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To The Stars

It turned out that the recommended way to do this with a laser was a dead end, for exactly that reason. Everything appears to line up nicely but once you add the camera you know better.

The solution to the collimation problem was a simple, yet expensive tool called a Cheshire Eye Piece. And lots of patience.

When I finally got a sharp picture I thought I was out of the woods. I was wrong, this isn’t landscape photography, after all. Duh.

The idea behind shooting with a telescope is not just better magnification, but to expose for longer as well. That’s what I got the motor kit for, right? Well, it’s not that straightforward unfortunately, at some point you need to learn about astronomy in order to understand how to achieve sharp pictures. It’s not enough to get something in focus, because things are moving all the time, very slowly so, but once you go past 1-2s exposure time that motion will show in your pictures as trails.

It’s paramount to align the telescope’s mount to Earth’s rotation axis, you can achieve that by pointing the mount at Polaris, the North Star, because it almost precisely marks the North Pole – which is where Earth’s rotation axis intersects with the surface. Once aligned all it takes to keep the telescope pointing at a particular object in the sky is to rotate the mount clockwise around the so-called RA (right ascension) axis at the same speed as the Earth goes – once in 24 hours. This procedure is called polar alignment – for obvious reasons.

But you can go one better by using a guiding system. This involves rigging the mount up to a laptop to control the motors and replacing the eyepiece of the finder scope with a CCD camera. You could then use guiding software to mark a particular star and have it follow that star, which would then be stationary for imaging purposes. That is what I decided to try but haven’t managed to get to work yet. The likely culprit is the software at the moment.

I spent 5-6 hours for 3 nights under the sky, trying to get the auto guiding software (PHD2) to work, to no avail. So I cut my losses and went with simple rotation around the RA axis instead and began shooting M42, the Orion nebula.

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