Finally, your long awaited refractor or Dobsonian telescope has finally arrived. It’s time to take it outside and explore the skies.
Just one question; where in the sky do you find Jupiter, or Saturn, or Mars?
Now, this is not a problem if you bought a computerised GoTo telescope. You simply select a planet on the hand controller and the telescope automatically swings to the right spot.
But if you have a manual telescope mount, whether an altazimuth or equatorial type, you need to know how to find planets. We have a couple tips plus some advice on the best telescope for planetary observations.
Two Ways to Find Planets in the Sky
1. Use Your Eyes
The simplest, though not necessarily the easiest, way to find planets is by looking up with your naked eyes. Some planets like Venus, Mars and Saturn are much brighter than stars, making them easy to spot even without a telescope.
You need to know the rough area of the sky to look at and what to look for.
The easiest way to find the location of planets is by figuring out the sun’s elliptic. This is the apparent path the sun takes across the sky. Most visible planets are never far from the elliptic.
To determine the elliptic, check the position of the sun throughout the day. Use buildings and other landmarks to remember its path.
At night, look for bright objects that do not twinkle. Venus and Mercury will be closest to the elliptic while outer planets like mars are further way from it.
Note that the elliptic changes during different season of the year, so keep checking the sun’s path to make it easy to find the location of planets at night.
You can identify different planets by the hues. Mercury is yellowish, Venus is brilliant white and mars is red-orange. Jupiter is a slight tan and Saturn has a yellow hue.
Keep in mind that not all planets are visible at the same time. It depends on the time of year and time of day. Sometimes, a planet will be visible only a short time after the sun sets or before it rises while at other time it’ll be visible all night long
Other planets like Uranus and Neptune are impossible to see without a pair of binoculars or by looking through your telescope’s eyepiece.
Spend some time sky-gazing and try to spot different planets. After a few sessions, you’ll find that it gets easier to spot a planet.
2. Use A Sky Map
An easier way to find planets is using a sky map or star chart. The advantage of using a sky map is that it shows you exactly where the planet is at a particular date and time.
Using the provided direction and altitude, you can swing your telescope mount to the right spot.
If you have an alt-az mount, you simply raise it to the right altitude and then swivel it to the right direction. You can use a compass to tell directions.
If you have an equatorial mount, first polar-align it. Then use the setting circles to adjust the telescope to the right position in the sky.
Many websites including TheSkyLive, TimeandDate and even Google offer a digital sky maps.
There are also several sky map apps available for iOS and Android.
The best thing about using a digital sky map is that locations of objects are specific to your location and the current day and time. In addition, most sky maps show the location of more than just planets.
You can check the location of stars, galaxies, nebula and other celestial objects.
The Best Telescope for Observing Planets
Two main features determine a telescope’s optical capability: aperture and focal length.
A wide aperture mean the telescope takes in more light. It delivers brighter images and allows you to see deeper in the sky. High-performance telescopes can have an aperture up to 8”.
A long focal length results in higher magnification, which proves clearer details on objects in the sky. However, you get a smaller field of view, which limits deep sky observations.
For observing planets, you want a telescope with decent aperture (at least 5 inches, but preferably 6-10 inches) and a fairly long focal length (at least 700mm, but preferably 1,000-1,300mm).
If you also spend a lot of time exploring deep sky attractions like galaxies, get an all-round telescope that balances between high magnification and a wide field of view. A 6”-10” aperture is ideal with a focal length between 400mm and 1,000mm.
Remember there are many other considerations that should go into your purchase decision including portability, type of mount and type of telescope.