Choosing a Mount For Astrophotography
Ok so lets cut straight to the chase. Skywatcher have the best low and mid ranged mounts for astrophotography. The reason I now know this is because I paid a visit to see the man who knows everything about mounts: Dave from Dark Frame Optics. He has spent years elbow deep in synta grease hyper tuning every variety of commercial mount you could imagine. Dave says Skywatcher mounts have the advantage of using accurate stepper motors combined with a simple design which can be easily tweaked by astro tweakers like us. I wish he’d told me 5 years and 5 mounts ago!
Which mount is right for me ?
There are basically two things to think about when choosing a mount. Can the mount carry the weight of my telescope (and camera and finderscope and guidescope and guide camera) and will the mount track the stars accurately enough for me to take great astro pictures.
Trusty HEQ5: I bought it second hand and the previous owner had had the mount tuned by Dave at Dark Frame Optics.
Lets talk about wobble
In order to take great astro pictures you need a mount that doesn’t wobble. Or to be more precise you need a mount that can track objects in space so accurately that the light from a distant star always falls onto the same pixel in your camera. A little bit of wobble is ok so long as the the wobble doesn’t cause the light to spill into the neighbouring pixels and blur your final image.
How much wobble can I get away with?
If you are using a small scope say the skywatcher 72ED and a canon 600d then every pixel would cover 2.11 arcseconds of the sky. So as long as your mount wobbles less than that then your image will be very crisp. You can work out how many arc seconds of sky each pixel of your set up covers at this brilliant website. Then all you have to do is make sure this resolution whilst guiding in arcseconds is larger than the wobble in your mount. To help you decide I have included the expected mount wobble of each of the mounts I recommend in the chart below and a dumbies link to the roughly the sort of scope you could use for astrophotography with the mount.