 | FAQ's
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Q: WHAT TELESCOPE IS BEST FOR MY YOUNG SON OR DAUGHTER? |
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There are a number of answers to this question, the best way to answer it though would be to ask what telescope is not suitable for my young son or daughter. Any telescope from a department/chain store that has a very high magnification stated on the box is not at all suitable. These telescopes generally have poor optics and flimsy mountings. More important things such as stability, optical quality and aperture far outweigh the need for magnification. A stable, crisp image should be the aim when looking for a child's first telescope. Our recommendation would be a smaller ~150mm Dobsonian telescope for ease of use or a 50mm pair of binoculars. |
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Q: CAN A TELESCOPE MAGNIFY 650X AS IT STATES IN THE AD? |
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No. Magnification on modern affordable telescopes is limited by aperture, optical quality, mount stability and the Earth's atmosphere. A good rule of thumb is to multiply the aperture (sometimes called 'D') of the telescope by 2 to 2.5x to get the maximum attainable magnification. For instance a telescope with an aperture (diameter) of 60mm would have a maximum magnification of 120-150x. To get 650x you would need a telescope of around 300mm diameter, and even then it would be limited by variations in the Earth's atmosphere and the stability of the mount. Generally, most large (>250mm) amateur telescopes are capable of up to 450x-500x magnification. Remember that magnification is not a true indication of the quality of a telescope. |
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Q: WHY IS MY TELESCOPE NOT GIVING SHARP IMAGES? |
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The most common reason for this to occur is that the optical elements of the telescope are out of alignment (collimation). This occurs with reflecting telescopes that have had a bump or have had their mirror(s) removed. Refracting telescopes rarely, if ever, need collimation. Collimation of Newtonian optics requires you to adjust the tilt of the primary and/or secondary mirrors until all mirrors and their reflections are concentric when viewing down the focuser tube, without an eyepiece. Schmidt Cassegrain telescopes allow only the secondary mirrors to be tilted, the primary is aligned in the factory. Other causes of un-sharp images can be the use of a poor quality eyepiece, use of the telescope at too high magnification and viewing of objects that are close to the horizon. |
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Q: WHY IS THE IMAGE DULL/WASHED OUT? |
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Your telescope mirrors may need a clean and/or recoat. Cleaning of mirrors should be done with the utmost caution and if in doubt contact Astro for a quote. A good indoor test to perform is to hold the mirror up to a clear 60-100W globe and look through from behind. If you can see the filament then the mirror nees a recoat. |
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Q: WHAT ACCESSORIES DO I NEED TO TAKE PHOTOS THROUGH MY TELESCOPE? |
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First off, you need a telescope that can track the sky smoothly. This generally requires an equatorial mount. Dobsonian mounts are made for visual observations only. Second, you will require a camera adapter and a t-ring for your camera model (see the Photographic Section at left). An SLR camera with a B setting is required for film photography, along with a cable release. For long exposures a dual axis motor drive system is required. Vixen Digital Camera Adapters are available for a wide variety of digital camera models.(See the Photographic section at left) |
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FAQ's
1 to 5 of 10 |