How to Use a Telescope: First Time Telescope User's Guide for Beginners
First Time Telescope User’s Guide
Congratulations! You’ve purchased your first telescope - an optical time machine that will help you explore our amazing Universe. You may have aspirations of discovering comets or becoming a published astro-imager someday; or you might want to simply enjoy views of the moon & planets from time to time. Whatever your astronomy goals, one thing’s for certain: We all must start at the beginning, and this guide will show you how to use a telescope. Feel free to skip to sections that intrigue you by using the Table of Contents at the end of this Guide, or go crazy and read the whole thing!
Before we start, please heed this important warning: Never look at the Sun through any telescope or finder without the proper filtration. It just takes a few seconds to irreparably damage your eyesight - think of how powerful sunlight is when focused through a magnifying glass! Visit the Recommended Accessories section to learn more about filters for safe solar viewing.
Assembling Your Telescope
Put your telescope together for the first time when you are indoors and have lots of light. Just because a telescope is normally used during evening hours doesn’t mean you have to set it up in the dark!
Give yourself plenty of room, and gather together a good portion of patience, as well as any tools that are required for assembly before you start.
Once you are finished with assembly, stay indoors and take some time to learn a bit more about its features before you take your telescope outside for the first time.
Get to Know Your First Telescope
What Mount Type Do You Have? How Does Your Telescope Move?
Before we begin, you will need to know whether you have a telescope on an alt-azimuth mount or an equatorial mount. Not sure? Let’s figure it out together.
If you are like the millions of people who use a camera tripod, you are the proud owner of at least one alt-azimuth mount. The tripod legs do not make a photographic tripod an alt-azimuth mount, its the "head" that sits on top and how it moves that earns it that distinction. This is the most common mount used to support and point telescopes, spotting scopes, and cameras.
An Alt-Azimuth mount allows you to move your telescope in straight lines - up, down, right, and left. In its simplest form, the alt-azimuth mount is completely manual with basic movement controls, like the one shown in the photograph to the left, but it is also used on some of the most high-tech telescopes today, and can be fully computerized with mega bells & whistles.
An easy way to tell if you have an equatorial mount is to look for the counterweights. If your telescope mount has one or more, there’s a 98% chance it's an equatorial.
An equatorial mount does not move in straight lines like an alt-azimuth mount does. It was designed to track the stars as they move in an arc across the sky. The shape of that arc depends on the latitude you are observing from, and an equatorial mount can be adjusted to compensate for your location in latitude. Equatorial mounts can be very basic or come with a wide range of capabilities and components, from simple motors on one or both axes, to a full-on computerized system that can handle observatory-sized telescopes.
How Your Telescope Moves
Practice moving your telescope in the comfort of your well-lit home. Whether you have an equatorial or alt-azimuth mount, positional adjustments are made in a similar fashion.
Non-Computerized Telescope Mounts: Start by loosening the lock knobs on the altitude & azimuth (for alt-azimuth mounts) or right ascension & declination axes (for equatorial mounts), then grasp the optical tube, push or pull it in the direction you wish to go, then re-lock to keep your telescope from moving on its own. This method is used to make large, sweeping movements across the sky. To make smaller, more incremental movements, manual mounts will have either one or two “slow motion control” cables or knobs. Using the slow motion control function of your telescope works great to keep objects in the field of view of your eyepiece, or to zero in on an object once you are very close.
Computerized “Go To” Telescopes: Use the included hand controller to move your computerized telescope. Choose the speed, or slew rate, based on how far you need to move the telescope across the sky. Faster speeds are used to move from one object to another, and slower speeds are used to center the object or keep it in your eyepiece. Take some time to try out these speeds and experiment with the directional buttons on the hand controller.
Depending on the model, your “GoTo” telescope may allow you to make manual movements as well as those achieved by your hand controller, but make sure and check your instruction manual first. Making manual movements on a computerized telescope can sometimes cause it to “lose its place” in the sky, requiring that you do a second alignment procedure if you want to take advantage of its “Go To” electronics.
Understanding Telescope Eyepieces & Barlows Lenses
Now that you have practiced moving your telescope, its time to take a look at some of the accessories that came with it. Regardless of the telescope you purchased, you should have received at least one eyepiece, and it is the most important accessory in the box. A telescope’s job is to gather and concentrate the light emitted by celestial objects into a point. An eyepiece’s job is to take that concentrated light and display the resulting image for you to enjoy. Just like telescopes, eyepieces come in a wide range of styles, sizes, and focal lengths. For the purposes of this guide, you need to understand just one thing about your eyepieces:
What the Numbers Etched on the Eyepiece Mean
Officially, the numbers represent the “focal length” of the eyepiece. For the moment, all we care about is what that translates to as far as magnification goes. In other words, how do you choose the eyepiece that will give you a higher or lower power view?
The rule of thumb is the opposite from what you’d think…the higher the number on the eyepiece, the lower the resulting power, or magnification, you will achieve on your telescope. For instance, let’s say you have two eyepieces, and their focal lengths are 25 mm and 10 mm. If I asked you to pick your lowest power eyepiece for a task, you should know right away that I am talking about your 25 mm eyepiece. There are lots of things one can learn about eyepieces to heighten your enjoyment of astronomy, but for right now, that’s all you need to know:
High numbers = low powers
Low numbers = high powers
What’s a Barlow Lens?
Some telescope packages come with a Barlow lens, or you may have purchased one as an accessory for your telescope. A Barlow (capitalized because it’s inventor is Peter Barlow) does not work on its own, but works in conjunction with an eyepiece to multiply the magnification of that eyepiece by a factor of 2 or more times. Most Barlows on the market today multiply by 2X, and it will be marked on the barrel of the Barlow just like the focal length is marked on an eyepiece. This means that if you have an eyepiece that provides 100X magnification through your telescope, that same eyepiece in the Barlow would magnify an object by 200X.
Barlows are a super economical way to increase the number of magnifications you have available. For instance, three eyepieces and a Barlow lens would give you six different magnifications. To use a Barlow, insert it into your focuser or diagonal just as you would an eyepiece, and then insert your choice of eyepiece into the open end of the Barlow and tighten the thumbscrew.
Aligning & Using Your Telescope’s Finder
So far, you have assembled your telescope, you have practiced moving it around, either manually, electronically, or both, and you have figured out which eyepieces are for lower powers or higher powers. Next, we are going to align your finderscope, and trust me, this simple step can either make or break your first observing session, so do not skip ahead!
Finders are an important telescope accessory, because they literally do what their name implies: finders help you find things! Without a finder on your telescope, you will spend most of your time trying to find objects instead of looking at them. Even the Moon, which seems like a slam dunk, can be difficult to observe without the help of a finder. It is also easy to upgrade your telescope's finder at any time if you find that you prefer one over the other.
Your telescope most likely came with one of two finder types: a “red dot finder”, or an “optical finder”.
An optical finder is a small telescope that is held onto the top of the main telescope with a finder bracket. It offers a low magnification view of the sky, usually anywhere from 6X - 10X, and when you look through the eyepiece, you will see a crosshair to help you center the object in the finder’s field of view.
Most optical finders can be focused by either turning the eyepiece itself or a focusing ring that wraps around the diameter of the barrel.
Finderscopes can either be "straight-through", as shown in the photo to the left, or right-angle, allowing the user to look down to see through the finder rather than positioning your eye behind the finder in a line-of-sight manner.
A red dot finder displays a wide field, zero magnification view of the sky. Instead of looking through an eyepiece, the user looks at a glass or plastic screen that a red dot, or in some designs, a bull’s eye, is reflected onto. This illuminated point is adjustable, both in brightness and in its placement on the screen.
Unlike standard optical finders, a Red Dot Finder needs a battery to operate, and most of the time, it is included. If your red dot finder doesn't illuminate, make sure and check that the battery doesn't have a piece of film or other barrier between the battery and the contact point. This film keeps your battery from running down between the time it leaves the manufacturer and arrives at your home. Another way to achieve this is to turn the battery upside down.
Red Dot Finders normally attach to a telescope by means of an elevated bracket. This added height makes it easier for the user to look through the finder.
Both telescope finder types work well, but they must be aligned to the telescope or they will be worthless. Check out your particular finder and make note of the adjustment knobs. They will either be on the red dot finder body itself or, if you have an optical finder, you will use the thumbscrews that suspend the finder in the bracket. Now, we are going to align your finder:
- Install the finder bracket and finder on your telescope as directed in the instruction manual.
- Choose the lowest magnification eyepiece you have available and put it in your focuser (if you have a Newtonian reflector) or diagonal (if you have a refractor, Schmidt-Cassegrain, Maksutov-Cassegrain, or other catadioptric style telescope).
- Take your telescope outside during the day and put it in a location that gives you a view of a stationary object that is a good distance away. A stop sign, lamp post, or a high voltage insulator atop an electrical pole all make good candidates, but don’t stress about it, just pick something that doesn’t move and is as far away as possible.
- Manually point your telescope as best you can at the target, and then look through the eyepiece. Hopefully, the object will be in the field of view, but if it isn’t, use the slow motion control knobs or dials on your telescope’s mount to make adjustments until the target is in the center of the eyepiece. Tighten the lock knobs on the telescope so it won’t move.
- Now, while looking through the finder, use the adjustment knobs on the finder or finder bracket to center your target as precisely as possible in the finder’s field of view.
- Check the view through the main eyepiece again. If the object is still centered in the field, and you have a second eyepiece or Barlow available, then you can move onto the next step, otherwise make adjustments until you are successful. If you only have one eyepiece, you are finished aligning your finder for now, and can skip to the next section.
- With your telescope locked down, carefully change your eyepiece to the next highest magnification or add a Barlow to the current eyepiece to double the magnification (see “Understanding Eyepieces” if you need a refresher on this topic). Follow steps 4 & 5 again to further tweak the precision of your finderscope alignment.
- When the target is centered in both your finder AND your eyepiece at the highest magnification you have available, your finderscope is officially aligned! We will tweak it further once we are out under the stars, but for now, your telescope is ready to trip the light fantastic!
Before You Start Observing
The equipment that you will use to observe the night sky is just one part of the equation for a successful evening of exploration. There are a few key questions you need to ask yourself before you head out, and a few accessories that we recommend you gather together that will help elevate your enjoyment and success.
How Will You Find Celestial Objects?
It’s a big Universe out there, so before you hop on the Galactic Highway, you might want to take some time to consider what you will use for directions. Does your “vehicle” have a built-in navigation system, or are you dependent upon maps from AAA? Either way, you have choices, so let’s get to it:
Non-Computerized Telescopes: People have been using non-computerized telescopes for hundreds of years, and they have enjoyed finding and viewing thousands of celestial objects. There are several ways to find objects without the assistance of automatic GoTo, from simple “star-hopping” to using an equatorial mount’s setting circles. Here are a few of the most common options for finding objects:
Naked Eye Astronomy
A time-honored, although limited, way to discover the universe! Here’s how it works: You look up, find something of interest in the sky, and point your telescope at it. Done. This strategy works for the Moon, visible planets, and really bright deep-sky objects like the Pleiades, the Orion Nebula, the Great Cluster in Hercules, and from darker locations, the Andromeda Galaxy. The downside, however, is the great majority of celestial objects are not easily seen with the naked eye, and so, sooner or later, you will want to pick up one or more of the following star guides:
This inexpensive, simple disc displays the night sky for a range of latitudes, including the constellations and more prominent celestial objects. By aligning the date with the time, you can quickly see which constellations are going to be up at any given moment.
If you have a planisphere, you can “star hop” to the more popular galaxies, nebulae, and star clusters that are marked on the chart. After lining up the correct date and time, orient yourself by holding up the planisphere and matching the chart with what you see in the sky. Once you find a few of the brighter stars, visually “hop” to the next star, and the next, until you find the general location of the object you wish to see, then find that point in your finderscope, and if you’ve aligned it correctly, the object you star-hopped to should be in your eyepiece. Voila!
High Point highly recommends a planisphere or a star chart with planisphere for anyone who is interested in observing the night sky, whether you have a telescope or not! Learning the constellations definitely enriches your experience in astronomy; it makes you feel more connected to the world around you, and expands your view. That is an important part of what astronomy is all about.
Star Charts & Atlases
A good star chart or atlas of the night sky has been the amateur astronomer’s Bible for decades. Some of them are in book form, and others are laminated charts in binders that allow each chart to lay flat, but regardless of their style, star charts have one thing in common…they depict areas of the night sky in detail.
Earthly maps have latitude and longitude marked on them so that those with training in surveying, navigation, etc. can find any point by locating those coordinates. Celestial maps, star charts, and atlases are very similar in that they are printed with the equivalent of longitude and latitude (right ascension & declination) so that astronomers and celestial navigators can find their way.
Use these maps to star-hop to an object, or dial in the celestial coordinates of that object with your equatorial telescope's setting circles. Learning how to use setting circles takes practice, but the results are worth it!
Star Chart Recommendations:
Apps for Smart Devices
If you have a smart device, such as an iPhone, iPad, or Android phone or tablet, there are several apps available for observational astronomy. Some apps will even tell you which celestial object you are looking at when you point your device at it! The apps listed below are just a sampling of what is available, and of course there are new apps being developed all the time.
A Few Available Apps:
An astronomy software program is a fun way to learn more about the Universe. Even the most inexpensive programs allow you to bring up a view of your local night sky for any date or time combination. Click a button to have the program show you where the planets are, or display the outlines of the constellations so you can get your bearings.
Once you have the chart looking the way you like, print it out, and now you have a blueprint of the sky for your latitude, at the exact date and time you will be outdoors with your telescope. This feat barely scratches the surface of what today’s planetarium software can do, and there are several programs to choose from for both Mac & PC operating systems.
Computerized Telescopes: This is pretty easy, because computerized telescopes have a built-in navigation system. Not only can they align themselves with little help from you, they have a built-in database and drive system that can show you thousands of objects with the push of a few buttons.
If you have a computerized, “GoTo” telescope, you may not feel you need anything more, but we recommend you consider a planisphere or some planetarium software so that you can learn the constellations, print out a detailed star chart for your evening’s observations, and further enrich your astronomy experience.
Buy or Make a Red Flashlight
Artificial light is the enemy of amateur astronomers. When you are out observing faint celestial objects, you need your eyes to perform at their best, and that can only be accomplished when your pupils are as dilated as possible. Our pupils dilate to allow us to see better in the dark, and any white light that interferes with that process also interferes with our ability to see detail in those beautiful, ethereal galaxies and other deep-sky objects. However, we are still human and we need to be safe whilst traipsing around in the dark! Enter the red flashlight.
Red light doesn’t interfere with the dark adaptation of our eyes, and so you will find that most every amateur astronomer you know will have one hanging around their neck or banging around in their pocket. You need a red flashlight, too. You can either buy a red flashlight, or make one.
Red Flashlight Recommendations:
To make a red flashlight, you’ll need a regular white flashlight, some red rubylith (available at artist’s supply stores), and some scissors. Unscrew the head of the flashlight and remove the glass covering the bulb. Trace around the glass onto the rubylith, and using your scissors, cut out a red circle. Then simply reinstall the glass, followed by the red film, and screw everything together. Badda-bing; a red flashlight!
You can also use red electrical tape in a pinch; just wrap it around the head of the white flashlight. Red electrical tape also works wonders for interior car lights and other offensive white light, but so does rubylith! In fact rubylith can be cut to fit the top of your iPhone, or your computer screen…the possibilities are endless!
Picking a Place to Observe
Where you place your telescope when observing is dependent upon your unique situation, but if you have a choice, follow these suggestions:
- Find a level or near level spot
- Choose grass or dirt whenever possible
- Stay away from decks or other elevated surfaces. They vibrate when you walk on them and will shake your telescope and therefore, the image.
- Concrete or asphalt is okay, but if it has been warm outside, it will take awhile before the surface stops radiating heat, which distorts the air and therefore, the image.
- Try to stay away from sources of light. Turn off your porch lights, and if you are friendly with your neighbors, ask them to turn theirs off as well, and then come share the view through your telescope! If you live in a light polluted location, welcome to the situation faced by millions of amateur astronomers! Take heart that Los Angeles has a very large population of telescope enthusiasts. The point here is to choose the darkest location possible for your situation, and then enjoy the views!
- Finally, pick a location with the widest view of the sky you can find. In wooded areas and those with lots of tall buildings, this can be a challenge, but just like the whole light pollution thing, the idea is to choose the best your situation has to offer.
Check Out Your Seeing Conditions
Why do you care what the seeing conditions are like? As long as it’s not totally cloudy, snowing, or raining, so what, right?
You will be amazed at how quickly seeing conditions change, and what effect they have on observations! The sky may be perfectly clear, but seeing can be so bad that Jupiter or Saturn might look like they are under water, and even low magnification views are not in focus. The next night (or the next hour!) those same planets will look perfectly focused in your highest magnification eyepiece, and all because the seeing conditions improved.
One of the biggest mistakes new amateur astronomers make is assuming that focus will be sharp on any subject, with any eyepiece, on any night. Understanding that seeing conditions can support high magnification views one moment and cause an unfocused mess the next will help you get the most out of your telescope and accessories, and lower your blood pressure! Before you set up your telescope for a night of observing, get in the habit of taking a few moments to look up and check conditions:
- Are the skies clear or are there passing clouds? Knowing there are clouds in the area helps you understand why an object you are gazing at suddenly disappears, or your GoTo telescope insists an object is there but you can’t see it!
- Are the stars twinkling? If so, are they steady overhead, or do they twinkle from horizon to horizon? Most of the time, stars overhead are steady and the twinkling increases as you move towards the horizon due to the increased atmosphere. If stars are twinkling overhead, you have “poor seeing”, but if they are steady almost to the horizon, then grab your scope and get set up, because the seeing is especially good, and who knows how long it will last!
- Is it especially humid out? Is dew already forming on surfaces? Dew is not a deal-breaker unless it gets so heavy that all of your optics are affected, but knowing whether it’s going to be a dewy night will help you plan your accessories. We’ll talk more about dew prevention in the “recommended accessories” section below.
- Is it windy? A slight breeze can help keep dew at bay, but too much wind can degrade seeing conditions and make observing uncomfortable.
Collect Your Telescope Gear: Whether you are driving to a dark-sky location or are observing in your back yard, it makes sense to make sure you collect everything you will need for an evening under the stars before you head outside. Some people find it works best to make a list and keep it near your telescope. Others keep everything they need in accessory cases for quick and easy access. Whichever organizational method you choose, keep in mind that it is better to bring everything out at once than to keep going back into the house and subjecting your eyes to white light, or worse yet, not have what you need when you are miles away from home. Don’t forget your red flashlight, remember to bring extra batteries, and pack some coffee or hot cocoa while you’re at it!
Level Your Tripod: If you’ve picked a relatively flat observing location, this should be pretty easy. Adjust your tripod legs until the tripod looks as level as possible. This is usually exact enough for basic visual astronomy, but you may want to increase the precision with a bubble level.
Align Your Telescope: The method used for telescope alignment depends on the type of mount you have and whether it is computerized or not. If you have a non-computerized alt-az mount, you can set your telescope down so that it points in any direction. If you have a non-computerized equatorial mount, you will want to set the telescope on the ground so that the polar axis is pointing north, and then follow the instructions in your manual to polar align your telescope. To find North, you can use a compass or navigational device, or learn how to find the North Star (Polaris) visually. The alignment method used for computerized telescopes varies by manufacturer and by telescope series. Follow the instructions in your manual to input the required data in your hand controller, and to align your telescope so it will accurately find objects for you.
Tweak Your Finder: If you followed the instructions in the Aligning & Using Your Finder section of this guide, your finderscope should need only the slightest adjustments to its alignment. Insert your lowest powered eyepiece and then point your finder at the largest object in the sky (other than the Sun, of course). This may be the Moon, or it may be Jupiter, or it may be a bright star. Center it in your eyepiece’s field of view as best you can, and then look through your finder and make any adjustments necessary to cause the object to be centered in the crosshairs. If you want greater precision, switch eyepieces and do the same thing at higher magnification.
This quick procedure should be done before you start any observing session, and normally it will take just a few seconds. However, if you accidentally bumped your finder or turned the adjustment knob by mistake, you may need to re-align your finder. This happens to everyone sooner or later, but you will get really good at it and even a major re-alignment will be a piece of cake.
Use Your Lowest Power Eyepiece Whenever You Start Observing, Regardless of the Object: Starting at low magnification accomplishes a couple of things. First, it tells you a lot about your seeing conditions. If you look at Saturn with a 30 mm eyepiece and it is “swimming” in the atmosphere, you know right away that you won’t be able to use a higher magnification eyepiece until conditions improve. Another reason for starting with the lowest power eyepiece has to do with the ease or difficulty of finding an object in the sky. This is true whether you are using a computerized telescope or not. It is way easier to find and center an object if you are searching for it in a wider swath of sky. The more magnification you use, the less celestial real estate you will see, and the more precise you will have to be to get your target into the field of the eyepiece. So, do yourself a favor and start with a low power eyepiece.
Remember to Focus: All telescopes have a focuser, and whenever you walk up to a telescope’s eyepiece, whether it is your telescope or someone else’s, you should focus the image so that it looks as sharp as possible. Remember, everyone’s eyes are different, and “almost” in focus isn’t good enough. You will miss subtle details with an out of focus image, so the first thing you should do after inserting an eyepiece into a focuser or diagonal is focus. Remind your guests to focus for their eyes, too…they will enjoy the experience way more if you do. By the way, sometimes focus is hard to achieve, especially at higher magnifications or during less-than-stellar seeing conditions. When this is the case, the best way to focus is to slowly adjust the focuser until you feel that you have just passed best focus, then back up to the sweet spot. If you cannot focus, you are trying to observe at a magnification that the image cannot support due to the limitations of the telescope or the seeing conditions. The best course of action when this happens is to remove that eyepiece and use something with less power.
Changing Magnification: When you are ready to look at an object at higher or lower magnification, it is time to change eyepieces or add a Barlow. Before you remove the eyepiece you are currently using, take a second and center the object in the field of view first. Now carefully loosen the thumbscrew holding the eyepiece in place, slide it out, and insert the new eyepiece. Remember to tighten the thumbscrew securely so that your eyepiece will not fall out when you move the telescope. You may need to re-focus for the new eyepiece. Some eyepiece sets are “parfocal” which means the manufacturer designed them to have little or no change in focus between eyepieces in a series, but most of the time, you will have different styles and models of eyepieces, and so re-focusing will most certainly be required. Most amateur astronomers have several eyepieces at their disposal. An average eyepiece count is between 3 & 5, with a Barlow thrown in for good measure. Extra eyepieces allow you to adjust the magnification to the evening’s seeing conditions, as well as match the magnification or field of view to the object.
Calculating Power: To figure out how much magnification an eyepiece provides for a given telescope, divide the focal length of the eyepiece into the focal length of the telescope. For instance, a telescope with 1000 mm focal length will yield 100X magnification with a 10 mm eyepiece. Use this formula when shopping for your next eyepiece. Check it out:
Let’s use the example of the 1000 mm focal length telescope, and then let’s say you have a 30 mm eyepiece (33X), a 10 mm eyepiece (100X) and a 2X Barlow, which would give you 66X with the 30 mm eyepiece and 200X with the 10 mm eyepiece. Since you know that you have four magnification choices (33X, 66X 100X & 200X), you might want to buy something that alone, would give you about 150X, and doubled, 300X. That would be either a 6 mm eyepiece (167X & 333X) or a 7 mm (143X & 286X). The idea is to fill in gaps in magnification without going too high.
How Much is Too Much? Wait, what do you mean, too high? Sorry, but Earth-based telescopes have their limits. We have this pesky thing called the atmosphere, and it isn’t completely transparent, even though we humans tend to think so until we try looking through it with a telescope. This is why space telescopes are so important; they don’t have the atmosphere to deal with and can provide much clearer pictures of the Universe.
The basic formula for the limits of magnification on a given telescope has to do with its aperture. The larger the optics are on a telescope, the more magnification it can handle…to a point. That point depends on, you guessed it, seeing conditions. That is why astronomers build big telescopes on the tops of mountains out in the middle of nowhere because those locations have a topography that tends to produce better seeing.
Here’s the rule for max magnification: Approximately 50X per inch of aperture. That means a 4” telescope will max out at about 200X, and an 8” telescope will max out at about 400X. These rules are super variable, however. Sometimes the seeing is so good a 4” telescope can easily do 400X, etc., so what’s a person to do if they want to figure out what their telescope can really handle?
Get out there and observe, and while you are enjoying the wonders of our Universe, pay attention. If you do, you will figure out quickly enough what seeing conditions tend to be in your area, and what kinds of magnifications the combination of your telescope and your location will support. If you have an eyepiece that gives you 200X, and when you put it in the Barlow you can only achieve focus about 50% of the time, then you will know that while 400X is doable, 500X will be way less likely, and you might not want to spend a good deal of money on an eyepiece that gives you that much magnification.
We also recommend you find a local astronomy club near you and plan to attend a star party. It may not be your cup of tea, but you should check it out and see. Besides the social aspect, a great benefit of observing in a group is the ability to try other people’s accessories on your telescope, or at least see how well you like them on someone else’s telescope! Also, if you have questions or problems with your telescope, there’s a good chance someone is nearby that can help you.
What Telescope Accessories Do I Really Need?
There are literally hundreds of accessories available to the amateur astronomer today, and as you get more experienced with your telescope, you will discover for yourself which ones are needed most. However, there are some accessories that pretty much everyone will end up buying as soon as they are able, and those are the ones we will concentrate on here. We already talked about Barlows and a red flashlight, and those items are right up there at the top of the list, including:
Extra Telescope Eyepieces Like we said earlier, a good eyepiece count is between 3 & 5. Everyone should have what they consider a low, medium & high power eyepiece, and then add more as you wish. You can spend as little as $30 for an eyepiece or as much as a grand or more. We suggest you spend as much as you can afford, because the views will only be as good as the weakest point in your optical chain. Other considerations when buying eyepieces are field of view (wider fields are necessary on some very large deep-sky objects), and eye relief (how close your eye must come to the glass to achieve focus). Those who wear eyeglasses need more eye relief than those who don’t.
Recommendations: Which eyepieces you require depends on many factors, including your telescope, what kind of observing you like to do, and your budget. To shop for an eyepiece, figure out what focal length you want, and then filter from there by price, field of view, barrel size, and manufacturer. In the following link we have ordered eyepieces by price...you can take it from there. If you need any help, you can always contact us and we will be glad to walk you through. Now, here's that link: Telescope Eyepieces Filtered by Price.
Dew Prevention Devices: Most amateur astronomers will be assaulted by dew at some point, and many deal with it on a regular basis. Dew can form on your telescope optics and shut down an observing session if it is not dealt with. Dew also coats eyepieces, filters, and other surfaces. The closer your telescope’s optics are to the tube opening the more likely you will have dew. The worst telescopes for dew are those with corrector plates. Schmidt-Cassegrains and Maksutov-Cassegrains are two examples of telescopes with a piece of glass near the opening of the tube assembly. Refractors have their optics near the front, but are usually set back a little bit by virtue of a built-in dew shield. If you have a Newtonian telescope, you will not have to deal with dew on your mirror, since the telescope tube naturally creates a giant “dew shield”, but you will still get dew on your eyepieces and finder if not prevented.
Here are a Few Options for Dealing with Dew on Your Telescope’s Optics:
- Dew Shield: These optical tube extensions fit over the front end of the telescope and delay the ability for dew to form on the optics. You can buy flexible dew shields that wrap around your telescope's outer diameter and will lie flat when not in use, or flexible heated dew shields that will raise the dew point of the surface to keep dew away. Choose a dew shield that is made to fit your telescope, or measure the outside diameter of the telescope and buy according to those dimensions.
- Dew Strips: Dew heaters, or dew strips, are thin strips of a thick material that have heater elements running along their length. They wrap around the outer most edge of the telescope tube, stay put thanks to Velcro, and plug into a hand controller, which allows you to adjust the amount of heat applied to the surface. Dew Controllers often are capable of handling more than one heater, so you can have one for your telescope, one for your finder, or any other number of accessories. Keep in mind that dew heaters and their controllers require DC power, so when considering them, think about how they will be powered.
- Hair Dryer: Many people use a hair dryer to blow away the dew. If you choose this method, keep in mind that you always want to use the LEAST amount of heat required to do the job. Overheating your mirror will only cause distortions of your image until the glass returns to ambient, and then the blow dryer is needed again. This is why most people use heater strips made for the purpose. They can be set to provide just enough heat to do the job, and only around the perimeter of the mirror, limiting the amount of heat distortion they cause.
An Alternate Form of Powering Your Telescope: Most telescopes will run on more than one type of power, assuming it is powered in the first place! If your telescope runs on household batteries, but will accept an AC or DC power adapter, we highly recommend you pick one or both of them up! An AC adapter will let you run your telescope off of a regular wall outlet. This is great for those who observe close to the house or garage, and is way better than using up a boatload of AA batteries! A DC power adapter comes with a cigarette lighter plug, and can run your telescope off of your car battery if you drive to your observing site, or from a portable DC battery. These DC battery packs can sit right under your tripod legs and, if charged up before you go, will run your telescope all night long. They can also run your dew heater straps, heated dew shield, or other DC powered accessories.
Recommended Power Accessories:
Moon Filter: The moon is amazingly bright, and casts a blinding light when observed with a telescope. A simple moon filter, also called a neutral density filter, will allow you to gaze at the Moon and still see all the subtle details of the lunar surface. A moon filter is inexpensive, and screws onto the barrel of standard telescope eyepieces. If you have 1.25” barrel eyepieces, then buy a 1.25” Moon Filter. There are also 2" moon filters available for larger barreled 2” eyepieces.
Recommended Moon Filters:
Telescope Case and/or Cover: A telescope case will protect your investment when you are transporting it to a dark sky site or storing it in your garage or closet. Some telescope models have hard cases available, but most will fit into a soft-sided case that is made for a range of telescope sizes. A soft case is sufficient unless you plan to travel by air and want to take your telescope with you. In these instances, a hard case is your best bet. There are also protective covers available for all sizes of telescopes. Some telescope covers are made of reflective material on one side so that you can leave your telescope set up during the day and then simply remove the cover to start observing in the evening. The reflective material helps reflect the sunlight to keep the telescope from getting hot. There are also covers made from a heavy-duty material that can handle more extended times out in the elements. Choose a good cover, and pick the right fabric for your observing habits.
Solar Filter: At the very beginning of this Guide you were warned about looking at the Sun, even for a few seconds, without the proper filtration. There are safe solar filters on the market today, and they are not very expensive. White Light Solar Filters are made from a special material that filters out all the damaging effects of the Sun and lets you observe features on the Sun safely. To use a safe solar filter, buy the correct size for your telescope and fit it snugly over the front end of your optical tube. The filter cell is threaded with thumbscrews that can be tightened to make sure the filter stays put. With this filter in place, you can see sunspots and watch solar eclipses in comfort. There are also filters available that will allow you to see other solar details, like prominences and flares, but they are more expensive than standard white light solar filters. If you enjoy viewing the Sun, you may want to look into more advanced H-Alpha solar filters. After all, observing our Sun allows you to get a close-up and personal view of a star, and that’s pretty cool!
Telescope Accessory Bundles: Before we say “The End” to the First Time Telescope User’s Guide, we wanted to tell you about an easy and inexpensive way to accumulate some of the most important accessories for your telescope. High Point Scientific has put together Accessory Bundles for some of the most popular telescopes available today. If you have one of the telescopes listed below, check out their bundles! They include items like extra eyepieces, power supplies, Barlows, motor drives for telescopes with equatorial mounts, and much more.
Just the Beginning
This may be the end of this Guide, but it is just the beginning of your adventures in astronomy! We hope we have helped clarify some of the questions most new astronomers normally have, and that we have made your first observing sessions more of a success. If you have any questions, or need help choosing products for the next stage of your journey, please feel free to give us a call, start a chat, or send us an email anytime.
The Staff at High Point Scientific
Table of Contents
In a hurry or only need a few questions answered regarding the set up or use of your telescope? Below is a list of links to sections in this Guide. Just find the question that best reflects what you need to know and click it to be taken to that section. Enjoy.
Eyepieces, Barlows & Magnification
Methods for Finding Objects in the Sky
When & Where Should I Observe?