Even a large telescope won’t reveal much detail on Neptune, although you will see its largest moon, Triton, which shines at magnitude 13.5. The thrill of observing Neptune comes when you first spot it through your telescope. Because it lies further from the Sun than Uranus, Neptune moves even more slowly. It takes approximately 85 days for the planet to traverse a Full Moon’s span. To the amateur astronomer with binoculars or a telescope, Neptune is no problem to find.
She has covered stories and features for publications such as Physics World, Astronomy Now and Astrobiology Magazine. Unlike Discover the best telescope for adults right here. (mostly) unchanging stars, planets can change — they rotate, they change their angle towards us, and they experience storms in their atmospheres. There’s always something to look out for, and armed with any of the aforementioned kit, you’ll be well placed to see the planets at their very best.
The optical tube is only 24” long and the weight is 27 lbs, making it easy to pack into a car for a weekend away from the city lights. The only downside to this telescope is that it doesn’t come with a cable you need to update the controller software, which often comes with an outdated version. The cable is only $10, but it’s not USB compatible, so you’ll need to buy an adapter for it as well.
A telescope’s magnification depends on its focal length and the focal length of the eyepiece. The planets will have more details with a 16″ telescope using 200x magnification than with a 4″ telescope using the same 200x magnification. So what is the point in buying a big aperture when you shouldn’t go over 200x most of the time? Well, the aperture’s size is also the telescope’s resolving power. The highest useful magnification is the magnification limit beyond which everything becomes a blurry mess.
If you need a general purpose telescope, then head to our ‘Best Telescope of the Year‘ reviews instead. However, during part of its orbit, Mercury is far enough away from the Sun’s glare that it can be safely observed through a telescope. Those times are called “greatest western elongation” and “greatest eastern elongation”. Mercury will appear as a dim, but a distinct dot of light either right after sunset or before sunrise.
Eyepieces are critical components for serious planetary observers. But if you use a refractor or compound reflecting telescope, don’t forget your star diagonal. Lower priced or stock diagonals with many telescopes do not have optimized surfaces or coatings and can somewhat degrade images of the planets and other celestial objects. A higher-quality diagonal is an investment, but it need not be prohibitively expensive.
Spotting scopes sometimes have sight lines to assist (much better for terrestrial viewing), but a finder scope is always a pleasure to use. Also, it is good to note that there are some spotting scopes that accept standard telescope eyepieces for greater magnification capabilities. If the stars are unexplored territory for you, the Celestron StarSense Explorer LT 80AZ is the fastest, cheapest, and most helpful model we’ve found for bringing the sky to life. The telescope is not computerized, which helps to make it the cheapest of any of our picks.