Posts Made By: John MacDonough

Billy,

Is the outside diameter of the tube of your C60 actually 60mm, or a bit larger?

You might also try William Optics or Parallax Instruments. If Mr. Nastasi doesn't have the exact rings you're looking for, he can machine one of his standard offerings to fit, for a bit extra.

I have two questions for the knowledgeable people here:

1: What is the best way to determine the proper length of the primary baffle tube for a Cassegrain telescope? I don't have any design software, so I hope there is a geometric or analytic solution that can be done with a piece of paper, pencil and calculator.

2: What is the best way to locate four points on the circumference of a circle that are 90 degrees apart? I tried one method that didn't work well when installing the spider in my scope. Note that I do not have a machine shop, I'll be working with basic hand tools.

So I'm finally getting to build an observatory. As you can see, I'm not very far along. Several friends have buildings around my site.

Has anyone out there seen an Orion HDX mount? Used one? They were introduced several months ago to roaring silence so I'm interested to hear if anyone has any experience yet.

I've asked this question of a few Astromart members via private messages, but I'm hoping this forum post will help me gather more information.

I'm getting ready to upgrade mounts and am wondering what people's experiences are with the Mountain Instruments MI-250 and the Losmandy Titan. I think either would satisfy my needs but would like to hear owners sing the praises of the mounts. Or curse them, if appropriate.

Are you unsatisfied with the go-to performance? Some other part of operation?

I'm not familiar with the firm ware in the AVX, but in the AS-GT predecessor backlash compensation is critical to getting good go-to performance.

I agree that it's bold of Orion to try this. I also agree that they won't sell many to individual astronomers. I hope that some astronomy clubs purchase a few. That's where the market is, I think.

I've climbed 12 or 14 feet up in the dark to see through a big scope. The view was worth it.

I finally got the scope to work. Thanks to those that sent suggestions. I built a sliding jig so I could change the mirror separation easily and quickly. I then tried forming an image of the sun on a white card. The sun was too bright, of course, so I had to wait for a full moon. Who would have expected that full moon nights would have been clouded out six months in a row?! The full moon turned out to be perfect and now the mirrors have been installed in the "permanent" OTA so I could verify that everything is working. Now, of course, everything is disassembled so I can do the painting and wiring (secondary dew heater and fans).

I took pictures, but they're too big to post. I'll have to post some of the finished scope.

Keith,

Looks like you did a nice job with the telescope resoration. Are you going to repaint the mount once you've got everything working correctly?

I'm not a really experienced Newtonian user but, as to your question about collimation: The first thing to do is make sure the secondary is centered over the primary. There is "word" out there that there should be some offset (I think toward the focuser" for the secondary. I think it's Suiter that recommends it in his book. I've never tried it, though. Then I insert my laser into the focuser. I tip and tilt the secondary until the laser hits the center of the primary mirror. I know you just got your mirror back, but perhaps the firm that coated it could also have applied a center spot. I think there are forum posts here for applying a center spot yourself. Then work with the primary to make the laser beam shoot back through the collimator and hit its center mark.

I think things are easier overall if the primary is centered in the OTA, but I don't think it's required. I think the main thing is to have the secondary centered over the primary.

Oops, I forgot to tell you where in the sky I'll be looking. Throughout the night, I'll be able to view from eastern Gemini to western Pegasus and as far south as -45 degrees (perhaps -50 degrees).