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BTS
09-06-2008, 11:38 PM
Hi everyone!
After lurking around the forums here for awhile now, I've come to the point where I need to get some advice on an ideal imaging scope/setup.
I've always had a passion for astrophotography and see think I finally need to do something about it....
I have a 13yr old Celestron 8" SCT with Vixen GP mount on which I have taken same planetary and lunar shots through. Very happy! But it very rarely gets used nowadays. I'd like to keep this scope to use....
....But I now want to move onto something bigger/better(?) for DSO imaging. I've already decided (but have not yet purchased) on my camera, a Canon EOS 40D. I'll later fit this with some of Hutech's Ha/nebula filters and a shutter release (although a laptop can be used while using the LiveView mode).
What I had in mind (and I'm open to ANY input here) was to buy a Gemini GOTO fitted G11 Losmandy mount (sturdy, yet bulky), fitted with a f/4 SW-254 (Skywatcher 10" newtonian) giving only 1200mm focal length. Is this practical as my f/10 SCT has 2000mm FL?? Should I go to a larger SCT? My budget doesnt expand much past what I suggested above.
Should I go for a fork setup, can someone recommend/refute this type of scope? or would I be better to stick to a GEM? I like the Losmandy mount but for the price of this I could buy a very decent SCT (sturdy enough??)....
I know choosing a scope is a personal thing too, being many factors involved ie. size, weight, car space.... but is there anyone out there that can please point me in the right direction? In a later post, I'll ask about guiding recommendations....
Thanks and clear skies to all!

madtuna
10-06-2008, 12:03 AM
Firstly, welcome to the forum Brent!

The C8 you have is a very capable imaging scope, especially on the G11 with the 40D you plan on getting.

Just my opinion I'd get a focal reducer, guide scope and guide cam and stick with the C8





but then I just sold my C8 cause I bought a Vixen VC200L which I'm whacking on a G11 so my opinion sounds somewhat hypocritcal lol

marki
10-06-2008, 12:40 AM
Hi Brent

I think you have started an age old argument here :lol:. Everyone seems to have their own preference for scope/mount/camera setups (its almost a religious belief sometimes:help:). I have never tried to image with a newtonian so I cannot comment first hand but I am led to believe the dredded coma can be a problem???

What I am seeing though is some excellent wide field shots being taken from small to medium sized (60 - 120MM) refractors with good cameras and decent mounts. Check some of these out, hard to believe it is a little 60mm scope.

http://www.televue.com/images/reeves_is/index.htm

One huge advantage would have to be the light weight of these scopes which would hardly tax something like a G11 which means you could stack a lot of other stuff on it without fear of overload. Many have purpose designed field flatteners as an option.

Another fabulous Choice would be an RCOS, paramount ME and STL 11000 if you have a spare sack of money lying around . One power ball.... guess what I would be buying:D.

I can, however, comment on fork mount SCT's being an owner of a 10"LX200R for the past 18 months. They are extemely bulky and very heavy. If you want to use them for DSO they must be mounted on an equatorial wedge which will set you back around $1000.00 new unless you can find one second hand. You will also have to use a focal reducer as the focal ratio is just too high for this kind of work and all this adds up in dollars spent. I cannot mount mine on the wedge by myself which means you will need a helper (or take up weight lifting :P) or mount it permenently. The weight of the scopes is a problem in this configuration as the arms are prone to flexing and the smallest amount of wind will cause it to vibrate thus making long exposure photography impossible at times. Note this is on the standard tripod, I have not tried on a pier... yet. Some also have questionable QC and in my case I have done much meddling internally in regards to gear mesh. It works ok now though ... well mostly. In their favour is a great big mirror to collect light and fabulous optics which deliver coma free views (R and ACF series). They can also hump a heap of extra weight around in the form of guidescopes, cameras etc.

If I stared again I would most likely buy a G11 with a 120mm refractor or something very similar.

Good Luck

AlexN
10-06-2008, 01:54 AM
Mark gives some very sound advice in that previous post....
Im getting into DSO imaging at the moment, and after reading everything I can find, I've ordered a EQ6 (the G11 will be better, But its out of my price range) and have organised a 152mm refractor, for which I already have a 300D alot of accessories... I believe that for ease of use/portability a large refractor is a much better place to start for DSO's. Mind you a lot of people are using Newts and SCT to capture incredible images... and your C8 is a very capable piece of equipment..

You said yourself, choosing your scope is a personal thing... you really need to weigh up the pros and cons of each setup... including OVERALL costs.. whilst a 10" newt may be cheaper than 6" refractor, once you get a coma corrector, a good low profile focuser etc etc.. the costs build up.

montewilson
10-06-2008, 05:54 AM
Everything else makes sense but IMO go for a refractor up to 5" and enjoy yourself and learn then move up to a large newtonian. You will throw yourself in the deep end with a larger scope at the start. You can always get good money for a refractor later if you want to sell it.

Hagar
10-06-2008, 08:28 AM
Hi Brent.... Imaging, a matter of personal choice. My sugestion is definitey a Losmandy G11. A GEM is almost imperative for deep sky imaging where time exposure is required. Scope choise is somewhat secondary. If you keep your C8 you will need a focal reducer to fit most DSO's into your field of view. You will also need a guide scope and dedicated guide camera to maintain acureate tacking during you time exposures. This does not need to be an expensive scope. An ED80 will allow for very good tracking and will also work as a wide field imaging scope with your DSLR. A set up of this type would give you two diistinct focal ranges allowing DSO imaging of some of the large nebulas through the 80 and some high mag imaging of small objects like galaxies with the C8.

To move to a newtonian you will also require a Comma corrector $500, guide scope $400 and guide camera and rings $500.

My sugestion would probably be the most cost effective and would allow a very good mix of focal lengths. Remove the fork mount and add a dovetail bar to your C8.

Basic DSO imaging rules:
1. MOUNT
2. MOUNT
3. Tracking and guiding
4. Mount

Good luck with your choices and I hope this is of some help.

ozstockman
10-06-2008, 12:47 PM
Do you really need to buy a ED80 just to use it as a guidescope? I guess any cheap refractor for $50 is capable of doing the same job.

cheers,

Mike

JimmyH155
10-06-2008, 01:19 PM
I have a Meade 8 inch SCT LX100 on a very solid wedge, and mounted on an even solider U.S.A. made chrome plated tripod. This comes with 2 field flatteners, DSI, and lots of stuff. See my advert in the for sale ad. I think it is now on page 2. Only asking $1500 the lot:D It might be worth thinking about.

Ian Robinson
10-06-2008, 02:37 PM
Go for the biggest , beefiest and best GEM you can afford. (It will pay dividends and will serve you for a very long time.)

A guidescope or an OAG is a good investment too if you want to do long exposure guided images and any prime focus stuff.

A comma corrector is a must if you go to a newtonian. (Only choices here are Vixen, Baader and TeleVue. Lumicon are no longer made and scarce as hen's teeth - I just bought one and I believe it was last unowned one in the universe and it took a lot hunting to find it)

Hagar
10-06-2008, 03:34 PM
The only reason I sugested an ED80 (which is very cheap from Andrews) i so he has a second imaging scope for wider field work of great quality. A $50 achro will do as a guide scope but is near useless for imaging.

BTS
10-06-2008, 03:38 PM
Wow, some great advice, thankyou guys!:D
Yeah, I've always had my mind set on a G11 but thought a bigger scope would be better. BUT, I also dont want to have to be buying little bits and pieces just to get halfway to where I want to go ie. coma corrector (as mentioned), low profile focuser etc, so I'm glad I asked about the newts! Scratch that idea for the moment.:lol:
I'll invest in a guidescope/camera and try some shots through my C8 for now while I contemplate a refractor.:lol:
Now, does anyone know of a cheaper price ($4800) for a new G11?:rofl:
Thanks again everyone.

[1ponders]
10-06-2008, 06:03 PM
Everyones just about covered the important bits, but I just thought I'd recap.

1. mount
2. mount
3. camera (one that comes with a lens ;) )
4. mount
5. Scope and webcam (doubles as guidescope and imaging scope (eventually)
6. MOUNT
7. Guidescope and guide rings.
8. MOUNT

Ok I think that has just about covered it in order of importance :lol:

marki
10-06-2008, 06:39 PM
Hi again Brent

Well you certainly got a lot of good advice :D. One thing everyone seems to have missed is the focuser. If you stick with the C8, get yourself a good quality crayford focuser (motor driven as a minimum). That way you can do the coarse focus using the standard C8 setup and use the crayford for fine focusing (important to avoid image shift). The motor driven is a must as you do not want any vibration what so ever when going for perfect focus. I use a JMI smart focus on mine which allows auto focus routines in MaximDL.

I can also recommend MoonLite products (http://www.focuser.com/) which are of exceptional value when weighed against the quality of the product. I ordered one through Steve at http://www.myastroshop.com.au/index.asp (very good to deal with) for my 80 apo. I had many custom changes made to the standard focuser (i.e collimatable, colour etc) and it only took a couple of weeks to arrive from the USA. I didn't put it on the scope for a few days as I just wanted to admire its sheer beauty. The smoothness of the focuser in use is exceptional and I have not used anything that is even close to this piece of mechanical art. Mine is a manual 8:1 reduction but they also have motorised and computer controlled options.

BTS
10-06-2008, 10:58 PM
Thanks for more helpful advice, Mark. I thought, though, the 40D should be able to take care of any fine focusing using the LiveView option through a laptop.
With the ED80, there seems to be 2 versions the standard and a Pro. From what I can gather the Pro comes with a case.... is this the only difference?

Also, what do people recommend for a guidecam?

Hagar
11-06-2008, 09:00 AM
Optic wise both scopes are the same. I think the pro comes with a different paint job and a case. Otherwise the same scope.

Live view is not what it is cracked up to be. It is only really of use on the brightest of stars. Good manual focusing whether motor or by hand is still the best way to go. eg. Expose,focus,expose, focus and so on until it is right.

BTS
12-06-2008, 03:59 PM
Ok, went and visited my friend, Don, at Bintel today and bought myself an ED80 Pro with the rings etc.
We chatted about the camera side of things and now he has me wondering if I should get a CCD instead of the Canon 40D I soooo had my mind set on.:lol:
I can see the pro's and cons for both, but what does everyone else think? I'm considering the new Orion Starshoot 6MP but its $500 more than what I can get a 40D for..... any help would be very much appreciated.

Hagar, point taken, thanks!

Omaroo
12-06-2008, 09:47 PM
Was that you in there today when I was there Brent? (Chris with the G11)

BTS
12-06-2008, 10:32 PM
Yes, Chris, that was me.....:lol:

Omaroo
12-06-2008, 10:33 PM
LOL! ... small world :)

Ian Robinson
12-06-2008, 10:54 PM
I agree , manual focusing is the way to go , as is a very good 2" low profile crayford focusor for prime focus imaging .

Ian Robinson
12-06-2008, 10:58 PM
Big mistake , visiting the telescope shop . Too many expensive and very tempting goodies and there are salespeople there too who want you to walk out with something and smaller bank account.

Keep in mind that a dedicated CCD camera is not going to be useable for happy snaps and you'll pay a lot of money to get a dedicated CCD device with the same number of pixcels as you will get relatively cheaply with a 40D , which can be used in your day to day photography too.

toyos
12-06-2008, 11:20 PM
Wouldn't a quality apo refractor give you better results compared to any reflectors? If everything else was the same including the mount & the imager's skills :)

Ian Robinson
12-06-2008, 11:24 PM
Sure - I'd love a 10" f4.7 high quality ED APO .... :D.... I don't think anyone here will ever be able to afford one , I certainly wont (unless I inherit or win a very large amount of money) so , a 10" f4.7 Newtonian with a comma corrector/ field flattener will suffice.
I can go deeper than any APO's I'll ever be able to buy in the forseeable future can go and resolve more.

BTS
13-06-2008, 12:20 AM
Yes, very!! Thanks for your input at the shop too :)

toyos
13-06-2008, 12:28 AM
What about a 6" Takahashi TOA-150 compared to a 12" Newtonian/SCT with a reducer for imaging on G11?

AlexN
13-06-2008, 12:34 AM
Toyos - I'll quote the age old rule... Aperture Rules.

12" will resolve more than a 6". no ifs whats or buts about it... (providing both are in equally good condition)

toyos
13-06-2008, 12:47 AM
I thought aperture was not as critical in imaging. Resolving power aside, what about the overall quality of the images? I have a 12" dob, a 12" Meade SCT LX200GPS, two 6" refractors, etc2. My 12"'s do have more resolving power especially the 12" LX200 (I can't be bothered to modify my dob), but my 6" refractors smoke my bigger reflectors in terms of image quality, visually. I'm not so sure how this will apply in imaging.

BTS
13-06-2008, 12:51 AM
Yes that was one the pros and cons I looked at Ian. While it would be handy to have another everyday camera, its going to cost abit to get it modded with a cooler which would put the price about on par with the Orion CCD I mentioned.....but on the other hand what kind of difference will I see between the two different pixel amounts?

toyos
13-06-2008, 01:38 AM
We can get 10" - 14" Apo's for USD$45k-140k http://www.tetontelescope.com/index.php?cPath=53_12_27&&page=3 Now I guess for some it may not be so much about affordability, but probably more about how much we are prepared to spend on this hobby. :) I'm sure quite a few people here have spent that much (or more) for their cars.

AlexN
13-06-2008, 02:01 AM
Well Toyos, How bout you go buy a 10" APO and let us all know how it goes :D Ps. Have fun finding a mount to hold it, let alone accurately track something for photography :D

Yes it is true that its not unobtainable, More so, Uneconomical. 45.9k US is a lot of coin. and to then compare that to a $2000 - $4000 AUD SCT/MAK or Newtonian is perhaps a bit ridiculous..

toyos
13-06-2008, 07:26 AM
Paramount ME can easily handle the 10" one (99lbs) :D. I was just pointing out that many of us could afford it if we really wanted to. :lol:

Being uneconomical is relative, some say it's unthinkable to spend 200k+ for a car even though they can afford it, and they buy a 14k car instead. Will still get you from A to B even though it doesn't feel the same.