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Old 01-October-2006, 06:47 AM
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Bokmakierie Bokmakierie is offline
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Default Afocal Astrophotography

I have a relatively inexpensive homemade 9" Dobsonian reflector without a motor drive and no GO-TO facilty. I cannot image deep sky objects but I find immense pleasure in simply positioning my inexpensive digital camera in front of the eyepiece and click away at the moon and planets and double stars. The 3x optical zoom of the camera obviates the need to replace eyepieces.
For those who wish to learn more about the technique and view my images, here is the URL:
http://home.telkomsa.net/mybirding/Afocal.htm
Enjoy.

Philip
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Old 01-October-2006, 11:54 PM
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Now that is very cool and should be an inspiration to all those starting out and struggling to get decent images, even with more sophisticated equipment (like me).

I have one question though - is it the best method to stack your planet images by adding the first two at 50% transparency, then adding a third to the result at 50% transparency, then a fourth to the result at 50%? Is this how it's normally done? It seems like it this would mean that the first image would give only 12.5% data to the final image compared to 50% for the fourth? Is it better to use a method that gives an equal 25% weight to the four combined images? Or is it that I simply don't understand the principle of stacking?

clop
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Old 02-October-2006, 02:27 AM
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Do you have any problems with the weight of the camera rig overbalancing the springs?
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Old 02-October-2006, 05:38 AM
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Thank you guys for your positive comments.
Clop, the technique I am using is similar to the one that some people use with Adobe Photoshop. Whether my method is mathematically valid I cannot say. The experts will have to judge. All I know is that it certainly improves the quality of the images. Registax does not work for me as the images are all over the show and it is a major task to get them all aligned. But I do sometimes succeed and the results are identical.
The weight of the camera is indeed a problem. My telescope has a counterweight and no springs. I will need to increase the counterweight at some stage but meanwhile a broomstick handle is my answer!! I stick it into the ground and the broom part prevents the telescope from falling over when observing objects close to the horizon. Not elegant at all but it works!
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Old 02-October-2006, 06:52 AM
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Of course, you do not need to fix the camera to the telescope if you have steady hands. But at 76 ( going on to 77) my hands get a bit shaky when I am excited about a beautiful view. I notice that I am still a "junior member"
I must be the oldest junior member on the block or do I have serious competition?
Phil
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Old 02-October-2006, 04:11 PM
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Thanx NIGHT G ! Unintenionally you solved my "falling over" problem. I simply added two elastic bands to the bottom end of the scope. They act as springs and can be adjusted just to provide the right tension. No broomstix for this kid any more

Phil
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