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using a barlow

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  • briandkolb
    Hello, this is my first post. I have just recieved my neximage camera. Before I use it I would like to understand a few things. First of all, I have read other
    Message 1 of 11 , Jun 4, 2005
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      Hello, this is my first post. I have just recieved my neximage
      camera. Before I use it I would like to understand a few things. First
      of all, I have read other posts claiming the use of a 2.5X barlow with
      an 8" f/10 optical system. I believe the neximage camera (because of
      the chip size) acts as a 4mm lense. So is it practical to use a 2.5"
      barlow on a focal length of about 2,000mm making a 5,000mm focal
      length, so that an effective 4mm eyepiece would yield 1,250 power?
      Since I'm new to this maybe my math is wrong, and it won't hurt my
      feelings to be corrected if I am. I have been told that to expect a
      good image from 300 to 350 power and higher is asking alot. You can
      see how I might be confused.
      Secondly, I was led to buying an IR filter. Do any of you use
      it or have any opinions about using it?
    • tommy hartline
      hello, I use the neximager, I went out and bought an IR filter just to see if I could tell a difference. I couldnt, I did contact Celestron and talked to a
      Message 2 of 11 , Jun 4, 2005
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        hello, I use the neximager, I went out and bought an
        IR filter just to see if I could tell a difference. I
        couldnt, I did contact Celestron and talked to a tech
        and he did tell me they came with a built on IR
        filter. The first part of your question....sponge bob
        has more on me, in that department anyway! Keep
        looking up!

        --- briandkolb <bkolb@...> wrote:

        > Hello, this is my first post. I have just
        > recieved my neximage
        > camera. Before I use it I would like to understand a
        > few things. First
        > of all, I have read other posts claiming the use of
        > a 2.5X barlow with
        > an 8" f/10 optical system. I believe the neximage
        > camera (because of
        > the chip size) acts as a 4mm lense. So is it
        > practical to use a 2.5"
        > barlow on a focal length of about 2,000mm making a
        > 5,000mm focal
        > length, so that an effective 4mm eyepiece would
        > yield 1,250 power?
        > Since I'm new to this maybe my math is wrong, and it
        > won't hurt my
        > feelings to be corrected if I am. I have been told
        > that to expect a
        > good image from 300 to 350 power and higher is
        > asking alot. You can
        > see how I might be confused.
        > Secondly, I was led to buying an IR filter.
        > Do any of you use
        > it or have any opinions about using it?
        >
        >
        >



        Starman2010 Burleson,Texas 32.53 N 97.31 W CCD/Digital Astronomy by Tommy Hartline: http://www.geocities.com/southbeach/cape/7654


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      • dieterkuespert
        Brian, the IR part has already been answered. Even though C advertised an IR filter for the Neximage they sell it with one built in. I have been using a 2x
        Message 3 of 11 , Jun 4, 2005
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          Brian,

          the IR part has already been answered. Even though C advertised an IR
          filter for the Neximage they sell it with one built in.

          I have been using a 2x Barlow with a NS11 GPS with great success, see
          pictures under ADK in the photo section. One is with and one without
          Barlow. Forget the calculated power, this is true for visual but for
          CCD it is only a comparison figure. As long as your object fits the
          CCD the Barlow is all right.

          Dieter

          --- In neximage@yahoogroups.com, "briandkolb" <bkolb@c...> wrote:
          > Hello, this is my first post. I have just recieved my neximage
          > camera. Before I use it I would like to understand a few things. First
          > of all, I have read other posts claiming the use of a 2.5X barlow with
          > an 8" f/10 optical system. I believe the neximage camera (because of
          > the chip size) acts as a 4mm lense. So is it practical to use a 2.5"
          > barlow on a focal length of about 2,000mm making a 5,000mm focal
          > length, so that an effective 4mm eyepiece would yield 1,250 power?
          > Since I'm new to this maybe my math is wrong, and it won't hurt my
          > feelings to be corrected if I am. I have been told that to expect a
          > good image from 300 to 350 power and higher is asking alot. You can
          > see how I might be confused.
          > Secondly, I was led to buying an IR filter. Do any of you use
          > it or have any opinions about using it?
        • zman818
          ... It has and it hasn t. I recently received a NI from telescopes.com and it definitely does not have an IR filter attached to the ccd. No magenta hue
          Message 4 of 11 , Jun 8, 2005
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            --- In neximage@yahoogroups.com, "dieterkuespert" <metalflash@g...>
            wrote:
            > Brian,
            >
            > the IR part has already been answered.

            It has and it hasn't. I recently received a NI from telescopes.com
            and it definitely does not have an IR filter attached to the ccd. No
            magenta hue anywhere - not even a hint. Additionally, I have been
            back and forth with C on this issue, even so far as to send them
            links to various threads discussing IR filters on the NexImage. They
            continue to claim (to me, anyway) that the NI does *not* ship with a
            built in IR filter.

            What does this all mean? First, Celestron has a split personality and
            has trouble getting the facts out and straight. Second, I'd imagine
            there were two production runs of the NI, each with a different spec.
            If I had to bet, I'd say they reversed course at some point and
            removed the IR filter, either due to production problems (I've heard
            of bubbling issues along the mating seal) or to get another $60 out
            of people for the standalone IR filter.
          • tommy hartline
            Thats interesting, mine does have the magenta hue, and C. techs told me they did come with them built in....mmmm Im going with the two production runs for more
            Message 5 of 11 , Jun 8, 2005
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              Thats interesting, mine does have the magenta hue, and
              C. techs told me they did come with them built
              in....mmmm Im going with the two production runs for
              more money!!!!

              --- zman818 <zman818@...> wrote:

              > --- In neximage@yahoogroups.com, "dieterkuespert"
              > <metalflash@g...>
              > wrote:
              > > Brian,
              > >
              > > the IR part has already been answered.
              >
              > It has and it hasn't. I recently received a NI from
              > telescopes.com
              > and it definitely does not have an IR filter
              > attached to the ccd. No
              > magenta hue anywhere - not even a hint.
              > Additionally, I have been
              > back and forth with C on this issue, even so far as
              > to send them
              > links to various threads discussing IR filters on
              > the NexImage. They
              > continue to claim (to me, anyway) that the NI does
              > *not* ship with a
              > built in IR filter.
              >
              > What does this all mean? First, Celestron has a
              > split personality and
              > has trouble getting the facts out and straight.
              > Second, I'd imagine
              > there were two production runs of the NI, each with
              > a different spec.
              > If I had to bet, I'd say they reversed course at
              > some point and
              > removed the IR filter, either due to production
              > problems (I've heard
              > of bubbling issues along the mating seal) or to get
              > another $60 out
              > of people for the standalone IR filter.
              >
              >
              >
              >
              >
              >



              Starman2010 Burleson,Texas 32.53 N 97.31 W CCD/Digital Astronomy by Tommy Hartline: http://www.geocities.com/southbeach/cape/7654




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            • Freddy Diaz
              Hello, I purcahsed a NI in early December and mine, like the one is in the photos archive, has the filter, however I have purchased another filter and so far I
              Message 6 of 11 , Jun 9, 2005
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                Hello,
                 
                I purcahsed a NI in early December and mine, like the one is in the photos archive, has the filter, however I have purchased another filter and so far I could see that installing the filter affects the exposure time by half.
                 
                Not sure, but it may looks like the factory installed filter is not good enough, now I wonder if removing the original filter will destroy the CCD chip.
                 
                Regards,
                Freddy
                 
                ----- Original Message -----
                Sent: Saturday, June 04, 2005 8:35 PM
                Subject: Re: [neximage] using a barlow

                hello, I use the neximager, I went out and bought an
                IR filter just to see if I could tell a difference. I
                couldnt, I did contact Celestron and talked to a tech
                and he did tell me they came with a built on IR
                filter. The first part of your question....sponge bob
                has more on me, in that department anyway! Keep
                looking up!

                --- briandkolb <bkolb@...> wrote:

                >        Hello, this is my first post. I have just
                > recieved my neximage
                > camera. Before I use it I would like to understand a
                > few things. First
                > of all, I have read other posts claiming the use of
                > a 2.5X barlow with
                > an 8" f/10 optical system. I believe the neximage
                > camera (because of
                > the chip size) acts as a 4mm lense. So is it
                > practical to use a 2.5"
                > barlow on a focal length of about 2,000mm making a
                > 5,000mm focal
                > length, so that an effective 4mm eyepiece would
                > yield 1,250 power?
                > Since I'm new to this maybe my math is wrong, and it
                > won't hurt my
                > feelings to be corrected if I am. I have been told
                > that to expect a
                > good image from 300 to 350 power and higher is
                > asking alot. You can
                > see how I might be confused.
                >         Secondly, I was led to buying an IR filter.
                > Do any of you use
                > it or have any opinions about using it?
                >
                >
                >



                Starman2010 Burleson,Texas 32.53 N 97.31 W  CCD/Digital Astronomy by Tommy Hartline: http://www.geocities.com/southbeach/cape/7654


                __________________________________________________
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              • zman818
                ... I stand corrected. I wasn t looking at a deep enough off-angle to see it, especially with the adapter neck still attached. I believe I now see the vaunted
                Message 7 of 11 , Jun 9, 2005
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                  --- In neximage@yahoogroups.com, tommy hartline <starman2010@y...>
                  wrote:
                  > Thats interesting, mine does have the magenta hue, and
                  > C. techs told me they did come with them built
                  > in....mmmm Im going with the two production runs for
                  > more money!!!!
                  >

                  I stand corrected. I wasn't looking at a deep enough off-angle to see
                  it, especially with the adapter neck still attached. I believe I now
                  see the vaunted "magenta hue" (this is starting to sound like a
                  Seinfeld episode).

                  http://skyward.digwig.net/equipment/ns5i/info/niir/IMG_0296_x.jpg

                  I have yet another email in to C to find out definitively what it is,
                  what it isn't, and what its relation to the standalone IR filter is.
                • Michel
                  That s a good question Freddy, I have bought a seperate IR filter. It s a badder. I would be temped also to remove the piece. Hopefully someone will find out
                  Message 8 of 11 , Jun 9, 2005
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                    That's a good question Freddy,

                    I have bought a seperate IR filter. It's a badder. I would be temped
                    also to remove the piece.

                    Hopefully someone will find out ... and get the truth.

                    Cheers -

                    Michel


                    --- In neximage@yahoogroups.com, Freddy Diaz <fjdiazg@y...> wrote:
                    > Hello,
                    >
                    > I purcahsed a NI in early December and mine, like the one is in the
                    photos archive, has the filter, however I have purchased another
                    filter and so far I could see that installing the filter affects the
                    exposure time by half.
                    >
                    > Not sure, but it may looks like the factory installed filter is not
                    good enough, now I wonder if removing the original filter will
                    destroy the CCD chip.
                    >
                    > Regards,
                    > Freddy
                    >
                    > ----- Original Message ----- From: tommy hartline
                    > To: neximage@yahoogroups.com
                    > Sent: Saturday, June 04, 2005 8:35 PM
                    > Subject: Re: [neximage] using a barlow
                    >
                    >
                    >
                    > hello, I use the neximager, I went out and bought an
                    > IR filter just to see if I could tell a difference. I
                    > couldnt, I did contact Celestron and talked to a tech
                    > and he did tell me they came with a built on IR
                    > filter. The first part of your question....sponge bob
                    > has more on me, in that department anyway! Keep
                    > looking up!
                    >
                    > --- briandkolb <bkolb@c...> wrote:
                    >
                    > > Hello, this is my first post. I have just
                    > > recieved my neximage
                    > > camera. Before I use it I would like to understand a
                    > > few things. First
                    > > of all, I have read other posts claiming the use of
                    > > a 2.5X barlow with
                    > > an 8" f/10 optical system. I believe the neximage
                    > > camera (because of
                    > > the chip size) acts as a 4mm lense. So is it
                    > > practical to use a 2.5"
                    > > barlow on a focal length of about 2,000mm making a
                    > > 5,000mm focal
                    > > length, so that an effective 4mm eyepiece would
                    > > yield 1,250 power?
                    > > Since I'm new to this maybe my math is wrong, and it
                    > > won't hurt my
                    > > feelings to be corrected if I am. I have been told
                    > > that to expect a
                    > > good image from 300 to 350 power and higher is
                    > > asking alot. You can
                    > > see how I might be confused.
                    > > Secondly, I was led to buying an IR filter.
                    > > Do any of you use
                    > > it or have any opinions about using it?
                    > >
                    > >
                    > >
                    >
                    >
                    >
                    > Starman2010 Burleson,Texas 32.53 N 97.31 W CCD/Digital Astronomy
                    by Tommy Hartline: http://www.geocities.com/southbeach/cape/7654
                    >
                    >
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                  • zman818
                    This from Celestron. They are once again confirming no formal IR filter on the chip: Mike Currently, the only coating that we have over the chip is an AR anti-
                    Message 9 of 11 , Jun 14, 2005
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                      This from Celestron. They are once again confirming no formal IR filter
                      on the chip:


                      Mike

                      Currently, the only coating that we have over the chip is an AR anti-
                      reflection coating. We suspect that the AR coating has some weak IR
                      blocking properties as well. We are experimenting with different
                      coating (or no coatings at all), but so far no change has been made to
                      the chip.



                      Tech
                    • Michel
                      How about doing the IR test using a TV remote control? That should register on the CCD if no IR filter is present? Am I making any sens? Michel ... filter ...
                      Message 10 of 11 , Jun 14, 2005
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                        How about doing the IR test using a TV remote control? That should
                        register on the CCD if no IR filter is present?

                        Am I making any sens?

                        Michel


                        --- In neximage@yahoogroups.com, "zman818" <zman818@h...> wrote:
                        > This from Celestron. They are once again confirming no formal IR
                        filter
                        > on the chip:
                        >
                        >
                        > Mike
                        >
                        > Currently, the only coating that we have over the chip is an AR
                        anti-
                        > reflection coating. We suspect that the AR coating has some weak IR
                        > blocking properties as well. We are experimenting with different
                        > coating (or no coatings at all), but so far no change has been made
                        to
                        > the chip.
                        >
                        >
                        >
                        > Tech
                      • John Boudreau
                        The NexImage CCD built-in IR filter photos in the files section are mine. I own both the Baader IR/UV block filter and a near-IR 780nm pass filter from Edmund
                        Message 11 of 11 , Jun 15, 2005
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                          The NexImage CCD built-in IR filter photos in the files section are
                          mine. I own both the Baader IR/UV block filter and a near-IR 780nm
                          pass filter from Edmund that I've used in the past few years with a
                          standard ToUcam 740K, which I've now modified with the monochrome
                          version of the Sony 1/4" HAD CCD. The NexImage was purchased to add
                          RGB data to the results of the monochrome camera, which is far more
                          sensitive and much less noisy than the standard color CCD.

                          With either the stock color or monochrome CCD, the ToUcam worked
                          fine with the near-IR pass filter. The NexImage is virtually blind
                          with that filter in place--- completely unusable in the near-IR.
                          That certainly indicates that the NexImage has a built-in IR
                          blocker. Having toyed with a couple of these 1/4" Sony CCDs, that IR-
                          block filter bonded atop of the NexImage CCD's coverslip sticks out
                          like a sore thumb. I've also owned the Astronomik IR-block filter in
                          addition to the Baader version, and the built in Celestron filter is
                          just as effective as either of those as best as I can tell.

                          That Celestron techs can't figure this out doesn't surprise me at
                          all--- I've owned Celestron scopes since my first C8 back in '73---
                          so I've dealt with them a few times through the years <g>. I've seen
                          3 NexImage's that were delivered late in '04, and each had the IR
                          blocker. However, it's certainly possible that the latest versions
                          are unblocked.

                          I've talked to a Celestron tech about this myself a few months ago.
                          He restated the company line that it doesn't have an IR-blocker.
                          When I described my filter testing, I could tell he didn't have a
                          clue what I was talking about.


                          John Boudreau
                          www.spacescenes.com


                          --- In neximage@yahoogroups.com, "zman818" <zman818@h...> wrote:
                          > This from Celestron. They are once again confirming no formal IR
                          filter
                          > on the chip:
                          >
                          >
                          > Mike
                          >
                          > Currently, the only coating that we have over the chip is an AR
                          anti-
                          > reflection coating. We suspect that the AR coating has some weak
                          IR
                          > blocking properties as well. We are experimenting with different
                          > coating (or no coatings at all), but so far no change has been
                          made to
                          > the chip.
                          >
                          >
                          >
                          > Tech
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