127 mm Orion Maksutov-Cassegrain

The 60 mm Tasco was great for getting me started on the road to photography with a good polar alignment. It’s chief failing is its small aperture which leaves me with a small selection of alignment and guide stars. So I went in search of something better (i.e., bigger)

I had already found I really liked what I was hearing about Orion Telescope’s (then new) Mak-Cas telescopes. The 127 mm version was getting some good reviews as being a good performer for the price. Since I was looking for a budget scope that could also serve for decent planetary views and hopefully some imaging of Mars during the 2003 approach, this looked like a good choice. The trick was that I didn’t need the whole equatorial setup Orion was selling but if I chose to purchase the spotting scope version I would have to go buy some additional parts that would put the price right back at that of the equatorial version. Enter astromart and Astronomy Mall, great places to search for used astronomy equipment. On Astronomy Mall, I found an ad from Ken Dauzat for a used 127 mm Orion Mak-Cas with some nice mods included a 2-inch diagonal with a Crayford focuser for about the same price as Orion’s equatorial version. I jumped at it, but someone had already contacted Ken. Fortunately for me, that deal fell through and the scope is now mine.

In the photo above, the Mak-Cas is shown with the camera mount bar and a (dead) Pentax A3000 on one of the ball mounts so you can better see how things are attached. Since I set this up solely for the purpose of taking a quick photo, I didn’t bother to attach any counterweights.

A month after the purchase, I went to NEAF where I picked up an additional counterweight for the CG5 mount and an extra dovetail bracket. The biggest question was how to attache the cameras. Ideally, I should have a nice bracket that would attach them to the OTA, and some stock versions are available, but I wanted to be able to mount at least two cameras and buying one ring for every camera seemed excessive.

I started out by ordering a small steel bar from McMaster-Carr to replace the finder mount. The original that had come with the scope was a bit too short after I replaced the Losmandy GM-8 bracket with the CG-5 dovetail. I discovered that I made a small error; the original was aluminum which is a lot easier to cut through (especially by hand with a hacksaw) than steel. I took the remainder of the bar and drilled three holes, one in the center and one near each end. The center hole is used to secure the bar to the CG-5 dovetail, the ones on each end hold a camera ball-joint mount. The arrangement is a bit kludgey, but it does work. I used it that July and August to take a series of shots which mostly came out well.

The arrangement is far from ideal. The long moment arm of that steel bracket allows vibrations. However, I have only one shot that shows anything that might be due to vibrations and even there I have convinced myself that the real culprit was something else, possibly a loose bracket on that camera (I was shooting both cameras, and one only end shows the blurring). The bigger issue is something most Mak-Cas owners are quite familiar with: mirror flop when crossing the meridian. I should have known that, but just didn’t think about it. So I have a few botched shots that were taken while crossing the meridian. The mirror flop for this scope is small, and I have no shots taken with a 50 mm lens that show it; only a couple with 135 mm and 200 mm lenses. Until I work out some scope mod to get a mirror lock in place, I’ve gone back to using the 60 mm Tasco as my guide scope.