Insights Planning to buy a first telescope? - Comments

[Drakkith]

I am looking to buy a telescope, what is cheapest telescope I can buy with highest magnification possible?

Except in the case of very small telescopes, your magnification* is often limited more by turbulence in the upper atmosphere than by the telescope itself. Not only that, you don't actually want maximum magnification for about 95% of targets. High magnification causes the image to dim and makes it harder to keep the image stable and to find targets in the first place. I often get a 'better' view of the planets with a relatively low power eyepiece instead of one that gives me the highest possible magnification I can get. My high-mag eyepieces often just make the image a dim, blurry mess. And this is with an $1500 8-inch reflector on a mount that costs just as much.

As for price, I would set a minimum price at around $100 USD (or even $200). Anything less than this and you will almost certainly be buying a very poor quality telescope. Even if the optics of this scope are average, or even good, the quality of the mount, the tube assembly, and the accessories will likely be poor and make the telescope frustrating to use.

Trust me when I say that saving up a little extra to buy a more expensive telescope is well worth the delay.

*Note that a telescope doesn't have a single magnification. Instead the magnification depends on the focal length of the primary optics (the big piece of glass at the front or the big mirror inside) combined with the focal length of the eyepiece you are using. Buying a couple of eyepieces of different focal lengths gives you a good range of magnifications to suit your needs. Many telescopes come with at least 2, one for low-mag and one for high-mag, if I remember correctly.

I had small telescope with max 40x magnification but I was not satisfied by it, mainly because it was very unstable where the least wind causes shaking and everything I see through it was very blurry including nearby planets like Mars and Venus.

This is most likely because you had a cheap telescope with a light, flimsy mount. I had one as a kid that broke the first night I had it thanks to flimsy plastic threads between the tube assembly and the focuser.

In regards to a specific telescope you should buy, I'm afraid I can't recommend a specific one. There's a saying in amateur astronomy: "The best telescope is the one that you will use." I stand buy that statement. If your nearest viewing location is four flights of stairs down and three blocks away on foot, then you probably don't want a 8-inch dobsonian that you'd need to make two trips for. If you are in a situation similar to this, a good pair of 5-7 inch binoculars might suit you best.

Try looking through this thread for more information: https://www.physicsforums.com/threads/planning-to-buy-a-first-telescope.391086/

 

[lomidrevo]

I am looking to buy a telescope, what is cheapest telescope I can buy with highest magnification possible?

This topic was discussed many times on this forum, so I recommend to search a little bit, I am sure you will find a lot of helpful inputs. In my opinion, one of the best hints is to begin with decent binoculars and a good sky atlas. It is the best investment you can do at the beginning, because both of them you will find helpful even in the case you already have a bigger telescope. Once you are sure this hobby is the right one, you can buy the telescope. Moreover at the time, you will probably know what kind of objects are the most interesting to you so you will know what kind of scope to buy (+ depending on the observational conditions in your area of course).

I had small telescope with max 40x magnification but I was not satisfied by it, mainly because it was very unstable where the least wind causes shaking and everything I see through it was very blurry

Surely, the problem was with a cheap unstable mount, not the optics I believe.

 

[Vanadium 50]

This topic was discussed many times on this forum, so I recommend to search a little bit

It's a sticky at the top of this page. https://www.physicsforums.com/threads/planning-to-buy-a-first-telescope.391086/

 

[russ_watters]

I am looking to buy a telescope, what is cheapest telescope I can buy with highest magnification possible?

I don't have solid background about astronomy, but I have general interest in it since I was a child, long time ago I had small telescope with max 40x magnification but I was not satisfied by it, mainly because it was very unstable where the least wind causes shaking and everything I see through it was very blurry including nearby planets like Mars and Venus.

A quick note on magnification itself, since others have done a good job addressing it; I have a fairly large and good quality telescope for an amateur, and my sweet spot for planetary viewing is about 180x magnification. I sometimes go higher, but "seeing" needs to be exceptional for it to be useful.

I want to try to head off a potential expectations gap though. Right now there are 4 good viewable planets, which is a rariaty, but because it is summer all are very low in the sky. That means the "seeing" is very poor and even with my equipment, the atmospheric distortion is noticable at 180x.

Also, I've only looked at Venus a few times, but since it is basically a flat white cloud, there isn't much to see. Mars, Jupiter and Saturn are the ones to be most interested in.

 

[lomidrevo]

It's a sticky at the top of this page. https://www.physicsforums.com/threads/planning-to-buy-a-first-telescope.391086/

ah good, it is there again :) If I good remember, it was unstuck for a longer period...

 

[lomidrevo]

I want to try to head off a potential expectations gap though. Right now there are 4 good viewable planets, which is a rariaty, but because it is summer all are very low in the sky. That means the "seeing" is very poor and even with my equipment, the atmospheric distortion is noticable at 180x.

Also, I've only looked at Venus a few times, but since it is basically a flat white cloud, there isn't much to see. Mars, Jupiter and Saturn are the ones to be most interested in.

I totally agree. And for majority of amateur astronomers, I believe, the Jupiter is the top (including the four Gallilean moons) among the planets.

 

[russ_watters]

And for majority of amateur astronomers, I believe, the Jupiter is the top (including the four Gallilean moons) among the planets.

Yes, Jupiter is so big and bright that a moderately skilled amateur with reasonable equipment can take near magazine-worthy photos.

 

[George Jones]

As an example of Russ's comments about "seeing', I tell my non-astro friends that, because of movement of the Earth's atmosphere, under too high a magnification, the Moon's surface looks like it is "boiling"; see 1:05 to 1:11 in the following video.

And for majority of amateur astronomers, I believe, the Jupiter is the top (including the four Gallilean moons) among the planets.

Before I got my scope (an 8-inch SCT) in 2009, I knew I wanted to look at Jupiter, but I didn't realize how endlessly fascinating I would find observing Jupiter: cloud belts; Great Red Spot; shadow transits; moons disappearing into Jupiter's shadow; moons reappearing from Jupiter's shadow.

One early evening a few of months ago, I took the scope out early to look at the Moon, which easily took high magnification. Since the seeing was excellent, I checked a magazine, saw that Jupiter's Great Red Spot was going to be near the meridian in a few hours, and decided to leave the scope out until it got dark. (At 54 north, total darkness hardly happens in spring/summer.) When I took a look, not only was the GRS clearly visible, so too was a very small dark spot on Jupiter. A shadow transit (the shadow of a moon is visible on the "surface" of Jupiter) was in progress, which was a nice surprise, as I had not looked into this before observing.

The cool thing about observing Venus with a scope is that, like the Moon, Venus goes through phases. Right now, Venus is almost first-quarter, but I have lost it behind a large hill that is just to the west of me.

 

[Drakkith]

It's a sticky at the top of this page. https://www.physicsforums.com/threads/planning-to-buy-a-first-telescope.391086/

ah good, it is there again :) If I good remember, it was unstuck for a longer period...

Yes, I had to dig it up earlier and I asked the mentors to sticky it again.

 

[Chronos]

Aperture is a word frequently mentioned by telescope reviewers. In a nutshell you want the most aperture available at your price point A 6 inch anything is going to offer way more ROI than a 3 inch anything else. The finest optics and accessories cannot compensate for the light gathering power of larger aperture. This is why you see tons of 12 inch reflectors and hardly ever see even a 6 inch refractor. Unarguably, a refractor is optically superior to a reflector . Unfortunately it is also many times more expensive and comparatively enormous at the same aperture. Portability is also a vital consideration. Unless you have an observatory, a beastly scope is simply impractical The awe of the view is rapidly outweighed by the labor and nuisance of setting up a viewing session. I would suggest a compromise and settle for the biggest aperture you can afford and still physically manage. To that end I would suggest a short F reflector. They are readily available, affordable and easy to set up and use. Cat'[hybrid reflector/refractor] scopes are also popular, but, most people are much better off getting some experience with a simple reflector before taking the Cat plunge. I own a fancy 8" Cat with all the bells and whistles, but, still prefer the view offered by my venerable [and much cheaper] 10" f4 Newtonian when seeing is good.

 

[davenn]

long time ago I had small telescope with max 40x magnification but I was not satisfied by it, mainly because it was very unstable where the least wind causes shaking and everything I see through it was very blurry including nearby planets like Mars and Venus.

well that is what happens with a cheap scope and mount

Quality cost money

again I aim you at the thread V50 posted where all this is discussed

https://www.physicsforums.com/threads/planning-to-buy-a-first-telescope.391086/So, what sort of budget do you have ? and keep in mind that something stable is going to cost
~ US$500 and up. Buying something less that ~ US$500 is going to give you all the same problems
that you had with that first scopeDave

 

[Drakkith]

So, what sort of budget do you have ? and keep in mind that something stable is going to cost
~ US$500 and up. Buying something less that ~ US$500 is going to give you all the same problems
that you had with that first scope

I'm not sure I agree that you need to spend upwards of US$500 to get a 'stable' scope. As long as you avoid the extremely low end of the price spectrum, under 100-150 USD, I think you can get a decent starter scope. Obviously it won't be nearly as stable in wind as my 8-inch reflector on my Orion Atlas mount and tripod, but it also doesn't weigh 70+ pounds and it doesn't need to be as stable anyways. I believe I spent somewhere between $150 and $250 to get a small computerized reflector on an alt-az mount that worked great for me. It was light enough to easily take outside, and sturdy enough to not be blown about by the slightest breeze.

 

[Deepblu]

Thanks all for your valuable advices..

My budget is $600 max, so what technical specs should I aim for under this budget?

Also I would like to see some stars and galaxies I am not sure if that will be possible under this budget.

 

[davenn]

I'm not sure I agree that you need to spend upwards of US$500 to get a 'stable' scope.

That's why I said "around" … not overly familiar with American pricing without delving into it

My budget is $600 max, so what technical specs should I aim for under this budget?

OK I don't know what country you are in ? …. here at B&H as an example …..

This would be an excellent start

https://www.bhphotovideo.com/c/product/1248233-REG/celestron_22203_astro_fi_130mm_f_5.html

a good quality brand … I own a Celestron myself …. a bit bigger than that one

that one is well within your budget and I see it has ports on it for handheld controller and auto guider ( if you wanted to get into that at a later date

It is very important that the mount is solid else you will still be plagued with vibrations every time you touch it to do focussing etcif you could push your budget a little bit more, you could aim for something like this …..

https://www.bhphotovideo.com/c/product/440825-REG/Celestron_11068_NexStar_6_SE_6_0_150mm.htmlon the other hand, if you want to do away with all the drive abilities, you could go with a dobsonian like this

https://www.bhphotovideo.com/c/product/1141702-REG/sky_watcher_s11610_8_traditional_dobsonian.html

I have also owned similar in recent yearsThere's some thoughts for you

cheers
Dave

 

[Chronos]

Nice list, Dave. The F! has enough aperture to actually see some interesting things. If computer control is not a 'must', the Meade Polaris is virtually the same scope on a much nicer mount at half the price.

 

[Deepblu]

@davenn
I am comparing the The SkyWatcher with the Celestron NexStar.
The SkyWatcher seems better to me .. it has larger aperture of 8 inch (vs 6 inch for Celestron) and comes at half price $378 (vs 750$ for Celestron).

In general should I aim for the largest aperture when deciding which telescope to buy?

 

[Drakkith]

In general should I aim for the largest aperture when deciding which telescope to buy?

If the additional weight isn't a problem, then yes. You should usually aim for a larger aperture over a smaller aperture for a general purpose telescope (one that you aren't using specifically for something like astrophotography or something).

 

[Chronos]

As Drak said your priority should be as much aperture as you can manage. The purpose of a scope is to gather light and the more you can gather the better so long as you can manage to prepare it for a viewing session. There is no accessory at any price that can increase the amount of light your scope can collect. Personally, i prefer an equatorial mount, but, I am old and lazy - so only needing to move the thing in one direction [along a single axis] to keep something in view appeals to me. It also vastly simplifies finding a new target at the same declination or right ascension.

 

[sophiecentaur]

on the other hand, if you want to do away with all the drive abilities, you could go with a dobsonian like this

A dobsonian has many advantages in that is a very simple arrangement. The mounts are often totally manual so you very rapidly find how to locate the objects you want to observe by 'star hopping'. (Starting with a well known star and then hopping between less well known stars, following the instructions you can find in books like "Turn Left at Orion") That's the way all amateur astronomers used to observe. If you buy a 'Go To' mount, that can take up most of a limited budget, before you even start paying for optics. Admittedly, you can be up and running quicker with a goto - but you still have to align the mount before you can point to most objects.
The first telescope I bought was an 8" Dobs and I was staggered by the view it gave. I compared it with smaller, go-to systems and I was more than pleased with my decision. You very quickly learn how to collimate a Newtonian telescope and that's pretty much the limit of where a Dobs can go wrong. If your budget is limited, you will probably need to pay someone to sort out any problem with the mount and that could mean waiting till you have more money.
I got rid of my Dobs because my joints couldn't cope with the antics involved in kneeling on the ground and squinting through the finder scope. That's just a problem with age!
I would agree with the comments about binoculars, though. Even a modest pair will reveal so many objects. You would need a fairly steady tripod, though, and binoculars with a thread for mounting to a tripod. Afaiaa, any decent bins (reasonable birding binoculars) will be suitable.

 

[lomidrevo]

Also I would like to see some stars and galaxies I am not sure if that will be possible under this budget.

I guess you are aware of that, but better to emphasize it: except the Sun, you won't be able to resolve any other individual star as "a disc". They all appear as a point-like sources in any amateur scope.

Regarding galaxies, the most important is to have dark sky - light pollution is a serious obstacle. And as mentioned in many posts above, bigger aperture is better, especially for deep-sky objects like galaxies. There are few galaxies you can see with a naked if the sky is dark enough, like M31 Andromeda.

 

[Chronos]

A right angle finder scope is on my 'must have' list for a newt or dob..

 

[sophiecentaur]

A right angle finder scope is on my 'must have' list for a newt or dob..

It's a 'must' - and it's something I bought PDQ, but you still need to 'sight' along the telescope barrel to get an initial pointing direction. No problem for a youngster without a 'bad' neck and back. I resorted to putting the scope on a firm table - then having to get up on a chair so that I could see through the scope (amusing to watch, I expect!). But the views through my Dobs were really cracking at times. You can't beat a light bucket for low cost visual.

 

[lomidrevo]

A right angle finder scope is on my 'must have' list for a newt or dob..

Also Telrad finder on my dob is pretty useful, I like it a lot. Since I use it, I do spend less time finding the objects, and more time observing them. But indeed, it often requires some physical exercise, especially for the targets near zenit

 

[sophiecentaur]

I acquired a Telrad for free, quite recently.It really does the job - especially when looking for nice bright alignment stars. You are viewing with no magnification so the brain needn't work quite so hard. The image is also the right way up! I think one should have two on a scope to reduce the Yoga aspect of Astronomy, though.

 

[jim hardy]

A dobsonian has many advantages in that is a very simple arrangement.

And it lends itself to fabrication at home with just basic tools. One might buy a secondhand EDIT department department store scope for very litt;e and make himself a decent mount for it.

Another thought - i have a friend who's an avid shooter. His inexpensive spotting scope does a great job on Saturn's rings .

 

[sophiecentaur]

"department"? I couldn't think what work the spellcheck substituted in order to get department.

 

[jim hardy]

"department"? I couldn't think what work the spellcheck substituted in order to get department.

OOPS i meant "Department Store" telescope.
Some actually have a decent mirror but they come with ridiculous eyepieces and flimsy tripods..
Since power sells they'll come with eyepieces having way too short focal length to be practical. Just try to hold a 400X 'scope still let alone find something with it.

One can take apart a thrown away "Point & Shoot" film camera and get a decent lens around 35 mm focal length. Such cameras bring just a couple bucks around here.
With some whittling and glue he can fashion a wood eyepiece from an old sewing spool,
and get surprising views of our and Jupiter's moons at 15 to 30X on a 'department store' scope. For probably under twenty bucks.

It's a cheap and fun way to get started.
And it might make a good finder for your serious 'big telescope' later on .

now i'll fix that post.. old jim

PS sorry for digression. Maybe i should have started one in the DIY thread.

 

[sophiecentaur]

Maybe i should have started one in the DIY thread.

That was a classic @jim hardy post and I enjoyed it.
Interestingly, (well, to me at least) I just purchased a half decent model (mini) lathe and the first real job I have done was to make a mount for some non-standard filters that @Andy Resnick sent me. Not a bad piece of lathe work, if I may say so, and it involved putting a 47mm X 0.75mm on the barrel. Thanks Andy - I have actually done something about that interesting package you sent me! I will be doing more DIY astronomy construction shortly.

PS The problem with DIYing scopes is more to do with the focusser than an eyepiece, I think. It would be quite a challenge to mount a gash lens onto a Newtonian reflector though my lathe could help . . . . .
There are some very entertaining descriptions of building a Dobsonian to be found with a Google search.

 

[Kevin the Crackpot]

Great article.

What kind of telescope to get depends upon what you want to do, as different telescopes may be good for different goals.

When trying to decide, keep in mind how different types of telescopes work, and you should become familiar with the ideas behind abberation, and the rules that dictate how abberation works.

For example, there is chromatic abberation, spherical abberation, curvature of field, coma, and astigmatism.

All abberations tend to be less toward the center of the image, and become more pronounced as you move toward the edge of the image.

All abberations tend to become less noticable as the focal length increases, and more noticable as the focal length decreases. This is usually given as an f-stop.

The focal length is usually indicated as an "f" number. An example might be an f-8 or an f-10.

The f-stop number usually means the focal length over the diameter of the mirror (or lens), also sometimes defined as the focal length over the aperature (opening) of the telescope. Since most telescopes (there are exceptions) don't have an adjustable opening, the f-stop is defined by the focal length over the mirror (or lens) diameter.

There are hybrid telescopes (called catadioptic) that use both lenses and mirrors.

An example is a Schmidt-Cassegrain telescope, which uses a special kind of lens at the aperature, and a Cassegrain focus telescope for the rest of the instrument.

Become familiar with the Cassegrain focus, Newtonian focus, Prime focus, and off-axis focus. There are other variations like the Gregorian focus, Hershelian focus, and so on . . . but are not as relevant to amatuer astronomers except as a historical intetest.

Catadioptic telescopes manipulate the light path to try and reach various compromises between the different limitations of the different designs.

A good Schmidt-Cassegrain telescope made by Celestron or Meade will provide excellent opportunities for astrophotography, and some come with computer-guided mounts that will precisely track a specific part of the sky (as the Earth rotates), and allow for long time exposures that will show the intricate and exquisite details of galaxies, nebulae, and so on that are invisible to the eye.

Another good design for amature astronomers is the Maksutov-Cassegrain, which uses a different kind of correcting lens at the aperature than a Schmidt-Cass, but still gives stellar (pun intended) results.

Get a subscription to Sky and Telescope, and follow the different things that are happening in the sky. You'll see charts that help you find and identify the 4 large moons of Jupiter, how many Messier objects you can spot at a specific time, and so on.

Some of the places where amatuer astronomers can make scientific contributions include comet hunting (actually best done with large binoculars on tripods) and observing the Moon for different phenomena (sometimes mysterious plumes are reported, which may be from pockets of gas or water), and so on.

Become familiar with the conventions for pinpointing objects in the sky . . . usually given as declination and right ascension. These intimidating-sounding technical terms are actually quite simple to understand, but beyond the scope (did you get the pun?) of a forum post. Look them up in a Google search.

In conclusion, a few safety issues with telescopes need to be brought up.

Observing the Sun requires specialized equipment and training. Trying to observe the sun in any telescope without the know-how and proper equipment may not only damage your instrument . . . but also your eyes. Note that Gallileo discovered sunspots, and lost a lot of his vision in the process.

Also, make sure your telescope is used in context. People have called the police and/or their burly, ape-like biker neighbors with baseball bats to take care of the pervert peeping Tom who likes to look in peoples' windows.

So, invite your neighbors and their children to share your interest in astronomy with pizza and beer (or maybe wine and cheese, or an ice cream party if there are kids). You may make some new friends, inspire young people to science, and--at the same time--avoid a trip to the hospital by sidestepping a dangerous misunderstanding that you're a pervert.

 

[sophiecentaur]

What kind of telescope to get depends upon what you want to do, as different telescopes may be good for different goals.

Absolutely and you have given a useful and pretty comprehensive list of facts. Unfortunately, newbies will not know what they actually want to do. The only way to find out that is by using someone else's equipment at least once. Astro societies are usually very happy to arrange to give people a go and show them a thing or two.

Also, you miss out the one important thing for beginners. It is that what they will actually see in a home telescope (whatever you spend on it) will be nothing like the Hubble Pictures in magazines. That simple thing can make a first timer very disappointed. I don't know the size of amateur telescope that will give more than a hint of the colours that Astrophotography will produce.

OTOH, the first glimpse of Jupiter and moons, even in a cheapy scope, could be stunning IFFFFF the viewing conditions are half decent. And the Orion Nebula will be memorable (and easy to find too)