Loading ...
Sorry, an error occurred while loading the content.

73RE: [ccd-newastro] guiding techniques

Expand Messages
  • Ron Wodaski
    Aug 1, 2000
    • 0 Attachment
      Yes, it's in the X and Y boxes. You can choose to display either pixels or
      arc-seconds (you'll need to enter telescope data to get accurate arc-second
      numbers).

      You can also select to have the guide corrections written to a file for
      later examination in detail; that's the best method for troubleshooting,
      since you have a complete record of the guiding session. I don't have the
      camera hooked up just now, but I think these options are available from the
      Settings button on the Guide panel, and then choose More for the logging
      option.

      Ron Wodaski
      The New Astronomy Book Site - http://www.newastro.com



      -----Original Message-----
      From: Focus [mailto:focus@...]
      Sent: Tuesday, August 01, 2000 8:04 AM
      To: ccd-newastro@egroups.com
      Subject: Re: [ccd-newastro] guiding techniques


      Hi Ron,
      Speaking of guiding, what is the increment or measurement in maxim in guide
      window that changes when you are guiding? It is the x and y box? I am not
      sure if I got good guiding....
      thanks
      Brian
      ----- Original Message -----
      From: Ron Wodaski <ronw@...>
      To: <ccd-newastro@egroups.com>
      Sent: Tuesday, August 01, 2000 9:04 AM
      Subject: RE: [ccd-newastro] guiding techniques


      > Because the mirror of an SCT shifts for a variety of reasons, and can
      shift
      > even during an exposure, it's not possible to maintain alignment between a
      > guidescope and an SCT. In other words, you either need to use a setup that
      > puts the guider in the same light path. That could be a camera with an
      > integrated guider (SBIG ST-7/8/9), or an off-axis guider. The SBIG
      camera's
      > are the simplest solution.
      >
      > You can also stick with unguided exposures, and throw out any that show
      > mirror shift problems.
      >
      > The longer your focal length, the more critical good guiding is. In the
      case
      > of the Fastar, you are shooting at a very short focal length (400mm), and
      it
      > is quite possible to take 1-2 minute unguided exposures successfully. I
      have
      > gotten good results this way, including color images, by stacking the
      > unguided exposures.
      >
      > The alternative is to lock the mirror in place, and use some other device
      > for focusing (e.g., a Crayford focuser on the back; the NGF-S motorized,
      > etc.).
      >
      > The most common application for using a guidescope successfully is when
      two
      > refractors are involved; it is relatively easy to make that kind of
      assembly
      > rigid and reliable. However, even something like a cheap focuser can throw
      > off a guidescope combination, and modifications to increase rigidity are
      > common.
      >
      > Ron Wodaski
      > The New Astronomy Book Site - http://www.newastro.com
      >
      >
      >
      > -----Original Message-----
      > From: Kevin Dixon [mailto:ksbtk@...]
      > Sent: Tuesday, August 01, 2000 1:55 AM
      > To: ccd-newastro@egroups.com
      > Subject: [ccd-newastro] guiding techniques
      >
      >
      > Good Morning Ron:
      >
      > I have a few questions regarding guiding while using a CCD camera.
      > If the camera is being used with an 8" SCT at a focal ratio of f/10
      > or f/6.3, can a guidescope be used or is it better to use an off-axis
      > guider (or similar device).
      >
      > Also, if the ST-237 is used with the Fastar lens assembly, it seems
      > that guiding would be done via a guidescope. Is this correct?
      >
      > Clear skies,
      > Kevin
      > ksbtk@...
      >
      >
      >
      >
      >
      > To unsubscribe from this group, send an email to:
      > ccd-newastro-unsubscribe@egroups.com
      >
      >
      >
      >
      >
      >
      >
      > To unsubscribe from this group, send an email to:
      > ccd-newastro-unsubscribe@egroups.com
      >
      >
      >




      To unsubscribe from this group, send an email to:
      ccd-newastro-unsubscribe@egroups.com
    • Show all 4 messages in this topic