Questions: Buying Telescope

[astropat]

Hi All,

I’m a beginner in telescope (although I’m a phd student in physics and once participated in astronomical research). I’m thinking of getting a portable telescope (approx 10kg or less including mount weight, and preferably short tube), so that I can hand carry it around to nearby darker locations. I have a budget of around AUS$700 or less. The reason for buying a telescope is that I’ve been doing naked eye astronomy for years and really want to learn more about operating telescopes and astronomy and seeing more. I read quite a few books and I know that I should get one with a big aperture and sturdy mount, and also one that I can use often (in this case, a very portable one). Now my first question is:

Any recommendations on what telescope I should get?

After searching on the web, I found that the biggest aperture telescopes with weight less than or about 10kg are 114mm diameter + EQ1 mount short tube reflecting telescopes. There are 3 telescopes that I have been thinking of with different f/ratios:

Orion StarBlast 4.5 EQ Reflector (f/ratio=4.0)

http://www.telescope.com/shopping/pr...dd=yes#tabLink

Tasco Galaxsee 46-114375 (f/ratio=5)

http://www.tasco.com.au/Default.aspx...tID=94&cid=209

Celestron FirstScope 114 EQ Compact (f/ratio=8.77)

http://www.celestron.com/c2/product....ID=6&ProdID=19

I know that smaller f/ratio telescopes are better for viewing deep sky objects, but I also heard that it is near impossible to collimate a f/ratio <= 5 telescope. So my second and last questions are:

Is it really near impossible to collimate a f/ratio <= 5 reflecting telescope? And what tools (if exist) do I need to overcome the difficulties?

If it is not too difficult to collimate a f/ratio <= 5 telescope, then which of the 3 telescopes above should I get?

Thanks,
Patrick

[mickoking]

G,day Patrick and welcome

Collomating a f5 newtonian telescope is not too difficult once you have done it a few times. A faster telescope will need collomation more than a slower one and you will need to be more precise but it is not a huge inconvenience. There are several gadgets that can help you collomate like a cheshire eyepiece and if you want to spend a bit more a laser collomater. I have both but I prefer the simple cheshire.

As for which telescope to get? If you want something reasonably portable but with descent aperture I would reccomend a 150-200mm newtonian on a Dobsonian mount (simply called a Dob). They are inexpensive and a joy to use. The 150mm(6") Dobs are usually f8 and the 200mm (8") are about f6

[xelasnave]

from me.
You can get various tools to tune your scope no problems there.
I had a 114 mm reflector and in a dark sight they are very handy. Have you considered a pair of binos the 80 tripletts seem to be the go ($200)..you would need a tripod but very portable and the views at 20x mag very useful except perhaps on planets (I have no idea). Not sure of their wiehgt however.
Good luck with it all and remember you just may end up with more than just one scope in time if the rest of us offer any clues.
alex

[janoskiss (Steve H)]

Welcome to IIS Patrick!

For under $700, by far the best telescope you can get is a 10" GSO Dobsonian. Couple of dealers:
www.bintelshop.com.au
www.andrewscom.com.au
If you want something closer to home (with Synta/Saxon/Skywatcher Dobs):
www.staroptics.com.au
www.sirius-optics.com.au

For under $500, the 8" Dobs are excellent also and will leave you with enough spare change for some accessories. They are a great size to start (and stick) with. With a very minor modification (couple of handles on the base) these can be turned into true grab-and-go scopes.

The larger aperture of these instruments makes a huge difference in what objects you will be able to see and the detail you will see in them.

Dobsonian mounts are inexpensive but sturdy and easy to use. Scopes on EQ mounts in this price range tend to be wobbly and frustrating. They may look more high-tech but don't let that fool you. It's usability that counts.

Re collimation: I have f/4, f/5, and f/6 Newtonians. By far the easiest to collimate is the f/4, for the simple reason that I can reach the collimation screws while looking through the focuser. The procedure is the same regardless of f-ratio. It's true that faster scope will need collimating more often (all else being equal), but that should not influence your decision. Having said that I'd recommend sticking to f/5 or slower, but for other reasons (demand on eyepieces, coma).

[jjjnettie (Jeanette)]

Hi Patrick,
Welcome to the forum.
My advise:
Get yourself to an observing night run by your local Astronomical Society and see the difference between the different size reflectors and then compare them to the views from a small refractor.
I had a 5" reflector on an EQ mount on loan to me a couple of years back.
It only took 3 months to realise that I needed a bigger scope.
The resale value on the smaller reflectors is not very good, that is if you can find a buyer for it.

[astro_nutt]

Hi Patrick...and welcome to IIS..
Definitly go to a local Star Party and if you can...view through the scopes that you might be after..then compare with some of the bigger ones..8" dobs are very easy to live with..have sufficient aperature...and transport easy too!!...plus the wealth of info from all the wonderful folk in this forum!!
Cheers!!

[Gargoyle_Steve (Steve)]

Just a quick few words that go straight to the 3 scopes you mentioned:

1/- Aperture rules!!!
Simply, the bigger diameter "hole" you have at the front of the scope to let light in, the clearer the image you will get. Trust me, as soon as you start trying to look at galaxies, nebulae ... in fact pretty near anything, the bigger your light bucket the better.

2/- The great advise I received from many folks on this site when I was buying my first scope (almost exactly 6 months ago) was clear: it doesn't matter what scope you get, if the mount is wobbly you will NOT have successful viewing. If your viewing is unsuccessful you'll not be inclined to keep trying - eventually you'll end up owning a scope that sits in a corner of the garage unused & unloved. EQ1 type mounts are NOT stable, in fact EQ2's don't seem great either - go for a minimum of an EQ3 or AZ3 scope if you really want a tripod mounted scope. You are going to find it very difficult (nigh impossible) to get a good quality scope on a sturdy mount and have it weigh less than 10kg's.

2/- Avoid "short tube" reflectors, unless they are worth LOTS of money. If you want a reflecter with a focal length of 1000 mm for example buy one that actually has a body 1000mm or so long, not half that with an internal "doubling" lens.

Having said all of that: for stability, cost effectiveness, and to get as much aperture as possible for your money, it is impossible to beat a Dob (ie Newtonian reflector mounted on a Dobsonian base) for power and value for money. I personally ended up buying a 10" Dob and have not regretted that decision for a split second.

Here's a couple of scopes that perhaps are worth looking at:

Skywatcher SW500 150 x 1000P EQ3 $499.00 AUD
Skywatcher SW-600 200 x 1000P EQ5 $799.00 AUD

Skywatcher SW-880 250 x 1250 (Dob base) $699.00 AUD

Guan Sheng GS-880 250 x 1250 Dob Deluxe-Crayford $649.00 AUD

Bintel BT-252 10" Premium Dobsonian Telescope $679.00

(These last 2 are actually the same scope, made by the same manufacturer,ie GSO, packaged slightly differently. The accessories in these 2 packages vary slightly. They are an f5 scope and quite good quality optics at unbelievably affordable prices.)

I hope this helps - as I went through the exact same issues so recently I thought perhaps my perspective may be helpful.

Whatever you do it is still a VERY good idea to try and get along to a club meet, informal gathering, etc of other scope owners - get an idea of how big, how heavy, how expensive the different scopes are, and how good the views are BEFORE spending any money.

Cheers, and good luck!

Steve

[toetoe (Peter)]

G'day Patrick and welcome to IIS.
The Tasco you mentioned above is the same as the one i have. It has been a great telescope to me with lots of great viewing. The only negative thing i could say about the tasco i have is that it is only 4.5 in diam and not 12" . Take all the advice mentioned and put it to practice if you can and don't rush into anything. The EP's which come with the tasco are only average to bad, with a good quality EP in my tasco has made a 100% improvement which has made things more enjoyable, the mount, well it does the job and only that but it has not put me off this little telescope at all. Why i don't have bigger and better is that when i have some cash to spare there is more important things that have to come first to me, untill that time comes to me for bigger and better i know i can still enjoy the great views with my Tasco.

[h0ughy (David)]

price, apature, portability! go a dob or a meade 8" lightbridge if you need to pack it up small

[mickoking]

Originally Posted by toetoe

G'day Patrick and welcome to IIS.
The Tasco you mentioned above is the same as the one i have. It has been a great telescope to me with lots of great viewing. The only negative thing i could say about the tasco i have is that it is only 4.5 in diam and not 12" . Take all the advice mentioned and put it to practice if you can and don't rush into anything. The EP's which come with the tasco are only average to bad, with a good quality EP in my tasco has made a 100% improvement which has made things more enjoyable, the mount, well it does the job and only that but it has not put me off this little telescope at all. Why i don't have bigger and better is that when i have some cash to spare there is more important things that have to come first to me, untill that time comes to me for bigger and better i know i can still enjoy the great views with my Tasco.

That is a very good point. I once owned a 114mm Tasco reflecter. With the eyepieces supplied the performance was abysmall. But when I used it with a quality eyepiece (25mm LV) it was transformed into a great little rich field scope.

[astropat]

I'm amazed by the number of responses. Thank everyone of you for all those valuable advices. After a long thought, I think I should start with a pair of 20x80 (triplet) binoculars + a tripod.

Is it true that many experienced amateurs use binoculars? If yes, in what occasion?

Any recommendation on the binoculars (<$300 and relatively light) and tripod (<$250) brand/model?

I may later move on to a back-pack-able/very-portable (<=10kg) telescope. I'm thinking of either the Orion StarBlast 4.5 EQ Reflector (114mm f/4 with EQ1 mount) that I mentioned, or the Skywatcher 1025AZ3 short tube refractor (102mm f/5 with AZ3 mount).

http://www.telescope.com/shopping/pr...dd=yes#tabLink

http://www.skywatchertelescope.com/1025.html

Is the Orion Reflector or the Skywatcher Refractor a better choice? And why?

Also, do experience amateurs use AZ3 mounts? If yes, in what occasion?

Many Regards,
Patrick

[snowyskiesau]

Originally Posted by astropat

I'm amazed by the number of responses. Thank everyone of you for all those valuable advices. After a long thought, I think I should start with a pair of 20x80 (triplet) binoculars + a tripod.

Is it true that many experienced amateurs use binoculars? If yes, in what occasion?

Any recommendation on the binoculars (<$300 and relatively light) and tripod (<$250) brand/model?

I'd say just about everyone in this forum has used binoculars to gaze skywards at some time.
It's quicker to grab the binoculars than it is to set up the telescope so I tend to use mine (20x80T) more often than the telescope.
I got mine are from Andrews Communications [http://www.andrewscom.com.au/site-section-11.htm] and cost $239 (a bit cheaper now I think)
The same binoculars are also available from AOE [http://www.aoe.com.au/aoe80.html].
Neither could be considered light at 2.7kgs so a mount/tripod is a must.

[janoskiss (Steve H)]

Originally Posted by astropat

I'm amazed by the number of responses. Thank everyone of you for all those valuable advices. After a long thought, I think I should start with a pair of 20x80 (triplet) binoculars + a tripod.

Beware that on a regular camera-style tripod you will not be able to use the binos higher than 40 degrees above the horizon. You just cannot get under the thing. For this you'd need a more elaborate counterweighted mounts (eg parallelogram mount). They are hard to come by in Oz, but you could build your own, maybe on top of existing tripod + mount head. (see one of Starkler's threads for an example)

You should also get a good FMC pair of low-power binos too. Something in the 7x-10x range with 40-50mm aperture. These will show you a much bigger chunk of sky and will be easy to use hand held.

Is it true that many experienced amateurs use binoculars? If yes, in what occasion?

Yes. Many objects look best in binoculars because they are too large for telescopes. Binos give a different perspective on things with much wider field. They are also an essential star-hopping aid and for learning the sky (esp low power ones, 10x and less).

I may later move on to a back-pack-able/very-portable (<=10kg) telescope.

A 5" Mak is probably the biggest backpackable scope around. e.g., Skywatcher or Orion 127mm. That would be my choice or a Zenithstar style 80mm apo or semi-apo. The mount will not fit in your backpack. Vixen Porta mount looks like a good one for portability and stability. AZ3 is okay but not great. There are different versions of AZ3 around. e.g., the AOE one is much cheaper but also lighter and weaker than the Bintel one AFAIK.

Is the Orion Reflector or the Skywatcher Refractor a better choice? And why?

I don't think a 4.5" Newt will be very backpackable. And the f/4 mirror is unlikely to be figured to the sort of precision you need for high powers. An EQ1 mount will be a frustrating to use. Short tube achromats have a lot of false colour. I really don't like them. For low powers they are okay, but then you'd already have binos for that.

[jjjnettie (Jeanette)]

The 20x80 binos are an excellent choice. There is a light weight ( LW )version, and they cost about $149.
I like Steve's suggestion of a 5" Mak.