Planning to buy a first telescope? - Comments

[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)

 

[Kevin the Crackpot]

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)

I agree.

A favorite target for me are the Pleiades. They are beautiful in a small, home telescope and--to me--seem to resemble diamonds spread across black velvet.

Another good target are the stars in the handle of the Big Dipper (Ursa major). There, one can see a binary star in a low-power home telescope.

 

[sophiecentaur]

A favorite target for me are the Pleiades.

Fairyland!

 

[DaveC426913]

OTOH, the first glimpse of Jupiter and moons, even in a cheapy scope, could be stunning

This is what sucked me in.
Went to a local star party, and they had a pair of binocs pointed at Jupiter.
It looked like it was hovering over the buildings! And its moons were right there!

 

[Kevin the Crackpot]

This is what sucked me in.
Went to a local star party, and they had a pair of binocs pointed at Jupiter.
It looked like it was hovering over the buildings! And its moons were right there!

I love looking at Jupiter's moons.

There is so much history behind those moons. Galileo was able to use observations of the 4 moons (which he discovered) to help prove that Earth isn't at the center of the Universe.

Also, the first realistic measurement of the speed of light (about 2/3 of the currently accepted value--but only because of faulty measurements of Jupiter's distance from the Earth. The mathematical reasoning was impeccable) came from studying Jupiter's 4 largest moons.

It makes me feel a sense of connectedness with all that history when I look at Jupiter's moons. It's probably silly to feel this way, but I do.

 

[sophiecentaur]

I remember reading a short story about a boy who spent nights laying on the roof of his house, looking at the moon. He started to hallucinate that he was looking down at and was falling towards the moon. High magnification through a 'good' scope can make you think in terms of a 'landscape' and the features that you can discern may only be as big as a large city.
PS Never spend long looking at the Moon without a Neutral Density Filter or you will think you have gone blind in one eye when you look away. An ND filter should perhaps be the first filter you ever buy!

 

[Michaela SJ]

When I was 12 (1958 or so), a schoolmate of mine (much smarter than me) had a quality 6" Newtonian telescope that his doting father bought him. One night while I was over at his house (in a Bay Area suburb with a lot of light pollution) he showed me the Andromeda Galaxy. I was absolutely taken with the view; being able to discern the arms and also one of the companion galaxies.
1978 rolls around and a friend of my wife, a PhD physicist was over dinner and I mentioned my earlier view of Andromeda and he mentioned he had an 8" f/4 Newtonian that he had ground the mirror and assembled the OTA himself and would I like it - well, yeah! I purchased a basic equatorial mount and the fire was lit.
2010 rolls around and $40,000 later.
Astronomy, as a hobby will eat up checkbooks as much as any hobby so be careful. I no longer have a complete telescope rig but my final rig consisted of a:

152mm f/8 APM/TMB Apochromatic refractor (near perfection) [I still have the OTA]
Paramount ME Equatorial mount (the best in its size)
QSI 683 full-frame 8.3 megapixel CCD camera with filter wheel
SBIG ST-4 Autoguider
Astronomy software
Way too many eyepieces​

I shot the Soap Bubble Nebula from my San Jose, CA backyard 30 days after discovery.
You don't need aperture, you need quality and patience.

 

[sophiecentaur]

Astronomy, as a hobby will eat up checkbooks as much as any hobby

Oh yesssss! And all your time, too. The family may forget what you look like if you spend too much time outside at night. The final straw that breaks the camel's back is when you decide to instal an Observatory in your garden. There are more of these around than you could ever imagine. If you can find a neighbour with one (via local Astro Society) then you may have a cheaper way into the business, although it's not quite 'the same' as having your own gear.

 

[enorbet]

I had been saving up to buy a decent telescope for my adult Son when someone bought him a cheapo (I think under $150 USD) as a gift. I don't think it's actually bad but it doesn't solve my two-pronged plan to get my prodigious grand-daughter interested as well as the height at which the tripod suits adults is still too tall for her. I'd still like to get a "real telescope" but I suppose it's wise to see if she develops any serious interest before I actually spend $300-400 USD. So I'm thinking one of those eyepieces that sends the image to a laptop (or maybe her phone! lol) would be a practical "whistle wetter". I've measured the diameter of the eyepiece and it is a rather standard size for cheapos (1.25") so can anybody either say "No. Not a good idea" or recommend one that would be appropriate? FWIW we live in the rural mountains and have pretty decent viewing situation.

 

[Drakkith]

So I'm thinking one of those eyepieces that sends the image to a laptop (or maybe her phone! lol) would be a practical "whistle wetter". I've measured the diameter of the eyepiece and it is a rather standard size for cheapos (1.25") so can anybody either say "No. Not a good idea" or recommend one that would be appropriate? FWIW we live in the rural mountains and have pretty decent viewing situation.

Tough to say. If you do end up buying one, I'd say go for a good quality one that allows the adjustment of the gain, exposure time, etc.

 

[davenn]

There are few galaxies you can see with a naked if the sky is dark enough, like M31 Andromeda.

To be specific, there are only 4 naked eye visible galaxies
1) The Milky Way
2,3) the Large and Small Magellanic Clouds
4) Andromeda Galaxy

All others require a telescope

 

[davenn]

@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?

In general Skywatcher scopes are not as good quality as Celestron, Meade or Orion. Hence why they are cheaper

As I said earlier ... if you want quality, you have to pay for it

 

[sophiecentaur]

As I said earlier ... if you want quality, you have to pay for it

Imo, you need experience before the quality differences are relevant. SW are good value , not rubbish and, let's face it, being able to see objects that are bright and sparkly in the eyepiece is the most likely thing to turn a first-timer into an enthusiast.
The second hand telescope equipment market is well worth while investigating. Amateur astronomers all seem to take care of their stuff and they will mostly be more critical of the scope they are offering you than a first-timer buyer will be.
But Astronomy is more likely to reward a beginner if they get in contact with and join a local Astro Society. Hands-on experience of equipment at night, with some friendly advice is much better than what you will get in a 'shop' that wants your money.

 

[davenn]

SW are good value , not rubbish

now, now, now ... don't misquote me/put words in my mouth
I didn't say they were not good value, and I definitely didn't say they were rubbish

Skywatcher are OK scopes ... I have one myself, a 120mm x 1000 mm refractor,

am not overly impressed with the chromatic and spherical aberration around the outer 1/4 of the field of view

but for AU$525, you cannot expect high quality optics

The Skywatcher mounts as in the pic above, the HEQ5 PRO is quite respectable and I would well recommend
them, as I have already done so. That mount on it's own cost me AU$1250. It was purchased separately from the scope,
around 4 years ago. Where the scope was purchased about a year ago.Dave

 

[sophiecentaur]

now, now, now ... don't misquote me/put words in my mouth

I know what you meant and I was not actually quoting you - just making sure that a less informed reader could be taking your summing up in a more extreme way than you meant it. I know well that SW mechanics is 'only just good enough'. They have some 'terrible' design features in the NEQ6 but those are built to a price. No one would suggest that a first time scope should be high end because the formula of their first choice would almost certainly eventually not suit their needs.
I am aware of quality in mechanical, electronic and optical devices and I tend to go in at a higher level so you could say that I don't always practice what I preach.
There are a few ground rules - which have been mentioned somewhere back ups this thread. Never buy stuff from a 'store' or new, off eBay. Read up about things and hold off before committing to any expenditure. Find someone local who knows about these things etc. etc.

 

[lomidrevo]

To be specific, there are only 4 naked eye visible galaxies
1) The Milky Way
2,3) the Large and Small Magellanic Clouds
4) Andromeda Galaxy

All others require a telescope

Wikipedia is listing some more: https://en.wikipedia.org/wiki/List_of_galaxies#Naked-eye_galaxies
To be honest, without a telescope or binos, I've seen only Andromeda (not counting the Milky Way ). But if you have really dark sky and eyes fully adapted, I can imagine that Triangulum and Bode's galaxy could be detectable.

 

[davenn]

Wikipedia is listing some more: https://en.wikipedia.org/wiki/List_of_galaxies#Naked-eye_galaxies
To be honest, without a telescope or binos, I've seen only Andromeda (not counting the Milky Way ). But if you have really dark sky and eyes fully adapted, I can imagine that Triangulum and Bode's galaxy could be detectable.

Triangulum Galaxy (M33, NGC 598) 5.7 2.9 Mly (900 kpc) Triangulum Being a diffuse object, its visibility is strongly affected by even small amounts of light pollution, ranging from easily visible in direct vision in truly dark skies to a difficult averted vision object in rural/suburban skies.[12]
Centaurus A (NGC 5128) 6.84 13.7 Mly (4.2 Mpc) Centaurus Centaurus A has been spotted with the naked eye by Stephen James O'Meara.[13]
Bode's Galaxy (M81, NGC 3031) 6.94 12 Mly (3.6 Mpc) Ursa Major Highly experienced amateur astronomers may be able to see Messier 81 under exceptional observing conditions.[14][15][16]
Messier 83 (NGC 5236) 8.2 14.7 Mly (4.5 Mpc) Hydra M83 has reportedly been seen with the naked eye.[17]Those would all be exceptional eyesight under exceptionally good conditions ... the avg person wouldn't have a chance .
Most people with reasonable eyesight can see down to around 5.5 - 6.0 ... anything fainter than M6.0 would fall into the exceptional conditions

M31 is an easy naked eye object, even for us southern hemisphere dwellers where it is low on the horizon.
Doesn't get more than around 10 - 15 deg for me in Sydney
I'm pretty sure I have never naked eye seen M33 in Triangulum. It's higher in the sky than M31 by another 5 - 10 deg
I did photo it a couple of weeks ago for the first time
Dave

 

[Michaela SJ]

To be specific, there are only 4 naked eye visible galaxies
1) The Milky Way
2,3) the Large and Small Magellanic Clouds
4) Andromeda Galaxy

All others require a telescope

I would like to add M33 - The Triangulum Galaxy. I have glimpsed this very sparse and wide fuzzy from the Santa Crus Mountains outside of Boulder Creek. It is very difficult and you must know where to look.

 

[davenn]

I would like to add M33

I'll give you that one :

 

[sophiecentaur]

I'll give you that one :

If you were having this conversation a few hundred years ago, the visually observable numbers would probably be higher. A rich person would have time to sit in the dark all night (no distractions) and with much less air and light pollution and loads of practice, there would probably be many more faint but visible objects.

 

[davenn]

Skywatcher are OK scopes ... I have one myself, a 120mm x 1000 mm refractor,

I know what you meant and I was not actually quoting you - just making sure that a less informed reader could be taking your summing up in a more extreme way than you meant it. I know well that SW mechanics is 'only just good enough'. They have some 'terrible' design features in the NEQ6 but those are built to a price. No one would suggest that a first time scope should be high end because the formula of their first choice would almost certainly eventually not suit their needs.
I am aware of quality in mechanical, electronic and optical devices and I tend

Well time has moved on and a couple of weeks ago and I added a top end refractor to my collection
Strangely enough, it is a Skywatcher. This came after looking at a number of refractor scopes at around the 100 - 120mm
objective size and what I was able to afford. Also my existing HEQ5 PRO had to be able to handle it. After talking to a number
of guys using either the 100mm or the 120mm. Their comments have been very encouraging with their high praise of the optics
particularly when used for astrophotography. One of them is a local guy whom I caught up with in person at a local club night under the stars

I present the Skywatcher 100mm ED ESPRIT ... AU$3500 ( that is just the scope and some accessories that come in the box)

https://www.bintel.com.au/product/s...be-assembly-triplet-refractor/?v=6cc98ba2045f

my one in the box ... and what a solid box it is aluminium outer covering with dense foam lining

I am very impressed and can't wait to do some astrophotography with it ... now only if we could get some cloudless nites
Those truly into astronomy will be well aware of the curse of "If you buy a new scope ... cloudy nights are sure to immediately follow"
view the www page for all the spec's ... the only thing not mentioned on that page is that it also has a 11:1 fine focussing
The scope tube and mechanics are very solidly built

I think I'm in love

Dave