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Magnification is an important factor when planning planetary observations. Not so much for deep sky objects because most of them are large in the sky; therefore a low magnification is advantageous.
Planets are very small objects to look at and you need the highest magnification your telescope can handle to see the most detail. As a general rule of thumb, magnification should not exceed 200x as atmosphere and viewing conditions are a limiting factor. Anything beyond that results in a larger but blurry image.
There are a few things you should know about scaling. The maximum usable magnification is given by the aperture of the telescope, and the usable magnification depends on the observing conditions at any given time.
Highest usable magnification for a telescope
Every telescope has oneincrease limitthis is referred to as the maximum usable magnification. This limit is calculated using the aperture of the telescope. The telescope aperture is basically the diameter of the primary mirror in a Newtonian reflector, or the diameter of the lens in a refractor telescope.
The easiest way to calculate the maximum usable magnification of your telescope is to take the aperture in millimeters and multiply by 2x. Or 50 times the aperture of the telescope in inches. Here is a table to help you determine the highest usable magnification for your telescope.
|2,7" (70 mm)||140x|
|4″ (100 mm)||200x|
|4,5" (114 mm)||228x|
|5″ (130 mm)||260x|
As you can see, even with a small telescope, the maximum usable magnification is high enough to push the limits of viewing conditions. In perfect conditions, you can use 200+ magnification, but such situations are rare.
So what's the point of buying a large aperture if you can't go beyond 200x? Well, the size of the aperture is also the resolving power of the telescope. The planets will be more detailed with a 16" telescope at 200x magnification than with a 4" telescope at the same 200x magnification.
And if you plan on photographing planets, you can easily exceed the 200x limit because the planetary photography process is called Lucky Imaging, where the software takes only the best images and stacks them.
Also read:How do telescope lenses work? (Explained!)
focal length and eyepiece
The focal length of the telescope and the eyepiece determine the magnification of the telescope. A longer focal length gives more magnification with a given eyepiece.
All you have to do is divide the focal length of the telescope by the focal length of the eyepiece. A telescope with a focal length of 1000mm and an eyepiece with a focal length of 10mm will provide 100x magnification.
For more information on scaling see my article onHow to increase telescope magnification.
Best viewing conditions for high magnifications
Atmospheric conditions are responsible for 50% of the image quality in your eyepiece. So it's important to plan your observation session around it.
The first thing to look for, of course, is clear skies, and the other is atmospheric turbulence. Atmospheric turbulence is small-scale, irregular air movement in the atmosphere. It's like looking through water. That is why the stars shine in the night sky.
There are two things to keep in mind when planning your observation session. First, always look for high-pressure systems in your area. These are the best conditions for observing planets.
And second, the Jet Stream, which is your number one enemy. If you see a jet stream over your area, don't even bother taking out your telescope unless you have a very limited number of clear nights during the year. A jet stream is a narrow, fast-flowing, tortuous stream of air. Too bad to use a telescope on the planet. You should always checkJet Stream Live-Karte.
What magnification do you need to see Jupiter?
Jupiter is best seen at 200x magnification or less. It's a very low-contrast planet, and high magnification results in less contrast.
If you go beyond 200x magnification, it gets worse, it gets big and blurry. Jupiter is the largest planet in our solar system, so you can use lower magnification to take advantage of cloud bands or the Great Red Spot.
Also read:The Best Telescopes to See Jupiter (Planet, Red Dot, and Moons)
What magnification do you need to see Saturn?
Saturn is the second largest planet in our solar system and is therefore easy to see even with smaller telescopes. You can use 200x magnification and maybe 250x magnification if viewing conditions allow.
To see more detail about Saturn's rings, you can zoom in even closer to 250x magnification. In my opinion, Saturn is the most beautiful planet to look at and you will be amazed when you first see it through the eyepiece.
Also read:What size telescope do you need to see Saturn's rings?
What magnification do you need to see Mars?
Mars is very small in the sky, so it's best to use the telescope's highest useful magnification.
The goal here is to make it bigger, otherwise you won't be able to see much surface detail. Depending on the viewing conditions, you can use a magnification of 200x or even more.
Learn more in this article:What size telescope do I need to see Mars?
What about the rest of the solar system?
Venus is a beautiful planet to look at because you can see how the phases of the crescent moon change as it orbits the sun. You can use a magnification of 200x or more as there is no surface detail to observe.
Mercury is also beautiful to look at, especially when you notice the crescent phases and some surface detail. You can use a magnification of 200-250x.
The rest of the planets like Uranus, Neptune and Pluto (yes, I said that, Pluto is a planet :)) are not very interesting in the eyepiece even at very high magnifications. They are too far away to see any detail as they are always tiny dots in the telescope.
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A few tips to get the best image quality at high magnification
You can view and enjoy the planets at low magnification, but to get the best image at the highest usable magnification I'd like to give you a few more tips.
Planets in opposition
The best time to observe the planets is when they are in opposition. What does that mean? When the planet is in opposition, it is closest to us, which is the largest in the sky.
Look at that "planetary calendar' for dates when the planets are in opposition.
If you are using a Newtonian reflecting telescope or other designIf you use mirrors to create the image, you need perfect collimation.CollimationIt's basically the alignment of the mirrors, and without that the image in the eyepiece is blurry.
Most people who complain about their telescopes say the image quality is poor even at low magnification, but the problem is that their telescopes are not collimated.
Another problem humans have is heat balance. The story goes like this: you check the weather, the jet stream and everything is perfect. He raises his telescope but sees a lot of distortion and turbulence through the eyepiece.
The problem is that your telescope has not yet reached the outside temperature and the hot air from the telescope itself will distort the image.
Therefore, you should always prepare the telescope in advance and take it out to acclimate it to room temperature. The time required depends on the aperture of the telescope. The larger the opening, the longer the acclimatization takes.
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The best telescope to see planets.
With all of this said, you may now be wondering which telescope is the best for use on the planets.
From what we have learned in this article, we need a telescope with a large enough aperture to see maximum detail and good resolving power. The second criterion is a long focal length in order to easily achieve high magnification with the eyepiece.
The most suitable candidate for the best telescope for observing planets is the Schmidt-Cassegrain telescope. These telescopes pack a long focal length into a small package, making them easy to use and portable to take anywhere.
An example of the best telescope for planets isCelestron NexStar Evolution 8″Schmidt-Cassegrain.
This telescope has an 8″ (200mm) aperture with the highest usable magnification of 400x. The focal length of this telescope is 2032mm, which makes it easy to get high magnifications.
It is mounted on a computer-controlled mount, which is also important because keeping the planet in the eyepiece's field of view at high magnification is a tricky task. Even the slightest touch or movement of the telescope will cause a planet to disappear from view. This telescope does that for you as it can track the object across the sky and keep it in the eyepiece for hours.