Gso rc8 (cf) + cg5

[codemonkey (Lee)]

Hey guys,

This won't be happening for a long time, given that I've just purchased an Atik 314L+ and will need guiding & filters, but...

Once I've gotten the above I'm likely to be looking at longer focal length scopes in order to better photograph my primary interest: galaxies.

I've seen these carbon fibre GSO RC8 tubes weighing in at 7.5kg with a focal length of 1.6m and I'm wondering whether my Celestron CG5 GT mount is likely to be able to handle that for imaging or whether I'll need to upgrade my mount first... any thoughts?

Cheers,
Lee

[glend (Glen)]

Based on the old adage that you should not run an image system that requires more than 2/3s of the mount rated capacity, your 7.5kg RC would need a mount rated at a capacity of 11.25kg.

Add in all the other stuff you would put on the scope, would you have a finderscope, a guide camera, imaging camera, dovetail mounts for the attachments, heaters, cables, etc and then work out the total capacity required.

I would imagine that your total weight with those extras might reach to over 10kg easy, which is putting you into the 15kg mount capacity range (using the 2/3rds rule).

Celestron published payload capcity for the Advanced GT VX CG5, is 35lbs, or 15.9kg.:

http://www.celestron.com/support/kno...tron+mounts%3F

You should be Ok, but check to se what other RC8 owners are using and why.

[alistairsam]

Hi Lee

I'd suggest investing an oag and a decent guide cam. At f8, you'd need to acquire at least 15 min subs not considering other factors and for that your guiding needs to be good, an oag helps compensate mount tracking errors and ota flexure to a certain extent as it sees what your main scope sees.
I went from guidescope guiding with okay stars to oag guiding with round stars for 30min exposures.
Only thing, your guidecam needs to be sensitive as your guidecam fov would be very small.

Cheers
Alistair

[codemonkey (Lee)]

Originally Posted by glend

Based on the old adage that you should not run an image system that requires more than 2/3s of the mount rated capacity, your 7.5kg RC would need a mount rated at a capacity of 11.25kg.

Add in all the other stuff you would put on the scope, would you have a finderscope, a guide camera, imaging camera, dovetail mounts for the attachments, heaters, cables, etc and then work out the total capacity required.

I would imagine that your total weight with those extras might reach to over 10kg easy, which is putting you into the 15kg mount capacity range (using the 2/3rds rule).

Celestron published payload capcity for the Advanced GT VX CG5, is 35lbs, or 15.9kg.:

http://www.celestron.com/support/kno...tron+mounts%3F

You should be Ok, but check to se what other RC8 owners are using and why.

Great, thanks very much Glen :-)

Originally Posted by alistairsam

Hi Lee

I'd suggest investing an oag and a decent guide cam. At f8, you'd need to acquire at least 15 min subs not considering other factors and for that your guiding needs to be good, an oag helps compensate mount tracking errors and ota flexure to a certain extent as it sees what your main scope sees.
I went from guidescope guiding with okay stars to oag guiding with round stars for 30min exposures.
Only thing, your guidecam needs to be sensitive as your guidecam fov would be very small.

Cheers
Alistair

Good call, Alistair, that's definitely on my list. My general plan goes:

1. CCD (paid, waiting for delivery)
2. OAG + Guide cam
3. Filter wheel + filters
4. New scope

[Peter.M]

Originally Posted by codemonkey

Great, thanks very much Glen :-)



Good call, Alistair, that's definitely on my list. My general plan goes:

1. CCD (paid, waiting for delivery)
2. OAG + Guide cam
3. Filter wheel + filters
4. New scope

Im not sure what that imaging rig will weigh, but consider a focuser to go with the new scope when you get it (or after ofcourse)

[codemonkey (Lee)]

Originally Posted by Peter.M

Im not sure what that imaging rig will weigh, but consider a focuser to go with the new scope when you get it (or after ofcourse)

I actually just bought a kick arse moonlite for my refractor... Not sure if I'll be able to get an adapter to have that work with different types of scopes (I assume not), but if not that's likely to be on the list too