Quick Answer: What Do The Numbers Mean On A Telescope?

What magnification do you need to see Venus?

The image above gives some idea of what Venus will look like using a 900mm focal length telescope with a 10mm eyepiece and a Barlow lens (180x magnification).

Venus is bright enough to dazzle so the aperture of the telescope may need to be reduced to lessen the glare..

How much magnification do you need to see planets?

Experienced planetary observers use 20x to 30x per inch of aperture to see the most planetary detail. Double-star observers go higher, up to 50x per inch (which corresponds to a ½-mm exit pupil). Beyond this, telescope magnification power and eye limitations degrade the view.

What is the best focal length for telescope?

around 1000mm to 1200mmA good all round first telescope should have a focal length of around 1000mm to 1200mm. All refracting telescopes use a glass lens as their primary focusing unit.

What magnification do you need to see Jupiter?

100xGreat seeing conditions and a very dark night are must-haves. After that, you’ll need to make use of at least 100x magnification and probably >150x to have a chance of seeing it. The very best opportunities come when Jupiter is at opposition because it is closer, giving a much larger target for us to see.

How strong of a telescope do I need to see Saturn?

Viewing Saturn’s Rings The rings of Saturn should be visible in even the smallest telescope at 25x. A good 3-inch scope at 50x can show them as a separate structure detached on all sides from the ball of the planet.

What does focal ratio mean in telescopes?

Focal ratio is simply the ratio between the focal length of a telescope and its aperture. For example, an 8″ (200mm) aperture telescope with a 1000mm focal length has a focal ratio of f/5. (1000mm/200mm = 5.) … For this reason, smaller focal ratios are called faster, while larger focal ratios are termed slower.

What can I see with a 4 inch telescope?

A four inch refractor telescope will show you all the planets of the solar system, including Pluto, which is technically no longer a planet. It will also show you deep-sky objects such as the Andromeda galaxy and the Crab Nebula, which is the remnant of a supernova explosion.

What can you see with a 20 mm telescope?

All telescopes have a fixed focal length, just like lenses on a camera. So a 20mm focal length will give you a wider field of view than say a 300mm. You will also notice that with a 300mm you get a larger image of the subject, be it a person or animal or even the moon.

Which telescope is best for deep space viewing?

The 10 Best Telescopes Comparison ChartProduct NameRankingMeade Instruments- Polaris 90mm Aperture Astronomy Telescope1 4.40Sky-Watcher Classic Dobsonian Telescope2 4.20Celestron- NexStar 127SLT Telescope3 4.20Orion SpaceProb 130 EQ Reflector Telescope4 4.206 more rows

What planets will be visible in 2020?

Mercury, Jupiter and Saturn are in the sky at dusk throughout September 2020, with Mercury hard to view from northerly latitudes. Bright Mars rises in the east in the early evening. Brilliant Venus rides high in the east in the hours before sunrise. Try Stellarium for a precise view of the planets from your location.

Can I see the rings of Saturn with my telescope?

The rings of Saturn should be visible in even the smallest telescope at 25x [magnified by 25 times]. A good 3-inch scope at 50x [magnified by 50 times] can show them as a separate structure detached on all sides from the ball of the planet.

What can I see with a 6 inch telescope?

The bigger the aperture the better. With a 6-inch telescope you can discern craters on the Moon as small as about a mile across — half the size of those visible in a 3-inch scope (under the same conditions using the same magnification).

What is a good magnification for a telescope?

A useful rule of thumb is that the maximum magnification your telescope can handle is around 50 times the telescope’s aperture in inches. Any higher and the image gets too dim and blurry. So, a 6 inch scope can magnify up to 300x, while an 8 inch scope can magnify 400x.

What is the F number of a telescope?

Scope Focal Ratio (f/number): A lens or mirror’s focal length divided by its aperture. For instance, a telescope with an 80-mm-wide lens and a 400-mm focal length has a focal ratio of f/5.

Is a 70mm telescope good?

However, a 70 mm refractor (which collects 36% more light than a 60mm telescope) is considered by many amateur astronomers to be the minimum size for a good quality beginner refractor telescope. It is acceptable for observing bright objects like lunar details, planets, star clusters, and bright double stars.

What magnification do you need to see Saturn rings?

50xSaturn’s rings should be visible in even the smallest telescope at a magnification of 25 times. A good 3-inch scope at 50x magnification will show the rings as distinctly separate from the ball of the planet.

How powerful does a telescope have to be to see planets?

If you purchase a cheap telescope to see planets, assume a usable maximum magnification of around 70% the theoretical maximum. Using the example from point 2 above, 70% of our 200x magnification is actually 140x usable magnification.

How can you tell how strong a telescope is?

The objective’s focal length (F or FL) is the key to determining the telescope’s magnification (“power”). This is simply the objective’s focal length divided by that of the eyepiece, which you’ll find on its barrel.