[jamespierce (James)]

Ultimately the most personal choice of an observatory depending on what you want to do with the observatory.

The Mount

I already had a Paramount MX+ which I had been using in a portable configuration. When I bought it I had this project in mind and really there are only a few viable choices for a remote observatory. You have to have a telescope which can either home itself on power up, or has absolute encoders so that it always knows where it is. It seems like there are more choices every day now, but when I was choosing there were not so many. In the future axis encoders are going to be an increasingly affordable and desirable option.

In an ideal world I’d get the largest mount I could, a Paramount MEII, a Planewave 200HR (discontinued) or a large 10Micron mount. But, you have to balance cost and benefit and end up with a balanced system overall. The MX+ works fine and can still carry quite large scopes. Every high end mount is very good, every high end mount has its quirks including the MX+.

If I did it again I’d seriously consider a 10 Micron mount or most likely a Planewave L Mount (which requires an offset pier for a wedge so you need to think about this from the very start).

The Telescope

I started with a refractor I already owned in the dome for my setup phase, but my intention was always to get a bigger scope. The lead time on these is significant so you order and you wait, 9 months in my case. My astronomical interests are varied so I wanted a scope with as much reach and aperture as possible while still keeping a reasonable field of view as well… I know, cake and eat it.

I landed on a CDK 14 with an IRF90 focuser - Basically the biggest and best setup I can carry on my MX+. It is beautiful telescope and a very substantial telescope. ~2.5m focal length @ F7.2 with a big 70mm image circle is a good compromise; I wish I could use a reducer, but the back focus is just too short to be practical. Already having the MX+ mount meant that any bigger would mean stepping up to an MEII or equivalent and another big step up in cost.

If I did it again I’d seriously consider the CDK12.5 which comes standard with a focuser and despite how nice the CDK14 is a CDK 12.5 would have been significantly cheaper. The rotator is an incredible focuser, but having rotated images adds complexity to gathering flat fields and scheduling images. It also adds to the complexity of choosing guide stars and so-on, before I had the option I lived in ignorant bliss, often imaging with sub-optimal guide stars but still getting good results.

The Camera

Matching the big field of the CDK I bought an SBIG STX 16803 while they were on sale and the AUD / USD was more attractive. They have effectively doubled in price now so a tricky choice. I'm still getting my head around getting the best performance out of this camera, there are a bunch of quirks that you have to learn to deal with these full frame chips. My KAF8300 camera was much more forgiving!

If I did it again I'd be seriously considering one of the new CMOS cameras it's obvious it's going to be the future, the question is just when.