Below are some of the handiest accessories you can get to make your observing easier and more enjoyable. Most are considered must-haves by experienced observers. So read on to see what you might need to enhance your stargazing!
Whether you are hunting down objects manually or have a computerized system, this device might be the best thing you can add to a telescope. Reflex finderscopes, such as the popular Telrad, work by projecting a red LED reticle onto a small piece of glass. This produces a heads-up display in which the reticle pattern (usually a dot or bulls-eye) appears on the sky. Reflex finders are far easier to use than standard finderscopes because the image is not magnified or inverted. Instead of showing you stars you cannot see with the unaided eye, the reflex finder shows you exactly where the telescope is pointed relative to the stars you can see and that are shown on most star charts.
Even for a computerized telescope, a reflex finder makes locating the first few stars for aligning the computer a much easier task. Also, with a reflex finder, learning the sky with a computerized scope becomes easier, since the finder will show you exactly where in the sky an object is located. Some telescopes now ship with reflex finders, but if your telescope only has an optical finderscope, consider upgrading to a reflex finder to make your stargazing much simpler.
There are a variety of charts available depending on the level of the observer as well as the desired amount of detail. A simple chart like aplanisphere is the best way to start learning the sky, even without a telescope. This type of chart plots the sky on a circular wheel that can be turned to show the sky any time of year at any hour of the night. For learning the constellations, there is no better way to go.
For more detail, there are many charts to choose from. For a beginner, stick with something simple to keep from being overwhelmed. It will take some time to see a lot of objects, so there is no need for a chart with 10,000 deep-sky objects plotted. Pick a chart where the scale is such that constellation shapes can still be picked out. Good choices for a novice stargazer are Orion's DeepMap 600 and Wil Tirion's Bright Star Atlas 2000.0. These charts are easy to navigate but contain many objects and descriptions. Many beginners' books also contain basic charts which are great for new astronomers.
For the advanced observer, there are charts available with more detail than you could ever possibly need. One of the best and most popular is Wil Tirion's Sky Atlas 2000.0. This chart contains thousands of deep-sky targets, but the scale is just small enough to easily find your way around the sky. More detailed charts have even more objects plotted for users of very large aperture telescopes, but they are often used in conjunction with a smaller-scale chart like the Sky Atlas to make navigation easier.
Charts are starting to be replaced in many cases by computer programs (described below), but the glow from a computer screen can ruin yourdark adaptation and a paper chart has the advantage of being easy to flip through for easily finding objects all around the sky. A printed chart is still a great accessory to have.
You'll need a way to view your star charts in the dark, and the best method is to use a red flashlight. The human eye is least sensitive to red light so these types of lights are least likely to affect your night vision. While red cellophane can be placed over the lens of a standard flashlight, red LED lights are preferable for several reasons. For one, LEDs are more battery friendly, and the bulbs themselves can last for 100,000 hours. Many LED lights, including the Rigel SkyLite, have rheostats for adjusting the brightness of the bulbs. This is a great feature as a dim light is great for reading charts and books, but a bright light might be useful for setting up the telescope. Some lights even incorporate both red and white LEDs, which is great if you drop something small like a screw into the dirt or something rustles in the bushes beside you in the dark.
Green Laser Pointer
The green laser pointer is quite possibly the coolest astronomical accessory in years. This pointer shoots a green laser beam up into the night sky for the purpose of pointing out constellations. We use laser pointers every night at Starizona and wonder how we ever pointed out celestial objects before this invention came along! At first, the novelty of seeing a laser beam shoot up into the sky will distract your fellow stargazers ("That is so cool, let me try!"), but once they settle down, teaching them the night sky will be easier than ever.
A green laser is used because the human eye is most sensitive to green light and because green light scatters so well off dust particles and moisture in the air. This is why a regular red laser pointer will not work. Also, the green lasers are more powerful, sending out a brighter beam. This accounts for why they are so much more expensive than red pointers, but the cost is well worth it if you like to share the night sky with others.
It is a laser beam, so a warning, of course. If you decide the green laser beam makes you unable to resist your deep inner longing to be a Jedi knight, and you start wielding it around a la Luke Skywalker, don't fire the beam into anyone's eyeball. And don't shoot it at airplanes if you don't want the FBI showing up on your house in the middle of the night and dragging you away in the middle of your observing session.
In most parts of the country, dew formation on optics can be a real problem. The ultimate solution is to move to the desert where dew never forms, but short of that there are some things you can do to keep your optics from getting soggy. Dew is problematic when it forms on the telescope optics (usually the corrector lens of a Schmidt-Cassegrain or the objective of a refractor) as well as on eyepieces and finderscopes.
In most conditions, it is sufficient to use a dew shield, which is simply a tube extending out from the front of the telescope. Most refractors have this built in, but it is an optional accessory for SCTs and other scopes. Newtonians do not require dew shields since, with the mirror at the bottom, the entire optical tube is essentially a long dew shield. There are metal dew shields as well as flexible shields that unroll for easy transport. Dew shields have the added advantage of blocking stray light, offering some protection to exposed optical surfaces, and counterbalancing heavy eyepieces or cameras.
When the air gets really humid--and for items like eyepieces that cannot use dew shields--the best protection is a dew heater. Dew heaters work by keeping the optical surface just above the dew point, preventing moisture from forming on the glass. Dew heaters are simply a strap containing resistors that wrap around the front of a telescope or top of an eyepiece, heating up the exposed optics and keeping the glass above the dew point. Dew heater strips plug into a control box which can set the amount of heating and can often power multiple strips.
Well, now that you have all these goodies, you certainly need some easy way to transport them. A carrying case probably seems like an obvious item, but there are some things to consider when picking one out. Most of your accessories--especially eyepieces and filters--can be both breakable and expensive. You could just toss everything into an old tackle box (and some people do), but not if you want to keep your stuff in good condition. The best cases have pluckable foam which you can easily customize to fit all your accessories. Aluminum cases are relatively inexpensive and provide pretty good protection. Better yet are hard plastic cases like those from Pelican (shown above). You can practically park a truck on these cases.
An important tip for buying a case: pick out one that is bigger than you need. You will always be able to fill it up, because there will always be more accessories you will want. A typical astronomer might have three eyepieces, a diagonal, two or three filters, a finderscope, and a red flashlight. But you might add other eyepieces, or get 2" eyepieces and a diagonal which take up more space, or a Barlow lens, or whatever. Buy a case expecting your accessory collection to grow and it will save you from having to spend on another case later.
There are a number of computer programs available for amateur astronomy. The most popular are planetarium programs like Starry Night andThe Sky. These program simulate the night sky from anywhere on Earth (and even from other planets). This is a great way to learn the sky, find objects to view, see when the sun and moon and planets are up or down, visualize events such as eclipses that you might not see from your location, and much more. These programs can also often be used to control a computerized telescope.
Other programs can be used to plan and log your observations. For photographers, software is available to capture, stack, and enhance imagesusing digital cameras or CCDs. There are even programs for portable devices that do simple but handy tasks like showing the moon's phase, calculating sunset and twilight times, or plotting the locations of Jupiter's moons.