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Old 20-01-2009, 10:37 PM
luka's Avatar
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luka is offline
Join Date: Apr 2007
Location: Perth, Australia
Posts: 1,158

I am not an expert on this but at least I can give you some hints with the camera. I have D80 as well and have taken a few photos with it. It is not the best camera for long exposures due to the amp noise but it will do several minutes ok.

1. You can attach the camera to the scope and do some widefield shots (depending on the lenses you have). I assume that EDX125 can track the sky so after finding a way to attach the camera all you have to do is experiment with exposures. This should be relatively easy.

2. You can attach the camera directly to the scope instead of an eyepiece and use the scope as a big lense for the camera. You would need a T-adapter which should be available in various astronomy shops. With its f/15 focal ratio and 1900mm focal length, ETX-125 is probably best used on moon/planets but I am not an expert on this. Also you may have issues in getting it to focus...

With D80, set it in manual mode and set ISO 1600 to start with. For method 1, try a low f-number first as this will give you more light.
Once you get the feeling, you can try lower ISO and different f-numbers. With your lense f-number should be few stops higher than the minimum as this will give you the best imaging quality. Try taking photos with different f-numbers and compare the quality in the corners to determine the lowest number with the best image quality.

Unfortunately you can get only up to 30s exposures (shakefree) with D80 unless you get a cable adapter or an infrared adapter. The latter are very cheap on ebay and work great. Set camera to manual, exposure time to B, set camera to use infrared and press the button to open shutter, press the button again to close it after the time you want. Longer exposures are a must for better photos.

Of course set the camera to highest quality - raw works the best. Beware that most of the Nikon cameras do some post-processing with raw files even when you tell them not to unless you do some nastry tricks so this raw is not a real raw . Still better than jpeg.

Once you get started, disable the noise reduction for high ISO and take dark and flat frames as well. You can also stack the photos to improve signal to noise - for example using Deep Sky Stacker. There should be lots of guides for this on the net.

Hope this helps,

P.S. Don't forget to post your photos
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