The time has gone while waiting for decent weather for testing the new toy and trying to familiarize myself with it. I did some testing indoors out through the window and noticed that the stock focuser does not work with the camera + adapter setup. The focus does not move enough inward. So some "small" changes needed to be done before going outside. The focuser and focuser tube were shortened in order to get the focus to infinity with the camera.
Finally on January 30 2011 the weather took a turn for better, well, enough to take the equiment out and do some quick testing. My intention was to test the camera mounting and see how things might go on a proper night of photography.
I chose M42 (The Orion Nebula) as my first target (surprise, surprise). The target was not located in the best possible direction from my observation site, it was just above the roof of the house. The good thing is that the roof is covered in snow, so there weren't any major updrafts of warm air. However the streetlights behind the house did manifest themselves in the longer exposures. I set up the rig and did a quick polar alignment, no drift alignment this time, because the temperature was dropping rapidly and I was oput only for a quick test.
First I took a few pictures with the camera optics only. The following image was taken at 55mm focal length, ISO400, 30s exposure, f/4,9.
The image is a cropped jpeg saved by the camera. No processing has been done on it. The Orion Nebula is already in this shot showing some nebulosity and color (i was a little surprised by this). The glow of the streetlamps behind the house can be seen coloring the bottom right corner yellowish extending almost to the top left corner. Also the tracking is not spot on, but sufficient for the tests I intended.
For the next images I installed the camera on the telescope. Focusing was done by taking short 2-5s exposures and adjusting in between. The focus is not as good as it could have been, but again enough for this session. I tried different ISO speeds and exposure times.
The next image is taken at ISO1600, 5s exposure. The graininess due to the high ISO -speed is clearly evident even though the exposure time is not that long. Also the shape and colors are quite distinct.
In the last image an exposuretime of 15s was used with ISO1600. The background glow is getting quite obvious and distracting. The image is losing contrast and of course the tracking error is also having its toll on the image. There is however a noticeable difference in the contrast between the different areas of the nebula.
All things considered, I consider the test successful. I managed to get my first images of a deepsky object with just a quick setup. Of course without guiding I need to pay a lot of attention on the tracking and polar alignment of the scope. Due to the lack of guiding I need to also keep the exposure times short, that means more processing later and larger stacks of images.
While I'm writing this the sky is clearing up again, so maybe I get another session going today.
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