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Re: [APML] A few more barn door shots


Hi Eric,

Those shots look pretty good. The barn door tracker seems to be working 
very well. Why don't you post a shot of it? Are you driving it by hand or 
with a motor? How are you polar aligning it?

I'm guessing that you scanned the prints from WalMart with the HP 4400c 
flatbed scanner?  You might want to check into having the images digitized 
when they are developed. I think Walmart offers this service, but I don't 
know how high of a resolution they offer.  You will get better quality that 
way for images you display on the web because they will be digitized 
directly from the original negatives and you won't lose quality and dynamic 
range by going the additional generation of the print.

Looking at your images in photoshop, I think you can improve them by 
re-setting the white point on them in Levels. You are not using all of the 
available dynamic range. The stars are not as white as they can be. For 
example, Vega, the brightest star in the picture of Lyra and Hercules, 
reads only 191,177,177 for the pixel values in the red, green and blue 
channels. They should be 255,255,255.

Jerry



At 10:59 AM 6/29/2003 -0700, you wrote:
>I finally got the tracking figured out, so almost all
>my shots feature round stars now, but the dew killed
>me on this roll.  Also, I found that shooting at f/1.8
>causes some annoying vignetting.  I used Kodak Max 400
>Versatility this time.  Here are links to the shots
>that came out Ok:
>
>http://members.aol.com/NGC5195/20030625/sagittarius.html
>http://members.aol.com/NGC5195/20030625/scorpius.html
>http://members.aol.com/NGC5195/20030625/mars.html
>http://members.aol.com/NGC5195/20030625/lyr_herc.html
>http://members.aol.com/NGC5195/20030625/beta_oph.html
>
>EZB
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