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Astronomy Hints




Clever And Useful Hints And Tips On Telescope Mounts

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Smart Tips On Telescope Mounts

Learn from these smart tips and hints from other amateur astronomers. These tips are not guaranteed to work for you, but hopefully you'll learn a thing or two.

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Motor Vibration
Try A Pipe Fitting Mount

Posted: 8/28/2011

Title: Motor Vibration

You may want to be sure that your motor drive isn't limiting the details you could be seeing through your telescope.

A few years ago I purchased a 6 inch f/5 Newtonian on an equatorial mount. It came with a clock drive. The drive had a nice hand held controller that let me select the nominal siderial rate for tracking, or one of a few different slew speeds. I happened to notice one time when I touched the motor housing that I could feel a bit of a small vibration. I think it was probably a 60 HZ hum.

So I did some critical viewing of Jupiter, and while peering through the eyepiece I turned on and off the motor a few times. Sure enough, each time the motor was off, a few more details became visible. While I couldn't feel the hum by touching the telescope, I could see that I was loosing a few arc-seconds of resolution by that motor vibration.

I purchased a different clock drive motor from JMI Inc that happened to exactly fit my telescope mount. The new motor uses a manual slip-clutch, and doesn't have any neat hand-held controller. But -- neither does it have any vibration.

I don't notice any such vibration with my ETX90, so at least not all inexpensive clock drives cause such a problem.

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Posted: 9/6/2011

Title: Try A Pipe Fitting Mount

I've had a few of those inexpensive 60mm refractors. Yep, the department store kind. One was a Bushnell that I grabbed on sale.

I have to say that all of them optically were fine, delivering sharp images and producing good star images when observing in and out of focus star patterns. All of them came with a Barlow lens that was pretty useless, and a short focal length eyepiece, usually 4mm, that was useless. The eyepieces were typically of the Huygens type. Actually the longer focal length eyepieces worked fine.

But the simple wooden leg, yoke mounting tripod in every case was way too shaky, making all but the lowest power observations nothing but an aggravation. So when I got my hands on a vintage Monolux 60mm telescope, I was probably fortunate that it did not come with a tripod. So I built one out of pipe fittings, like folks used to do in the 40's and 50's. You can see the mount at www.astronomyhints.com/tripod.html. I used 2 inch pipe in the construction to hold my 60mm telescopes.

The threads of the pipe elements that are bearing surfaces were prepared by turning in with automotive valve grinding compound, then (after cleaning), applying a light coat of grease. With 2 inch pipe, the threads turn very smooth, but have enough friction to hold position with a well balanced telescope. Now I can enjoy viewing with these oft maligned but actually well performing telescopes at their maximum potential.

If you look at my embarrassingly simple design, you may find you want to drop about $50 on your own mount, and toss the one that came with your telescope.

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