Setup for imaging galxies

[RobertI]

Hi all,

I am still in my first year of imaging and am looking forward to imaging galaxies this spring. I need some advice on whether my current setup is suitable. I have a megrez 72 with 0.8x reducer/flattener and canon EOS 1100 D which I have used for widefield, nebulae etc. I also have a celestron c8 with no reducer which I have used for imaging Jupiter using e/p projection with the canon. Both setups live on a guided cg5.

Would either of these setups be ok for imaging small scale galaxies? I am thinking the Meg72 may be too widefield and the C8 is too far the other way.

Any advice? Thanks.

[GuillermoBarrancos]

The C8 is actually the Scope to use in your case to image small DSO´s and galaxies.

The common setup for small DSO imaging is a Ritchie-Cretien or SCT setup, as you need long focal length to properly frame small targets.

The best way to use your C8, is to use a Focal reducer and On Axis Guider setup.

Something like this:

http://www.teleskop-express.de/shop/product_info.php/info/p2791_TS-f-6-3-Corrector---Off-Axis-Guider-for-Schmidt-Cassegrain.html

Tho a DSLR isn´t the best camera to use (due to small pixel size) at long focal lengths. The C8 With 0,63 focal reducer ain´t too bad to start out with, without having to invest in a CCD camera with larger pixels.

I think with a C8 + 0,63 Focal Reducer + Canon 1100D you will be imaging at roughly 0,8 arcsec pixels.

So I would go for it and try it out. Especially since you already have most of the Equipment, including a good guide camera!

[RobertI]

Great, thanks for the detailed answer Guillermo. Looks like I need to go shopping!

[ollypenrice]

Assuming you can get the guiding right at that resolution (and an OAG would be best) then the C8 would be the one to use, but it will be slow going. Very careful PA and balancing will help.

Olly

[RobertI]

Thanks Olly. Yes this seems to be quite a big step up from what I am currently doing. I hopE MY PA

[RobertI]

...finger trouble, I was saying I hope the CG5 is up to it!

[GuillermoBarrancos]

Load capacity wise the CG5 can handle the C8 easy. So that shouldn´t be a problem. And stability wise it should be ok too, as the CG5 has the same tripod as the NEQ6 Pro (2 inch).

More interesting will be the motors of the mount. But if you have already been succesfully imaging with the Megrez 72 and the guider. No?

In worst case you will find out you need a more accurate mount later on, like the Advanced VX or HEQ5 Pro.

[RobertI]

True i have been imaging with meg 72 and guider. Between them they weigh 5.5kg which is not much less than the c8 so hopefully not an issue. The motors are the old non goto so I guess I will have try and see. Will definitely be aiming to upgrade in a year or two.

[ollypenrice]

There tends to be far too much emphasis on mount weight capacity when long focal length imaging comes up. Yes, of course it matters but accuracy matters as well. Because I don't like faffing about (and my guests don't like me doing so while they wait!!!) I tend to stick to a metre or so on the sub-megabucks mounts. The HEQ/NEQ mounts can and do work at longer FLs but they often need more input and sweet talk!

Olly

[RobertI]

Thanks Olly that's a useful guideline. I also need to minimise the faff factor as I have to transport all my gear to a nearby field!