Re: Bright Sat Photometry?

From: Tom Wagner (
Date: Tue Sep 15 2009 - 00:33:56 UTC

  • Next message: George Roberts: "Re: Bright Sat Photometry?"

    I did a project in college that required that I measure the size of star 
    images on B&W film (I used a microscope designed for this) and to compare 
    them with magnitude. I was looking for a correlation between brightness and 
    dot size. There was one but the stars were hazy dots. Because a satellite 
    moves the exposure would differ not only from brightness but from the speed 
    of its movement across whatever part of the sky it's in. I image that makes 
    accurately estimating satellite's brightness from a photograph quite 
    Tom  Iowa  USA
    ----- Original Message ----- 
    From: "npr61" <>
    To: "Gerhard Groenewald" <>; <>
    Sent: Monday, September 14, 2009 6:01 PM
    Subject: Re: Bright Sat Photometry?
    > Mr. Groenewald:
    > I'm wondering if I can use a DSLR to take raw images and do comparative 
    > brightness (Sat vs. ref star).  With only a 50mm lens & short exposures, 
    > bright stars should remain point-like and thus amenable to measurement 
    > with an aperture.  The short sat trail, entirely within the frame, would 
    > require a rectangle to encompass it.  I imagine it will be tough to avoid 
    > saturation, and may not give useful results at all.  I basically wondering 
    > if it is possible to "measure a streak".  The goal is not research grade 
    > work, just fun with a camera and software.
    > Forgive my ignorance, but I figured this would be the place to ask about 
    > measuring sat brightness.  All of the AAVSO info I've read does not really 
    > address sats.
    > Neal Robichaux
    > 29.9884N
    > 92.1498W
    Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive:

    This archive was generated by hypermail 2b29 : Tue Sep 15 2009 - 00:35:01 UTC