Getting Started in Astronomy

 

By Jerry McBride

For many of us, that first look at the moon or Saturn through a telescope and WHAM - we're hooked. Regardless of how each of us becomes interested, the same questions usually arise. How do I get started? What is the "right" beginner's scope? Who can I talk to?

This article provides some answers to these questions, and describes some pitfalls to avoid along the way. If you wish to get more information, are some excellent books and web articles (listed below), which go into more depth.

Avoid Department Store "Christmas Trash Scopes"

Generally, any telescope sold in a department store is not worth owning. Most often they have poor optics (e.g. lousy view), and flimsy tripods that wiggle like jello. Don't be deceived by claims on the box that say "450 power" etc. Such claims are extremely misleading. The optics in these scopes are of mediocre to low quality. At higher magnifications stars will appear fuzzy and the view will be horrible. Keep in mind that scopes costing thousands of dollars don't even make such wild claims.

Besides, as we'll discuss in a moment, magnification is NOT the most important factor astronomy. This sounds a little crazy, but its true!

Aperture, Not "Power", Reigns Supreme
(but don't get carried away)

A bigger telescope aperture (telescope diameter) provides a much bigger improvement than simply boosting "power" (magnification).

Why is this? Stars, galaxies, and star clusters are not as bright as daytime objects. Thus, the most important consideration (along with quality) is how much light the telescope can gather. The fact is, the larger the telescopes diameter, the brighter sky objects will be.

Many beautiful sky objects require LOW magnification: Keep in mind that many of the most lovely objects in the sky require LOW magnification to observe properly. The Pleadies are a prime example.

Quality Matters

Another important factor here is telescope quality. Department store scopes, by a wide margin, have the lowest quality in every aspect - optics, mechanical features (such as the focusing system), and tripod. Surprisingly, the tripod is just as important as the optical quality. A flimsy tripod allows the scope to jitter constantly, blurring the image. Stock up on Dramamine!

Buying a beginner scope from a reputable telescope dealer will provide a big leap in quality. This will affect how bright and sharp the stars look, how easy the scope is to focus, and how stable it is on its tripod (or other type of "mount".

Don't Buy a Gigantic Scope the First Time Out

Don't run out and buy a telescope that dwarfs the main guns on a battleship. This is not a good idea for beginners. Overwhelmingly, when a "dreadnought" class scope is the first purchase, the new astronomer gets tired of lugging the monster and setting it up. After one or two views of the sky such scopes often languish in the closet or garage. The beginning astronomer, once excited about the hobby, soon looses interest. This is why beginners should stick to a maximum size of 6 to 8 inches aperture.

Smaller aperture scopes of good quality have advantages too. We'll discuss this later.

Learn the Sky

The most successful beginners are interested in the hobby because the universe fascinates them - and they take the time to learn their way around the sky. Become familiar with some constellations, brightest starts, a few start clusters, etc.

It is frustrating to take a new scope outside, and not know where anything is. The most fun way to learn is to go observing during star parties, or take the classes offered at Robert Ferguson Observatory (in Sugarloaf State Park www.rfo.org). There are also some good books out there. See the list at the bottom of the page.

When learning your way around the sky, often the best "telescope" is your own eyes, or a good pair of binoculars!

Look Through Some Telescopes before You Buy

This is so obvious that it's often overlooked. Nothing substitutes for actually looking through the various types of telescopes. It's easier to get a feel for telescope sizes and heft first-hand. You can't get this real-life experience by looking through a catalog.

Go to a star party or one of the RFO events where various scopes are present.

When Choosing Your First Scope, Don't Succumb to "Paralysis by Analysis"

Later in this article we'll describe several fundamental telescope designs and compare their relative benefits. Very often, the beginner becomes obsessed with choosing the "perfect" scope, comparing every tiny variation of performance between the different designs. I cover key characteristics of the main varieties below, but keep these points in mind:

Remember this: You can't go terribly wrong with any modern telescope design.

Each of the main design types provide good performance, or no-one would buy them and they would be taken off the market. As long as you buy a quality product (and avoid the pitfalls mentioned in this article) you can't really "go wrong" with any of them.

Your first scope likely will not be your last

Your experience will likely result in a lifelong love of the hobby. But occasionally a person will realize that it's not their cup of tea. For those that love the hobby, their first scope will not be their last. For those that move on to bird watching or spelunking, you'll be glad you didn't spend a million dollars on your foray into Astronomy.

Consider a previously-owned scope

Astronomers are some of the most honest folks I've ever met. A little nerdy, but honest! They are proud of their hobby, and there is an unspoken code of honor among them. They also tend to take very good care of their equipment. This means that purchasing a used scope at a site such as Astromart (www.astromart.com) is a very good option.

Telescopes maintain a high resale value:

Also keep in mind that YOU can also sell your beginner scope later. KEEP YOUR SHIPPING MATERIALS if you think you might want to sell it when you move on. It's common for scopes to keep around 75% of their new value. This assumes you've taken good care of your scope - and it's not banged up or scratched.

Comparing Telescope Types

Although there are other types of telescopes, the following three main designs are most common. The table below provides a summary of key attributes and differences between the main designs. After this I provide more in-depth information.

Reflector Long, wide tube. Open in the front, with a mirror in the back. The eyepiece juts out of the side (near the top). Usually on a convenient swivel base called a "Dobsonian mount".

Summary:
  • My Top Recommendation for beginners

  • Lowest cost per inch of aperture! 6" units cost $270-$380 while 8" units cost $370-$500!

  • Drop-dead easy to set up

  • Larger, but very manageable in sizes up to 8". Not difficult in 10" sizes, but have plenty of room in the family truckster

  • Brighter images, higher magnification than refractors

  • Comes with swivel base, eyepiece height is always at a comfortable level

  • Manually-guided Goto available

  • Shows weak "spikes" on really bright starts. These are faint and don't really affect the experience. Only a handful of stars in the sky evey show them

  • Not useful for astro-photography

  • Pointing at objects directly overhead is very hard

  • Recommended Brands: Orion, Mead, Discovery

 

Refractor (looks like a large version of a "ship-captain's telescope", there is a larger lens in the front (usually 3 to 4 inches), and eyepiece in the back). This type of scope usually sits on a special tripod called a "German Equatorial Mount" (Often called an "E Q" Mount for short).

Summary:

  • Very good beginner scope, but now the mount (i.e. "tripod") and associated costs become a factor.

  • $300-$400 for a very good 3" scope, $2,200 for an excellent 4" scope, with many offerings in the middle

  • Light, portable, wider angle

  • Great for general star viewing, sharp image

  • Tripod often sold separately $200 - $400 typically

  • Goto capability is available, but adds to the price

  • Longer tube lengths require gymnastic skills because the eyepiece height changes drastically depending on how high in the sky you are looking. Hope you like gravel

Recommended Brands: 

  • Stellarvue(especially Nighthawk, "SV80/9D", SV80ED, SV102ED)

  • Vixen, William Optics, Orion (80ED model)

  • At Higher $ Range: Televue, Stellarvue

Cassegrain These are short scopes, but have a good-sized aperture.  These usually sit on a very sturdy tripod (either an EQ mount, or a "fork mount")

Summary:

  • Not so great as a beginner scope

  • Able to transfer the vacuum of space into your wallet. Even at entry levels. Price of admission is $2,000 - $3,000

  • Of the three types, my least-recommended first scope.

  • Can be purchased permanently coupled on a "fork mount", or for a higher price, you can mate it to a separate mount which can be used for more than one telescope

  • Heavy for the size, but not difficult in 8" size

  • Eyepieces are always at a comfortable height

  • Take somewhat longer to set up.

Recommended Brands: Mead, Celestron

Design Comparisons Some of the variations between scope designs are:

 

Refractor

Viewing experience:
The views through the entry-level scopes of reputable brands are VERY good. Companies such as Stellarvue, Vixen, and William Optics, put out very nice scopes in the entry-level range. Orion has a nice scope (the 80ED) as well. Hey, what about the big brand names, Celestron and Mead? In my opinion, these lag in terms of quality, fit, and finish. Especially compared to Stellarvue scopes.

False Color: Many low cost refractors will have some yellow and blue color fringing around bright objects (such as the moon, Jupiter, and Venus). This "fringing" is often called "false color". If you lived in the 60's, YOU know what I'm talking about! - Uh, just kidding. Some telescopes use a higher quality "Semi-Apo" glass which costs a bit more, but greatly reduces false color. These scopes usually carry the letters "ED" in the name. 

There are refractors made with fully "Apochromatic" lenses which eliminate false color completely. These are more expensive. 

There are two last points on false color: 

You can also buy eyepiece filters which greatly reduce false color. 

Refractors with short tube lengths tend to have more false color that those with a longer tube. But again, remember the disadvantage of longer refractors - sitting near the ground when looking high in the sky.

Perfect Stars:
Low cost refractors made in China do not always show stars as sharp pinpoints. The key is to read reviews (see the links to review sites in the links area of our website.) Stellarvue has a good reputation in this area. Each scope is star tested.

Cost per inch of aperture:
Refractors are very affordable in 3 inch sizes. some 4 inch scopes are not too expensive. Above this aperture, cost increases at an alarming rate.

Ease of transport and setup:
3" to 4" refractor telescopes are easy to transport and setup. They usually come with an EQ mount.

Automatic star tracking:
Star Tracking is usually not provided as standard equipment, but available at low cost.

"GoTo" availability:
"GoTo" (automatically aiming at sky objects) is available on some brands of refractors. Orion, Celestron, and Mead offers some of their refractors with GoTo capability. But you're paying more for this feature. Check review web sites when buying these brands. Companies may be tempted to skimp on scope quality when GoTo is added at the entry level.

Susceptibility to "dewing up" on cool moist nights:
Depends on the model. If the scope's tube extends several inches past the main lens, dew will take a much longer time before it affects a typical refractor.

Cool down time before you can get good views:
Virtually no cool down time is needed on a refractor.

Need for periodic adjustment:
Unless you pound nails with it, there is no periodic alignment required.

 

Reflector 

Viewing experience: 
The quality of low cost reflectors is very good. Quality does not vary a large amount between most brands. (As with other types, there are ultra-expensive brands with truly superb quality at equally breathtaking prices). 

False Color:
Reflectors have NO false color. A handful of very bright stars will have faint "spikes" of light extending from them in the four compass directions. This occurs due to the telescope design. The moon, planets, and most stars will not have these faint spikes. Many beginners wonder how much this characteristic really impacts the view. In reality, very little. Most of the time astronomers are looking at breathtaking a star clusters, double starts, etc.

Cost per inch of aperture:
When talking bang for the buck, it's really hard to beat a reflector telescope. The design does not use large expensive primary lenses, so cost per inch of aperture is low. In a 6 or 8 inch size, the scope offers views on par with much more expensive scopes. You would have to pay $5,000 to $8,000 for a 6" refractor. Not including the truck to carry it.

Ease of transport and setup:
In 8 inch sizes or smaller, these scopes are very easy to transport and set up. However, they do require more room than a refractor because of the big tube. The web sites of vendors will generally list dimensions of the telescope. Measure your car interior before buying to make sure it will fit. 10 inch models are fairly large and heavy (you have an SUV right?). Any scope larger than 10 inches get into the "dreadnaught" class and are not recommended for beginners.

Automatic star tracking:
Not available

"GoTo" availability:
Some have computer-assisted aiming that guide you to the sky object - but you actually move the scope. Still, this is a very convenient feature.

Susceptibility to "dewing up" on cool moist nights:
Low

Cool down time before you can get good views:
10 to 20 minutes

Need for periodic adjustment:
Reflectors require periodic alignment, but this is a very easy task and is quickly learned. In 6 and 8 inch sizes, this task is rarely needed.

 

Cassegrain

There are two common types of Cassegrain Telescope. 

"Schmidt-Cassegrains" (SCTs) are used for typical observing much like the scopes discussed above. They have notably higher magnifications than Reflectors and refractors, but also more narrow viewing area.

"Maksutov-Cassegrains" are very high magnification scopes that excel at viewing planets. However, because of the higher power, they have very narrow fields of view. You won't be looking at larger sky treasures with a "Mak-Cass". They also have a long cool down delay.

You can buy Cassegrains in two common mount options. "GoTo" scopes usually are inseparable from a heavy fork assembly. 8" inch sizes can be heavy and more difficult to transport and set up. 

"Fork" mount versus "EQ mount: Fork mounts cannot be separated from their telescope without major surgery. A more flexible approach is to purchase "tube only" scope - and place it on an high quality German Equatorial mount. 

The advantage: The high quality mount can be used with any refractor or "tube-only" Cassegrain. If you ever sell your scope and buy a different one, the same mount can be used. EQ mounts allow for long-duration astro photography. "Fork" mounts do not - unless you buy a heavy add-on. 

The disadvantage: These high quality mounts and "mount" into some serious bucks.

Viewing experience:
Very good, with no false color or spikes on bright objects.

Cost per inch of aperture:
Even though the cost per inch of aperture is "Medium", you'll still end up paying much more for a Cassegrain than for other entry level scopes. The "cost of admission" is usually 2-3 times higher and depends heavily on automatic features you choose. 

Ease of transport and setup:
Cassegrain telescopes with fork mounts are heavy for their size. 5 inch scopes are fairly easy and can be carried without difficulty, 8 inch GoTo scopes are fairly heavy. 10 inches are plain heavy and anything larger is definitely "gutbuster" class. Buying a "tube only" Cassegrain lightens the load, but then the heavy part becomes the Equatorial Mount. 

Automatic star tracking:
Available on most Fork Mount units. For Tube Only scopes, this obviously has to be done by the separate equatorial mount.

"GoTo" availability:
Fork Mounted Cassegrains are available with build-in motors and software that allow them to find and find and track sky objects. Again, for Tube Only scopes, this has to be done by the separate equatorial mount.

Susceptibility to "dewing up" on cool moist nights:
The Cassegrain, with it's large primary lens, is the wimp of the pack on dewy eves. There are accessories that help, but to really stay up with the refractors and reflectors, you need a heating band that goes around the front of the scope, as well as a controller for it. Be thinking around $200 for complete immunity.

Cool down time before you can get good views:
10 to 30 minutes typically. Perhaps significantly longer for a Maksutov Cass. Cooldown times are shorter if the scope is stored in an unheated area that is close to the outdoor temp.

Need for periodic adjustment:
Yes, occasional adjustment of secondary mirror.

Noise Level:
Stuffed with motors and gears, GOTO scopes do make some noise when aiming at sky objects. Different brands can have a big difference in how noisy this process is. Celestron GOTO SCTs tend to be rather quiet. Meade GOTO SCTs - while being very good scopes, nevertheless can be loud enough wake the dead. I should know, I own one.

Final Recommendations With all the facts considered - for those that simply want the best performance for the lowest cost. There are two options:

6 or 8 inch "Dobsonian" (swivel base) reflector. This is the same type of telescope SCAS gives to the winners of its Striking Sparks program. Bang for the buck, it's very hard to beat. These will have greater light gathering power (brighter stars) and higher magnification compared to refractors. Because the eyepiece is near the top of the scope, you can point it anywhere in the sky and still be in a comfortable seated viewing position. Also, you don't have to pay for a tripod (as you do with a typical refractor).

3" refractor. There are two major designs here:

Normal / long Tubes:
Refractors with longer lengths have higher magnification than short tubes versions, so they are better when viewing planets. (Keep in mind this is still less magnification compared to Reflectors and Cassegrains). From a comfort standpoint, long refractors are worst-in-class when aimed at objects high overhead. You might end up on your knees, or even sitting on the ground.

Short Tubes:
These offer wider angle views for sky treasures such as the pleadies, the beehive cluster, and others. The short tube also means less gymnastic skills are required when viewing objects that are high overhead. In this class, one scope worth considering is the Stellarvue Nighthawk - which has received rave reviews for optical quality and uncompromising mechanical design. Stellarvue scopes are also made affordably right here in the U.S.A. Orion, Borg, Williams Optics, Vixen, Celestron, and others make short tube scopes as well. These tend to be from Asia. Orion's 80ED has many happy owners. It offers Semi-Apo performance at a very attractive price. Both Stellarvue and Orion offer best-in-class customer support.