Somewhat disappointed with the quality of the astronomical images I’ve captured so far I searched for information on why this might be. I found a web site about our particular telescope, a Meade LX90, which went into some detail about improvements which can be made.
Apparently the main problem in achieving good images is getting the focus spot on. It seems that the focussing system used on our telescope is subject to backlash. This makes it difficult to be certain that you have homed in on the optimum focus point. Two ideas to help came out of my investigation.
The first cost money. This is a kit with precision ball bearings which, when fitted to the focussing control, takes out most of the slack which causes backlash. The kit came from America and cost me $32, around £17. Interestingly I found the same kit sold by an online UK astronomy shop for £29! The kit was ‘reasonably’ easy to fit and resulted in a much smoother focussing.
The second was free. It consists simply of a mask which fits on the front of the telescope. The mask has two holes in it. The idea is that when the image is not in focus it splits into two images. To ensure accurate focussing it is simply necessary to merge the two images. Here is a picture of the mask I made:
Armed with the mask and improved focussing control I set up the telescope last night to see what I could achieve. Unfortunately Mars and Saturn have moved away so I couldn’t photograph them. My modified webcam is not sensitive enough to photograph star clusters, galaxies or nebula so I spent some time trying out the mask and improved focussing using an eyepiece. At 11.30pm I was delighted to see Jupiter appear. It was very low so I didn’t expect great results but I just look at my first attempt. I’m delighted.
Can’t wait for Jupiter to get higher in the sky and out of the heat haze. I think by the end of July I should be getting even better pictures.
