Buying a telescope

In My Humble Opinion
1

Hi all

I want to buy my wife a telescope so she can stargaze (and me too).

I know nothing about telescopes and what features are desirable. I see many options in lots of different budgets but i though i’d ask the clever folks on SD to see if can get some advice.

What features are ones that i should opt for? I’m not after any specific recommendations of telescope; just features that a home telescope ideally has. That said, I have no idea what the ‘good’ telescope brands are so any help will be, well, helpful…

I’ve seen different budget options from £50 to astronomical (pun intended). I’m not super-rich but i’m open to budgetary malleability.

Thanks in advance, guys and gals… :cool:

2

My advice is to contact a (hopefully) local astronomy club. While the advice is bound to be opinionated, it will get you pretty far in the right direction.

Just to add, I got a free telescope which I played around with. After talking to them I found out that they would not recommend that one if bought at retail. To them, while they did use high quality optics, the optics are really mismatched and do not let enough light in for the ‘fine’ optics to really be useful. In short it was a way to increase the selling price while sounding better and having the buyer feel good about it and leave positive reviews, without actually improving the quality of the experience. To make a analogy something like 4K HDTV on a 6 inch screen.

3

Some purists might insist that you must use the telescope by walking uphill (both ways) barefoot through 10 miles of snow to use a telescope, just like in the olden days. I say to hell with pureism and get a telescope with a GoTo mount–you set the telescope up and can choose from a tiny computer what you want to look at and the telescope aims and tracks for you.

4

I’ve said this here before but will state again that binoculars are the best first telescope. Why?

  1. Binoculars are great for other things (sports, birdwatching), so if you give up on astronomy, you’ll still use them (unlike a telescope).

  2. Binoculars are much more portable than telescopes and so more likely to be used.

  3. Binoculars are easy to use and require no unusual mental maps (many telescopes flip images left/right or up/down).

  4. For any given dollar amount, binoculars will be of much higher quality than the correspondingly priced telescope. This is especially true for telescopes at the lower end where many are simply unusable.

  5. In order to use a telescope for astronomy, a person should first have some familiarity with “the night sky”. Along with the good old naked-eye, binoculars are ideal for doing so.

5

So maybe i should ask the same OP referring to binoculars instead! :smiley:

Ok, i’ll investigate astronomy clubs. That’s a good idea i didn’t think of…

6

This sort of thing is definitely a subject that i’d rant about in the Pit :mad: :mad: :mad:

7

Binoculars are a great first step into astronomy, or second step if you consider dark skies and looking up to be the first.

The biggest rules for casual use is portability and light gathering. It has to be easy to bring out and put away or you’ll only ever use it for special events where the effort is almost worth it. Once you find something that can be brought out easily you want to have a tool that can gather lots of light. Don’t worry about magnification, worry about how big of a light bucket you can get your hands on. On a grand scale this is why observatories are always talking about their 12’ mirrors or 30m mirrors. More light gathering area, more photons, more details.

So a 4" mirror gets you ~12.5 square inches. A 6" gets you 2.25 more area and an 8" 4 times as much.

Some astronomy stores/clubs will actually let you rent a telescope, so that might be a good approach before going out and buying one.

8

Where will you be observing from? If it’s a city or suburb, you might as well give up on deep-sky objects (esp. nebulae and galaxies) and buy a telescope that’s good for looking at planets and star clusters. That means something capable of high power, with tracking.

If you live under a dark sky, or can easily go to a dark sky site, I would recommend a pair of large binoculars on a tripod.

9

When you check for an astronomy club, find out if they do “star parties”. Those are events where anyone can come and you’re allowed to look through the scopes that people bring, which may inform you as to what you want to buy.

10

Which GoTo mount do you recommend for beginners? I’ve had a lot of trouble getting my Celestron (NexStar Evolution with StarSense) to work, but that may be because I’ve only tested it in suburban areas.

11

This.

Binoculars are great for the larger deep-sky objects as well as the moon, and don’t require much in the way of special equipment.

In general, you want large-ish objective lenses (the part you point at whatever you’re looking at) and moderate(7x-10x) magnification.

50mm is probably the bare minimum objective that is recommended- common combinations are 7x50, 10x50, 8x56 and 9x63, with the first two being very common due to their use for other non-astronomical purposes.

Of course, if you have a pair already that are reasonably close like say… 8x42 or something similar, I wouldn’t go buy new ones. But if you have tiny little 10x25 binoculars, they may not gather enough light to be useful, and you wouldn’t be able to see anything except the moon.

12

This is a subject which comes up regularly so check out previous threads, for example:
https://www.google.com/search?sxsrf=ACYBGNR302BXmWt5LwEWRquAj-66o-nKmQ%3A1580746487217&ei=90Y4XqXjDI--tAb30qdg&q=site%3Astraightdope.com+buy+telescope&oq=site%3Astraightdope.com+buy+telescope&gs_l=psy-ab.3...2407.5748..6375...1.0..0.153.1324.12j3......0....1..gws-wiz.WXhpyXeccoQ&ved=0ahUKEwjluubG47XnAhUPH80KHXfpCQwQ4dUDCAo&uact=5

13

The last telescope I bought was before they were a thing (or at least affordable to mere mortals.) I only know what a PITA trying to find objects the old-fashoned way is.

14

But the satisfaction in succeeding to do so was sublime.

15

I bought a Celestron telescope about 10 years ago. Never used it. In Summer, it gets dark too late (49th Parallel). In Winter, it’s too cold. Autumn, Winter, and Spring is usually cloudy. Too bad. It has a motor-driven equatorial mount, 8-inch mirror, tripod, manual… I don’t know where the software is. I need to put it on Craigslist.

16

FYI, it can be even more of a PITA to get a GOTO telescope to work properly. My current one is supposed to align itself using built-in cameras but it I’ve only gotten that to work once. The one I had before that (an iOptron) was a bit better, but still didn’t work very reliably when slewing over a long distance (i.e. align on one part of the sky and then tell it to find an object 180 degrees away in azimuth).

17

The first thing to know: Never buy any scope that lists its magnification on the box. It’s crap. You can get any magnification you want with the right eyepiece, but if the quality isn’t there, you’ll just see a big blurry blob instead of a small blurry blob.

Quality of the optics is the first consideration. There’s a maximum limit to how good optics can get, and all of the major manufacturers (Meade, Celestron, Orion, Astroscan) hit it. If you’re not buying from one of them, the key word to look for is “diffraction limited”.

After that comes aperture, the diameter of the main optics. More is always better. The only limits are price and portability. 8" is usually a good compromise point.

Focal length is also relevant, but it’s a tradeoff. Longer focal lengths are better for seeing fine details; shorter are better for dim objects. Length can also impact portability.

Next up is the mount. That’s either altitude-azimuth, or equatorial. Equatorial is a must if you’re planning on doing astrophotography, but it’s more complicated and hence more expensive. And all of the other benefits of equatorial can be gotten more easily nowadays, so unless you’re doing astrophotography, I’d get an alt-az.

Then there’s the drive. The sky moves, and so your telescope needs to move with it (either manually or automatically), to keep the same object in view. It’s simpler with equatorial, but that’s what we have computers for: It’s easy to find computerized drives that will work with alt-az mounts, and which will point you straight towards any interesting sky object you’d like. Alternately, if you’re on a budget, there’s a very cheap undriven sort of alt-az mount called a Dobsonian mount that lets you get a lot of telescope for your money, and can even be made yourself if you’re handy with carpentry.

And then there’s the accessories. I would recommend a naked-eye reticle (Telrad makes a good one), a finder scope, and a good book of interesting objects (preferably one that shows your naked-eye reticle of choice in the illustrations).

18

Of course, a cheap Dobsonian mount with a Newtonian scope keeps the cost way down. It’s a very affordable way to get pretty good aperture and be able to see cool things without breaking the bank. The disadvantage is you’re basically winching the damn thing around by hand, and cannot mount any sort of computer, but with a telrad it’s not all that hard to find a lot of interesting targets.

Having said that… I wholeheartedly agree the way to start is with a set of binoculars with a lot of aperture, and a good beginner’s skywatching guide. If after a lot of that you still have a hunger for a telescope, THEN buy one.

19

Dobsonian digital setting circles.

CMC fnord!

20

Let’s see, going by the negatives:

Binoculars are great, but it’s a fixed magnification, and astro models are heavy and difficult to see anything near the zenith.

Reflectors (Newtonian, dobsonian) are great, but they require the optics to be aligned on a regular basis.

Catadioptrics (Scmidt-Cassegain, Maksutsov) are great, but they’re heavy to move around and set up, and require a long cool down time.

Refractors are great, but they’re the most expensive per inch of aperture, and by more than a few pennies.

Light buckets are great for seeing faint fuzzies, but faint fuzzies often aren’t qualitatively much different than the brighter fuzzies.

High magnification scopes are great for seeing planet and moon details and splitting doubles*, but only when those thngs are up, and Saturn and Jupiter are the only planets that really have any details for the amateur.

If you’re not in a hurry to decide, I definitely recommend trying to hit a star party or 2 with a local club. Go early and stay late, if you can, and get a feel for the set up and tear down, some are more trouble than they’re worth, unless they’re exactly what you need.
*Splitting doubles is kind of a geeky pursuit that I haven’t gotten into. The only time I saw a split double that was awe inspiring was through the 60’’ scope at Mt Wilson.

Full disclosure, I’m a refractor guy, I like the robustness, and the easy handling. I also like the crisp detail and contrast.** PM me if you’re interested, I have a refractor and some binoculars I’d sell you.

**There’s a (mostly) friendly disagreement between the obstructed (reflector, catadioptric) and the unobstructed (refractor) fans about the merits of each. The correct answer, of course, is that it’s a toolbox, and job determines the best tool. (but refractors are best)
Last but not least, the telescope is only one piece of the puzzle. Eyepieces and mounts are important to your experience (and can be equal money pits)