Actually, this is one of the first questions that arises in most novice astronomy enthusiasts. Someone thinks that you can see an American flag in a telescope, planets the size of a soccer ball, colored nebulae, as in photos from Hubble, etc. If you think so too, then I will immediately disappoint you – the flag is not visible, the planets size like pea, galaxies and nebulae are gray colorless spots. The fact is that a telescope is not just a tube for entertaining and receiving “happiness to the brain”. This is a rather complex optical device, with the correct and thoughtful use of which you will receive a lot of pleasant emotions and impressions from viewing space objects. So what can be seen through a telescope?
One of the most important parameters of the telescope is the diameter of the lens (lens or mirror). As a rule, beginners buy inexpensive telescopes with a diameter of 70 to 130 mm – so to speak, to explore the sky. Of course, the larger the diameter of the telescope’s lens, the brighter the image will be with the same magnification. For example, if we compare telescopes with a diameter of 100 and 200 mm, then at the same magnification (100x) the brightness of the image will differ by 4 times. The difference is especially noticeable when observing faint objects – galaxies, nebulae, star clusters. Nevertheless, it is not uncommon for beginners to immediately acquire a large telescope (250-300 mm), then marvel at its weight and size. Remember: the best telescope is the one that is most often observed!
So, what can be seen in a telescope? First, the moon. Our space satellite is of great interest for both beginners and advanced amateurs. Even a small telescope with a diameter of 60-70 mm will show lunar craters and the sea. With an increase of more than 100x, the moon will not be placed in the field of view of the eyepiece at all, ie only a piece will be visible. As the phases change, the view of the lunar landscapes will also change. If you look through a telescope at a young or old moon (narrow sickle), you can see the so-called ash light – the faint glow of the dark side of the moon caused by the reflection of earth light from the lunar surface.
Also in the telescope you can see all the planets of the solar system. Mercury in small telescopes will look just like a star, and in telescopes with a diameter of 100 mm you can see the phase of the planet – a tiny sickle. Alas, Mercury can only be caught at a certain time – the planet is not far from the Sun, which makes it difficult to observe
Venus – the same evening star in the morning – is the brightest object in the sky (after the Sun and the moon). The brightness of Venus is so high that it can be seen in the afternoon with the naked eye (you just need to know where to look). Even in small telescopes, one can consider the phase of the planet – it changes from a tiny circle to a large sickle like the moon. By the way, sometimes people, looking for the first time at Venus through a telescope, think that this is what the moon shows. 🙂 Venus has a dense, opaque atmosphere, so seeing any details will not work – just a white sickle.
The Earth. Oddly enough, the telescope can also be used for ground-based observations. Quite often, people buy a telescope both as a space peeper and a telescope. Not all types of telescopes are suitable for ground-based observations, namely lens and mirror-lens – they can provide a direct image, while in Newton’s mirror telescopes the image is inverted.
Mars. Yes, yes, the same one that is seen every year on August 28th as two moons 🙂 And people go from year to year to this stupid joke, asking questions from familiar astronomers 🙂 Well, Mars, even in fairly large telescopes is seen only as a small circle, and even then only during the period of confrontation (once every 2 years). However, in the 80-90 mm telescopes it is quite possible to consider the darkening on the disk of the planet and the polar cap.
Jupiter – perhaps it was from this planet that the era of telescopic observations began. Looking at a simple home-made telescope at Jupiter, Galileo Galilei discovered 4 satellites (Io, Europa, Ganymede and Callisto). Later, this played a huge role in the development of the heliocentric system of the world. In small telescopes you can also see several bands on the disk of Jupiter – this is a cloud belt. The famous Great Red Spot is quite accessible for observation in telescopes with a diameter of 80-90 mm. Sometimes satellites pass in front of the disk of the planet, casting their shadows on it. This can also be seen with a telescope.
Saturn is one of the most beautiful planets, each time from the sight of which I was just breathtaking, although I have seen it more than one hundred times. The presence of the ring can be seen already in a small 50-60 mm telescope, but it is best to observe this planet in telescopes with a diameter of 150-200 mm, in which you can easily see the black gap between the rings (Cassini divide), cloud belts and several satellites.
Uranus and Neptune – the planets circling far from the rest of the planets, small telescopes look only in the form of stars. Larger telescopes will show tiny bluish-green discs without any details.
Star clusters are objects to be observed through a telescope of any diameter. Star clusters are divided into two types – globular and scattered. The globular cluster looks like a round misty spot, which when viewed in an average telescope (from 100-130 mm) begins to crumble into stars. The number of stars in globular clusters is very large and can reach several millions. Scattered clusters are clusters of stars, often irregularly shaped. One of the most famous open clusters visible to the naked eye is the Pleiades in the constellation Taurus.
Galaxies. These star islands can be found not only through a telescope, but also through binoculars. It is to find, not to consider. In the telescope, they look like small, colorless specks. Starting with a diameter of 90-100 mm, the shape of a bright galaxy can be seen. The exception is the Andromeda Nebula, its form can be easily viewed even with binoculars. Of course, about any spiral arms and there can be no talk to a diameter of 200-250 mm, and then they are visible only in a few galaxies.
Nebulas. They are clouds of interstellar gas and (or) dust highlighted by other stars or remnants of stars. Like galaxies, in a small telescope they are visible as faint specks, but in larger telescopes (from 100-150 mm) you can see the shape and structure of most bright nebulae. One of the brightest nebulae – M42 in the constellation of Orion – can be seen even with the naked eye, and the telescope will show a complex gas structure, like a cloud of smoke. In some compact bright nebulae, you can see the color – for example, the NGC 6210 “Turtle” nebula, which is visible as a small bluish disk.
Double stars. Our Sun is a single star, but many stars in the Universe represent a double, triple or even quadruple system, often stars turn out to be of different mass, size and color. One of the most beautiful double stars is Albireo in the constellation Cygnus. To the naked eye, Albireo looks like a single star, but all you need to do is look through a telescope and you will see two bright dots of a different color — orange and bluish. By the way, all the stars in the telescope are visible as points due to the huge distance. Everything,
…except for the sun. Immediately I warn you – it is very dangerous to watch the sun without special means of protection! Only with a special aperture filter that should be securely mounted on the front of the telescope. No dubbing films, smoked glass and floppy disks! Take care of your eyes! If all precautions are taken – even in a tiny 50-60 mm telescope you can see sunspots – dark formations on the sun’s disk. These are the places from which the magnetic lines exit. Our Sun rotates with a period of about 25 days, therefore, watching the sunspots every day, you can see the rotation of the Sun.
Comets. From time to time, bright “tailed guests” are visible in the sky, sometimes accessible even to the naked eye. In the telescope or binoculars, they are also visible, as are galaxies with nebulae — small, colorless specks. In large bright comets, you can see the tail and greenish color.
If after reading this article you still have the desire to purchase a telescope – then I congratulate you, because there is one more important step ahead of you – the right choice of telescope, but this is already in the next article.
If you already own a telescope, I recommend reading the articl “I have a telescope. What’s next?”