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

Re: "Sharpness" in CCDSoft

Expand Messages
  • Andy Schlei
    ... focusing ... Yes, autodark was on. ... average 3 or ... and ... The seeing was moderate and there was ample light pollution and moon glow. Nonetheless,
    Message 1 of 4 , Jun 1, 2004
    • 0 Attachment
      > Did you have Autodark turned on? Hot pixels can make a mess of
      focusing
      > algorithms.

      Yes, autodark was on.

      > Also: what
      > was the seeing like? If seeing jumping around, then you need to
      average 3 or
      > more readings at each focus position in order to clean up the data
      and
      > remove seeing-induced noise.

      The seeing was moderate and there was ample light pollution and moon
      glow. Nonetheless, the seeing figure did not in any way reflect
      what were obvious visual changes to the focus. If I read the manual
      right, it is a relative measure based on a starting point that is
      out of focus. Perhaps I reset the graph too close to critical focus?

      Prior to trying sharpness, I had been using maximum pixel with good
      results, but wanted to try the measure that was supposedly better.
      Designed more for automated than manual focusing?

      After trying out the new MaximDL tonight and using FWHM, it worked
      very well. I did have a situation where the focus suddenly changed
      by 1.5mm, as measured by the DRO. I need to do a little checking to
      see why that may have happened -- that's for another post.

      Thanks,

      --Andy
    • Wodaski Yahoo
      You wouldn t reset the graph during a focusing run. For one thing, as you get close to focus, the numbers tend to jump around for everything (FWHM, sharpness,
      Message 2 of 4 , Jun 1, 2004
      • 0 Attachment
        You wouldn't reset the graph during a focusing run. For one thing, as you
        get close to focus, the numbers tend to jump around for everything (FWHM,
        sharpness, brightest pixel, etc.) because of seeing. In fact, I use the
        sudden onset of jumping in all variables to tell me I am close. That is
        where averaging pays off in the automated focusing tools.

        When evaluating focus manually, I use every available measure, never just
        one.


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

        -----Original Message-----
        From: Andy Schlei [mailto:andy_schlei@...]
        Sent: Tuesday, June 01, 2004 1:37 AM
        To: ccd-newastro@yahoogroups.com
        Subject: [ccd-newastro] Re: "Sharpness" in CCDSoft

        > Did you have Autodark turned on? Hot pixels can make a mess of
        focusing
        > algorithms.

        Yes, autodark was on.

        > Also: what
        > was the seeing like? If seeing jumping around, then you need to
        average 3 or
        > more readings at each focus position in order to clean up the data
        and
        > remove seeing-induced noise.

        The seeing was moderate and there was ample light pollution and moon
        glow. Nonetheless, the seeing figure did not in any way reflect
        what were obvious visual changes to the focus. If I read the manual
        right, it is a relative measure based on a starting point that is
        out of focus. Perhaps I reset the graph too close to critical focus?

        Prior to trying sharpness, I had been using maximum pixel with good
        results, but wanted to try the measure that was supposedly better.
        Designed more for automated than manual focusing?

        After trying out the new MaximDL tonight and using FWHM, it worked
        very well. I did have a situation where the focus suddenly changed
        by 1.5mm, as measured by the DRO. I need to do a little checking to
        see why that may have happened -- that's for another post.

        Thanks,

        --Andy








        Yahoo! Groups Links







        __________ NOD32 1.778 (20040601) Information __________

        This message was checked by NOD32 antivirus system.
        http://www.nod32.com
      Your message has been successfully submitted and would be delivered to recipients shortly.