Caoimhín's Content

Today, we are looking far ahead to the end of the month yet again, we are going to be looking at various objects with various tools from the city and from the countryside. If you are looking to acquire a telescope or a binoculars, especially if you’re looking to get it for someone else, it’s a good idea to figure out what kind of objects the person wants to look at or what kind of objects you want to look at, as well as the kind of conditions you’re going to be observing under. Then you can make an informed decision based on that information.

To start with, binoculars. Even quite a small binoculars is great for looking at something like the Pleiades or the Seven Sisters. Taking a look at that cluster with a reasonably small binoculars, we can still see a little bit of the fuzzy nebulosity, even from the city, and we can certainly see the dense cluster of stars that the Seven Sisters are. Going with or a binoculars that’s good without being too good, not something that would be way out of a normal price range, say a 7×50, is still plenty. A 7×50 is not a crazy big binoculars, but that kind of binoculars is great for taking a look at something like the Pleiades or the Seven Sisters. If we take a look at planets, we won’t see much at all. We’ll start with Venus because of course, Venus is nice and close, and it’s very bright. However, we’re not quite going to see the phases of Venus with just a binoculars. If we take a look at Saturn, we’re not quite going to see the rings, and it looks like Titan is invisible no matter what we do with Saturn either. It’s the same with Jupiter no moons visible. A binoculars isn’t really suitable for looking at planets, but for looking at larger things in the sky, that’s where binoculars can be really good because they usually have a reasonably big field of view.

From the city, I don’t have much confidence that any binoculars will give a particularly good view of the Andromeda Galaxy. Even though binoculars have sufficient magnification, light pollution can still obscure faint objects. Without too much light pollution the view isn’t too bad, it is very, very faint, so that’s going to make it difficult to make out, but it is still visible simply because the Andromeda Galaxy is so large. Not just that it’s a giant galaxy, which of course it is, but because it takes up so much room in the night sky. Due to a combination of its massive size and its proximity to the Earth, it is quite a wide object, even from here on Earth you can see it really has a spread to it.

Using something like a binoculars, something that has a big field of view, makes observing those kinds of big objects a little bit easier, even if they are quite far away. As long as the target object is still large, as long as they take up a big portion of the sky, binoculars can still be useful. If we take a look at the Sword of Orion through a binoculars, it’s going to be a similar thing. Nebulae like this, they span several stars, they’re quite large objects, so even from here on Earth, they still take up a reasonable portion of the sky and they’re the kind of objects that binoculars are great for observing. Even in the city, binoculars can be useful for looking at those kinds of larger objects. If we want to look at a galaxy that’s a little bit further away, we might need a different tool. The Whirlpool Galaxy is often my go to for a medium distance galaxy, simply because it is quite distant and it looks quite nice. It’s so much further away from us than the Andromeda Galaxy, it doesn’t take up as much room in the sky. Taking a closer look with binoculars, and they reveal nothing, which is exactly what I expected from a binoculars looking at a galaxy that’s so far away.

Telescopes don’t have to be incredibly big to be way, way better than a binoculars for looking at objects that take up less room. Coming back to sunset at this time of year, and Venus is visible just above the sunset. The phases of Venus are a lovely thing to catch if you have a large enough telescope. I will stick with just one ocular for all the telescopes. I don’t want the ocular to provide too much help, but you need an eyepiece on your telescope. Telescopes occasionally come with their eyepieces built in, but almost always with most more serious telescopes, you’ll be able to swap in and out the eyepieces, whether they’re a refractor or a reflector. Different oculars can make a big difference to field of view in particular, with some wider field of view oculars being helpful for observing galaxies and nebulae with a telescope. We’ll start with a pretty small telescope, just 60×700, which shows Venus as a bright sphere. Going up to something a little bit larger and the phases of Venus should become apparent. Too close to sunset it be too bright for the phases of Venus to be clear. Waiting until its darker should help. Adding a couple of Barlow lenses would help as well. Barlow lenses are extra lenses that you usually insert between the eyepiece and the body of the telescope to add extra magnification. Another possible addition is a reducer, which steps down the amount of light you’re seeing. That can be very useful for looking at the Moon, which is of course very bright, especially when it’s full if you’re observing it through a telescope. Once we’re up to a a 16 inch telescope, The phases of Venus should be clear. You do need a bigger telescope to see the phases of Venus, although Venus is close to us it’s not particularly big.

Coming back down to an 8 inch, this is usually fine for looking at the larger planets, and planets like Saturn and Jupiter are some of the most visually impressive. Even with such a comparatively small telescope, we’re certainly seeing moons and you at other times might be able to see a little bit of the rings shape around Saturn. Saturn’s ring is almost edge on to the Earth at the moment so it is a little bit harder to see than normal. Still, with an 8 inch aperture telescope, you can absolutely see the moons moving around Saturn and going up a little bit more, up to about a 16 inch again, we’re definitely starting to see rings. If you go out a few nights in a row, you’ll see the moons moving around and you’ll see the rings aren’t moving. At the moment, it almost looks like a Saturn is skewered on something, almost like an olive on a toothpick, because the ring looks so, so thin. That is just because of the tilt that Saturn has at the moment, so at other times of the year it may be easier. We don’t have many other times of the year left this year, but in other years in the future as Saturn’s tilt with respect the Earth continues to change, that’s going to change as well and we will start to see things a little bit differently.

Jupiter of course is a lot closer to us than Saturn again. Back down to an 8 inch telescope and not only are we seeing Jupiter’s moons very clearly, we’re seeing the stripes on Jupiter as well. We’re not quite seeing the Great Red Spot, so we’ll move up to a larger telescope, we’ll get back up to 16 inches aperture. This is just about enough that you should be able to see the Great Red Spot, if just barely.

16 inches aperture seems to be the largest simulated telescope Stellarium offers, after that it crosses into telephoto lenses. Telephoto lenses are the things that a photographic camera would use. A telephoto lens is very, very similar to a telescope, a bunch of lenses that go in front of a camera that allows you to magnify your view, so you can take photos of things that are very far away and make it look like you’re closer to them. Telephoto lenses normally get used for terrestrial photography rather than for astrophotography. If you’re doing astrophotography, it’s generally easier to attach your camera to a telescope rather than using a telephoto lens, but if you have a telephoto lens anyway, they can be used for astronomy.

Moving later in the night at this time of year gives us a chance to look at Mars. Even with a 16 inch aperture telescope, and we’re not really seeing much detail. We can see Mars’s moons, but they are tiny, they are very difficult to spot in reality. Going down to an 8 inch aperture telescope, and maybe, you might just about be able to see the moons at the edge of Mars, but again, they are very, very small. They are both comparable in size to asteroids or meteors, more so comparable to asteroids than meteors. If one of Mars’s moons crashed into the Earth, that would be pretty bad.

All of that would be visible from the city, it is always a good idea to go out to the countryside if you are looking for fainter galaxies, especially more distant objects like the Whirlpool galaxy. Unless you have an incredibly big telescope, stargazing from the city isn’t really an option for fainter objects like this it is much, much better to get out to the countryside, whether you’re using a telescope or a binoculars, and whether you’re using it for photography or not. Even with an 8 inch aperture telescope, something that struggles to see the phases of Venus, we’re clearly seeing the Whirlpool galaxy and we can see the whole thing. If we go up to a larger telescope, we will get a better view of the center, but the edges will get cut off. This can be a little bit of a counterintuitive thing, but especially for photography, if you want to get a picture of the whole galaxy, lower magnifications with a wider field of view are good because you get to see the whole thing. Even if you’re maybe losing some detail in the center, if you were using a much larger telescope, you’d have to take several images and knit them together, which is a bit of a painstaking process, you usually need software to do that kind of thing.

Going back to the Andromeda Galaxy and at the Pleiades with a big telescope as well, just to help show how inappropriate they are. With a larger telescope, you may only see one of the Seven Sisters at a time, which barely looks like the Pleiades, it just looks like a star surrounded by some nebulosity. Even if we get rid of the Barlow lenses, our field of view doesn’t really increase enough to see it properly. Going down to a smaller telescope will let us see something that looks more recognizably like the Pleiades. If we go down to something like a C5 or even less, then we’re getting to see the whole cluster.

Taking a look at Andromeda, a slightly smaller telescope won’t be as egregious. A small telescope is just fine, even better than just fine, a small telescope can be quite good. It should lets you see the whole galaxy, but it’s right on the edge. Once we start going bigger than that, we’ll get a fantastic view of the center of the Andromeda Galaxy, but we’re cutting off loads of the edges because we’re using a telescope that’s too big. It might seem strange that a telescope can be too big, but I hope that this serves to illuminate the point. With a 16 inch telescope, you can get amazing detail of the fuzzy rings in the center of the galaxy, but we’re losing so much of what we would otherwise see with the arms. If we were to add Barlow lenses, we’d be cutting off those edges even more.

I hope you enjoyed this quick look through some telescopes and binoculars and the kind of objects that they are appropriate for at different sizes and the reasons why. If you did enjoy this piece, make sure to like it, and if you’d like to see more from me then make sure to subscribe to this website and my YouTube channel. Thank you for reading and hopefully I’ll see you back here next time.