The 8 inch HD or the 9.25 SCT?

[Willow127mm]

Hi all I have been given the opportunity to buy a new scope and I was tossing up between a Celestron advanced vx 8 inch HD or for the same money the advanced vx 9.25 SCT I think there both OK but I like the Faster F2.2 imaging option on the HD but I lose 1.25 inches.
Can anyone recommend these mounts are they any good?
Is appature really everything in this case?
I think the 8 is more than enough FL and app but I'm really just an an amature.
I would really appreciate some input from some more advanced icein spacers.
Thanks in advance
Brad

[brian nordstrom]

:) Hi Brad , lucky you .
All I will say is this , the 8 inch HD would have to be very , very special to beat my C9.25 , these C9's are a very special scope that perform excellently :thumbsup: , also the extra 1 1/4 inches does make a dig difference .

My C9 rides very well on its HEQ5 .
But if you want to go the 'Whole Hog' as they say that Losmandy G11 that's just popped up in the classifieds would be the one , great price too.

Brian.

[casstony]

C9.25 has slightly brighter images.

C8 Edge is easier to cool due to vents and less mass.

In my observing conditions I place a higher priority on cooling so I chose the C8 Edge. Visually both provide pleasing views (once cooled) with the C9.25 having less outer field aberrations than the 8" and 11" standard SCT's, though the outer field is better again in the Edge scopes.

I have the AVX mount and like it a lot. It's sturdy having the heavier duty tripod, it's not heavy to move, next to no backlash and the setup and alignment is very easy.

[Willow127mm]

Thanks mate yeah unfortunately the G11 would be pushing it a bridge to far but I hope to slowly work my way up and up as do most of us I suppose.
Dones your OTA have the removable connection on front the scope for a DSLR T Ring for imaging?
This was the thing that leans me towards the HD as they don't say whether or not the SCT has this capability or not but I would love to know as I think in that case I would go for the extra AP.
Anyway thank for your input
Brad

[Willow127mm]

Hi Tony thank for the advice mate yeah I like the idea of the cooling vents and the other benefits of the edge I think your right that the images are only slightly brighter in comparison also I think the 8 would be better for imaging with the smaller FL but I'm only assuming of course I'm certainly no expert.
Thank for the review on the mount it gives me more confidence in the purchase.
Thank again Brad

[Camelopardalis]

For imaging...can't imagine the extra aperture would make a huge difference. Many (if not all) the larger SCTs (non-Edge) are reported to be shipping with FASTAR now so if you're still undecided you could always speak to the supplier. One thing to bear in mind is that the central obstruction is substantially smaller on the C8 than the C9.25 and C11, so you'd want to be extra careful minimise the aperture incursion by your CCD/DSLR with the smaller scope.

Visually...the C9.25 has about 40% more mirror area so (all things being equal) will of course give a brighter show. However, while the 9.25 has a legendary status, there's no magic to em and the Edge scopes give a flatter and coma-free field...of course aperture wins if you're going after faint fuzzies. Personally I prefer the flatter sharper wide field so went for the Edge. If all you care about is mostly in the centre of the field, the aperture wins again.

How useful the vents are depends on your climate, as ultimately they're passive. I fitted the Tempest fans to mine and I'm very happy with them, cools (or warms) the scope in next to no time.

I bought the Edge 8 on the AVX and it's effortless. I haven't tried any imaging with that setup yet though as I have a modded EQ6 also... which seems to want a good polar alignment for good Gotos where the AVX seems to do a better job of that for visual.

[Camelopardalis]

Btw, I went for a C11 Edge for deeper visual as it gathers about 2x the light of the C8 which I find makes quite a difference. The C9.25 is pretty much in the middle.

[Merlin66]

I have and use both the C9.25 and the C11
The issue for me with the HD version is the lack of affordable reducers.
The C9.25 is a very nice instrument- I like it.

[Camelopardalis]

The reducer for Edge 8 is US$299, 11 $599. There is no reducer for the Edge 9.25...yet. Either are quite a step up from the standard 0.63x reducers. For the money you get quite a solid lump of glass and metal!

Neither necessary for FASTAR of course...

[glend]

Pick the one which is less of a dew magnet.

[Camelopardalis]

How many dew heater tapes do you use Glen?

[glend]

Well I have a good ducted and baffled fan on my newt mirror so normally just two one for the guidescope objective and one for the finderscope. If really bad I can add two to the newt tube.

[Camelopardalis]

Similarly I use one for the corrector - and wish I had one for the finder scope :lol: