New scope advice

[EezerGeez]

Hi,

I'm Gareth and I live near Cambridge.

I'm hoping to buy a scope but have a few requirements/question that I thought a few of you knowledgeable lot might know the answers to.

Firstly, say a budget of £1000

Secondly, I want to be able to connect it to my PC and see the images reproduced on the screen - is that possible for my budget?

Thirdly, could I get a scope in my budget that is electronically controlled (movement/focus etc)?

Fourthly, are second hand scopes worth considering?

Finally, what impact will light pollution have if I position the scope in my garden?

Thanks everyone. Any links to appropriate scopes would be very much appreciated.

[Whippy]

Hi Gareth, I'm just down the road for you in St. Neots .

A budget of £1000 will give you quite a few options! Essentially, the more gadgets (ie: electronics) you have, the more expensive it gets. Your main gadget will be GOTO which after an alignment process will find objects for you up in the night sky. Your budget won't stretch to electronic focus or indeed using a video camera for viewing images on a monitor. You can look at second hand scopes as an option but you best be aware that you can be sold a lemon, steer well clear of Ebay!!

With regard to light pollution, I figure your skies are worse than mine (depending on where you are in Cambridge) and it does affect your ability to look at fainter objects. However, you can buy light pollution filters that can help by cutting out certain light frequencies such as street lamps.

With your budget and if you really want GOTO, I'd go for one of these: http://firstlightoptics.co.uk/proddetail.php?prod=200heq5pro . Good mount with a scope that has a good all round performance for most types of object.

Tony..

[EA2007]

Hi Gareth,

I am going to sway completely the opposite way to what 'Whiplash' said on a couple of things.

If this is your first scope then I would recommend not going down the route of astrophotography straight off..... as you will find it better to find things first with your eyes, there is always plenty of time to get into imaging, for now I would focus on using good old eyesight.

However, if you did want to go down that route then you can get definitly get away with a reasonable setup for imaging. As an example I would perhaps go for this http://firstlightoptics.co.uk/proddetail.php?prod=C8nGT, as it gives you a very large aperture for a beginner, goto and the ability to take images if you so wish. Alternativly go for the skywatcher 200p (non-goto) http://firstlightoptics.co.uk/proddetail.php?prod=200heq5 for around £500, this will leave you with £500 to get your webcam / ccd / dSLR and extras

Of course you will need a digital SLR or webcam / CCD for imaging. Even a cheap dSLR such as the Nikon D40 will happily get you on your way. But if you want to see results on a laptop then go for a wedcam, you can get modified ones to take longer exposures from astronomiser.co.uk and other sites.

For £1000 you can actually get quite a bit, I should know as I am a student!! If you go into a shop for something, definitly haggle the price down or see what extras you can get thrown in. You will need a t-adapter and t-ring if your going for a dSLR and you will also need a 12V powertank to power any goto or motorised scope.

Light pollution can be a massive pain in the 'rear'. As Whippy said, you can get a filter for this and I know from experience that this works a treat! Otherwise you are left with a washed out orange image which looks like a dog has spilt orange juice all over it!!

Enjoy!

[EezerGeez]

Thanks for some fabulous advice, chaps.

I think - if nothing else - I've realised that 1. there is far more choice than I first realised and 2. there are a plethora of options and technological capabilities.

I think I'd perhaps be best to visit a scope dealer [armed with your recommendations] and view the equipment and discover the accessories that are available. I'm still not entirely sure whether I'm looking for suitable aparatus to view our immediate neighbours or whether I want to peer deeper ito space [a decision, it seems, which narrows down one's choice of scope significantly].

I'm going to arrange to visit green-witch in Dry Drayton. It seems most local and hs been recommended to me.

I'll report back here when I've answered some questions only I can answer and when I've physically checked over my equipment options.

Thanks very much to those who have generously taken the time to reply. I'm very grateful.

Gareth.

[EA2007]

deleted due to interference

[Whippy]

Whoa there EA, lets rewind it back a few steps here .

I believe Gareth was implying he was interested in viewing objects live through a monitor instead of an eyepiece. This would involve using something like a Mallincam. Astro imaging is a completely different bag of headaches which isn't done in realtime.

A refractor can only really go upto 6 inches in aperture, after that the primary mirror is liable to collapse and also the lens. Refractors are your basic scope that require no 'collimation' and aren't too big. Better suited for DSO (Deep Sky Object) work but they work alright for planetary work. The focal ratio is usually around 5 to 7, which is considered fast, so faint objects (DSO's) appear well but you may not be able to get much detail in planetary observations.

I've never heard of a refractor having a mirror, let alone one that collapses! I've seen refractors up to 10" for sale but they're hideously expensive and will need a VERY strong mount to cope with them. Some refractors refractors can be collimated, it depends on if the lens cell is collimatable! Focal ratios can vary from f5 up to the Antares f15 (and longer).

Reflectors are probably the best all rounder and you can get these from anywhere between 4 inches to 12 inches (or bigger if you have millions of pounds to spend). There are 2 main types of reflectors, Equatorially Mounted (EQ) or Dobsonians. Dobsonians are great for DSO work and also planetary and very easy to use, you just aim it to where you want to look, lock it in place and there you go. But due to its Alt-Az mount (not equatorial) it is useless for astrophotography as it cannot track an object. However afocal photography (hovering a camera over the eyepiece) of planets can be done (I have managed to get Jupiter, Saturn and Venus with my dob.) An EQ mounted newtonian reflector (named after Sir Isaac Newton who designed it) is a better choice for imaging, especially DSO's. Reflectors are subject to collimation errors (where the primary mirror is out of alignment with the secondary mirror) but this is easily overcome and happens rarely, I haven't had to collimate my dob since I got it 2 years ago.

Reflectors are indeed the 'best bang for the buck', but I wouldn't recommend a Dobsonian mounted one for planetary work due to the often high magnification needed to get detail and hence the constant 'nudging' of the mount to keep the object in the field of view. I think you'll find a lot of experienced imagers actually prefer refractors or catadioptric scopes over reflectors due to issues such as coma, collimation and lack of focus. I'm not saying people don't image with them because there's plenty of people who produce great images with one (I started with an afocal setup which gave good results) but I'm sure if you asked around, most would prefer other designs. Collimation isn't a big deal but I think you'll find many people have to collimate their newts fairly often to keep the optics in alignment.

Schmidt-Cassegrain and Maksutov-Cassegrain telescopes are the short barelled scopes you may have seen. Due to a high focal ratio of 10-14 these are considered slow and not very good for DSO photography as objects appear faint. This can be overcome with what is known as a focal reducer (I have learnt that if you purchase a Catadioptric scope and a webcam / ccd you can also get an Atik 0.5x focal reducer which makes it a lot 'faster'). Catadioptrics are quite expensive for aperture but give great images of the planets.

Many, many people use these scopes for imaging and get spectacular results, whilst the focal ratio may be slow and you'd need longer exposure times, because of the long focal length you get a smaller field of view so in effect you get a higher magnification. A good example being you'd be able to image M51 with a short refractor but it'd be tiny. Image it with a Mak or SCT and M51 will be a lot bigger.

By all means go down to your local astro shop or astronomy society and have a look at your intended scope, pictures really don't give the idea of scale and weight these things can sometimes be! Or if you're prepared to wait a couple of weeks, if you can get to the Kelling Heath star party there's going to be loads of people (including me) who will only too happy to give you some advice and let you have a look .

Tony..

[AlexG]

Hi Gareth

I notice that Green Witch are holding a star party on April 1 - pray for it to be clear! - which would allow you to look through lots of different telescopes and get a feel for these things.

You may already have seen and handled some of these telescopes but often people are really surprised how big and cumbersome they are (after just looking at pictures on the net). The practicalities sometimes mean people have an optical telescope and one devoted to imaging, and you might want to give that a thought too.

AG

[EA2007]

Knew this would happen....nevermind.

I meant lens not mirror, so what, I made a mistake gees! ALSO Gareth has a budget of £1000's so he is not going to be able to get a refractor larger than say 6 inches. The reason I mentioned 'collapse' is because the lens is made of glass material which (at large scales) is liable to sag, bit like when people get old!

If you read my post you would also realise it had the words 'ccd and webcam'-BOTH can give realtime views through a scope.

(Some people are always there to disagree, but thats life)

[Whippy]

Are they Alex? T'is a shame , I'd love to go for a look but weekday nights are a nono for me (L'Missus works nights).

Knew this would happen....nevermind.

I meant lens not mirror, so what, I made a mistake gees! ALSO Gareth has a budget of £1000's so he is not going to be able to get a refractor larger than say 6 inches. The reason I mentioned 'collapse' is because the lens is made of glass material which (at large scales) is liable to sag, bit like when people get old!

If you read my post you would also realise it had the words 'ccd and webcam'-BOTH can give realtime views through a scope.

(Some people are always there to disagree, but thats life)

Hang on, glass does not sag! I've lived in houses with Victorian sash windows with the original glass, no sagging there. Nor is there in any of the vintage refractors people have in their collections.

Yes webcams can give a realtime image but it's pretty much a featureless blob without stacking these images to produce one good still image. Like I said, something like a mallincam which is specially designed to give a realtime view through a monitor would be suitable. Google it and you'll see what I mean.

Sorry if you feel offended, but we were all newcomers once and it can be daunting making that first purchase which is why it's important to give the right advice.

Tony..

[RobH]

Hello Gareth,

A couple of points here....

Refractors are probably the best scopes inch for inch for planetary work, due to the lack of a central obstruction. In all other commonly found types of scope, there is some sort of central obstruction, usually a secondary mirror, but sometimes a camera, which has the effect of decreasing contrast somewhat. While this is not so crucial on deep sky objects, it makes the refractor a little better on planets.

The biggest refractor ever built has a lens of 40 inches in diameter (please correct me if there was a bigger one!) above this it was considered that, due to the size and weight of the lens, and the inability to support it from one side, as you can with a mirror, sag would become a problem. That's a pretty big lens though!

Look on Optcorps site at some of the refractors for sale there....huge money but monstar scopes....lottery win material

For Deep sky stuff, what you need more than anything is light...a lot of these objects are very faint. You will get more inches of aperture for your money with a reflector than anything else.

For lowish power viewing a Dobsonian would be your best bet as you're not spending a lot of budget on a mount.

If you want higher powers, and/or want to image, you will need your scope to be on a good, sturdy equatorial mount, with drives if you want to do long exposure photography (makes it much easier visually too).

For a bit of both, a catadioptric scope is probably the way forward.

Your money will buy you more aperture than a refractor, pound for pound, so you will have that all important light gathering power, plus, at F10 or so, you will have high magnifications available for planetary work.

If you want to view some of the larger DSO', you can get a focal reducer quite cheaply to drop your focal ratio down to F5 or 6.

They are also physically very compact scopes.

I recently sold a 10" Meade LX200 classic for £1000, a great scope which served me well in all capacities until I got my current permanent setup.

You could do worse than pick up one of them, or the 8 inch version.

Hope this helps

Cheers

Rob

[centroid]

Orwell AS have a 10" refractor that was made in 1879, it still has the original objective lens, and its still as good as the day when it was made 129 years ago.

Dave

[EezerGeez]

Thanks for all your advice folks.

I appreciate all info/opinions and have heeded the +/- aspects for each scope type.

I hope I have't instigated a forum feud - that's the last thing I wanted!

With the Easter weekend it'll be a few days before I can visit a dealer but I'll report back when I have.

Thanks again.