Telescopes
by Dr.D.


Entry level is probably either a 60mm or 70mm alt-azimuth refracting telescope (such as the one pictured from Meade -- priced at about $80) which is perfect for the very casual observer or any child over the age of nine.



The 60mm is a 2.4” objective which is bare minimum for planetary observing, thus the 70mm at almost 3” is a tad better and provides more magnification with the 700mm focal length.

Rule of thumb is about 50 magnification power (“x” or 50x) per inch of “objective” lens. So a 2.4” telescope (the 60mm type) provides about 125 power, while the 70mm (almost 3”) provides closer to 175 power!

Refractors (telescopes with a clear lens up front, like a camera) are the easiest telescopes to take care of. They require little maintenance and if you keep them tucked away with a cap over the front they will last for a long time. Refractors are somewhat bulky, with a long tube.

What you lose with something like this little scope is the ability to “track” stars and planets with a single control or electric drive. “Alt-azimuth” means the telescope moves up and down, plus sideways. Planets and stars move in a smooth arc path in the sky. Also, as one would expect, this scope is minimally manufactured in China with somewhat flimsy materials. But if you care for it, this little under $100 telescope will suffice for the casual observer or get a child up to college level!



This next refractor from Meade, while offering less magnification (it has a 350mm focal length instead of a 700mm focal length, so it will only get up to about 100 power, maximum) is a better quality device. It is made from better materials and has a mounting that allows you to track stars with a single movement. In fact, it even has an automatic star finder and motor to keep things on track.

Priced at about $300 it is a more serious optical instrument and if you are considering such a high quality instrument then you might want to look at the next one from Meade...




This one is a Cassegrain reflector with a 90mm mirror instead of a clear lens at the top. This mirror is at the back side and reflect light up to another mirror near the top of the tube. That light is then reflected back through a small hole in the 90mm mirror, so you are effectively getting only about 70mm of actual light gathering, but with a 1,250mm focal length, which will allow you to get well over 200 power or magnification.

Like the one above, this model has a “star finder” and “star drive” that will track an object automatically. Priced over $500 this beauty is more for the serious person who really wants to see the stars and planets in style.



As we go up we reach the Meade 10” reflector that uses the same folded optics concept from above, thus you are actually getting about 8.6” of actual light gathering power. This size of a mirror and tube also adds weight to the package and this one is well over 50 pounds.

Priced at nearly $3,000 this telescope is a real telescope. One that is actually close to what small planetariums and observatories use. It is an ultra high quality instrument that probes deep enough into outer space to show you the outer planets Uranus and Neptune and objects like the Ring Nebula, the Andromeda Galaxy and the Great Nebula in Orion with some good detail you won’t see in smaller telescopes.

This is a deep sky telescope designed for serious viewing and you can even get mountings to attach a digital or film camera to this scope to take pictures of some deep sky objects, which will reveal even more detail!



The 12” telescope, with an effective objective of over 10 ½” is an ultimate deep sky instrument good enough for a small observatory, high school or college. This one, priced at close to $4,000 is a very serious investment that will make you the pride of the neighborhood!

At the 120 pounds of weight you must mount this outside under an enclosure or move it in several pieces.

As with the other telescopes of this type, it will automatically find and track deep sky objects and get you down so close you can actually see Pluto, the most distant planet, along with very dim deep space objects down to about 12th magnitude with magnifications of up to 500 power (500x) with great clarity and wonderful “rich field” observing at lower magnifications such as 50 or 100 power, showing you more stars per square inch than you imagined possible if you are located somewhat away from big city lights. With this you can readily see the disk of Uranus and Neptune. You will clearly see the Ring Nebula along with the central star...

This is a true astronomy buff’s unit!

About eyepieces: Some low priced telescopes use small eyepieces of about .9". The defacto "standard" for a telescope is actually 1 1/4" so if you get something with a smaller fit than this you may have to look harder to find extra lenses and may not be able to find better quality lenses.

The millimeter (mm) of an eyepiece determines how much magnification, field of view and brightness you can see. Generally a 6mm lens is the most you should go, unless you have a really high quality telescope and get a very high quality 4mm lens! Most telescopes tend to come with either a 20mm or 12.5mm lens and a 6mm lens. These are excellent for general viewing. The 12.5mm eyepiece will give you brighter viewing than the 6mm, but with less magnification. A 6mm lens with a 350mm focal length will give about 60 power, while with a 700 mm focal length it will give about 130 power. At 60 power you can see the entire moon with crater, the disk of Jupiter and 4 of the brighter moons, the rings of Saturn, although 130 power will make those rings look more distinct.

Do you have to get a Meade? No. It is one of our affilate sites so we show them to you as both information and advertisement. In the low end, Tasco also makes a nice 60mm refractor, Swift makes an excellent refractor and some good reflectors (one is pictured at right), plus there are great offerings in the higher priced range from Optical Craftsman, Unitron and Questar. Meade does, however, make a good telescope in both the low priced end ($80) and an very high quality instrument starting at $300. The low-end Meade is very similar to the Tasco. The high end Meade comes close to Optical Craftsman and Questar in quality for a reflector telescope.

Look around, see what you can find at a good price new or used. Remember, you get a maximum of about 50 power (50x) per effective inch of the objective (so the 12" Meade we show above has just over 10" of effective objective after you take the hole into consideration). Yes, you can get more, especially with a "Barlow" lens that comes with some telescopes, but the objects get dimmer, fuzzier and yellower.

Remember if you are paying more than $300 get a quality optical instrument, even if it means getting less in objective or focal length!

Remember, the better telescopes have 1 1/4" eye pieces and the cost of a great eyepiece can easily be as much as $100!

Remember, never look directly at the sun! Use a high grade sun filter or white card to reflect the image!

Remember, 50 power or more will let you see Saturn, Jupiter and the carters on the moon with ease, athough 100 power is far better for detail! To see deep sky objects (Nebula) you must have an objective lens that is effectively 6" or greater! A truly serious astronomical instrument has an effective objective of 10" or better! To really see the detail of such objects requires a camera with the ability to make long time exposures. The pictures you see of nebula in a magazine or book were generally taken with hours of exposure time to bring out the fine detail. In even the best of telescopes these are often a smudge or a whisp.

Remember, to see "outer space" the best way with any telescope you should be far, far from the city lights and haze or smog! This does not mean you can't observe in the city, but don't expect to see a dim object like Pluto or faint detail of a Nebula like the Great One in Orion from the heart of the city with any good telescope!



These pictures taken by John Kagey approximate the view you would see through a small home telescope at around 150 magnification.

Our Outer Space Special Continues With The Following From 2005...

Space Special | Rocketing Into Space | India In Space | Europeans In Space
Women Among The Stars | Cosmology and Astronomy | Reaching For The Stars
Antigravity (Fiction) | Not To Go Into Space (Opinion) | Telescopes
Night Skies January-February 2005 | Space in Film, TV, VHS and DVD
Astrology January-February | Cartoons Part 5 (Marvin The Martian) | Books (Space in Print) | Music (Space in Melody)

 






The Musician's PlaceTo Shop!
Instant Gift Certificates!














© 2001-2005 Issues Magazine.
All Rights Reserved.
editors@issues-mag.com




Get 15 FREE prints!