Start with Dob or SCT?

[Veil]

After much research i'm about to buy my first telescope. I have reached a crossroads and am open to advice. Do I:

1. start with a dobsoian (8" or 10"), and continue what i've been doing for a while with my binoculars - learning the sky with no technical complications (ps. I'm 6'4" and 15 stone, so size of scope is not a major problem) or

2. Go for an 8" Celstron SCT. I hope to one day dabble with photography so will end up here someday anyway (with hyperstar and ccd, given the very slow speed of this scope). What puts me off starting here is learning the technology/set up/ mount etc, whilst still not knowing my way around the sky that well.

Cost is not really my limiting factor, i'm far more concerned with getting the right equipment.

Thanks in advance for your advice,

[clarkent]

Ditto moi....

I joined an astro soc and started to borrow their scopes one by one. In the meantime I could not resist an offer of an ETX125 mak and got that. 

Poor move.

To summarise my experience, the SCTs (and maks) have great optics but are a pain to setup and guide to objects, even bright planets, but can be used for ap.

Newts are much easier to guide and observe with and do not suffer from dew as quickly as sct/mak types.

Dobs are a joy for the fastest to setup and start viewing, by far. 

If I was starting again, I'd get a s/h Dob (as you say 8"/10") and just enjoy the observing, getting to know the night sky. AP can come later.

Cheers

Andrew

[AstroAdam]

Yep - I'd agree - a dob gives you best bang for buck aperture wise, and will give you a larger range of objects for less layout....  Then you can decide if you want to move up to something a bit more challenging.  My 8" dob lasted me 9 years before I moved on, and I still have it!

[ChrisLX200]

For observing you need aperture, so both SCT and Newtonian (which the Dobsonian mounted Newt is) tick those boxes. A Dob is practically useless for imaging apart from planetary or moon, and even there it's a pain because the target will drift through the FOV fairly quickly at high mag, and just getting the target on your chip/camera is a chore. Neither is the SCT ideal for imaging simply because the long native focal length makes it a challenge to work with - the demands on the mount are high, the FOV is small, and longer exposures are required. A focal reducer will help but at the expense of a non-flat FOV. The SCT does have uses in imaging for smaller objects - galaxies, planetary nebulae and globulars for example, whilst a Hyperstar is good for the wider field images but does require the right type of camera - the small cross-section type (like an Atik 460/490 etc.). However, you can't use a normal filterwheel with Hyperstar because it would block too much of the incoming light so manipulating single filters is your only option (or use a one-shot colour). For imaging I believe the way to start is with a smaller, fast f/l APO refractor 80-100mm or so. Learn using that and move up to something with a larger aperture (like an R/C for example) later if you need the extra reach. For imaging then good results demand a good mount, something not essential for visual observing, so getting an all-in-one solution at the outset, an instrument suitable for both visual and imaging, is difficult and a compromise. You might not be happy either way you go - imaging or observing - with such an instrument. What will never be a bad purchase is a quality mount, get that and then decide what optics you want to mount. A cheap Newt, or SCT optical tube (or a Mak, Schmidt Newt, refractor or whatever) can be chopped and changed, but a good mount will stay with you and perform as needed.

ChrisH

[itmo]

Astrophotography is an endless money sink. Get an 8" dob and learn with it , you can use it later to watch the skies while your 10kpound rig is clicking away.

[Veil]

Thanks all. Really appreciate you taking the trouble to reply.

[Tinker1947]

i think a 10" newt and a NEQ6 would sort you out, it does what a Dob does and it does AP, you also get to learn the night sky by star hopping or speed it up a bit and use the GoTo another nice option is EQMod which is a really smart program, i used a 10" newt and for AP unguided you can get some really nice easy, simple images....

M13........ 10 X 30 seconds, 800 ISO, Canon 1100D unmodded, 10" newt, NEQ6 mount, DSS Stacked only

[Veil]

Hi tinker.

I did consider exactly that scope - Explorer 250 PDS on EQ6 Pro mount. However, as a novice, i was put off by such a huge scope on an eq mount.

I agree that for someone who can handle it, it fits the bill very well for what i want to do (a good all-rounder for visual and AP)

[Tinker1947]

Hi tinker.

I did consider exactly that scope - Explorer 250 PDS on EQ6 Pro mount. However, as a novice, i was put off by such a huge scope on an eq mount.

I agree that for someone who can handle it, it fits the bill very well for what i want to do (a good all-rounder for visual and AP)

It was a bit of a pain setting up every time and this needs to be thought about, built a small Obby and that made a huge difference, i use a 11" SCT atm and i wouldn't want to set this up every time......

[ronin]

Your signature says London. With the general light pollution present you may need a goto to actually get to see anything.

A big dobsonian is fine if you can locate the object, however light pollution tends to hamper that.

I would guess that something like the 2 stars in Andromeda used to hop to M31 with are invisible to you.

You could well have a problem with star hopping simply because of the loss of "visible" stars.

Visit Baker Street Irregular Astronomers in Regents Park and see what they use and what they say and suggest and why they suggest any particular scope.

[clarkent]

Sound sense to contact your local astro-soc, as ronin suggests.

[swamp thing]

I would stay well away from a 10" newt on an EQ mount myself. Setting that up every time you wish to observe will drive you round the bend. I used to do it, it becomes tedious very quickly.

From London you've the choice of grin and bear It (regarding LP) or get out of there. I tried the former, for me the end results are so utterly disappointing that getting out of town is the only option.

Therefore I recommend a portable set up. Basically buy whatever you can move out of London easily.

[Charon]

SCT's are not hard to set up, in fact once  having done the process three or four times it is easy and the 'goto' accurate. but if you want to learn how to find your way around the stars then a dob is the way to go Each telescope has it's good and bad points. What you need to do is work out the better points on each scope that will satisfy your initial needs, because I can guarantee whatever scope you first buy you will change at a later date. I have plans to sell my CPC800 and buy a 14" dob but this is for next year.

[Luke]

Light pollution might be an issue if you are in London, as mentioned. I have an 8 inch SCT and a 10 inch dob and under okay skies I wish I had started with a 10 inch dob. It is my most used observing scope now (ignoring my solar scope), very low on hassle apart from it ideally needs a bit of time to cool down to the outside temperature (or you can save on cool down time by storing in a shed/unheated outbuilding). Last night was a good example. It looked like clouds might be coming in and I was not feeling that great. But my dob is pretty light and only takes a few seconds to pop outside and set up, so out it went. I had a nice little session, the highlight being observing the super nova in M82. As it happened, the clouds took their time, but with the UK you never know if it really will be clear, which is why I love a very practical scope with a reasonably large aperture. The scope is pretty big, definitely check out the dimensions, but it sounds like you are prepared for that so I think the issue might be light pollution.

All scopes have their plusses and minuses, I love my SCT too. It comes out to play when I want to observe or image the moon (the moon with a binoviewer and SCT is amazing!) and it makes a compact mini light bucket for transporting. It can of course do DSO imaging too when used on an Equatorial mount, but I personally prefer an ED80 for DSO imaging (which in turn is very limited for general DSO observing). Not that I image DSO's much these days, I am more into solar system now, especially the Sun and Moon.