Learn with OPT
What can I see with a telescope?
It depends on the telescope. Each telescope will give a different view, depending on their focal length and aperture. However, most telescopes, even many beginner telescopes, can see craters on the moon, Jupiter's four main moons, Saturn's rings, and possibly some brighter deep sky objects like the Pleiades Star Cluster.
Away from city lights, more faint deep sky objects become visible. This includes the Andromeda Galaxy, the Orion Nebula, and many other objects. To find out what's in the sky tonight and the coming weeks, head to EarthSky.org for reference. Telescopes with larger apertures (front openings) will give better and more detailed views.
With larger aperture telescopes of around 8" (200mm) and up, even more details can be revealed. You can begin to see details like the Great Red Spot on Jupiter with the right eyepiece. With even larger telescopes, the sky is the limit — literally!
What are the three main types of telescopes?
The three main types of telescopes are:
- Refractors: use lenses to focus incoming light
- Reflectors: use mirrors to focus incoming light
- Catadioptrics: use a combination of lenses and mirrors to focus light
All optical telescopes fall under one of these three categories, and each have their strengths and weaknesses. To learn about each type in more detail and understand the pros and cons of each, head to our blog post about The Basic Telescope Types.
How does a telescope work?
A telescope gathers large amount of incoming light through an opening at the front called the aperture. It then uses lenses, mirrors, or both in combination to magnify and focus that light, which gets projected out of the telescope to an eyepiece or camera. You can read more (and watch a helpful video) on how a telescope works here.
What telescope is best for visual astronomy?
There are many telescopes that are great for visual astronomy. If you're a beginner just starting out on a limited budget under $250, check out our bestselling visual telescopes. If you have a little more budget to spend between $250-$500, you can get a larger aperture telescope including some full-size Dobsonians. Above $500, you can choose from many telescopes with go-to capability, which automatically point to and track objects. For visual astronomy, we recommend buying the largest aperture telescope you can both carry and afford.
Which telescope is best for deep sky astrophotography?
While many telescopes are great for visual astronomy, a much smaller percentage of telescopes are great for deep sky astrophotography. Here are some general features to look for in telescopes for deep sky astrophotography, regardless of telescope type:
- Fast focal ratio of around f/7 or lower (or attainable with a reducer)
- An image circle large enough for your camera's sensor (or attainable with a reducer)
- The telescope weighs less than half of your equatorial mount's payload capacity
- A quality equatorial mount is just as important as the telescope for deep sky imaging
Which telescope is best for planetary astrophotography?
While it's true you can take photos of the planets with just a smartphone, you can get even better results with the right telescope and a planetary imaging camera. Here's what to look for in a telescope for planetary imaging:
- Long focal length, ideally 2000mm or longer
- The largest aperture telescope you can afford, ideally 7" or larger
- Preferably a SCT or Maksutov-Cassegrain optical design
Which telescope has the best resolution?
Generally speaking, telescopes with larger apertures than others will have better resolution. This also depends on the optical design, but large aperture telescopes can resolve more detail than those with smaller apertures.
Is it safe to look at the sun through a telescope?
Never look at the sun without the proper filters, especially through a telescope! Since telescopes gather much more light than the human eye, looking at the sun without proper equipment can cause serious injury or even blindness. Before you even point your telescope at the sun, you need to attach a solar filter based on your telescope's size.
There are also dedicated solar telescopes that are designed to only observe the sun with h-alpha filters. These telescopes will provide even better views and images than a normal (white light) solar filter. Click here to shop dedicated solar telescopes.
Can a telescope see flags the Apollo astronauts left on the moon?
We wish! Not even the Hubble Space Telescope can see the flags left on the moon. You can, however, locate the approximate location of the Apollo landing sites with most telescopes and a lunar map.