This deserves its own post because I nearly forgot but it’s kinda important:
If you end up buying a reflector telescope from a garage sale, DO NOT CLEAN THE MIRRORS. Unless you can’t see your reflection in them at all, just don’t touch them. You’ll be shocked at how little the dust actually impacts your view, but these mirrors are super crazy easy to permanently mess up. If you must clean them, DO NOT use a rag, DO NOT use compressed air! Use a gentle stream of distilled water to rinse it clean. The big danger here is that you could end up dragging sharp/hard debris across the mirror and cutting some serious gouges into it. This is also true of the eyepieces. Don’t use re-usable rags to clean them. I use lintless cotton eyeglass patches to clean my pieces after fogging them up with my breath (that’s cheap and readily accessible distilled water) once I’m satisfied that they’re free of any large debris. I wipe in one direction, flip it, wipe in another direction, and dispose of it. That’s it. The eyepieces being a little dirty will mess up your view, but a dirty mirror probably won’t. Only clean it if you’re 300% convinced that you must.
Also good advice: try using the telescope at least twice before you go to the event. The moon is probably the easiest, brightest target, and it’s a good place to start with making sure your focus is close to perfect. Once you’ve got the moon, move on to a few slightly more challenging but still easy targets that you should be able to see, even in an urban area, to make sure you understand how to use the scope and put it through some actual use. A pretty easy target would be the first star out from the cup on the handle of the big dipper. Tell me what you see when you find it in the scope. Jupiter is also a pretty easy, rewarding target. The sword of Orion is another bright, easy one. Lastly, Venus is a really easy target and has a little surprise for you when you find it. But two uses is enough to get familiar with your equipment, get familiar with its use, and identify any problems before you actually get out there.
Tl;Dr getting focus before you leave isn’t SUPER important. It can be kinda tricky to figure out for newcomers, and you’re better off using your time to assess the action and components of the scope.
Yeah, so, you’re going to want to spend some time on YouTube U learning about how to focus a telescope. It could be trickier with a dobsonian/newtonian because you may need to collimate it (though the smaller the telescope is, the less important that becomes) to see clearly, and someone at a garage sale may or may not be willing to do it for you / trust you to do it. Generally speaking, though, if all the moving parts move like you expect them to and don’t move like you don’t expect them to, the lens or mirrors aren’t obviously damaged or scratched, the eyepieces aren’t obviously damaged or scratched (eyepieces are MUCH more sensitive to any kind of damage than mirrors or lenses in terms of user experience), then you’ve got a winner. It’s hard to think of a situation where a telescope’s parts would be in working order and good condition but somehow be broken in a way that prevents it from achieving focus.
For assessing movement: with a dobsonian in particular, but really any mount, you’ll want it to be very easy (ALMOST but not quite frustratingly easy) to move the telescope so that you can track targets across the sky easily. The telescope, however, shouldn’t move on its own without some force acting on it (i.e. touch, wind, etc). If it’s moving under gravity, then either the balance is off (very possible with a dob, and usually easy to fix too), the friction is off (also an easy fix with a dob), or the mount could be bad if it uses some other kind of altitude-azimuth (left-right-up-down) mount that uses clamps and locking knobs and such. Also, make sure you try adjusting the focuser tube. They stick out and tend to get whacked, and if your focuser tube is busted, you’re SOL. Just check to see that it moves when it should and not when it shouldn’t, and that it goes all the way in and out without falling out; if it doesn’t, check for some little thumbscrews on the focuser. Sometimes, when those are tightened down, they’ll keep the focuser from moving, or let it move way too easy if they’re too loose. If those thumbscrews aren’t the problem, then the focuser is busted and you should give it a pass.
I also highly recommend checking the finder scope- that’s the little buddy telescope that’s attached to the telescope that’s there to do business. They stick out a bit and have a habit of getting damaged. It’s not a huge deal if it’s broken, they can be easily replaced, but you’re going to want to replace it before you head out or you’re going to have a bad time. Lots of people love Telrad finders, I’m an absolute nut for RACIs; beware the little straight-through scopes, though, as they’ll murder your neck when you have to look at something high up.
If you really want to try and look at something (not a bad idea, per se, just not the most effective use of your time. I’m assuming neither you nor the seller will immediately know how to achieve focus with the scope), try to pick something both big and very, very far off. If the moon’s up, try looking at that. If not, try to pick the furthest, biggest thing you can see (big makes it easy, but if it’s too close, you simply will not be able to get focus on it, period) and try to sight it in.
Do NOT buy a $200 telescope new. You’re going to overpay to get a piece of kit that’s okay at best and unpleasant to use at worst (possibly due to uncomfortable eyepieces, difficulty in actually using the scope with bad alt/az controls, bad ergonomics with the stand, etc).
If you want a cheap scope just to find out if you’ll like amateur astronomy: Go hit some garage sales or a resell app or Craigslist or something, but I particularly recommend garage sales. There’s plenty of these cheap ‘hobby killer’ telescopes that can be had for a fraction of their retail price this way, and the resell value is a little more reflective of what they’re actually worth.
Alternatively: drop about 1/4 of that on some good binoculars. You can absolutely stargaze with binoculars, I actually always bring some when I do public outreach. I’m very fond of 7x50s, because the low magnification (the 7) works really great on open clusters and makes them easier to steer, while also not being so heavy that they wear out your arms after ten minutes. The 50 describes the aperture size, which means that your binoculars will have plenty of light- gathering capacity. The bigger the apertures, the more light they’ll collect, but the heavier and harder to use they’ll be. Plus, their magnification won’t be too far beneath the maximum magnification of a generic retail telescope.
If you want a great starter scope: I’d suggest that you save your money, don’t burn your budget on a crappy retail refractor. I’d also suggest doing one of the two above things to decide if you even like astronomy enough to spend the money on a good scope. If you do like it, and you do want a good starter scope, it’s hard to go wrong with a 6" dobsonian. They’re relatively cheap for what they are, very portable and manageable, and there’s a LOT you can see with them, even in the city, but especially in dark skies. Also, you could probably find some good used ones in your area for a bargain; there’s lots of folks who splurge on telescopes and fall out of love with them, and then just have it sitting in the corner of the garage for years and years. Like I said, garage sales are really great for this.
Btw, don’t get aperture fever and splurge on a double-digit aperture. I did that, but I specifically did it for outreach purposes; if I was getting it strictly for my own use, I’d have a $1500 oversized dust collector because it can be a real PITA to move outside.
Got moved to tonight at my spouse’s request, didn’t get out until 2100.
Seeing was good, not the clearest I’ve seen, but not bad. The stars seemed overall dimmer than usual, but not shimmering or twinkling. Light pollution was definitely slapping though
What I managed (using 12" f5 dob, 30mm wide field eyepiece in 2x Barlow):
M65 and M66. Took me two or three tries to starhop to them. I did not manage to visualize NGC 3628, but m65 and M66 appeared as vague foggy shadows, oval in shape, both tilted to point upper left and lower right, the right above the left. Very difficult to visualize directly, almost had to visualize exclusively via averted gaze.
Bode’s Galaxy: this involved more dumb luck than I’d like to admit. I tried to starhop here by using the bear’s neck stars to form a pointer to a dimmer bunching of stars that would point to the galaxy. I tried probably four different times until I got on the same group of stars and slewed a bit right and maybe a degree down. Bode’s Galaxy has a more circular appearance than 65 and 66, the core is brighter, and it’s beefy enough to tolerate direct gaze. Still a faint fuzzy, but it left me in less doubt about whether I was just imagining it.
What I missed:
Jupiter, Rosette Nebula, everything in Canis Major, Orion, Gemini, and Monoceros: just didn’t get out in time and my views got blocked =(
NGC 2419: The moon stole the show here, unfortunately. It wasn’t directly blocking my view, but it was bright enough to wash out my view in this area
M97 and M108: Tried maybe six different times and got nowhere fast. Not sure why, but trying to star hop here just showed me a bunch of fairly unremarkable stars and that’s all. Maybe I needed higher magnification?
The Pleiades and Hyades should still be fairly high in the sky, and make great targets for binoculars. I’m also VERY partial to the little beehive cluster in Canis Major (go to the first barely visible star down from sirius, along the dog’s spine, and move directly right from there). If they’re strong enough, the Orion Nebula also makes a great target. The regular beehive cluster is alright; it can be tricky in the city, but you should juuuust be able to see what kinda looks like a faint, blurry star just left of the angle of you make a right angle between Pollux and Procyon. There’s also a few binary stars that make good targets right now. You should be able to split the first bright star out from the cup in the handle of the big dipper into three stars.
I just finished STALKER 2. It’s a fucking mess and was unplayably broken for half a month at one point for me, and I fucking love it. It took me 80 hours of mostly focusing on advancing the story to reach the end, and I feel like I only saw maybe 30% of what’s out there. I can already tell that this is going to be my new Skyrim, tooling around with 500 hours in the game and still finding new situations. I’m SO FUCKING PUMPED for anomaly 2-- a lot of the same modders that worked on anomaly are already putting out modpacks for Stalker 2.
Tbf, it’s kinda bullshit that we can’t double jump IRL. Double jumping just feels right, like it’s something we should be able to do.
Yeah, no, it’d likely be really awful for us. I mean, can you imagine what porn would be like on that? That’s a fermi paradox solution right there. I could see the tech having a lot of really great applications, too, like training simulations for example, but the video game use case is simultaneously exhilarating and terrifying.
Idk, I’d say that pursuing realism is worthy, but you get diminishing returns pretty quick when all the advances are strictly in one (or I guess two, with audio) sense. Graphical improvements massively improved the experience of the game moving from NES or Gameboy to SNES and again to PS1 and N64. I’d say that the most impressive leap, imo, was PS1/N64 to PS2/XBox/GameCube. After that, I’d say we got 3/4 of the return from improvements to the PS3 generation, 1/2 the improvement to PS4 gen, 1/5 the improvement to PS5, and 1/8 the improvement when we move on to PS5 Pro. I’d guess if you plotted out the value add, with the perceived value on the Y and the time series or compute ability or texture density or whatever on the x, it’d probably look a bit like a square root curve.
I do think that there’s an (understandably, don’t get me wrong) untapped frontier in gaming realism in that games don’t really engage your sense of touch or any of the subsets thereof. The first step in this direction is probably vibrating controllers, and I find that it definitely does make the game feel more immersive. Likewise, few games engage your proprioception (that is, your knowledge of your body position in space), though there’ve been attempts to engage it via the Switch, Wii, and VR. There’s, of course, enormous technical barriers, but I think there’s very clearly a good reason why a brain interface is sort of thought of as the holy grail of gaming.
Awesome, thanks! Don’t hold your breath, though. Right now, this thing is paying for itself, and it’s not much. My first goal is to get a used DSLR so I can take promotional pictures. I know it’s a manually slewed scope, but I’m not trying to take crazy multi-hour exposures, I’m trying to show what people might expect to see IRL, and take promotional shots of people on the class. Then, I’ll probably look at making the radio telescope rig more seriously, hopefully before summer.
This is great advice, I’m very grateful that you responded! I did start out pointing out the constellations and the different features we would look at, but after reading this, I realize now that I got people looking into the scope way too early, and there was basically nowhere left for me to go after that. This also makes me think about doing a separate thing just for helping people get astronomical league certs, then.
Thanks, that all makes sense! I noticed in hindsight that people were a little less jazzed about Trapezium than I was expecting. I mean, they appreciated it, but compared to my own initial reaction in seeing it (I had to go and tell someone right away), it was pretty muted. Sounds like I’ll have to do some homework.
That last line really grabbed my attention.
And treat the telescope like it’s the least important thing of the night until someone asks about it.
Can you elaborate a bit on what you mean here?
Also, I should probably make clear that this is going to be a weekly recurring class that happens at different city parks. I’m trying to get people interested in actually doing amateur astronomy.
It doesn’t take too long to adjust unless somebody really headbutts the scope, which happens. Typically it’s just slewing targets back into frame because of the Earth’s rotation, which at 110x and a good RACI, is pretty easy. I think it takes maybe 15-20s every third guest to make sure they’ve got a good view (takes a bit longer sometimes if they’ve pushed the focuser in). I’m definitely thinking that a GOTO/PUSH TO modification kit might be in my future, but I’m trying not to spend more money at the moment.
Nope. No. Nuh-uh. Stop fucking up this planet, then we can talk. I’m drawing a line in the sand, I’m going to become an eco-terrorist if I see a fucking Coca-Cola ad when I look into the night sky.