out of
                  the payload is pretty minimal.  This is why aerospace outfits have solar
                  flux vacuum chambers to test their birds.
                  
                  73 de Mike W5VSI
                  
                  On 4/14/2012 16:12, Ted wrote:
                  
                  
                   From the standard atmospheric data referenced on the EOSS page:
                  
                  ftp://nssdcftp.gsfc.nasa.gov/models/atmospheric/cira/cira86ascii/nht.lsn
                  
                  Looks like for January at 100,000 feet it’s 228 K (-45 C). For July, it’s 235
                  K, or -38 C.
                  
                  If you only had pressure data, you could calculate the temperatures using the
                  hypsometric equation.
                  
                  As for the diurnal air temperature variations, it’s not going to be much
                  aloft. The impact of your object absorbing solar radiation could be different.
                  
                  Ted
                  
                  *From:*GPSL@yahoogroups.com [mailto:GPSL@yahoogroups.com] *On Behalf Of *Joe
                  *Sent:* Saturday, April 14, 2012 9:06 AM
                  *To:* gpsl
                  *Subject:* [GPSL] Darkness prediction
                  
                  Say using the near space ventures prediction page
                  
                  is it too late to get a prediction that is all at night anymore/?
                  
                  IE: I'm mainly looking for temps aloft but at night now.
                  
                  Joe WB9SBD
                  
                  --
                  
                  The Original Rolling Ball Clock
                  Idle Tyme
                  Idle-Tyme.com
                  http://www.idle-tyme.com
                  
                  
                  
                  
                  
                • Ted
                  Yes, that s the idea. Mike s point was there is very little air (~1% of sea level) to conduct (or convect) away the heat. However, if the payload is a black
                  Message 8 of 15 , Apr 14, 2012
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                    Sig

                    Yes, that’s the idea.  Mike’s point was there is very little air (~1% of sea level) to conduct (or convect) away the heat.  However, if the payload is a black lump of metal, it may be able to irradiate away any heat absorbed, rather than losing it by conduction.  As Mike pointed out, this is why the satellite people have their expensive test chambers. 

                     

                    And that brings up a good trivia question.  In deep space, what is the temperature?  The answer is 1000 C.  However, you would freeze to death, of course.  That’s because your body would lose all of its heat; although the mean molecular speed gives a temperature of 1000 C, there are so few molecules moving around that the heat cannot transfer back to your body. 

                     

                    Ted

                     

                    From: Joe [mailto:nss@...]
                    Sent: Saturday, April 14, 2012 3:49 PM
                    To: Mike Manes
                    Cc: Ted; 'gpsl'
                    Subject: Re: [GPSL] Darkness prediction

                     

                    hmmmmmm,,,

                    So saying that if on that chart it is -30 that is the actual air temp, but physically due to solar heating it may feel warmer to the payload. And when the sun sets, it looses this radiation benefit and the payload experiences in reality closer to the real -30 temp that it really is in.

                    Joe


                    The Original Rolling Ball Clock
                    Idle Tyme
                    Idle-Tyme.com
                    http://www.idle-tyme.com


                    On 4/14/2012 6:23 PM, Mike Manes wrote:

                    Ted's quite right in suggesting that solar flux heating is a far more
                    significant factor in payload thermals than is air temp. Since the air
                    density is quite low at altitude, it's ability to convect heat out of
                    the payload is pretty minimal.  This is why aerospace outfits have solar
                    flux vacuum chambers to test their birds.
                      
                    73 de Mike W5VSI
                      
                    On 4/14/2012 16:12, Ted wrote:
                      
                      
                     From the standard atmospheric data referenced on the EOSS page:
                      
                    ftp://nssdcftp.gsfc.nasa.gov/models/atmospheric/cira/cira86ascii/nht.lsn
                      
                    Looks like for January at 100,000 feet it’s 228 K (-45 C). For July, it’s 235
                    K, or -38 C.
                      
                    If you only had pressure data, you could calculate the temperatures using the
                    hypsometric equation.
                      
                    As for the diurnal air temperature variations, it’s not going to be much
                    aloft. The impact of your object absorbing solar radiation could be different.
                      
                    Ted
                      
                    *From:*GPSL@yahoogroups.com [mailto:GPSL@yahoogroups.com] *On Behalf Of *Joe
                    *Sent:* Saturday, April 14, 2012 9:06 AM
                    *To:* gpsl
                    *Subject:* [GPSL] Darkness prediction
                      
                    Say using the near space ventures prediction page
                      
                    is it too late to get a prediction that is all at night anymore/?
                      
                    IE: I'm mainly looking for temps aloft but at night now.
                      
                    Joe WB9SBD
                      
                    --
                      
                    The Original Rolling Ball Clock
                    Idle Tyme
                    Idle-Tyme.com
                    http://www.idle-tyme.com
                      
                      
                      
                      
                      
                  • BASE
                    Joe, The sounding data from http://www.weather.uwyo.edu/upperair/sounding.html could give you some actual readings.  Considering Green Bay, in most of
                    Message 9 of 15 , Apr 14, 2012
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                      Joe,

                      The sounding data from http://www.weather.uwyo.edu/upperair/sounding.html could give you some actual readings.  Considering Green Bay, in most of February and October the 0 Z (UTC) flights are in the dark and the 12 Z (UTC) flights are in the daylight.

                      Howard, KC9QBN


                      From: Joe <nss@...>
                      To: Ted <tedmisc@...>
                      Cc: 'gpsl' <GPSL@yahoogroups.com>
                      Sent: Saturday, April 14, 2012 6:41 PM
                      Subject: Re: [GPSL] Darkness prediction

                      Awesome Data chart!  wow!  Thats a keeper.

                      Now I wonder where we can learn for sure how much change there is day vs night there really is.

                      Joe WB9SBD
                      Sig
                      The Original Rolling Ball Clock
                      Idle Tyme
                      Idle-Tyme.com
                      http://www.idle-tyme.com

                      On 4/14/2012 5:12 PM, Ted wrote:
                      Sig
                      From the standard atmospheric data referenced on the EOSS page:
                       
                       
                      Looks like for January at 100,000 feet it’s 228 K (-45 C).  For July, it’s 235 K, or -38 C. 
                       
                      If you only had pressure data, you could calculate the temperatures using the hypsometric equation. 
                       
                      As for the diurnal air temperature variations, it’s not going to be much aloft.  The impact of your object absorbing solar radiation could be different.
                       
                      Ted
                       
                      From: GPSL@yahoogroups.com [mailto:GPSL@yahoogroups.com] On Behalf Of Joe
                      Sent: Saturday, April 14, 2012 9:06 AM
                      To: gpsl
                      Subject: [GPSL] Darkness prediction
                       
                      Say using the near space ventures prediction page

                      is it too late to get a prediction that is all at night anymore/?

                      IE: I'm mainly looking for temps aloft but at night now.

                      Joe WB9SBD
                      --

                      The Original Rolling Ball Clock
                      Idle Tyme
                      Idle-Tyme.com
                      http://www.idle-tyme.com


                    • Mike Manes
                      Well, sort of. depending on how much heat is being generated inside the payload and the R value of the thermal insulation. And if you re floating at altitude,
                      Message 10 of 15 , Apr 14, 2012
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                        Well, sort of. depending on how much heat is being generated inside
                        the payload and the R value of the thermal insulation. And if you're
                        floating at altitude, there'll be nearly zip convection to the atmosphere.
                        Norm Kjome's told me about some payloads that have actually overheated
                        on a 100K'+ ZP floater.

                        73 de Mike W5VSI

                        On 4/14/2012 16:48, Joe wrote:
                        > hmmmmmm,,,
                        >
                        > So saying that if on that chart it is -30 that is the actual air temp, but
                        > physically due to solar heating it may feel warmer to the payload. And when
                        > the sun sets, it looses this radiation benefit and the payload experiences in
                        > reality closer to the real -30 temp that it really is in.
                        >
                        > Joe
                        >
                        > The Original Rolling Ball Clock
                        > Idle Tyme
                        > Idle-Tyme.com
                        > http://www.idle-tyme.com
                        >
                        > On 4/14/2012 6:23 PM, Mike Manes wrote:
                        >> Ted's quite right in suggesting that solar flux heating is a far more
                        >> significant factor in payload thermals than is air temp. Since the air
                        >> density is quite low at altitude, it's ability to convect heat out of
                        >> the payload is pretty minimal. This is why aerospace outfits have solar
                        >> flux vacuum chambers to test their birds.
                        >>
                        >> 73 de Mike W5VSI
                        >>
                        >> On 4/14/2012 16:12, Ted wrote:
                        >>>
                        >>> From the standard atmospheric data referenced on the EOSS page:
                        >>>
                        >>> ftp://nssdcftp.gsfc.nasa.gov/models/atmospheric/cira/cira86ascii/nht.lsn
                        >>>
                        >>> Looks like for January at 100,000 feet it’s 228 K (-45 C). For July, it’s 235
                        >>> K, or -38 C.
                        >>>
                        >>> If you only had pressure data, you could calculate the temperatures using the
                        >>> hypsometric equation.
                        >>>
                        >>> As for the diurnal air temperature variations, it’s not going to be much
                        >>> aloft. The impact of your object absorbing solar radiation could be different.
                        >>>
                        >>> Ted
                        >>>
                        >>> *From:*GPSL@yahoogroups.com [mailto:GPSL@yahoogroups.com] *On Behalf Of *Joe
                        >>> *Sent:* Saturday, April 14, 2012 9:06 AM
                        >>> *To:* gpsl
                        >>> *Subject:* [GPSL] Darkness prediction
                        >>>
                        >>> Say using the near space ventures prediction page
                        >>>
                        >>> is it too late to get a prediction that is all at night anymore/?
                        >>>
                        >>> IE: I'm mainly looking for temps aloft but at night now.
                        >>>
                        >>> Joe WB9SBD
                        >>>
                        >>> --
                        >>>
                        >>> The Original Rolling Ball Clock
                        >>> Idle Tyme
                        >>> Idle-Tyme.com
                        >>> http://www.idle-tyme.com
                        >>>
                        >>>
                        >>>
                        >>>

                        --
                        Mike Manes mrmanes@... Tel: 303-979-4899
                        "Things should be made as simple as possible, but not more so."
                        A. Einstein
                      • Mike Manes
                        Quite right, and that s why satellites depend on radiative heat transfer (to the blackness of space) to keep hot stuff cool. Now, Ted s also right about a
                        Message 11 of 15 , Apr 14, 2012
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                          Quite right, and that's why satellites depend on radiative heat transfer
                          (to the blackness of space) to keep hot stuff cool. Now, Ted's also
                          right about a good heat absorber being a good heat radiator, but that's
                          only correct if it's a thermal "black body". Most materials have wavelength-
                          dependent absorbtivity, emissivity and reflectivity; a familiar example is
                          greenhouse gas, e.g. CO2< which passes shorter wave IR and visible light with
                          little attenuation, but which is a strong reflector at the longer wave far
                          IR, such as the Earth's albedo. This is the same trick used by selective
                          glazing for solar hot water heating panels.

                          I learned that a while back when I was working for an "electric reading
                          machine" (aka OCR) company. We'd built a test jig to repeatedly pass the
                          same letter-size document under our line scanner, comprising a 12"
                          circumference drum made from Aluminum. We bead blasted and black anodized
                          the surface in order to provide sharp contrast to the edges of the paper.
                          When we first ran it, we were dumbfounded to see that the scanner, which
                          had peak sensitivity at about 1.3 micron near-IR, could not distinguish
                          the white paper from the drum! We soon learned that although black anodize
                          sure looks black to the human eye, it's a great reflector at 1.3 um! So we
                          simply repainted the drum with some good carbon black bearing spray paint
                          and voila!

                          A more familiar example (to some) may be chrome plated car bumpers in the
                          summer sun. Ouch!

                          So I use bare Al heatsinks for the TO-220 voltage regulators in my payloads,
                          and they work just fine.

                          73 de Mike W5VSI

                          On 4/14/2012 17:42, Ted wrote:
                          > Yes, that’s the idea. Mike’s point was there is very little air (~1% of sea
                          > level) to conduct (or convect) away the heat. However, if the payload is a
                          > black lump of metal, it may be able to irradiate away any heat absorbed,
                          > rather than losing it by conduction. As Mike pointed out, this is why the
                          > satellite people have their expensive test chambers.
                          >
                          > And that brings up a good trivia question. In deep space, what is the
                          > temperature? The answer is 1000 C. However, you would freeze to death, of
                          > course. That’s because your body would lose all of its heat; although the mean
                          > molecular speed gives a temperature of 1000 C, there are so few molecules
                          > moving around that the heat cannot transfer back to your body.
                          >
                          > Ted
                          >
                          > *From:*Joe [mailto:nss@...]
                          > *Sent:* Saturday, April 14, 2012 3:49 PM
                          > *To:* Mike Manes
                          > *Cc:* Ted; 'gpsl'
                          > *Subject:* Re: [GPSL] Darkness prediction
                          >
                          > hmmmmmm,,,
                          >
                          > So saying that if on that chart it is -30 that is the actual air temp, but
                          > physically due to solar heating it may feel warmer to the payload. And when
                          > the sun sets, it looses this radiation benefit and the payload experiences in
                          > reality closer to the real -30 temp that it really is in.
                          >
                          > Joe
                          >
                          >
                          > The Original Rolling Ball Clock
                          > Idle Tyme
                          > Idle-Tyme.com
                          > http://www.idle-tyme.com
                          >
                          >
                          > On 4/14/2012 6:23 PM, Mike Manes wrote:
                          >
                          > Ted's quite right in suggesting that solar flux heating is a far more
                          >
                          > significant factor in payload thermals than is air temp. Since the air
                          >
                          > density is quite low at altitude, it's ability to convect heat out of
                          >
                          > the payload is pretty minimal. This is why aerospace outfits have solar
                          >
                          > flux vacuum chambers to test their birds.
                          >
                          >
                          >
                          > 73 de Mike W5VSI
                          >
                          >
                          >
                          > On 4/14/2012 16:12, Ted wrote:
                          >
                          >
                          >
                          >
                          >
                          > From the standard atmospheric data referenced on the EOSS page:
                          >
                          >
                          >
                          > ftp://nssdcftp.gsfc.nasa.gov/models/atmospheric/cira/cira86ascii/nht.lsn
                          >
                          >
                          >
                          > Looks like for January at 100,000 feet it’s 228 K (-45 C). For July, it’s 235
                          >
                          > K, or -38 C.
                          >
                          >
                          >
                          > If you only had pressure data, you could calculate the temperatures using the
                          >
                          > hypsometric equation.
                          >
                          >
                          >
                          > As for the diurnal air temperature variations, it’s not going to be much
                          >
                          > aloft. The impact of your object absorbing solar radiation could be different.
                          >
                          >
                          >
                          > Ted
                          >
                          >
                          >
                          > *From:*GPSL@yahoogroups.com [mailto:GPSL@yahoogroups.com] *On Behalf Of *Joe
                          >
                          > *Sent:* Saturday, April 14, 2012 9:06 AM
                          >
                          > *To:* gpsl
                          >
                          > *Subject:* [GPSL] Darkness prediction
                          >
                          >
                          >
                          > Say using the near space ventures prediction page
                          >
                          >
                          >
                          > is it too late to get a prediction that is all at night anymore/?
                          >
                          >
                          >
                          > IE: I'm mainly looking for temps aloft but at night now.
                          >
                          >
                          >
                          > Joe WB9SBD
                          >
                          >
                          >
                          > --
                          >
                          >
                          >
                          > The Original Rolling Ball Clock
                          >
                          > Idle Tyme
                          >
                          > Idle-Tyme.com
                          >
                          > http://www.idle-tyme.com
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >

                          --
                          Mike Manes mrmanes@... Tel: 303-979-4899
                          "Things should be made as simple as possible, but not more so."
                          A. Einstein
                        • Joe
                          How about something with zero insulation, and zero heat being generated? IE: the balloon and the gas inside it? Joe The Original Rolling Ball Clock Idle Tyme
                          Message 12 of 15 , Apr 14, 2012
                          • 0 Attachment
                            How about something with zero insulation, and zero heat being generated?

                            IE: the balloon and the gas inside it?

                            Joe
                            Sig
                            The Original Rolling Ball Clock
                            Idle Tyme
                            Idle-Tyme.com
                            http://www.idle-tyme.com

                            On 4/14/2012 9:08 PM, Mike Manes wrote:
                            Well, sort of. depending on how much heat is being generated inside
                            the payload and the R value of the thermal insulation.  And if you're
                            floating at altitude, there'll be nearly zip convection to the atmosphere.
                            Norm Kjome's told me about some payloads that have actually overheated
                            on a 100K'+ ZP floater.
                            
                            73 de Mike W5VSI
                            
                            On 4/14/2012 16:48, Joe wrote:
                            
                            hmmmmmm,,,
                            
                            So saying that if on that chart it is -30 that is the actual air temp, but
                            physically due to solar heating it may feel warmer to the payload. And when
                            the sun sets, it looses this radiation benefit and the payload experiences in
                            reality closer to the real -30 temp that it really is in.
                            
                            Joe
                            
                            The Original Rolling Ball Clock
                            Idle Tyme
                            Idle-Tyme.com
                            http://www.idle-tyme.com
                            
                            On 4/14/2012 6:23 PM, Mike Manes wrote:
                            
                            Ted's quite right in suggesting that solar flux heating is a far more
                            significant factor in payload thermals than is air temp. Since the air
                            density is quite low at altitude, it's ability to convect heat out of
                            the payload is pretty minimal.  This is why aerospace outfits have solar
                            flux vacuum chambers to test their birds.
                            
                            73 de Mike W5VSI
                            
                            On 4/14/2012 16:12, Ted wrote:
                            
                               From the standard atmospheric data referenced on the EOSS page:
                            
                            ftp://nssdcftp.gsfc.nasa.gov/models/atmospheric/cira/cira86ascii/nht.lsn
                            
                            Looks like for January at 100,000 feet it’s 228 K (-45 C). For July, it’s 235
                            K, or -38 C.
                            
                            If you only had pressure data, you could calculate the temperatures using the
                            hypsometric equation.
                            
                            As for the diurnal air temperature variations, it’s not going to be much
                            aloft. The impact of your object absorbing solar radiation could be different.
                            
                            Ted
                            
                            *From:*GPSL@yahoogroups.com [mailto:GPSL@yahoogroups.com] *On Behalf Of *Joe
                            *Sent:* Saturday, April 14, 2012 9:06 AM
                            *To:* gpsl
                            *Subject:* [GPSL] Darkness prediction
                            
                            Say using the near space ventures prediction page
                            
                            is it too late to get a prediction that is all at night anymore/?
                            
                            IE: I'm mainly looking for temps aloft but at night now.
                            
                            Joe WB9SBD
                            
                            --
                            
                            The Original Rolling Ball Clock
                            Idle Tyme
                            Idle-Tyme.com
                            http://www.idle-tyme.com
                            
                            
                            
                            
                            
                          • Ted
                            Yeah, I was thinking that was the question you were after. Short answer I I m not sure. My guess is the rather low mass of the balloon and gas compared to
                            Message 13 of 15 , Apr 14, 2012
                            • 0 Attachment
                              Sig

                              Yeah, I was thinking that was the question you were after.  Short answer I I’m not sure.  My guess is the rather low mass of the balloon and gas compared to the large surface area means it will stay close to the ambient air temperature.   In other words, it will lose heat just about as quickly as it gains it. 

                               

                              I can’t quite remember now, but wasn’t there some discussion of slight increases in altitude with sunrise for the recent transatlantic flight?  If so, that suggests the balloon gas is heating relative to the air outside the balloon.  If you assume the increase is a function of balloon heating, you could calculate the size of the temperature rise based on the change in altitude.  

                               

                              You could probably determine how much of an impact solar heating would have with a near-surface experiment.  Fill a balloon with helium, or dry air if cost is an issue (I think water vapor will skew results).  Hang it from the neck, with a temperature probe suspended inside the balloon.  Do this all early in the morning.  Once the sun comes up, compare air temps inside and outside the balloon, and also measure the circumference of the balloon. 

                               

                              Ted

                               

                              From: Joe [mailto:nss@...]
                              Sent: Saturday, April 14, 2012 7:41 PM
                              To: Mike Manes
                              Cc: Ted; 'gpsl'
                              Subject: Re: [GPSL] Darkness prediction

                               

                              How about something with zero insulation, and zero heat being generated?

                              IE: the balloon and the gas inside it?

                              Joe


                              The Original Rolling Ball Clock
                              Idle Tyme
                              Idle-Tyme.com
                              http://www.idle-tyme.com


                              On 4/14/2012 9:08 PM, Mike Manes wrote:

                              Well, sort of. depending on how much heat is being generated inside
                              the payload and the R value of the thermal insulation.  And if you're
                              floating at altitude, there'll be nearly zip convection to the atmosphere.
                              Norm Kjome's told me about some payloads that have actually overheated
                              on a 100K'+ ZP floater.
                                
                              73 de Mike W5VSI
                                
                              On 4/14/2012 16:48, Joe wrote:
                              hmmmmmm,,,
                                
                              So saying that if on that chart it is -30 that is the actual air temp, but
                              physically due to solar heating it may feel warmer to the payload. And when
                              the sun sets, it looses this radiation benefit and the payload experiences in
                              reality closer to the real -30 temp that it really is in.
                                
                              Joe
                                
                              The Original Rolling Ball Clock
                              Idle Tyme
                              Idle-Tyme.com
                              http://www.idle-tyme.com
                                
                              On 4/14/2012 6:23 PM, Mike Manes wrote:
                              Ted's quite right in suggesting that solar flux heating is a far more
                              significant factor in payload thermals than is air temp. Since the air
                              density is quite low at altitude, it's ability to convect heat out of
                              the payload is pretty minimal.  This is why aerospace outfits have solar
                              flux vacuum chambers to test their birds.
                                
                              73 de Mike W5VSI
                                
                              On 4/14/2012 16:12, Ted wrote:
                                
                                 From the standard atmospheric data referenced on the EOSS page:
                                
                              ftp://nssdcftp.gsfc.nasa.gov/models/atmospheric/cira/cira86ascii/nht.lsn
                                
                              Looks like for January at 100,000 feet it’s 228 K (-45 C). For July, it’s 235
                              K, or -38 C.
                                
                              If you only had pressure data, you could calculate the temperatures using the
                              hypsometric equation.
                                
                              As for the diurnal air temperature variations, it’s not going to be much
                              aloft. The impact of your object absorbing solar radiation could be different.
                                
                              Ted
                                
                              *From:*GPSL@yahoogroups.com [mailto:GPSL@yahoogroups.com] *On Behalf Of *Joe
                              *Sent:* Saturday, April 14, 2012 9:06 AM
                              *To:* gpsl
                              *Subject:* [GPSL] Darkness prediction
                                
                              Say using the near space ventures prediction page
                                
                              is it too late to get a prediction that is all at night anymore/?
                                
                              IE: I'm mainly looking for temps aloft but at night now.
                                
                              Joe WB9SBD
                                
                              --
                                
                              The Original Rolling Ball Clock
                              Idle Tyme
                              Idle-Tyme.com
                              http://www.idle-tyme.com
                                
                                
                                
                                
                                
                            • Ted
                              Nope, not an exact science! And sometimes it doesn t seem like a science at all! The heat capacity of helium is 5x that of air, thermal conductivity is 6x. So
                              Message 14 of 15 , Apr 15, 2012
                              • 0 Attachment
                                Nope, not an exact science! And sometimes it doesn't seem like a science at
                                all!

                                The heat capacity of helium is 5x that of air, thermal conductivity is 6x.
                                So perhaps that explains the behavior.

                                As I think about it, another possible explanation for the behavior you saw
                                was the first balloon was allowed to equilibrate with air temperature, where
                                the second balloon (released just after fill) still contained gas colder
                                than ambient. I think you could check this by measuring the neck load
                                immediately after fill and then again just before launch, as long as the
                                balloon was not exposed to the sun. I think your solar heating theory is a
                                bit more likely, but this does make me wonder how readily the balloon gains
                                or loses heat.

                                Ted

                                -----Original Message-----
                                From: GPSL@yahoogroups.com [mailto:GPSL@yahoogroups.com] On Behalf Of Mike
                                Manes
                                Sent: Sunday, April 15, 2012 11:46 AM
                                To: Ted
                                Cc: 'Joe'; 'gpsl'
                                Subject: Re: [GPSL] Darkness prediction

                                I think He has different thermal properties from air. Not that some fission
                                power reactors use He rather than water for a heat transfer medium.

                                A few years ago, we flew a 2-fer with KCI-3000's and near identical neck
                                loads. The 1st balloon was filled and tied off before sunrise, but due to
                                some delays in getting the student payloads ready to fly, that balloon was
                                didn't get off until about 30 minutes after sunrise, after which we filled
                                the 2nd to the same neck lift, tied on the payload string and let it go.
                                We were surprised to see the ascent rate of the 1st flight exceed the 2nd by
                                nearly 500 fpm! So we theorized that the 1st balloon's neck lift rose quite
                                a bit due to solar heating after the sunshine hit it.

                                Not an exact science, is it?

                                73 de Mike W5VSI, EOSS

                                On 4/14/2012 21:37, Ted wrote:
                                > Yeah, I was thinking that was the question you were after. Short
                                > answer I I'm not sure. My guess is the rather low mass of the balloon
                                > and gas compared to the large surface area means it will stay close to
                                > the ambient air temperature. In other words, it will lose heat just
                                > about as quickly as it gains it.
                                >
                                > I can't quite remember now, but wasn't there some discussion of slight
                                > increases in altitude with sunrise for the recent transatlantic
                                > flight? If so, that suggests the balloon gas is heating relative to
                                > the air outside the balloon. If you assume the increase is a function
                                > of balloon heating, you could calculate the size of the temperature rise
                                based on the change in altitude.
                                >
                                > You could probably determine how much of an impact solar heating would
                                > have with a near-surface experiment. Fill a balloon with helium, or
                                > dry air if cost is an issue (I think water vapor will skew results).
                                > Hang it from the neck, with a temperature probe suspended inside the
                                > balloon. Do this all early in the morning. Once the sun comes up,
                                > compare air temps inside and outside the balloon, and also measure the
                                circumference of the balloon.
                                >
                                > Ted
                                >
                                > *From:*Joe [mailto:nss@...]
                                > *Sent:* Saturday, April 14, 2012 7:41 PM
                                > *To:* Mike Manes
                                > *Cc:* Ted; 'gpsl'
                                > *Subject:* Re: [GPSL] Darkness prediction
                                >
                                > How about something with zero insulation, and zero heat being generated?
                                >
                                > IE: the balloon and the gas inside it?
                                >
                                > Joe
                                >
                                >
                                > The Original Rolling Ball Clock
                                > Idle Tyme
                                > Idle-Tyme.com
                                > http://www.idle-tyme.com
                                >
                                >
                                > On 4/14/2012 9:08 PM, Mike Manes wrote:
                                >
                                > Well, sort of. depending on how much heat is being generated inside
                                >
                                > the payload and the R value of the thermal insulation. And if you're
                                >
                                > floating at altitude, there'll be nearly zip convection to the atmosphere.
                                >
                                > Norm Kjome's told me about some payloads that have actually overheated
                                >
                                > on a 100K'+ ZP floater.
                                >
                                >
                                >
                                > 73 de Mike W5VSI
                                >
                                >
                                >
                                > On 4/14/2012 16:48, Joe wrote:
                                >
                                > hmmmmmm,,,
                                >
                                >
                                >
                                > So saying that if on that chart it is -30 that is the actual air
                                > temp, but
                                >
                                > physically due to solar heating it may feel warmer to the payload.
                                > And when
                                >
                                > the sun sets, it looses this radiation benefit and the payload
                                > experiences in
                                >
                                > reality closer to the real -30 temp that it really is in.
                                >
                                >
                                >
                                > Joe
                                >
                                >
                                >
                                > The Original Rolling Ball Clock
                                >
                                > Idle Tyme
                                >
                                > Idle-Tyme.com
                                >
                                > http://www.idle-tyme.com
                                >
                                >
                                >
                                > On 4/14/2012 6:23 PM, Mike Manes wrote:
                                >
                                > Ted's quite right in suggesting that solar flux heating is a
                                > far more
                                >
                                > significant factor in payload thermals than is air temp. Since
                                > the air
                                >
                                > density is quite low at altitude, it's ability to convect heat
                                > out of
                                >
                                > the payload is pretty minimal. This is why aerospace outfits
                                have solar
                                >
                                > flux vacuum chambers to test their birds.
                                >
                                >
                                >
                                > 73 de Mike W5VSI
                                >
                                >
                                >
                                > On 4/14/2012 16:12, Ted wrote:
                                >
                                >
                                >
                                > From the standard atmospheric data referenced on the
                                EOSS page:
                                >
                                >
                                >
                                >
                                > ftp://nssdcftp.gsfc.nasa.gov/models/atmospheric/cira/cira86ascii/nht.l
                                > sn
                                >
                                >
                                >
                                > Looks like for January at 100,000 feet it's 228 K (-45 C).
                                > For July, it's 235
                                >
                                > K, or -38 C.
                                >
                                >
                                >
                                > If you only had pressure data, you could calculate the
                                > temperatures using the
                                >
                                > hypsometric equation.
                                >
                                >
                                >
                                > As for the diurnal air temperature variations, it's not
                                > going to be much
                                >
                                > aloft. The impact of your object absorbing solar radiation
                                could be different.
                                >
                                >
                                >
                                > Ted
                                >
                                >
                                >
                                > *From:*GPSL@yahoogroups.com [mailto:GPSL@yahoogroups.com]
                                > *On Behalf Of *Joe
                                >
                                > *Sent:* Saturday, April 14, 2012 9:06 AM
                                >
                                > *To:* gpsl
                                >
                                > *Subject:* [GPSL] Darkness prediction
                                >
                                >
                                >
                                > Say using the near space ventures prediction page
                                >
                                >
                                >
                                > is it too late to get a prediction that is all at night
                                anymore/?
                                >
                                >
                                >
                                > IE: I'm mainly looking for temps aloft but at night now.
                                >
                                >
                                >
                                > Joe WB9SBD
                                >
                                >
                                >
                                > --
                                >
                                >
                                >
                                > The Original Rolling Ball Clock
                                >
                                > Idle Tyme
                                >
                                > Idle-Tyme.com
                                >
                                > http://www.idle-tyme.com
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >

                                --
                                Mike Manes mrmanes@... Tel: 303-979-4899
                                "Things should be made as simple as possible, but not more so."
                                A. Einstein



                                ------------------------------------

                                Yahoo! Groups Links
                              • Mike Manes
                                I think He has different thermal properties from air. Not that some fission power reactors use He rather than water for a heat transfer medium. A few years
                                Message 15 of 15 , Apr 15, 2012
                                • 0 Attachment
                                  I think He has different thermal properties from air. Not that some fission
                                  power reactors use He rather than water for a heat transfer medium.

                                  A few years ago, we flew a 2-fer with KCI-3000's and near identical neck
                                  loads. The 1st balloon was filled and tied off before sunrise, but due to
                                  some delays in getting the student payloads ready to fly, that balloon was
                                  didn't get off until about 30 minutes after sunrise, after which we filled
                                  the 2nd to the same neck lift, tied on the payload string and let it go.
                                  We were surprised to see the ascent rate of the 1st flight exceed the 2nd
                                  by nearly 500 fpm! So we theorized that the 1st balloon's neck lift rose
                                  quite a bit due to solar heating after the sunshine hit it.

                                  Not an exact science, is it?

                                  73 de Mike W5VSI, EOSS

                                  On 4/14/2012 21:37, Ted wrote:
                                  > Yeah, I was thinking that was the question you were after. Short answer I I’m
                                  > not sure. My guess is the rather low mass of the balloon and gas compared to
                                  > the large surface area means it will stay close to the ambient air
                                  > temperature. In other words, it will lose heat just about as quickly as it
                                  > gains it.
                                  >
                                  > I can’t quite remember now, but wasn’t there some discussion of slight
                                  > increases in altitude with sunrise for the recent transatlantic flight? If so,
                                  > that suggests the balloon gas is heating relative to the air outside the
                                  > balloon. If you assume the increase is a function of balloon heating, you
                                  > could calculate the size of the temperature rise based on the change in altitude.
                                  >
                                  > You could probably determine how much of an impact solar heating would have
                                  > with a near-surface experiment. Fill a balloon with helium, or dry air if cost
                                  > is an issue (I think water vapor will skew results). Hang it from the neck,
                                  > with a temperature probe suspended inside the balloon. Do this all early in
                                  > the morning. Once the sun comes up, compare air temps inside and outside the
                                  > balloon, and also measure the circumference of the balloon.
                                  >
                                  > Ted
                                  >
                                  > *From:*Joe [mailto:nss@...]
                                  > *Sent:* Saturday, April 14, 2012 7:41 PM
                                  > *To:* Mike Manes
                                  > *Cc:* Ted; 'gpsl'
                                  > *Subject:* Re: [GPSL] Darkness prediction
                                  >
                                  > How about something with zero insulation, and zero heat being generated?
                                  >
                                  > IE: the balloon and the gas inside it?
                                  >
                                  > Joe
                                  >
                                  >
                                  > The Original Rolling Ball Clock
                                  > Idle Tyme
                                  > Idle-Tyme.com
                                  > http://www.idle-tyme.com
                                  >
                                  >
                                  > On 4/14/2012 9:08 PM, Mike Manes wrote:
                                  >
                                  > Well, sort of. depending on how much heat is being generated inside
                                  >
                                  > the payload and the R value of the thermal insulation. And if you're
                                  >
                                  > floating at altitude, there'll be nearly zip convection to the atmosphere.
                                  >
                                  > Norm Kjome's told me about some payloads that have actually overheated
                                  >
                                  > on a 100K'+ ZP floater.
                                  >
                                  >
                                  >
                                  > 73 de Mike W5VSI
                                  >
                                  >
                                  >
                                  > On 4/14/2012 16:48, Joe wrote:
                                  >
                                  > hmmmmmm,,,
                                  >
                                  >
                                  >
                                  > So saying that if on that chart it is -30 that is the actual air temp, but
                                  >
                                  > physically due to solar heating it may feel warmer to the payload. And when
                                  >
                                  > the sun sets, it looses this radiation benefit and the payload experiences in
                                  >
                                  > reality closer to the real -30 temp that it really is in.
                                  >
                                  >
                                  >
                                  > Joe
                                  >
                                  >
                                  >
                                  > The Original Rolling Ball Clock
                                  >
                                  > Idle Tyme
                                  >
                                  > Idle-Tyme.com
                                  >
                                  > http://www.idle-tyme.com
                                  >
                                  >
                                  >
                                  > On 4/14/2012 6:23 PM, Mike Manes wrote:
                                  >
                                  > Ted's quite right in suggesting that solar flux heating is a far more
                                  >
                                  > significant factor in payload thermals than is air temp. Since the air
                                  >
                                  > density is quite low at altitude, it's ability to convect heat out of
                                  >
                                  > the payload is pretty minimal. This is why aerospace outfits have solar
                                  >
                                  > flux vacuum chambers to test their birds.
                                  >
                                  >
                                  >
                                  > 73 de Mike W5VSI
                                  >
                                  >
                                  >
                                  > On 4/14/2012 16:12, Ted wrote:
                                  >
                                  >
                                  >
                                  > From the standard atmospheric data referenced on the EOSS page:
                                  >
                                  >
                                  >
                                  > ftp://nssdcftp.gsfc.nasa.gov/models/atmospheric/cira/cira86ascii/nht.lsn
                                  >
                                  >
                                  >
                                  > Looks like for January at 100,000 feet it’s 228 K (-45 C). For July, it’s 235
                                  >
                                  > K, or -38 C.
                                  >
                                  >
                                  >
                                  > If you only had pressure data, you could calculate the temperatures using the
                                  >
                                  > hypsometric equation.
                                  >
                                  >
                                  >
                                  > As for the diurnal air temperature variations, it’s not going to be much
                                  >
                                  > aloft. The impact of your object absorbing solar radiation could be different.
                                  >
                                  >
                                  >
                                  > Ted
                                  >
                                  >
                                  >
                                  > *From:*GPSL@yahoogroups.com [mailto:GPSL@yahoogroups.com] *On Behalf Of *Joe
                                  >
                                  > *Sent:* Saturday, April 14, 2012 9:06 AM
                                  >
                                  > *To:* gpsl
                                  >
                                  > *Subject:* [GPSL] Darkness prediction
                                  >
                                  >
                                  >
                                  > Say using the near space ventures prediction page
                                  >
                                  >
                                  >
                                  > is it too late to get a prediction that is all at night anymore/?
                                  >
                                  >
                                  >
                                  > IE: I'm mainly looking for temps aloft but at night now.
                                  >
                                  >
                                  >
                                  > Joe WB9SBD
                                  >
                                  >
                                  >
                                  > --
                                  >
                                  >
                                  >
                                  > The Original Rolling Ball Clock
                                  >
                                  > Idle Tyme
                                  >
                                  > Idle-Tyme.com
                                  >
                                  > http://www.idle-tyme.com
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >

                                  --
                                  Mike Manes mrmanes@... Tel: 303-979-4899
                                  "Things should be made as simple as possible, but not more so."
                                  A. Einstein
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