Telescopes and star gazing.....

Good thread Ali. I have long toyed with the idea of buyinga good telescope but I too have no idea where to start.

I had a 6 inch reflector many years ago and built a motor drive system for tracking the stars. It was however, very fustrating as I live close to a large city and light pollution is a real problem.

If I were buying a scope now I would buy something portable and easy to set up so I could take it on holiday with me.

Ali

It depends on what you want.

Refractors are best for lunar and planetary observations, but will be fairly limited in aperture (which will determine the amount of light gathering possible) as they have to have a much longer tube for a given diameter.

Newtonian reflectors are better for deep sky and are generally very cheap. The problem with these again is they tend to be quite large although not as long as refractors for a given diameter. For the same diameter a refractor will give you more magnification but are generally more expensive for a decent one. Reflectors will usually have a larger diameter at any price point.

Steer clear of the cheap Tasco models at all costs which bost incredible magnification. Magnification is not the most important factor as there is no point in hugely magnifying a fuzzy image. The quality and light gathering powers of the mirror/lens are what matter here.

There are also the catadioptric designs such as the Schmidt-Cassegrain or Maksutovs which are a great compromise as they have a very short tube and enable you to have a large diameter mirror in a manageable sized telescope. They are good all-rounders.

It then depends on budget.

I would suggest starting off with a cheap decent refractor of around 2.5" - 3" or a Newtonian of around 4"-4.5" diameter to learn your way around the sky and how to use a telescope.

Then progress on to one of the larger diameter catadioptrics where you can get motorised drives and computerised GOTO facilities. These lend themselves well to astral photography.

Tal is a Russian make that has some very good entry level products. I currently have a Tal 100R refractor which I don't often use these days because of the appalling 'seeing' where I live.

Some of the better more up market catadioptrics are made by companies like Meade and Celestron.

Also make sure you always get one with an equatorial mount.

You could start off with a cheap catadioptric 'goto' telescope which does make life easier as it finds all the objects for you. You just punch in the object you want to find and it moves to get it in view.

I always think you should do 'the hard yards' first, though and get a manual 'scope to really learn the skies properly, although it can result in many really frustrating nights trying to find a fuzzy Messier object like a galaxy or even getting a planet in to view if you have the initial magnification too high.

When you finally do get that elusive first glimpse of the Andromeda galaxy or the Orion Nebula though, it is extremely rewarding and does start to give you some idea of thescale of the universe.
Ultimately it depends on what you want to do.

Have a look here for some of the better brands.

Regards

Mark

Mark,

Excellent post. Thanks.

Acad

Acad

You are welcome.

Mark

We bought a small Meade scope with their motorised tracking system. Cheap as chips and great fun!

David

Thanks Mark, acad was right - great information there!

Looks like (no pun intended, honest) I'm interested in a Newtonian Reflector, and I should have said that an SLR mount or compatible adaptor (or something) would be essential. I've used warehouse express before - bought filters/bits/bobs for my Nikon D70s and I never thought to look there....
Also found www.opticalvision.co.uk which had a couple of reviews and comparable prices.

Here's my other effort from Wales using my D70s, mini-tripod, and exposure of about 20 minutes....I only managed a couple of decent ones as the in-camera Noise Reduction took as long as the exposure!!



The light vertical blur, left of centre, is the Milky Way.

The cottage is in a great location, up in the valley above Faibourne, so very little light pollution. The first star trail looking north has the orange glow from Fairbourne and also Barmouth across the estuary.

Portability of the 'tube' would be handy as we live quite close to Aberdeen and light's pretty crap, but it doesn't take long to escape into the country.... Plus the cottage in Wales is owned by relatives so we are likely to visit again. We were out one evening watching the sky and saw a couple of shooters, a few satellites, and the clearest Milky Way I have seen in a while - spectacular!

Thanks again Mark.

Are there more enthusiasts on here, or other websites handy for info that you know of....???

Cheers,
Ali

I would add to the above:

- Don't dismiss binoculars on a solid mount.

- If you buy a scope on a mount with a computerised go-to system it will probably be on an altazimuth mount.

- If you get a scope with a computerised go-to system, make sure you know what the magnetic declination is where you are observing as most of these systems require you to set the telescope level and pointed true north before they calibrate themselves. While many of the Celestron and Meade models now have GPS built into them, I doubt that end of the market is what you are aiming at.

- Look into good eyepieces for your telescope. They are probably the cheapest, most effective and most immediately noticeable upgrade you could ever make without replacing the primary optics themselves.

- Think about how compact the Schmidt-Cassegrain systems are. You will be using your scope late at night and will not have a permanent observatory. If you are a little tired, and your telescope is large or unwieldy, then you will tend to get less use out of it - and therefore less use out of the money that you spent on it.

- Following from the last point: in my opinion, the location of the eyepiece at the top of a Newtonian scope makes them a bit of a challenge at times.

- Learn the constellations rather than relying completely on the go-to system. It will set you up for a lifetime of skywatching and is an excellent way to navigate around the sky - doing so will enable you to find things from descriptions in magazines etc.

- Astronomy is one of the few (perhaps the only) branch of science where amateurs continue to make a valuable contribution to the field of knowledge. Look into this because collecting information and submitting it to National observatories etc widens your understanding and gives you something to actually do with your observing. Timing occultations and lying on your back doing meteor watches with others is kinda fun (if you ask me...)

quote:

Originally posted by Deane F:

- Look into good eyepieces for your telescope. They are probably the cheapest...

On reflection, I think I should have said "inexpensive"...

Excellent advice there from Deane.

I thought about it afterwards when I had logged off. Binoculars are an excellent and relatively inexpensive way to learn your way around the sky.

The comment about the eyepiece location on the Newtonians is also true, especially for a shortarse like me! You will probably need a small pair of steps to stand on.

Ali

Another fantastic pic. Keep 'em coming.

You mention the light in Aberdeen but it is nowhere near as bad as where I am. I married a girl from Lhanbryde so I know what the light is like up there just out of the cities.....you don't know how lucky you are!

Mark

Some excellent posts, many thanks. It is this kind of stuff, sadly absent recently, which attracted me to this forum.

During the closing years of the last millennium I traveled with a few close friends to the isolated isle of Santorini, although no Mauna Kea the night viewing was rather better than that in London. Some evenings I would spend a few hours away from the beer crazed crowds and be found relaxing on the beach or way up on the caldera edge with my well thumbed Norton Star Atlas (c1966?) - not something you see on the Club 18-30 adverts. The viewing was stunning and at last the letters WOBAFGKMRNS started to become clear, simple pleasures are often the best.

From the web -

'The order of star colours are:

(Hottest) Blue - White - Yellow - Orange - Red (Coolest)
Not counting brown/black dwarfs etc.

The classification system is by letters and goes
(Hottest, bluest) W O B A F G K M R N S (Coolest)

Which is remembered by the mnemomic

"Well, Oh, Be A Fine Girl, Kiss Me Right Now Sweetie!" - '

I had to google W O B A F G K M R N S as you were too mean to provide any info Roy.

Hertzsprung-Russell Rules!

Excellent. Cheers Roy.

Hi,

I have spent years wanting a telescope before taking the plunge, we made the mistake of buying a cheap scope and regreted it - following two 'cheap' newtonians and a lot of frustration we settled on a Meade ETX125. It wasn't cheap (circa £600) however it is priceless! It is computer contolled, so after finding north and switching it on it select's two alignment starts (you have to tell it lat, long and time) all that it then requires is that you center the alingment stars and away you go! The moon and planets are awesome - saturn and jupiter defy belif with their beauty!

We have since invested in software called 'The Sky 6' to control the scope via a laptop - so now we get a picture of the sky on the laptop and we can select objects to view. The Sky also allows you to simply down load commet data and then slew the scope to the commet - easy!

Our next purchase will be a light pollution filter to cut down the glare from the heavily light polluted area that we live in.

Hope this helps.

Paul

I was just about to open a topic on buying a telescope. You people have saved me a job. What are the faults with buying a cheap 4-6" newtonion for a starter scope. There are loads on fleabay going for pennies from brand new sellers. Most from germany. I also want it to look nice in the corner of my room. Its more of a talkig piece but something I can use occasionally to look into the sky (and the neighbours bedroom out the back.)JOKE!

Like Hi-Fi you get what you pay for, however...

Like life size matters, the bigger the bucket the more light that get's in and the brighter the image.

But IMHO the learing curve is the biggest issue, it's steep - whilst it may be easy to find the moon it is a lot harder to fathom out which one is Saturn - we found it very frustrating (which is why we bought a computer controlled one).

Meade make a number of smaller scopes - I would suggest a smaller one say a meade etx90 or similar.

The other choice is to go to an astronomy club (there is one at the observatory next to the castle eden walkway - never been, but they all are friendly to newcomers - so I am told!).

Paul

thanks paul, knowledgeable and local. As I said tho, i,m not wanting to take it up as a hobby, just another boys toy really.

There's nothing "wrong" with Newtonians. The contrast is usually much better than a catadioptric design. They are very simple, usually very light, and a cheaper/easier to collimate.

However, the best sky is straight up or very nearly, as there is less atmosphere for light to travel through. With the eyepiece at the top of the assembly it can be a pain in the arse.

Also, because the tube is open the mirror can quickly form condensation after a temperature change - such as when you take the setup outside. This will mean you'll have to wait for the condensation to clear before viewing. The Schmidt Cassegrains are sealed and so are less prone to this. Maksutov Cassegrains likewise.

I've always wanted a Questar myself - ever since seeing the ads in Scientific American when a boy...

I don't think condensation will be a problem in Aberdeenshire......
Especially this time of year!!

Maybe when we take the tube back in doors though....

I was chatting with my gorgeous other half last night and mentioned the fact I was investigating a telescope, asked if she would be interested and got a positive response. She did ask questions about the use of it, something I had been pondering myself....
I wouldn't want to spend the kind of budget I'm looking at, somewhere in the region of £300-400, to only use it a couple of times - which I don't think will happen but.....well, I've never done this kind of thing before......
I totally see where Paul is coming from though in the fact that I would want to buy something we can grow into. Same applied to my first D-SLR, I bought a D70s not a D50 (then they bring out the D80, don't get me started, but hey at least my CF cards will fit into a D200.... ) this also applies to our stereo, jumping in at the deep end of CDX2/202/200 and not upgrading our way to that point!

So, we're back to the light pollution. Mark rightly pointed out that it 'aint that bad up here, but I don't see us making trips into fields all the time. Ideally it would be great if we could use it in our back garden patio. We live in a small suburb outside Aberdeen and I'm not sure how this will limit the use of a scope.

This may be a daft question but can you get such things as lens hoods (similar to camera ones but larger) and I'd imagine we would be limited to only viewing the uppermost skies - less atmosphere but also less chance of getting light pollution down the tube.....??

As for the type of scope I am still undecided, and probably won't be rushing into anything, a bit like the stereo - that's been almost three years in the waiting!
Portability, as I mentioned earlier, would be handy, but from the short time I've researched it appears the Newtonian Reflector has it's downsides too..... The primary mirror at the base can be knocked out of alignment quite easily, especially when transporting it, meaning it has to be set up before you can use it. Now I don't know, but, just how easy can this happen...??

Anyhoo, more research to do, while it's quiet of course.......

Oh, and Mark, thanks for the compliments regarding the star trail pics! They were the best two out of the trip, it was really windy - I used a couple of wheelbarrows on their sides as a shelter! But also managed to leave my aperture too high (shut in) on the first night, but I enjoyed the learning curve....

Cheers,
Ali

quote:

Originally posted by arf005:
I don't think condensation will be a problem in Aberdeenshire......
Especially this time of year!!

Maybe when we take the tube back in doors though....

It's a change in temperature that causes the condensation on the mirror - and it can happen no matter where you are and in any season. If you take the telescope outside where it is cooler the mirror will not reach the same temperature as the outside air as quickly as the air inside the tube will - and condensation will form on the mirror. It does clear but could take an hour. It's not a big problem and you can work around it in a number of ways. It's something to think about with open tubes though.

quote:

I wouldn't want to spend the kind of budget I'm looking at, somewhere in the region of £300-400, to only use it a couple of times - which I don't think will happen but.....well, I've never done this kind of thing before......

You could get a 4.5" Meade Newtonian on a computerised mount - plus a good eyepiece or two - for that sort of money. The Meade Newtonians do have the advantage of shortish tubes. I personally think that you should start with more money if you plan to get a refractor.

quote:

I totally see where Paul is coming from though in the fact that I would want to buy something we can grow into.

That would be an 8" Schmidt-Cassegrain by Meade or Celestron. You'd be able to mount a CCD on it and track with it for a few hours, building up a nice digital image. It would be worth building a little observatory for - a dream for many - which means youu just have to roll back the roof and start observing, with everything handy. No having to set up the mount and aligning the scope. Starts at around three times the money you're talking though.[/QUOTE]

quote:

So, we're back to the light pollution. This may be a daft question but can you get such things as lens hoods (similar to camera ones but larger) and I'd imagine we would be limited to only viewing the uppermost skies - less atmosphere but also less chance of getting light pollution down the tube.....??

It's not the light shining down your telescope that's the problem. The light coming from the sky is very dim and if there is street lighting then it just can't compete. You can get filters for refractors but they incur penalties of their own. Many people stuck in light polluted areas pursue lunar or planetary observing - which rewards refracting telescopes.

quote:

but from the short time I've researched it appears the Newtonian Reflector has it's downsides too..... The primary mirror at the base can be knocked out of alignment quite easily, especially when transporting it, meaning it has to be set up before you can use it.

Believe me, you'll be ever so careful with your baby when you're moving it around! Oh, and every type of optical assembly needs collimating at some point to perform at its best. A Newtonian just has two mirrors though, so its simplicity means it easier (or less expensive) to maintain.

Thanks Deane, lots to think about there....

Do you know of any good websites for info...??

Could save me a bit of time....also, I've requested a couple of books for Chrimbo, should be good reading.

Cheers,
Ali

Hi Ali

No I don't know any good websites I'm afraid. I haven't dome any observing for years. I'd recommend going to your library and getting some "Sky and Telescope" magazines though. Start reading them and build up a picture of the field.

And if you have some binoculars, then turn off all the lights you can, go outside when its really dark, lie down and look at the sky with the glasses. The field of view with binoculars is absolutely amazing and there will be thousands more stars there than you're used to seeing. If you are pursuing a sense of wonder at the night sky then that will keep you happy for a wee while. Then you might try resting the binoculars on something. You can make out four moons of Jupiter with any magnification really, and a crescent moon will look great with binoculars.

Deane

quote:

Chrimbo

If you mean Christmas, then I am starting to wonder if you're Australian...