Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

I have a Celestron 130 SLT reflector. I am having some issues with it and I hoped you all could help me. I'm looking for some low tech and inexpensive solutions.

  1. My telescope shakes like crazy. I understand this is probably the cheap aluminum mount. As much as I would love to buy a wooden mount, they are out of my price range right now. Is there a low tech solution for this problem? Would a heavy pendulum hung from the center solve this problem to some extent like it does for swaying buildings? Would it put to much unnecessary strain on the mount?

  2. The focuser knob on my eyepiece seem to tight. Any time I try to focus the eyepiece it torques the telescope out of position leaving me with nothing to focus on. Once I let go of the knob I have to wait for like 10 seconds before the telescope stops shaking enough that I can check the focus again. I was thinking of some WD40 to loosen it up, but then I thought it might get on the optics. Is there a better solution? Can I loosen the focuser knob up a bit? Can I use graphite on it?

  3. I received a digital camera mount for my telescope this Christmas. When I set my camera on a 10 second delay (to wait for the shaking to calm down) it takes pretty good pictures. I've been using a high speed night mode on my camera and that seems to do pretty well for the moon, but when I take pics of Jupiter and Saturn they seem over exposed and out of focus. Does anyone have any tips on setting I might try on the camera that might yield better pictures?

share|improve this question
add comment

2 Answers

up vote 2 down vote accepted

Unfortunately, these problems are widespread on many inexpensive telescopes. Notice that I said many; by choosing carefully, you could have bought a telescope without these problems, or with them greatly diminished, for about the same money. That's why I always recommend good optics combined with a manual Dobsonian mount, rather than computerized mounts on tripods. However, it's probably too late to return this scope and exchange it for a better one, so here's what you can do.

  1. Vibration. Tighten everything on the mount as tight as you can get it. Hang a weight from under the tripod head. Get a length of chain and hang it on the inside of the tube with half of the chain hanging out; this is a very effective vibration suppressor. I own a set of vibration pads, but have never noticed that they make much difference. Last solution: build a new mount, a simple Dobsonian. You'll lose the goto, but you'll also lose the vibrations!

  2. Focusing knob. Most rack & pinion focusers, even the cheapest, are adjustable. There should be a couple of screws between the knobs, which allow adjustments. Chinese telescopes use a nasty glue-like substance to grease mechanical parts like focusers and mounts. Try degreasing them with a solvent and then replacing with lithium snowmobile grease.

  3. Overexposed planets. This is caused by a very small planet in a large black field of view. All exposure meters try to render everything neutral grey, which is fine for the Moon, but not for the planets. If the camera makes the background grey, it grossly overexposes the planets. If your camera allows, try underexposing by two stops. Try some of the other settings, perhaps backlight.

share|improve this answer
    
Choosing carefully is a lot easier said then done for a beginner, but I completely understand. I originally purchased a 5" Meade and that turned out to be a disaster. 3 replacements in 2 months before Craig over at Oceanside allowed me to exchange it. He told me that the Celestron was a better scope so I went with it. But anyway, Thank you!! I kinda figured a pendulum might work like it does for swaying buildings. I am going to try this when I get home from work tonight. –  Albion Jan 9 '12 at 20:41
    
So I tried the tighten and weight method last night. Two problems. First, because of the attachment method of the computerized control there isn't a place to attach the weight. I had to fashion a rope around the three legs and over the top of the control to create a mounting point underneith. Secondly there is a support mechanism for the tripod about 1/2 meters under the control mount so I could only hang the weight about a 1/3 meter or so below the head of the tripod. Still, it worked! It didn't remove all the shaking, but it's about 80% better. Thanks Geoff! –  Albion Jan 10 '12 at 16:01
add comment

If it is the mechanics of, or the components added to, the telescope that are shaking the telescope that may be hard to solve.

The Celestron Vibration Suppression Pads can be very helpful to stabalize movement of the telescope and its components somewhat, but absolutely help dampen vibrations from the ground.

Brief description of the VSPs, taken from the Celestron Website:

Telescope and spotting scope vibration is caused by windy conditions, an unsteady mount or tripod or even an accidental bump to the instrument, and results in reduced image quality. Celestron's set of three Vibration Suppression Pads will reduce vibration time by almost 100% and decrease vibration amplitude. The pads fit between the bottom of the tripod legs and the ground, a simple and functional solution to the problem of image disturbance. They work on any surface: grass, dirt, concrete, asphalt, wood, etc., for both telescopes and spotting scopes.

share|improve this answer
    
Have you tried these little vibration reducing feet? I I've seen Celestron's description of how they're supposed to work, but McDonalds also displays a much bigger and juicer burger in their advertisements then they actually offer at the store. I'm not trying to be a jerk, but I'm interested in experience more then advertising. –  Albion Jan 9 '12 at 16:39
    
Funny anaolgy :-) I actually own them and use them with my Celestron Nexstar 8SE. They help!, but in NO WAY eliminate it. –  TryTryAgain Jan 9 '12 at 16:44
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.