C8-NGT for Astro photography.

Iomrall

Hi,
I was thinking of purchasing a Celestron C8-NGT. I am new to astronomy but would very much like to do some astro photography especially deep sky photography.
I was wondering if anybody has any experience of using this telescope for astro photography or any advise?.
My main concern is back focus. I have read that I may not be able to achieve focus with my 35mm camera ( I have a Canon 450d).
I was also thinking of a NexStar 6 SE but it is much more expensive and I was told that the C8-NGT would be better but heavier.

Thanks

dmcdona

Astrophotography is a huge field within astronomy. There are many pitfalls, gotchas, disappointments, pain and suffering. Yes - and I've been through them all

I have certainly used an 8" SCT (Celestron) for astrophotography with good results. But that was after going through all the negative aspects listed above. I've even used a 70mm refractor of dubious quality and got excellent results.

Fundamentally though, you need to be clear about what you want to do. Unfortunately, there really isn't one telsecope/imager combination that will allow you to take photographs of, say, the planets and deep sky objects. You really need two different kinds of setup. Even within a particular setup, you need flexibility as regards things like focal reducers and filters.

Backfocus for sure tends not to be a show-stopper - you can get various (cheap) attachments that will help you achieve that.

Of the two models you propose below, the C8-NGT would probably be the better choice simply because its a German Equatorial mount. Fork mounted scopes will give you field rotation (stars look like little arcs) when taking longer exposures.

I don't want you to think I'm pouring cold water over your clear enthusiasm - in fact, I'd strongly support you and hope that you can at least do *some* astrophotography.

But it is a minefield and I'd recommend you do the research. For example, after I dipped my toe in the water and figured out want I wanted to do, I did the research on my "ideal" astrophotography setup. From the start of that project to the day I was able to take the kinds of images I wanted took me close on three years.

As a starter, there are really good posts in the astrophotography forum at www.irishastronomy.org Also, you'l find that any questions you have will probably get a better response than here (no offence to boards .ie but all the astro freaks tend to hang out there rather than here )

I hope that at least helps you on the way at least to dipping your toe in the water...

Dave

dbran

Hi Iomrall

dmcdona is correct in all he says.

I know someone who has this scope and it is very good. However a newtonian on an equatorial mount can be a pain in the ass to do observing on as you can get into the most contorted positions. The orientation of the eyepiece to the observer can on occasions be annoying not to mention uncomfortable:)

So my two cents are to decide if you really want to do astrophotography to the detrement of observing. Then an equtorial is definately for you as it allows you to go long exposure of over two minutes.

If on the other hand you want to observe and just dip your toe in the water for the moment on astrophotography then a fork mount is very useful. An 8" on a good fork mount can easily get you good shots of the brighter nebula and planets easily within 1.5 minutes exposure. You can then take multiple exposures and stack them to get the equivalent of a longer exposure. (of course you will not be able to go as deep as an equitorial). Here is a sample of some of the shots I have got on my lx90 which is a fork mount.http://www.flickr.com/photos/bertthebudgie/.

Also an equitorial mount on its own does not guarantee you deep images. A lot depends on proper polar allignment, tracking, focus, accuracy of the mount itself, sky conditions etc. The longer the exposure length the more unforgiving the above factors can be. So 10 shots of 10 minutes when you have to through out 7 due to trailing of the stars will not be as good as 100 shots of one minute that you only have to throw out 20 images

Hope this makes sense/helps

Dbran

Iomrall

Thank you both very much for you feedback,

I have done some research and I think that I have my expectations in check. I am not expecting to be able to take good astro photography shorts at the outset. In fact I think I would become bored very quickly if it was too easy .
Part of the enjoyment of me will be the challenges and learning the techniques involved and from what I have read there will be a alot.

My main concern would be that I would buy a scope that was totally unsuitable for me. What I am really looking for is a scope to get me started and that I can build on over time.

Iomrall

dmcdona

Iomrall

The work you put into astrophotography is directly related the the results you get. If, as you say, you like a challenge, you won't get much tougher than this

I can see your going to love it!

As regards buying a scope, I started off with an 8" SCT on a fork mount. I then upgraded the mount to an equatorial wedge (which got rid of field rotation). I then moved onto a piggybacked 70mm refractor - so I could image through either scope. I started off with a webcam (home-brew) then moved up to a CCD imager (budget type).

Whilst doing all this, I honed my skills, learned the trade and then started researching a system that would be within my budget but as good as I could get. So I ended up with a setup that would've bought me a luxury car - but my results are excellent.

The lesson you can take is that yes, there is a progression you can follow that will help you learn and keep you in credit. And you *will* be able to upgrade. Don't forget, 8" scopes are great beginner's scopes - so you could easily sell it on to upgrade.

Go for as big an aperture as your finances allow (but no more than 8") - refractor or reflector - your choice.

Try and get a GEM rather than a fork - unless you can get a fork with a wedge. Use your 450D (but bear in mind you'll need adapters) or go for a cheap CCD.

Prepare to learn a whole chunk of stuff and if you're not a proficient computer user, you soon will be :eek:

Bear in mind that there are great bargains out there in the 2nd hand market (see the IFAS website and post up a "wanted" ad). I've even see some folks give stuff away in recent months.

When you're ready to upgrade, let me know. I can give you the low down on getting the best bang for your buck and making the right choices.

By the way, with a little help, there's no reason why you *couldn't* take good photos within a matter of weeks...

Let me know if there's anything I can do to smooth the path to righteousness