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What is this device you call a 'telescope'


impwarhamer

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A few months back I received an old cheap telescope from a friend who was clearing out his stuff and didn't have the space for it. Having always wanted one, i gladly took it and a few weeks later I tried it out in my back garden. The stand was terribly unstable, half the lens-things that came with it where just black and i could barely make out anything, but I spent an enjoyable 3 hours sitting outside looking at stars and such.

Anyway, as a COMPLETE amateur who doesn't really know the slightest thing about a telescope, I was wondering if you guys could spread some light on the subject. Anything to do with how they work, how much you can expect to pay, how much light pollution plays a role in what you can see, etc. would be much appreciated. :D

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The common wisdom seems to be that a good pair of binoculars is the best way to get your feet wet with astronomy. Low end telescopes are truly horrible, and many things in the sky are invisible not because they are small but because they are dim (trivia: Andromeda, if visible to the naked eye, would be larger than the moon). Aim for binoculars or a telescope with large lenses but relatively low magnification, it is the size of the light trap that will determine what you can see.

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Proud owner of a relatively large expensive telescope here. I mainly use it for astrophotography, but I think I can still help you out. Light pollution is an incredibly large factor when it comes to observing things, especially deep sky objects like star clusters and nebulae. Even though I still manage observing from my suburban part of town, try and get out into a rural area if you can. You might not like this next part, but the costs add up pretty quickly for a nice scope. I would recommend a computerized GoTo telescope if you're willing to upgrade. After a simple alignment procedure that involves you pointing the telescope at a few random stars, the telescope will automatically target anything you chose from it's database. Celestron makes a great series of introductory GoTo scopes called the NexStar SE series. (http://www.celestron.com/browse-shop/astronomy/telescopes/series/nexstar-se-computerized-telescopes) I started out on the six inch model, which costs around $900 if you get some of the optional accessories. Due to their advanced mounts, you won't get that large of a telescope for your money. If you think you can handle tracking manually, go for a Dobsonian telescope. An eight inch GoTo will cost you $1,200, but an eight inch Dobsonian telescope might cost you half of that. No matter what you buy, if you ever decide to invest in a new telescope, you certainly won't regret it. I got my old six inch telescope about a year ago, and I've been hooked ever since. I even bought a larger telescope just recently. On an related note, check out some of the free night sky apps if you have a smart phone. Saturn and Mars are both visible after sunset, and should be easy to find with the aid of an app that shows you what you're looking at. Let me know if you have any more questions, i'll be more than happy to answer them.

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(trivia: Andromeda, if visible to the naked eye, would be larger than the moon).

Good advice.

Andromeda is actually visible to the naked eye from a dark location- which makes it the largest gravitationally bound object, that can be seen by the unaided human eye.

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Depending on the age, the black one MAY have been intended for the sun. I wouldn't recommend it though. Dark glass was typically used for sun viewing in decades past. It would darken the sun enough for you to look at it without squinting, but it wouldn't filter out the UV rays. Before 'solar viewing film' was a thing (that stuff you typically see on cheap paper sunglasses that get sold when an eclipse is going to happen), kids were known to smoke their own glass as a DIY for viewing eclipses. If it really is just a super dark lens, don't use it. Get a solar viewing film attachment and put it on the end of the telescope (and remember to get one for your viewfinder too so you can line it up without going blind).

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As for how telescopes function, a good first step is (as always) Wikipedia:

http://en.wikipedia.org/wiki/Telescope <--- general history and etymology

http://en.wikipedia.org/wiki/Refracting_telescope <--- you probably have this type

http://en.wikipedia.org/wiki/Reflecting_telescope <--- the other kind of optical telescope

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Well, there are a few important differences in telescopes ...

the most important is the diameter ... the thicker the tube, the more light it can collect (and, if you can collect more light you can not only see faint objevts better, but also use a higher magnification (i.e. thicker ocular lenses) before objects get too dim.

Also it is of interest, whether you have an reclector telescope (i.e. with a miror on the backside) or a refractor (i.e. with lenses at the beginning and the end ... like standard spy glasses)

Another important distinction is the telescope mount ...

as your comments don´t indicate any measure of confusion or helplessness, I assume it is a standard azimutal mount (with other words, a fork between the telescope is mouned so that it can be swiveld sideways and up/down).

More pofessional telescopes rather use an equatorial mount ... for which you first have to take some tim to align the main axis to Polaris, but which then allows you to easily follow the movement of a star or planet just by turning on one of the adjustment screws for one of the axis every now and then)

to illustrate:

Alt-Azimuthal mount:

4560700_M.jpg

Equatorial mount:

koord08.jpg

So, maybe you can shed some light into what telscope you have :)

As for observing the sun ...

if you want to get absolutely sure that your eyes don´t get hurt, better use a white sheet of paper at the right distance between your ocular, so that the image of the sun gets orojected upon the paper (you may have to vary the distance till you find the one that gets you a clear image of the sun) ... this also allows you to draw the sun and its sunspots on the paper

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Good advice.

Andromeda is actually visible to the naked eye from a dark location

True, but the most i have ever seen of it was probably just the bright part of the core of the galaxy, nowhere near "6 times as large as the Moon". Should it even be possible to see the entire Andromeda galaxy wit the unaided eye?

19bal4d1p8fncjpg.jpg

http://sploid.gizmodo.com/the-incredibly-huge-size-of-andromeda-1493036499

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I have seen the whole thing once, in the middle of winter on a trip to the catskills (mountains in new york). However, it was extremely dim, and only appeared as a glowing smudge in the sky.

It was amazing.

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The stand was terribly unstable
This obvious wants fixing. The magnification of a telescope magnifies every wobble too, and an unstable mount is frustrating. Here's one of many sources with suggestions for improving cheap scopes: http://www.jotabout.com/portuesi/astro/ds_scope.html
half the lens-things that came with it where just black and i could barely make out anything
Black to look at or black to look through? If you have something that's a piece of black glass in a holder with a screw thread, bin it. As described here: http://astunit.com/tonkinsastro/sun/esf.htm they're an obsolete and highly dangerous type of solar filter.

If you're seeing nothing when looking through an eyepiece, it's probably just a combination of the high magnification meaning there's nothing bright in view, and being out of focus meaning faint stars aren't visible.

how much you can expect to pay
Anywhere from £50 up. Bear in mind a cheap small scope will be inherently limited and you need to choose wisely to get one that's enjoyable to use.
how much light pollution plays a role in what you can see
I observe from a city and have managed to cope. How much light-pollution affects things depends on the object. Objects with low surface brightness, which tends to mean those that appear larger, are more affected. Light pollution won't hurt the views of the Moon, planets, or double or variable stars much if at all. Star clusters, both open and globular, do pretty well. For nebulae light-pollution impairs the view more, but if you have a large enough scope you can use a nebula filter to help. Galaxies are the worst hit and it's really tough to see them in the city.
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I'm reading this thread (and the other on amateur astronomy) because I might break out for a telescope, something I've never used before. I'd consider spending up to 500$ on something, assuming it can do more than just view (track and attachments for smartphone/tablets etc). I don't see spending more than that on something that might end up in the closet.

What does this mean:

If you have something that's a piece of black glass in a holder with a screw thread, bin it.
Edited by xcorps
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See the sort of thing shown in the link I posted. They're meant as sun filters but they're really dangerous, since they're trying to absorb the sun's light and heat after the main lens/mirror has concentrated it, and that heat can easily crack the filter. As such they're best just disposed of to avoid being tempted to use them. Modern solar filters go on the front of the telescope, blocking 99.999% of the light before it even reaches the telescope's lenses or mirrors.

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I had a telescope that my father bought from Germany, it had a really large diameter and the place where you would look in was in the front. My brother broke two of its legs and I couldn't use it so I gradually lost all the lenses for it (I was young and naive). Now I am regretting the decision to not repair the telescope and just lose it somewhere :(

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Thanks for all your advice! I'd just like to clear up the confusion, the old telescope I mentioned is probably not worth much more than £20 and I don't expect to be using it, I just brought it up because I wanted an anecdote for my post.

From what you guys have said, it looks like if I am to get something it should be a pair of binoculars, since i can't really spend much into the 3 digits as I'm saving up for some computer components (plus there's the oculus on the horizon). How much do you think you could see with binoculars? (or a telescope below £100 if you think that's better)

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See the sort of thing shown in the link I posted. They're meant as sun filters but they're really dangerous, since they're trying to absorb the sun's light and heat after the main lens/mirror has concentrated it, and that heat can easily crack the filter. As such they're best just disposed of to avoid being tempted to use them. Modern solar filters go on the front of the telescope, blocking 99.999% of the light before it even reaches the telescope's lenses or mirrors.

Ah, bin it means throw it in the bin. The trash.

Thanks.

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...

From what you guys have said, it looks like if I am to get something it should be a pair of binoculars, since i can't really spend much into the 3 digits as I'm saving up for some computer components (plus there's the oculus on the horizon). How much do you think you could see with binoculars? (or a telescope below £100 if you think that's better)

As mylargest telsope I have a 70mm Refractor (that means a still rather small telescope) with equatorial mount and it is sufficient to make out (and draw) the major cloud bands of Jupiter and get a good view of Moons Features.

Inside a city that is, that means, inside an area with lots of light pollution (which makes a big difference as you can already see with the naked eye ... with light pollution you see only a fraction of the stars, whereas without it, the whole ....ing stunning band of the milky way lies before you)

2 Advices I can give you regarding your purchase (no matter whether you buy a telesope or a night glass):

1. (if not already included, as is usually the case with a Telescope) buy a good stable Tripod as well. It is rather awkward to observe the sky, if the hands holding the nightglass tremble from its weight :D

2. An alt-azimuthal mount will suffice for your first telescope (while I mentioned some advantages of the equatorial mount in my last posting, it takes some time and knowledge to setup)

As for what to get ... aside from nightglasses, a reflector (especially the simple newtonian ones) AFAIK still offer the largest diameter for your bucks. So maybe this is preferable over a Refractor, if you want to spent not too much money

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Due to an unfortunate turn of events funnily enough I have acquired a large amount of cash since I posted 2 days ago, so it looks like I can afford to spend a couple of hundred pounds on a telescope!

So, uh, I guess I'd like to ask about what sort of telescopes I can get for that sort of money

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£200 is a nice budget. A 6 inch Dobsonian such as the Skywatcher Skyliner 150 runs for about that. It's a capable scope but be prepared for a big box! If you want something a bit more portable there's the Skywatcher Heritage 130, very well regarded.

Binoculars still might be a better first buy though. Examples of things to see include Jupiter's moons, the Pleaides star cluster (spectacular and better in binos than most scopes), Uranus (just looks like a star but it's cool to see it), and the Andromeda Galaxy. And that's just what I found on my first two nights!

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If money didn´t matter, I for my part would buy a Celestron 8 Schmidt-Cassegrain (Reflector with 8" diameter, but in contrast to a Newtonian with the ocular on the back, like in a refractor)

http://www.celestron.com/browse-shop/astronomy/telescopes/advanced-vx-8-schmidt-cassegrain-telescope

Prices are hard to give, as Celectron has several combinations of C8 and mounts ... some of them with computer control, some of them in standard german mount ... the Tubus of the Telescope alone AFAIK is around 1000 € ... with mount it may amount to maybe 1600 € upwards, depending on the mount )

Edited by Godot
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Ok, so I googled 'Skywatcher Skyliner 150' and i found this: http://www.firstlightoptics.com/beginner-telescopes/skywatcher-skyliner-150p-dobsonian.html

On that website it was listed under 'beginner telescopes', so i thought I'd have a look at other ones they had to offer. (http://www.firstlightoptics.com/beginner-telescopes.html)

The problem is, I don't know really what the difference between the scopes are. I can sorta tell which ones have good mounts, but otherwise I'm clueless.

I'm gonna do some research now, but I thought I'd ask you guys what you think.

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If I see this correctly, most of them are Newtonian reflectors ... with the exception of the single refractor and the Celestron, which is a Maksutov Cassegrain (that measn it is a reflector, but has a closed Tubus with a lense and reflects the light to the back of the telescope)

I for my part would go with the Celectron Nexstar 5", due to its good combination of diameter and focal ratio and the fact that it has a computerized mount

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The Heritages and the Skyliner are all on Dobsonian mounts. Simple and stable, you just move them up and down, left and right. The Heritage 100 will need sitting on a table, the Skyliner 150 goes straight on the ground, the Heritage 130 can be either way depending on how you feel. None need tripods.

The explorer 150 is on an alt-az mount on a tripod. Pretty similar, might transport a bit more compactly than the Skyliner.

The NexStar is on a GoTo alt-az mount. Once you go through an alignment procedure you can then input what yiu want to look at on the controller and the scope will point to it. Sounds great, but drawbacks include the need for batteries, the scope sometimes getting off target, and losing the satisfaction of finding stuff yourself.

The Celestron Astromaster and the Evostar are on equatorial mounts. These have one axis aligned parallel with the Earth's axis, so by driving that axis in reverse the scope cancels out the Earth's motion to stay pointed at the same star or planet. They take more getting used to than the alt-az mounts, and with Newtonian reflectors like the Astromastrr 130 they can put the eyepiece at annoying angles, but once you get the hang of them they're good to use.

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Ok, I've done some research and i think I've some idea now on the differences between them, but I can't seem to find out the advantages/disadvantages of reflectors and refractors. I get how they work, but what is the difference between them?

Also, I'd just like to ask about the astromaster (this one: http://www.firstlightoptics.com/beginner-telescopes/celestron-astromaster-130eq-telescope.html), It looks good but it's quite cheap, is there anything obviously wrong with it?

Finally, just gonna thank you guys for being really helpful, I probably would have given up by now (or bought something stupid) had I tried to do this myself.

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