Wei Shen Oh: Introduction to Amateur Astronomy (Tools of the Trade)

Hi, everyone I’m Wei Shen, and today, I’m going to share a few about amateur astronomy But before I begin my talk proper, I just want to share a little bit about myself first So I grew up in Singapore, and I got started in astronomy after attending a stargazing session at a Singapore Science Centre at the age of eight Observing the planets through a telescope that night literally opened my eyes to the beauty of the night sky, and I’ve never looked back ever since Currently, I’m pursuing a PhD in astrophysics at the Australian National University So this is how my talk is going to go today I’m going to introduce you to amateur astronomy, and how you can get started on this amazing hobby, including choosing your first telescope and preparing for your first stargazing session This talk will be about 15 to 20 minutes long And as I’m talking, feel free to leave questions down below in the comments, as I’ll be answering them at the end So what is amateur astronomy? Amateur astronomy is a hobby where people enjoy observing objects in the night sky, including planets, stars, and nebulae Why did they do so? It’s because they appreciate the beauty of the night sky, and they want to spread this passion of astronomy to other people I could give you many reasons why you should become an amateur astronomer, but, I guess, the best way to convince you is for you to see these amazing objects for yourself Sometimes the main motivation for amateur astronomy is to take pictures of the night sky, as seen in these pictures below This is called astrophotography Frankly speaking, there is nothing amateurish about astrophotography as it can be quite complicated to capture these beautiful images of space But that is not what I’m going to talk about today Rather, I’m going to talk about the main aspect of amateur astronomy, which is stargazing People all around the world gather to look up at the night sky together, whether it’s through the telescopes or just with the naked eye This can happen in a small group or in a large group through events such as star parties This creates a sense of community between the amateur astronomers, all united by the love of the skies As you can see in this picture over here, it shows the Milky Way comprising of millions of stars in our galaxy This is a prominent feature that amateur astronomers love to observe when stargazing While average astronomy is essentially about stargazing, doing it isn’t as simple as going out to see the stars Some form of preparation is definitely needed I like to think of it as going out for camping You can’t just go out in your t-shirt and a small water bottle You can try, of course, but it will not be a pleasant experience So planning a stargazing trip essentially boils down to these three mini-specs– location, time and weather, and essential equipment Let’s look at the first one– location So it goes without saying that an ideal stargazing site should be dark enough to see the stars You should aim to be far enough from the city such that the street lights do not outshine the stars in the sky This is commonly known as light pollution Thus, you do not want to be at a site that is similar to the picture on the right, which shows a significantly light polluted area To understand this better, let’s use Canberra, as an example If you’re living here, you’re pretty fortunate that the nearest dark skies are not too far away, some even accessible within 15 minutes– by car, of course The areas circled in red show places with a larger density of residents, which means that there will be more light pollution in those areas Of course, it doesn’t mean that you wouldn’t be able to see any stars in at those locations, but it just wouldn’t be as dark as a more secluded location where the Milky Way will be much more visible Some examples of good stargazing spots, as shown in arrows, include the east and west sides of Canberra One of them is at the Mount Stromlo Observatory, which is why we strongly encourage you guys to join us for our public astronomy nights when this COVID-19 situation is over, of course If you’re feeling a little more adventurous, you might want to try going further out to Lake George or [INAUDIBLE],, which offer even better skies than the ones mentioned earlier

For example, this is a photo of the Milky Way taken at Lake George As you can see, there isn’t much light pollution to interfere with the starlight That is why it’s an excellent stargazing spot Again, just a reminder, if you have any questions, do leave them below in the comments Another thing you should consider when planning your stargazing trip is the time and weather Make sure you have mostly clear skies before you go out Looking at today’s weather forecast, unfortunately, it doesn’t look very promising because it’s mostly cloudy It is also important to check the sunrise and sunset timings before you go out This is because we live in a seasonal country, and the timings will vary considerably In winter, since sunrise is earlier and sunset is later, you will get a longer duration of dark skies And the opposite is true in summer Additionally, you should also pay attention to the moon rise and moon set timings Most beginner astronomers tend to forget this, but the moon really plays a big role in terms of the quality of the dark sky that you get Even if you are in the most secluded spot possible, if the moon is up, it will ruin your stargazing experience because it blocks out most of the stars in the sky, including the Milky Way That is the reason why it is not advisable to stargaze when the moon is up, unless the moon is what you want to observe Moving on to the essential equipment for your stargazing trip You should make sure that you dress warmly and comfortably as it will get cool, especially during winter Also as you will most likely be in the open, bring a camping chair or even better, a waterproof ground mat so that you can lie on your back and have a perfect view of the stars It is also advisable to bring a red torch You might wonder, why red? It is because when you stargaze your eyes need around 30 minutes to be adapted to the dark so that you can see as many stars as possible When you use white or other individual colors of light, it will ruin your dark adaptation Red is the only color that will have the least effect on your eyes If you don’t have a built-in red torch, that is fine because you can simply put a piece of red cellophane over a white torch and that will work, as well Next up for essential equipment are tools that will allow you to navigate around the night sky On a clear dark night, it is easy to be overwhelmed by the number of stars that you see until you are sure of what you are looking at Fortunately, you can either use a planisphere, which is a physical star chart that you can bring around, or stargazing apps on your phone, which are more commonly used today All you need to do is to key your location and time into your phone after you’ve downloaded the app, and you can start using it to identify objects that you’re looking at These are the two popular stargazing apps being used And the good thing about them is that they are free For Android users, Sky Map, also previously known as Google Sky Map, is a great tool to use for stargazing And for Apple users, you can download SkyView Lite Even though it’s just the basic version, it’s good enough for you to learn about objects in the night sky And for the final and most important piece of equipment that you need for stargazing– which some of you have been waiting for– yes, I am referring to hot chocolate and cookies Just kidding, I’m actually referring to a telescope So what does a telescope do? And why is it important for stargazing? Well, a telescope is an optical instrument that makes objects look bigger Which is great for stargazing because most of the things that we want to observe in the night sky are distant and tiny So this allows us to see them in greater detail, such as the moon below Also, an important safety reminder for you guys is to never use a normal telescope to look at the sun, as it might cause you to go blind If you want to look at a sun there are special solar telescopes for this purpose Now, getting your first telescope can be an exciting, yet daunting time, regardless of your age And it’s understandable because most telescopes cost a few dollars, and the last thing you want to do is to invest in something that you only use once, be disappointed, and then store it away forever So what I’m going to do is to give you some important guidelines that you can consider when you are about to get your first telescope I’m also going to give some recommendations, but these are definitely not exhaustive as there are many good telescopes out there Now, here are some guidelines when it comes to choosing your first telescope Try to get telescopes on reasonable size and quality so that you get the most out of your stargazing experience

When you get a cheap telescope, the danger is that the quality won’t be great Sure, you might be able to observe the moon and some planets, but a plastic built, cheap lens, and unstable tripod will most likely not allow you to observe anything else Also, don’t get a telescope that claims to have an extremely high magnification, such as above 200 times Why is that so? When you increase the magnification to an extreme amount, it’s harder to focus And the amount of light reaching your eyes decreases sharply and all you get is just a sad blurry blob So this as over here is an example of a telescope that you should never, ever get It is also recommended that you don’t get a computerized telescope as your first one For those who are unfamiliar with this term, a computerized telescope is one that is able to find and track objects for you with just a push of a button If it’s such a cool and convenient piece of equipment, why am I telling you not to buy it? Firstly, it’s much more expensive than the metal ones, at least twice the costs But more importantly, it defeats the purpose of familiarizing yourself with the night sky From personal experience, the satisfaction of finding the objects yourself using a metal telescope is much greater, even though it may be challenging at the start And you can even point out the objects that are observing to others In my opinion, the only reasons that you should get a computerized telescope is when you’re organizing stargazing parties or when you need it for astrophotography Therefore, you should get telescopes from well-known brands such as Celestron, Meade, and Orion And, of course, there are many more And you should know when and where you want to use your telescope, as it will really affect the kind of telescopes that you should get So if you are stargazing from your backyard and since it’s relatively dark there and you don’t see a point of traveling for your stargazing trips, you should get a Dobsonian telescope A Dobsonian telescope is a reflector that uses mirrors to magnify the image The pros are it is relatively cheap, it’s easy to use, and it has a bigger aperture, which means it captures more light and has a brighter image However, the cons are it is bulky and heavy, not portable-friendly, and the mirrors can be sometimes misaligned Now, if you’re traveling often to stargaze and portability is an issue, you should consider getting a refractor telescope which uses lens to magnify the image The pros are it is relatively cheap It’s easy to use just like the Dobsonian telescope But it’s also easy to maintain because there are no misalignment issues with the mirrors And it’s also very possible However, the cons are it has a relatively low aperture size, which means you get a slightly dimmer image So if you’re not ready for a telescope yet, there’s still an option for you You can consider getting a pair of binoculars The good thing about binoculars is that it’s much cheaper and portable than a telescope You do it slowly, which means that you can easily hold it in your hands Because of its lower magnification, you can also simply use it to scan across the sky to look for interesting objects Even till today, I sometimes bring a pair of binoculars out for stargazing instead of the telescope due to its convenience Before I move on, another reminder to leave questions below so that I can answer them at the end during the Q&A session Just some tips when it comes to buying a pair of binoculars You might find that by binoculars are usually described by two numbers The first number represents magnification, while the second number represents the diameter of the lens in millimeters The 10 by 50 configuration is highly recommended if you want to have a good balance between magnification and brightness To end off, here are some final tips on becoming an amateur astronomer As I’ve mentioned before, amateur astronomy is about sharing this passion and hobby with the rest of the community That is the reason why you should join a local astronomy club when you can The two clubs I know in Canberra are the ENU Astronomy Club, as well as the Canberra Astronomical Society By joining these clubs, you actually get a chance to interact with experienced amateur

astronomers, as well as learn a thing or two from them Another thing would be to keep reading and stargazing What I’ve covered today is just the tip of the iceberg and there are still lot of things to learn in astronomy Fortunately, we live in an age where there is plenty of information on the internet, as well as in books With patience and some determination, this hobby can grow into a wonderful journey of a lifetime With that, I thank you all for listening to my talk Any questions? So we will wait and see if there are any questions, otherwise we will wrap this talk up If there are no questions yet, I just want to just point out something I think I didn’t emphasize this enough, but when it comes to choosing a telescope, the brightness of the image is actually more important than the magnification, as I mentioned So the brightness is, like, you should get– the minimum size of the telescope should be around 3 inches, which is about 75 millimeters– wait, is that correct? Yeah, it’s about 3 inches So the diameter of the lens or the diameter of the aperture should be at least 3 meters in openings OK, we have one question More info– so when it comes to telescopes, there are actually, I would say, three different types of telescopes I’ve mentioned the reflector, which uses mirrors There’s also a refractor, which uses lenses And there’s also the last type, which I didn’t mention in the talk just now, it’s called catadioptrics So catadioptrics is a very special optical instrument which uses lenses, as well as mirrors to magnify the image So Orion is actually– I’ve mentioned– is a pretty good brand in terms of a telescope There’s also Celestron, Meade, there’s Sky-Watcher When it comes to choosing a telescope, of course, you shouldn’t just go for the brand You must do even more research, like, you should check if it’s portable, if the size is good enough for you, if it’s not too expensive All these other factors that you should consider, as well Someone asked about phone apps and any recommendations Let me just go back to the slide So as mentioned, these two are more popular apps that I use for stargazing You have Sky Map for Android users, as well as a SkyView Lite for Apple users So I’m pretty sure there are more apps out there on the app store, but these two are just the ones that I know that are the most popular So what about a telescope where a camera can be attached? Yes– so actually, when it comes to astrophotography, I know I didn’t really talk about this much When you want to do astrophotography, you need an adapter This is called a T-ring adapter So it’s something that you put in front of the eyepiece or you remove the eyepiece You replace it with the T-ring adapter, and you can actually install a DSLR or even a CCD camera on top of it, and that allows you to capture images of the things in space But I would just like to point out that I’m actually not a very experienced astrophotographer Actually, I’ve never done much The only times I’ve done some astrophotography is when I’ve borrowed some cameras from my friends And I don’t really have much experience in that So I actually mentioned about phone apps, just like this one, but there’s actually another one which is pretty popular if you are using a computer One of the apps that I or one of the software that I use when I’m using my laptop is actually Stellarium Stellarium is actually a software that is a planetarium software that allows you to see the stars at a particular location and a time So the good thing, again, it’s free

You can simply just go onto Google and just type Stellarium and you should be able to download the software into your computer It’s really easy to use And yeah, I had a lot of fun playing with it What is the best way to find amateur astronomy clubs in Sydney? Unfortunately, I’m not very familiar with that because I’m from Canberra So I don’t think I can answer that question But I’m pretty sure there are many astronomy clubs in Sydney Some of them would be part of the schools Some of them will be part of, like, community clubs and things like that So you might just have to go online and try to find them OK, can Dobsonian telescope mirrors misalignment be fixed without taking it to the shop? Yes, it can So Dobsonian telescopes are actually a type of reflector telescopes– as mentioned And the thing about Dobsonians or reflectors is that they can be misaligned due to the mirrors And the process that you need to do to actually correct this misalignment is actually called collimnation So collimnation, it sounds a bit complicated, but once you actually follow the steps, it can be quite easy So what you do is that you use a laser and you try to align the laser as it reflects off the mirrors, and try to make sure that it stays at a certain point So by using the laser as a guideline, you can actually turn some screws to adjust the mirrors so that the two mirrors become aligned And that is one way that you can fix misaligned Dobsonian without taking it to the shop OK, can you use a power device to run a computerized telescope, instead of using a battery? Yes Yes, you can So I can’t remember the device on the top of my head, but it’s actually, a power bank So it’s, like, you know how we have power banks for your phone that you can bring out to use? But there’s also something like a huge power bank for your computerized telescope I hope that I’m answering this question properly So basically, what it does is that it has a much bigger capacity than just using like a small AA batteries and things like that You can actually use it to basically, last for your entire night of stargazing without actually having to change the batteries Will it be a good– OK, sorry, next question Will it be a good idea to start with a binocular first before spending money on telescope? Yeah, definitely Especially if you think that you are still maybe too young or maybe inexperienced to use a telescope It’s definitely advisable to use a pair of binoculars first Because, I think, the good thing about binoculars is that you don’t actually need much There isn’t really, like, anything to learn You just have to pick it up, look through the eyepiece, and maybe just learn how to focus there the binoculars And there you go, you can actually use it for your stargazing trip So it’s really, really easy to use Definitely, it’s nothing like using a telescope And the good thing is that you can even get a good pair of binoculars for, maybe, about like $50 $50 to $100 you can get a really decent pair of binoculars OK, so if they are no more questions, we will wrap up Just wait for maybe a few more OK, one more question How do you properly maintain a telescope? Yeah, good question So I think for the telescope, if it’s possible– I would say only if it’s possible– the best is actually to keep it in a location with low humidity So the reason for this is because that when you store, let’s say, like a camera or even something with lenses in high humidity, the risk is that you might actually develop mold or things on the surface of the lens, which can be really hard to clean So it’s very important that you keep these telescopes in a low humidity place And also, try to every once in a while give it a good wipe So that dust and things like don’t accumulate And the same goes to the eyepieces– the eyepieces which you use to observe which you attach on to the telescope Remember to keep them properly, as well

OK, another question, what’s a good brand of binoculars? A good brand of binoculars would also be the ones that I mentioned for telescopes, such as Celestron, Meade, and Orion And Sky-Watcher, as well What are the best focal length eyepieces for a basic telescope? OK, good question So this one, I’m going to go a bit technical here The focal length of the eyepiece basically determines the field of view, as well as the magnification So if, let’s say, you have a smaller focal length, you will get a larger magnification If you have a larger focal length, you will get a smaller– sorry If you have a larger focal length, you– OK, I think I’m confused So basically, the focal length affects that magnification And if you increase the focal length, you get a larger field of view And if you decrease the focal length, you get a smaller field of view, but a larger magnification So it really depends on what you want to see Let’s say if you know that the object that you’re observing is very small, you probably need a smaller focal length so as to increase the magnification to view the object But if you’re looking at something as big as, let’s say, a star cluster or Andromeda Galaxy– a big object– then it’s advisable to use a larger focal length, which means you get a lower magnification and a larger field of view So the next question is every time I use binoculars, I can’t get them to focus and I have to close one eye to see through them, and then everything is always blurry And any tips for that? Yeah So when you’re using a pair of binoculars, there’s always some calibration that you have to do before you can use it properly One of the things that– that is actually one of the ways to actually calibrate your pair of binoculars before you actually use it Because you know that you need both sides to be at the right focus If one side is not focused and one side is focused, you’ll definitely get an unpleasant viewing experience because you can’t get both to view at the same object properly So there is actually one way So what you do is that you cover one side of the lens There should be one side which allows you to focus the one side of the binoculars individually And that allows you to make sure that both sides of the binoculars are focused correctly OK, can we see Cygnus from Canberra during the winter? Winter, you mean like June, July, right? So I’m actually not very sure, to be honest with you You probably have to check with the Stellarium app for this But I’m pretty sure– I do think you will get a very good view Yeah, you might have to check the Stellarium app So the next question, is a power bank better than a single battery? How does a power bank work? Yes So the thing about a power bank is– as mentioned earlier– it’s like using it for your phone You can actually have– it basically stores much more– has a bigger capacity than as compared to just using individual batteries So with a power bank, what you do is that there’s a wire which you can connect to the telescope And yeah, it basically allows you to use the telescope for, like, at least more than five, six hours But whereas, if you just use a set of batteries, you can only use it for about maybe 30 minutes and most one hour Yeah, it’s quite easy to use OK, what are some interesting objects we can look forward to see in the winter? Seems like this is a question which is pretty common So I don’t really have like interesting objects in particular in winter, but I do know at this location in Canberra, or even in Australia, at this time, the things that we can observe well would be at Southern Cross, as well as the Milky Way– Milky Way And also, probably, maybe Sagittarius? Yeah, you can observe Sagittarius But I would say that if you want to observe Sagittarius, you’ll probably have to wait for a little while more–

not at this time because you’re asking for winter So yeah, Sagittarius is slowly starting to rise, maybe about like 8:00 or 9:00 PM But if you wait until winter, it should be up, like, really early So another question would be, what’s a good time to see Saturn? Unfortunately, I do not know this answer You probably have to check the app, again So the good thing about the app– just to reiterate– it’s a very intuitive app All you need to do is just input your location and time, and it will tell you what other objects you can see at a particular time in the sky So yeah, just play around a bit It will definitely be a very fun experience to see what other things you can observe Saturn– Saturn, OK Someone said– oh, Saturn looks better from the end of June So yeah, go for it If you need some tips on looking at Saturn, I think, definitely you need to have a telescope because you wouldn’t be able to see the rings and the features using just a pair of binoculars or with your naked eye You definitely need a telescope to see the rings of Saturn What are some factors that could affect a good stargazing session? So I mentioned earlier in the previous– in the slides, so this, I would say, this would be the main factor when it comes to your stargazing session– the time and weather I would say that in terms of whether the moon is up, the weather and also whether there are nearby street lights that is interfering with the stars in the sky So I think this is something that you have to do your own planning and preparation before you go out to that site for stargazing OK, if not, we will wrap up Thank you so much for listening to the talk today Hopefully, there’ll be more in the future And stay tuned for more on astro talks in the Mount Stromlo Facebook page All right, bye-by