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pixel counts for flat fielding

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  • Al Brockman
    I have been wanting to ask this question for some time but was afraid of sounding a little naive. I have the ST-8 camera and would like to know the full well
    Message 1 of 18 , Jun 6, 2001
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      I have been wanting to ask this question for some time but was
      afraid of sounding a little naive.
      I have the ST-8 camera and would like to know the full well capacity at
      various bin modes.
      Since it is 16 bit,
      bin 1 x 1 = 65,500
      bin 2 x 2 = 4 x the surface area, therefore = 262,000
      bin 3 x 3 = 9 x the surface area, therefore = 589,500
      For flat fielding, the aim is to get exposures giving counts between
      25%-50% of the fwc, therefore for:
      bin 1 x 1 = 16,000 - 32,000
      bin 2 x 2 = 65,500 - 130,000
      bin 3 x 3 = 150,000 - 295,000
      These numbers are obviously wrong. In practice, for bin 1 x 1, I go for
      counts around 15,000 and for bin 2 x 2, counts around 30,000 but I don't
      understand why these particular counts given the surface area changes.
      Given the orderly progression, perhaps a pixel count for bin 3 x 3 should
      be 1round 45,000.
      Could someone fill me in what the correct counts should be for flat
      fielding at the three bin modes and how you come by these numbers?

      Thanks, Alan
      ______________________________
      Al Brockman
      Shoklo Malaria Research Unit
      PO Box 46
      Mae Sot, Tak 63110
      Thailand
      Fax: 66-55-544442
      Ph: 66-55-545177
      http://smru.thehealthzone.com
      http://www.geocities.com/alan_astro
    • Eddie Trimarchi
      Hi Al, I ll hazard a guess here! Even though you are combining pixel values, the 16-bit ADC in the camera is still only capable of returning a 16-bit value.
      Message 2 of 18 , Jun 6, 2001
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        Hi Al,
        I'll hazard a guess here! Even though you are combining pixel values, the
        16-bit ADC in the camera is still only capable of returning a 16-bit value.
        i.e. 65535 is still the max pixel value that the camera can return with
        on-chip binning, regardless of the binning mode. You will just get there
        quicker if you bin.

        One way to get around that is to bin off-chip. i.e. get the software to do
        it, then the only limit is the size of the data types available from your
        programming language of choice. Or you could use image processing software
        that can do it, to do it. I know Mira can, not sure about Maxim or AIP. Of
        course when off chip binning, you still have to read out the entire frame so
        there is no readout time saving.

        Regards,

        Eddie Trimarchi
        ~~~~~~~~~~~~~~~
        http://users.fan.net.au/~eddiet

        >-----Original Message-----
        >From: Al Brockman [mailto:alanb@...]
        >Sent: Wednesday, June 06, 2001 6:00 PM
        >To: ccd-newastro@yahoogroups.com
        >Subject: [ccd-newastro] pixel counts for flat fielding
        >
        >
        >I have been wanting to ask this question for some time but was
        >afraid of sounding a little naive.
        >I have the ST-8 camera and would like to know the full well capacity at
        >various bin modes.
        >Since it is 16 bit,
        >bin 1 x 1 = 65,500
        >bin 2 x 2 = 4 x the surface area, therefore = 262,000
        >bin 3 x 3 = 9 x the surface area, therefore = 589,500
        >For flat fielding, the aim is to get exposures giving counts between
        >25%-50% of the fwc, therefore for:
        >bin 1 x 1 = 16,000 - 32,000
        >bin 2 x 2 = 65,500 - 130,000
        >bin 3 x 3 = 150,000 - 295,000
        >These numbers are obviously wrong. In practice, for bin 1 x 1, I go for
        >counts around 15,000 and for bin 2 x 2, counts around 30,000 but I don't
        >understand why these particular counts given the surface area changes.
        >Given the orderly progression, perhaps a pixel count for bin 3 x 3 should
        >be 1round 45,000.
        >Could someone fill me in what the correct counts should be for flat
        >fielding at the three bin modes and how you come by these numbers?
        >
        >Thanks, Alan
        >______________________________
        >Al Brockman
        >Shoklo Malaria Research Unit
        >PO Box 46
        >Mae Sot, Tak 63110
        >Thailand
        >Fax: 66-55-544442
        >Ph: 66-55-545177
        >http://smru.thehealthzone.com
        >http://www.geocities.com/alan_astro
        >
        >
        >
        >To unsubscribe from this group, send an email to:
        >ccd-newastro-unsubscribe@egroups.com
        >
        >
        >
        >Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
        >
        >
        >
      • Al Brockman
        Thank you Eddie, I was right to fear that I would expose my ignorance. Of course you are right that 16-bit maxes out at 65535. For flat fielding, the aim (so I
        Message 3 of 18 , Jun 6, 2001
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          Thank you Eddie,

          I was right to fear that I would expose my ignorance. Of course you are
          right that 16-bit maxes out at 65535.
          For flat fielding, the aim (so I understand) is to aim for 25-50% of the
          max pixel count which equates to 16,000-32,000
          Is it as simple as that? We aim for pixel counts in that range regardless
          of the on chip binning?

          Alan

          At 18:12 06/06/01 +1000, you wrote:
          >Hi Al,
          >I'll hazard a guess here! Even though you are combining pixel values, the
          >16-bit ADC in the camera is still only capable of returning a 16-bit value.
          >i.e. 65535 is still the max pixel value that the camera can return with
          >on-chip binning, regardless of the binning mode. You will just get there
          >quicker if you bin.
          >
          >One way to get around that is to bin off-chip. i.e. get the software to do
          >it, then the only limit is the size of the data types available from your
          >programming language of choice. Or you could use image processing software
          >that can do it, to do it. I know Mira can, not sure about Maxim or AIP. Of
          >course when off chip binning, you still have to read out the entire frame so
          >there is no readout time saving.
          >
          >Regards,
          >
          >Eddie Trimarchi
          >~~~~~~~~~~~~~~~
          >http://users.fan.net.au/~eddiet
          >
          > >-----Original Message-----
          > >From: Al Brockman [mailto:alanb@...]
          > >Sent: Wednesday, June 06, 2001 6:00 PM
          > >To: ccd-newastro@yahoogroups.com
          > >Subject: [ccd-newastro] pixel counts for flat fielding
          > >
          > >
          > >I have been wanting to ask this question for some time but was
          > >afraid of sounding a little naive.
          > >I have the ST-8 camera and would like to know the full well capacity at
          > >various bin modes.
          > >Since it is 16 bit,
          > >bin 1 x 1 = 65,500
          > >bin 2 x 2 = 4 x the surface area, therefore = 262,000
          > >bin 3 x 3 = 9 x the surface area, therefore = 589,500
          > >For flat fielding, the aim is to get exposures giving counts between
          > >25%-50% of the fwc, therefore for:
          > >bin 1 x 1 = 16,000 - 32,000
          > >bin 2 x 2 = 65,500 - 130,000
          > >bin 3 x 3 = 150,000 - 295,000
          > >These numbers are obviously wrong. In practice, for bin 1 x 1, I go for
          > >counts around 15,000 and for bin 2 x 2, counts around 30,000 but I don't
          > >understand why these particular counts given the surface area changes.
          > >Given the orderly progression, perhaps a pixel count for bin 3 x 3 should
          > >be 1round 45,000.
          > >Could someone fill me in what the correct counts should be for flat
          > >fielding at the three bin modes and how you come by these numbers?
          > >
          > >Thanks, Alan
          > >______________________________
          > >Al Brockman
          > >Shoklo Malaria Research Unit
          > >PO Box 46
          > >Mae Sot, Tak 63110
          > >Thailand
          > >Fax: 66-55-544442
          > >Ph: 66-55-545177
          > >http://smru.thehealthzone.com
          > >http://www.geocities.com/alan_astro
          > >
          > >
          > >
          > >To unsubscribe from this group, send an email to:
          > >ccd-newastro-unsubscribe@egroups.com
          > >
          > >
          > >
          > >Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
          > >
          > >
          > >
          >
          >
          >To unsubscribe from this group, send an email to:
          >ccd-newastro-unsubscribe@egroups.com
          >
          >
          >
          >Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
        • John Smith
          Hi Alan, With my ST-8E NABG, I have been having good luck by targeting flat fields for a count of 20,000 average, whether 1x1 or 2x2. The SNR is very
          Message 4 of 18 , Jun 6, 2001
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            Hi Alan,

            With my ST-8E NABG, I have been having good luck by targeting flat
            fields for a count of 20,000 average, whether 1x1 or 2x2. The SNR is
            very acceptable and the resultant image seems well corrected. This
            was a recommendation Ron W. made in his book and it seems pretty good
            to me. My camera has a max count of about 51,000 in 1x1, so that
            isn't a whole lot different than the maximum binned count of 65,535.

            John

            --- In ccd-newastro@y..., Al Brockman <alanb@c...> wrote:
            > I have been wanting to ask this question for some time but was
            > afraid of sounding a little naive.
            > I have the ST-8 camera and would like to know the full well
            capacity at
            > various bin modes.
            > Since it is 16 bit,
            > bin 1 x 1 = 65,500
            > bin 2 x 2 = 4 x the surface area, therefore = 262,000
            > bin 3 x 3 = 9 x the surface area, therefore = 589,500
            > For flat fielding, the aim is to get exposures giving counts between
            > 25%-50% of the fwc, therefore for:
            > bin 1 x 1 = 16,000 - 32,000
            > bin 2 x 2 = 65,500 - 130,000
            > bin 3 x 3 = 150,000 - 295,000
            > These numbers are obviously wrong. In practice, for bin 1 x 1, I go
            for
            > counts around 15,000 and for bin 2 x 2, counts around 30,000 but I
            don't
            > understand why these particular counts given the surface area
            changes.
            > Given the orderly progression, perhaps a pixel count for bin 3 x 3
            should
            > be 1round 45,000.
            > Could someone fill me in what the correct counts should be for flat
            > fielding at the three bin modes and how you come by these numbers?
            >
            > Thanks, Alan
            > ______________________________
            > Al Brockman
            > Shoklo Malaria Research Unit
            > PO Box 46
            > Mae Sot, Tak 63110
            > Thailand
            > Fax: 66-55-544442
            > Ph: 66-55-545177
            > http://smru.thehealthzone.com
            > http://www.geocities.com/alan_astro
          • Ron Wodaski
            If you have subscribed to the web version of the book, this is covered in detail in the third section of chapter 6:
            Message 5 of 18 , Jun 6, 2001
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              If you have subscribed to the web version of the book, this is covered in
              detail in the third section of chapter 6:

              http://www.newastro.com/newastro/book_new/c6_c.asp

              If not, the basic issue here isn't the bit depth; it's the full well
              capacity divided by the gain. For example, the ST-8E has a full well of
              100,000 electrons, and a gain of about 2.3. That is, it takes about 2.3
              electrons to generate one ADU (analog to digital unit). If a pixel has a
              brightness value of 100, that means that it took 230 electrons to generate
              that brightness level.

              To find your saturation level, divide the full well capacity by the gain
              (100,000 divided by 2.3). For the ST-8E, your saturation level is about
              43,000. So for a good flat field at 1x1, which would be 33% to 50% of
              saturation, shoot for an average background value of about 15-20k.

              Binning doesn't change the full well capacity of individual pixels; the
              pixels are simply ganged together during readout. So even though the full
              well capacity for a group of 4 pixels is 400,000, if any one pixel goes over
              100,000, it will bloom, so the full-well for binning isn't the same as for a
              camera that has larger pixels to start with.

              And as a practical matter, your 1x1 flat field can simply be resized to work
              for binned images. <g>

              Ron Wodaski
              The New CCD Astronomy
              http://www.newastro.com

              -----Original Message-----
              From: Al Brockman [mailto:alanb@...]
              Sent: Wednesday, June 06, 2001 1:00 AM
              To: ccd-newastro@yahoogroups.com
              Subject: [ccd-newastro] pixel counts for flat fielding


              I have been wanting to ask this question for some time but was
              afraid of sounding a little naive.
              I have the ST-8 camera and would like to know the full well capacity at
              various bin modes.
              Since it is 16 bit,
              bin 1 x 1 = 65,500
              bin 2 x 2 = 4 x the surface area, therefore = 262,000
              bin 3 x 3 = 9 x the surface area, therefore = 589,500
              For flat fielding, the aim is to get exposures giving counts between
              25%-50% of the fwc, therefore for:
              bin 1 x 1 = 16,000 - 32,000
              bin 2 x 2 = 65,500 - 130,000
              bin 3 x 3 = 150,000 - 295,000
              These numbers are obviously wrong. In practice, for bin 1 x 1, I go for
              counts around 15,000 and for bin 2 x 2, counts around 30,000 but I don't
              understand why these particular counts given the surface area changes.
              Given the orderly progression, perhaps a pixel count for bin 3 x 3 should
              be 1round 45,000.
              Could someone fill me in what the correct counts should be for flat
              fielding at the three bin modes and how you come by these numbers?

              Thanks, Alan
              ______________________________
              Al Brockman
              Shoklo Malaria Research Unit
              PO Box 46
              Mae Sot, Tak 63110
              Thailand
              Fax: 66-55-544442
              Ph: 66-55-545177
              http://smru.thehealthzone.com
              http://www.geocities.com/alan_astro



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              ccd-newastro-unsubscribe@egroups.com



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            • Randy Nulman
              Re-size a 1x1 flat to produce a binned flat...Excellent suggestion and time saver. (You earned your dollar for the day!)...Too bad it won t work for
              Message 6 of 18 , Jun 6, 2001
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                Re-size a 1x1 flat to produce a binned flat...Excellent suggestion
                and time saver. (You earned your dollar for the day!)...Too bad it
                won't work for darks...that would really save some time.
                Randy


                --- In ccd-newastro@y..., "Ron Wodaski" <ronw@n...> wrote:
                > If you have subscribed to the web version of the book, this is
                covered in
                > detail in the third section of chapter 6:
                >
                > http://www.newastro.com/newastro/book_new/c6_c.asp
                >
                > If not, the basic issue here isn't the bit depth; it's the full well
                > capacity divided by the gain. For example, the ST-8E has a full
                well of
                > 100,000 electrons, and a gain of about 2.3. That is, it takes about
                2.3
                > electrons to generate one ADU (analog to digital unit). If a pixel
                has a
                > brightness value of 100, that means that it took 230 electrons to
                generate
                > that brightness level.
                >
                > To find your saturation level, divide the full well capacity by the
                gain
                > (100,000 divided by 2.3). For the ST-8E, your saturation level is
                about
                > 43,000. So for a good flat field at 1x1, which would be 33% to 50%
                of
                > saturation, shoot for an average background value of about 15-20k.
                >
                > Binning doesn't change the full well capacity of individual pixels;
                the
                > pixels are simply ganged together during readout. So even though
                the full
                > well capacity for a group of 4 pixels is 400,000, if any one pixel
                goes over
                > 100,000, it will bloom, so the full-well for binning isn't the same
                as for a
                > camera that has larger pixels to start with.
                >
                > And as a practical matter, your 1x1 flat field can simply be
                resized to work
                > for binned images. <g>
                >
                > Ron Wodaski
                > The New CCD Astronomy
                > http://www.newastro.com
                >
                > -----Original Message-----
                > From: Al Brockman [mailto:alanb@c...]
                > Sent: Wednesday, June 06, 2001 1:00 AM
                > To: ccd-newastro@y...
                > Subject: [ccd-newastro] pixel counts for flat fielding
                >
                >
                > I have been wanting to ask this question for some time but was
                > afraid of sounding a little naive.
                > I have the ST-8 camera and would like to know the full well
                capacity at
                > various bin modes.
                > Since it is 16 bit,
                > bin 1 x 1 = 65,500
                > bin 2 x 2 = 4 x the surface area, therefore = 262,000
                > bin 3 x 3 = 9 x the surface area, therefore = 589,500
                > For flat fielding, the aim is to get exposures giving counts between
                > 25%-50% of the fwc, therefore for:
                > bin 1 x 1 = 16,000 - 32,000
                > bin 2 x 2 = 65,500 - 130,000
                > bin 3 x 3 = 150,000 - 295,000
                > These numbers are obviously wrong. In practice, for bin 1 x 1, I go
                for
                > counts around 15,000 and for bin 2 x 2, counts around 30,000 but I
                don't
                > understand why these particular counts given the surface area
                changes.
                > Given the orderly progression, perhaps a pixel count for bin 3 x 3
                should
                > be 1round 45,000.
                > Could someone fill me in what the correct counts should be for flat
                > fielding at the three bin modes and how you come by these numbers?
                >
                > Thanks, Alan
                > ______________________________
                > Al Brockman
                > Shoklo Malaria Research Unit
                > PO Box 46
                > Mae Sot, Tak 63110
                > Thailand
                > Fax: 66-55-544442
                > Ph: 66-55-545177
                > http://smru.thehealthzone.com
                > http://www.geocities.com/alan_astro
                >
                >
                >
                > To unsubscribe from this group, send an email to:
                > ccd-newastro-unsubscribe@egroups.com
                >
                >
                >
                > Your use of Yahoo! Groups is subject to
                http://docs.yahoo.com/info/terms/
              • Ron Wodaski
                Polar alignment is really a matter of figuring out how to get the most out of a particular mount s capabilities. After that, you use standard drift alignment
                Message 7 of 18 , Jun 7, 2001
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                  Polar alignment is really a matter of figuring out how to get the most out
                  of a particular mount's capabilities. After that, you use standard drift
                  alignment to refine your polar alignment to the degree you require. I've
                  already included some tips on polar alignment, and will probably include
                  more as I write the remaining chapters.

                  Drift alignment, by the way, takes a lot of time and mostly is viable for
                  more or less permanent setups. It can take an hour or more to do a really
                  good job, since you spend time waiting to see if the star is drifting. Film
                  imagers will aim for as much as 30 minutes of zero drift before signing off
                  on their polar alignment, but CCD imagers don't have to go that far. I think
                  the main reason for drift aligning would be as you suggest to take longer
                  unguided exposures. The periodic and random errors of your mount, of course,
                  also limit how long of an exposure you can take.

                  Drift alignment is painfully simple; directions can be found in chapter 5 in
                  the "Autoguiding in Action" section. The idea is to watch for star drift in
                  two places: either at the east or west horizon, and due south on the
                  celestial equator. You adjust your mount in Alt and Az according to the
                  directions you'll find in chapter 5 until you have a lack of drift over the
                  time period you require.

                  You can use your camera to measure drift, of course, but to do so you must
                  determine what directions are east/west/north/south on the chip, and that
                  can take a bit of head scratching to figure out, as it totally depends on
                  the rotation of your camera.

                  Ron Wodaski
                  The New CCD Astronomy
                  http://www.newastro.com

                  -----Original Message-----
                  From: Kevin Dixon [mailto:ksbtk@...]
                  Sent: Tuesday, June 05, 2001 5:49 PM
                  To: ccd-newastro@yahoogroups.com
                  Subject: Re: [ccd-newastro] New book content posted


                  Good evening Ron:

                  Great to have you back! Will the book address polar alignment using a CCD
                  camera (or do you have this already written up elsewhere)? I am most
                  interested in this as a procedure as I think it would enhance my unguided
                  images significantly.

                  Clear skies,
                  Kevin
                  ksbtk@...

                  From: "Ron Wodaski" <ronw@...>


                  > The first of the new content that I wrote while traveling through New
                  Mexico
                  > and Arizona has just been posted to the web site:
                  >
                  > * @Focus in CCDSoft is now covered in chapter 2
                  > * Chapter 3 is essentially complete, with new material added to the
                  existing
                  > sections and content added in two formerly blank sections.
                  >
                  > Keep in mind that "complete" means content is completely written, but that
                  > final technical review, copy editing, and indexing have not yet occurred.
                  >
                  > I have quite a bit of additional, already-written material to add in the
                  > next few days; stay tuned.



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                • Ron Wodaski
                  Sorry I haven t gotten these done yet; been very busy writing content and posting it to the web site. The full moon is starting to pass, so I ll work on the
                  Message 8 of 18 , Jun 7, 2001
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                    Sorry I haven't gotten these done yet; been very busy writing content and
                    posting it to the web site. The full moon is starting to pass, so I'll work
                    on the list tomorrow (Friday) and get it posted.

                    Ron Wodaski
                    The New CCD Astronomy
                    http://www.newastro.com

                    -----Original Message-----
                    From: Kevin Dixon [mailto:ksbtk@...]
                    Sent: Tuesday, June 05, 2001 1:28 PM
                    To: ccd-newastro@yahoogroups.com
                    Subject: [ccd-newastro] June imaging targets


                    Good afternoon Ron:

                    Can you please assemble a list of June imaging targets, with a few
                    that are well suited to the ST-237. Thanks.

                    Clear skies,
                    Kevin Dixon
                    ksbtk@...



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                  • gboutin@yahoo.com
                    ... This may sound like a stupid question, but I ve only just gotten into this hobby in the last two months. Still visual only, and haven t gotten far enough
                    Message 9 of 18 , Jun 8, 2001
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                      --- In ccd-newastro@y..., "Ron Wodaski" <ronw@n...> wrote:
                      > Polar alignment is really a matter of figuring out how to get the
                      >most out of a particular mount's capabilities. .....

                      >You adjust your mount in Alt and Az according to the directions
                      >you'll find in chapter 5 until you have a lack of drift over the
                      >time period you require.


                      This may sound like a stupid question, but I've only just gotten into
                      this hobby in the last two months. Still visual only, and haven't
                      gotten far enough to try drift alignment yet.

                      If you only make adjustments in Alt and Az, does drift alignment make
                      up for errors in the third axis? That is, if my levelling isn't
                      absolutely perfect and is "leaning" a tad to either East or West.

                      -------------
                      Gerald Boutin

                      BTW, I use your M27 jpg on my PC desktop. Hope you don't mind. That
                      is one amazing shot.
                    • Ron Wodaski
                      The main reason to level your mount for drift alignment: it reduces the interaction between ALt and Az adjustments. If you mount is NOT level, then when you
                      Message 10 of 18 , Jun 8, 2001
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                        The main reason to level your mount for drift alignment: it reduces the
                        interaction between ALt and Az adjustments. If you mount is NOT level, then
                        when you make an adjustment in Alt it will have an affect on your Az
                        adjustments. So it will take longer to drift align. The reason behind this
                        is that if the mount is orthogonal to your horizon, Alt and Az adjustments
                        exactly match the local frame of reference.

                        If your mount IS level, then you can make the Alt and Az adjustments
                        independently, and the process will be simpler and faster. But a lack of
                        level won't make alignment impossible at all; you can still make the RA axis
                        parallel to the earth's axis.

                        Ron Wodaski
                        The New CCD Astronomy
                        http://www.newastro.com

                        -----Original Message-----
                        From: gboutin@... [mailto:gboutin@...]
                        Sent: Friday, June 08, 2001 12:27 AM
                        To: ccd-newastro@yahoogroups.com
                        Subject: [ccd-newastro] Re: New book content posted


                        --- In ccd-newastro@y..., "Ron Wodaski" <ronw@n...> wrote:
                        > Polar alignment is really a matter of figuring out how to get the
                        >most out of a particular mount's capabilities. .....

                        >You adjust your mount in Alt and Az according to the directions
                        >you'll find in chapter 5 until you have a lack of drift over the
                        >time period you require.


                        This may sound like a stupid question, but I've only just gotten into
                        this hobby in the last two months. Still visual only, and haven't
                        gotten far enough to try drift alignment yet.

                        If you only make adjustments in Alt and Az, does drift alignment make
                        up for errors in the third axis? That is, if my levelling isn't
                        absolutely perfect and is "leaning" a tad to either East or West.

                        -------------
                        Gerald Boutin

                        BTW, I use your M27 jpg on my PC desktop. Hope you don't mind. That
                        is one amazing shot.


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                        ccd-newastro-unsubscribe@egroups.com



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                      • Chris Warnes
                        Ron, Just to let you know, it appears that chapters 8 and 9 can be viewed in HTML without the need for a password. Is this intentional, or is it because it is
                        Message 11 of 18 , Jun 8, 2001
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                          Ron,

                          Just to let you know, it appears that chapters 8 and 9 can be viewed
                          in HTML without the need for a password. Is this intentional, or is
                          it because it is new content it has not yet had the password
                          activated?

                          Chris
                        • Tom &/or Elizabeth Skinner
                          Hello, Has anyone out there successfully adapted the CB245 to autoguide an LX200? OK, then, can you provide some advise or source of information? Tom
                          Message 12 of 18 , Jun 8, 2001
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                            Hello,

                            Has anyone out there successfully adapted the CB245 to autoguide an LX200?
                            OK, then, can you provide some advise or source of information?

                            Tom
                          • Ron Wodaski
                            Thanks for the heads up; that was my oversight. It was trivial to fix, and is secure now. Thanks again! Ron Wodaski The New CCD Astronomy
                            Message 13 of 18 , Jun 8, 2001
                            • 0 Attachment
                              Thanks for the heads up; that was my oversight. It was trivial to fix, and
                              is secure now. Thanks again!

                              Ron Wodaski
                              The New CCD Astronomy
                              http://www.newastro.com

                              -----Original Message-----
                              From: Chris Warnes [mailto:c.w.fullwood@...]
                              Sent: Friday, June 08, 2001 10:39 AM
                              To: ccd-newastro@yahoogroups.com
                              Subject: [ccd-newastro] Re: New book content posted


                              Ron,

                              Just to let you know, it appears that chapters 8 and 9 can be viewed
                              in HTML without the need for a password. Is this intentional, or is
                              it because it is new content it has not yet had the password
                              activated?

                              Chris


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