* Damn 35 F Rain - Staying Warm Inside Is Winning Today wrote :
* Troy Piggins wrote :

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http://piggo.com/~troy/photos/2009/2...er091023_1.jpg

All up I'm pretty happy with it. Suspect the scope needs some
tweaking of the collimation which should give a sharper image.
Will have to try that next time, haven't done it before.

Much depends too on "seeing" conditions. The atmospheric stability. Most
times you just have to wait and hope for the best days. The very same
perfectly collimated optics can provide a draw-dropping 3D-looking view of
Saturn one day, and an irregular mushy blob the next. Look into the
sharpening techniques that web-cam astrophotographers use, by combining
details from many many frames to virtually look through the turbulent
atmosphere, capturing and combining those bits of each image that are
stable and sharp.

Yes, this image was stacked from around 2500 frames of an avi
file using Registax. Suspect that's the technique you're
referring to.

You might also try stopping down the aperture of your telescope during bad
seeing conditions. A larger aperture means that your telescope is trying to
image through larger lower-frequency areas of atmospheric turbulence. If
the turbulence that night is mostly of the lower-frequency variety it will
help to filter it out. I keep a 6" mask handy for those times to put on my
16" scope. Apodizing masks also cure things on some days for planetary
imaging.

How does one stop down the aperture of a fixed aperture scope?
The bare scope is f/10. With the 2.5x powermate it becomes an
equivalent f/25. I haven't heard of people using those masks
you're referring to. I'll look into it. Thanks.

--
Troy Piggins