All I want for Christmas is a telescope
In today's article, let's talk about telescopes! And what should you look for in your first telescope!
Seasons greetings! The nights are getting longer in the northern hemisphere as the winter solstice approaches. It's the season of giving and lots of folks are looking for the perfect gift. Maybe this year it will be a new telescope!
What should you look for in a telescope? And what can I expect to see? With a descent telescope, you should be able to see the red spot on Jupiter, the red coloration of Mars, the beautiful rings of Saturn, the craters of the Moon, and countless stars.
Telescopes come in all different shapes and sizes. There are three basic categories of telescopes. Refractors, reflectors, and Catadioptric telescopes.
TYPES OF TELESCOPES
Refractors telescope uses a lens to refract, or bend light to form an image at the eyepiece. To correct for color aberration, many telescopes use more than one lens called a doublet, triplet to help eliminate color fringing. All my current telescopes are refractors. Large refractors are great for wide-field astrophotography and deep sky observations. They are good for general night viewing and low magnification of the Moon and planets.
Reflectors only use mirrors to reflect light at various angles to the eye piece. In the process, the magnify the image.
These telescopes are often more affordable than refractors with the same aperture. Dobsonian telescopes are a popular telescope in this category of reflector telescopes.
Catadioptric telescopes combine both lens and mirrors in a compact setup that is more portable than the previous two types of telescopes. They are several types in this category to include Schmidt-Cassegrain and Maksutov-Cassegrain telescopes. Catadioptric are great for viewing planets, the Moon, galaxies, and nebulas. Most if not all come with computer-controlled telescopes mounts. I am considering a Maksutov-Cassegrain telescope for my next telescope to get some good imaging of the planets and moon.
Now that we know the three different types of telescopes, lets talk about what you should look for in a beginning telescope. That would be aperture, magnification, telescope mount, cost and ease of use.
APERTURE
In cameras and telescopes, the aperture is the opening in a lens that controls the amount of light that passes into the optical tube. The larger the diameter of the lens, the more light the telescope can be collects.
Aperture is measured in millimeters or inches. This Meade 80mm Refractor telescope I'm using tonight has an aperture at 80mm, or 3.1 inches. It's been a great telescope for deep sky astrophotography, but really lacks the magnification for lunar and planetary observations, which you will see here shortly.
At a minimum, I would not go less than 3 inches of for a telescope. If you want impressive views, I would look more toward the larger end around 8-10 inches. Why not even bigger? When you start getting telescopes with a larger aperture, the price increases as wells as the size and weight. If your telescope is too large, bulky, and heavy, is not practical anymore? You probably want to have a telescope that is easy to bring outside for an evening of stargazing.
MAGNIFICATION
The second thing you want to look for in a beginning telescope is magnification. Magnification is how much an object will be enlarged. In telescopes, it is determined by the focal length of the telescope divided by your eyepiece lens. Focal length in general terms is the the distance between the telescope's primary lens or mirror and the point where the light rays come together in focus. All these figures are located on the telescope's specifications.
So for example, my Meade Refractor telescope has a focal length of 480mm. If I take this Celestron 32mm Plossl eyepiece, I get a Magnification of 15x larger than what I would see with my unaided eye.
Since Jupiter is out tonight, lets check that out with this lens at 15x Magnification. These images were taken using my Google Pixel 8 phone camera through the eyepiece lens.
Not very big at all. Using my William Optics SPL 3mm eyepiece, I will get 160x Magnification. Here is what Jupiter looks like under this magnification.
It's better than the 15x, view, but my refractor has its limits as I discussed before.
What about telescopes that offer 1000x Magnification on the package? Be wary! There is a limit to magnification, called maximum useable power. This number is determined by multiplying the aperture of your telescope. Double the aperture in millimeters, or 50x that of inches.
My Meade refractor telescope aperture is 80mm, or 3.1 inches. That comes out to 160x or 155x maximum useable power under ideal conditions, depending if you are using millimeters or inches.
NOT IDEAL CONDITIONS
Unless your in a dark sky site with perfect seeing condition in a higher quality telescope viewing a bright object, you will have less than ideal conditions. Magnification is limited by atmospheric conditions such as humidity, smoke, haze, wind and atmospheric turbulence, light pollution, your equipment performance and quality, and what you are observing (bright object verse faint object).
Using too high of a magnification may result in a shaky, dim, and blurry object. Be sure to check out the useful magnification of the telescope you are thinking of buying.
TELESCOPE MOUNT
Next, you want to think about the telescope mount which will hold and move your telescope and all attached accessories. You want to pay attention to the payload. If you are purchasing a mount that is separate from your telescope optical tube, be sure to add up all the potential weight of your astrogear that your mount will carry to include your telescope, eyepieces, lens, filters, focusers, view finders, controllers, and counterweights.
There are several types of mounts available. Alt-Azimuth and Equatorial Mounts.
Alt-Azimuth mounts move your telescope in four basic directions. Up and down. Left and right. They are perfect for lunar and planetary observations.
Equatorial Mounts are designed to locate your night sky object, and compensate for the rotation of the Earth along one axis. They must be polar aligned. They are perfect for the astrophotographer that need the finest movements of the telescope for image tracking.
For the beginner telescope, I would recommend a computerized go-to Alt-Azimuth mount.
COST AND EASE OF USE:
Finally, you want to consider cost and ease of use. For the beginner, I would go with a telescope that is easy to use. This means the telescope and the mount is portable to transport from your living quarters to your night sky location in the yard. When you turn on the telescope mount, you should be able to navigate the menus on the computerized hand controller with ease. Orient the telescope by locating a few major stars, and then tell your hand controller that you want to see a visible planet, the moon, or some other celestial object. Press enter and the telescope points to the object and after focusing the telescope, you enjoy the wonders that is our universe.
A few telescope companies offer telescope bundles. These are great for beginners. If I started from scratch on this hobby, I would consider getting the Celestron Nexstar series telescope. These Schmidt-Cassegrain telescopes come in 4,5,6, and 8 inches for an aperture. The useful magnification on the 8 inch Nexstar is 481x magnification under ideal conditions. It uses a go-to alt azimuth mouth that is computerized with a hand-controller.
They are easy to use. Portable. Lots of accessories available. Celestron is a reputable company and their bundled telescopes are among the top best sellers.
There are many other telescopes out there that are available for the beginner astronomers, such as Apertura and Meade. Be sure to do your research.
WHERE TO BUY?
If your like me, there is no telescope and astronomy stores in your area. I recommend High Point Scientific for all your astronomy needs. They have a team of gear expert that know astronomy, and can help you. They are amazing and nearly everything I have in my astronomy gear has come from them.
I hope this was a helpful and I want to wish you and your family a happy Christmas, wonderful holiday and great New Year! Clear skies!
Be sure to check out this video online on YouTube!
Enjoy learning more about Astronomy and Astrophotography? Come explore with me with my newsletters and YouTube channel.
Visit my YouTube channel for more astrophotography
https://www.astrobortle.com/
For my Astrophotography at Bortle 5 website, visit
https://astrophotography-at-bortle-5-omsmyt.mailerpage.io/
For the latest Blogger updates, subscribe to my Newsletter
https://tinyurl.com/2arry74k
Comments
Post a Comment