Time To Tune Up That Telescope.
Your scope may be modest, but don’t let that prevent you from using it! An inexpensive telescope that gets used,even infrequently, is superior to a premium scope that sits in storage.
The nights are nice and clear now so go to it! Even the smallest scope can provide fine views of the Moon, the planets, and many showcase celestial objects. It can teach you how to get around the sky, provide the thrill of discovery, and foster a lifelong passion for astronomy.
Perhaps it was a holiday gift. Maybe you bought it on impulse while shopping for something else. Excited, you tried to use your brand-new telescope, but you just couldn’t make it work. Now it sits in your closet, collecting dust. Your dust collector is likely a “department-store” scope, sold through a mass-market outlet for around $100. You would be lucky to get a decent view through most of these scopes at 50×, let alone the 575× advertised on the box. They’re typically wobbly, hard to aim, and difficult to look through. No wonder you’re frustrated!
What can you do about it? Obviously, you could replace the whole thing. But maybe you don’t have enough money for an upgrade. Or perhaps the scope has sentimental value, and you’re determined to make it work. Here’s the good news: a small amount of effort often makes these scopes much easier to use. Besides, tinkering is fun, and you’ve got very little to lose.
Before you set to work, try to figure out what your scope’s main defects are. Perhaps it needs only a few minor tweaks to work well. Also think about how much you’re willing to spend. You can probably make the scope a lot sturdier at very low cost, and a substitute finder can be cobbled from scrap material. But you can’t replace the entire set of eyepieces without spending some real money. Remember that every scope is different — what works for one may not help another. Feel free to experiment, and try out ideas of your own.
Maybe it just needs some TLC, so go grab that scope again and try these tips to get it working satisfactorily for you. First, clean off all the dust and clean the main lens at the front if it’s a refractor, or carefully clean the mirror if it’s at the bottom of a long tube reflector. Do not remove the mirror! Use the same cleaning gear as you would a camera lens.
Now look at your eyepieces and give them a good clean too. Only clean the outside glass – NEVER pull eyepieces apart, there are lots of lenses inside to mix up. It may surprise you to know that even cheap telescopes have good quality mirrors or main lenses, it’s the eyepieces that are junk. Replace them with better quality ones and see your telescope dramatically improve!
Many designs are available, but you can’t go wrong with some basic Plössls — they’re excellent all-around eyepieces and a great value starting at around $40 apiece. Kellner eyepieces and their close cousins the modified achromats also provide good views at somewhat lower cost.
Your “must-have” eyepiece is the one that gives low-power views, about 25 mm in focal length. It will help you navigate with its wide field of view, and it’s great for observing large objects such as star clusters. Then get a high-power eyepiece, perhaps 10 mm in focal length, to observe details on the Moon and planets.
Must have extra
If your budget allows, follow up with a Barlow lens. This device looks like a long tube with a lens at one end. It goes into the focuser before your eyepiece, and using one doubles or triples the magnification. It’s an excellent way to “double” your eyepiece collection. The prices vary according to quality. Some are over $100.
If your telescope is a reflector (using mirrors rather than a lens to gather light), there’s another easy way to improve your view. When your reflector’s main mirror is warmer than the surrounding environment, it creates tiny air currents that distort the view, much like looking over hot pavement on a sunny day. You’ll get better results if you set up your scope, then wait at least a half hour for it to adjust to the outdoor temperature. Storing your scope in an unheated garage or shed will minimize the cool-down time.
Stability Is Key
In most case, the worst feature of a low-end telescope is the mount — the tripod that supports it and the head that holds the tube and lets it point to different parts of the sky. A telescope doesn’t magnify just the things you’re looking at; it also magnifies every wobble and vibration in the mount. Does the view through the eyepiece dance around when the wind picks up? That’s probably because the tripod’s not rigid enough. Do you see wild vibrations every time you touch the focusing knob? The problem might be in the tripod, the head, or both.
To fix a bad case of wobbles, first check the tripod itself:
* Tighten the wing nuts at the top of the tripod, where the legs meet the mount head.
*Shorten the tripod legs as much as you can. The lower the scope, the less it will shake. Try observing from a sitting position — you might even find that you like it better than standing!
*Fill a largish jug with water or sand and hang it between the tripod’s legs. The extra weight will keep a light mount from swaying in the breeze, and it may help damp vibrations.
*Cut a triangular piece of wood to use as a brace. Wedge it between all three tripod legs just below the mount head.
Extra weight and rigidity always make telescopes less wobbly, but vibration is trickier to analyze and combat. Tap the end of the scope while looking through the eyepiece and time how long the view takes to settle. A couple of seconds is fine, but 10 seconds is way too long. Now try various remedies and see if they reduce the damping time.
A few small but measurable improvements add up to a major difference. But be prepared for surprises: some “improvements” may actually make things worse! Here are some things to try:
*Place the tripod on grass instead of concrete or asphalt.
*Check the tightness of the mount parts, especially any locking screws that hold the scope in position. They shouldn’t be so loose that the scope flops around, but a little slack often helps to dissipate vibrations.
*A square plastic clip from a bread bag can shim space between loose parts.
*If your mount has slow-motion adjustment knobs at the end of long springy cables, they may jiggle in the breeze and impart oscillations to the mount. You can replace them with knobs from your local hardware or electronics store.
*Hang two or three feet of medium-weight chain from the end of the telescope tube. Each link absorbs a little vibration. If tube balance becomes a problem, try one chain in front and a shorter one in back. Hey, don’tb laugh. Some of these home remedies really work! Source: Sky and Telescope
- Photos of the Moon using my iPhone and a telescope. (briangreenberg.net)
- Telescope buying advice (aquillam.wordpress.com)
- How To Avoid Buying a JunkTelescope (davidreneke.com)