Celestron C9.25 or ???

[johninderby]

Getting back into the hobby and looking for a new OTA to use with a SkyTee II mount . Price up to  £1,000.00 or so.

Primarily for use from a typical suburban light polluted back garden but compact enough for easy transport. The SkyMax 180 is an excellent planetary performer I know but cool-down could be an issue with that thick glass but on the other hand holds alignment really well.

Always wanted a C.9.25 and the SkyTee would handle it without any problems. Better for all-round use than the SkyMax but can need fairly frequent alignment. Used with a CatCooler cool-down is actually pretty good.

May have to have a word with Steve at FLO.You never know he might have an open box C9.25 lying around.

          John

[Grotemobile]

The C9 .25  is what I would go for. Don't think

U will do better than that ,  from a light polluted

back garden. Same problem as me. I did have

a C11, but it was just to big. Ok from a dark site.

Don't forget , a heated dew shield, which is a must.

Steve.

[ollypenrice]

Yes, the need for a dew heater can have a big impact on portability since you need to take something to power it.

Opinions vary on scopes for beating LP but personally I'd probably put the catadioptics at the bottom of that list and the refractors at the top. LP attacks contrast and refractors have the most to start with.

On the other hand the 9.25 gives a big aperture for a low relative volume. Just don't be caught out by the dew problem. I came from Derbyshire and fighting the dew on my 8 and later 10 inch SCTs was quite a struggle.

Here on the continent there has been a movement away from trying to cool SCTs to ambient. Many owners are now hyper-insulating them to slow down formation of destructive tube currents. This might have a favourable effect on the dew problem as well. I only pass this on since I've not tried it myself.

Olly

[osbourne one-nil]

Would something with such a long focal length marry well with a non-driven mount? I know plenty do but I think I'd get frustrated. 

EDIT: Forgot it's got slow-mo!

[ollypenrice]

Would something with such a long focal length marry well with a non-driven mount? I know plenty do but I think I'd get frustrated. 

EDIT: Forgot it's got slow-mo!

This is my view as well but it seems that plenty of people enjoy SCTs undriven.

Olly

[johninderby]

Of course the C9.25 could be used on the SkyTee now and later on a driven mount The Red Carton is f13 and is easy to track manually so the C9.25 with it's shorter focal length wouldn't be a problem.

Plenty of time yet to decide as won't be buying anything until the move.

John

[Mr Spock]

I got my C9.25 from FLO. It's been a great scope so far

[Grotemobile]

Tube currents was a major problem with my  

C11, when I had it. U had to use a heated 

due shield, which only compounded the problem.

The C8hd  has vents at the back, which do

seem to help a lot. Sometimes bigger,  is not

always better, as I found out.

[dweller25]

As Grotemobile says - the C8 edge with cooling vents and optical corrector may be more useable than the standard C9.25.........

[cgarry]

As Grotemobile says - the C8 edge with cooling vents and optical corrector may be more useable than the standard C9.25.........

I would disagree with this advice.  The little vents on the HD scopes are next to useless, the corrector lens in the baffle prevents a CatCooler from being used and this lens itself holds lots of thermal energy increasing the time required for cool down.

I have both a normal C14 scope and an EdgeHD C14 scope and only ever use the normal C14.  The normally C14 is so much easier to get thermally stable with a CatCooler but the EdgeHD version is a nightmare being almost impossible to get thermally stable with thermal currents randomly starting up at any time.

Basically I strongly advise the standard C9.25 with a CatCooler to speed up the cool down time.  It is cheaper and better suited to your requirements!

Cheers,

Chris

[johninderby]

Have had both a C8 and a C11 and found the C8 a little too small and the C11 a little too big so the C9.25 should hit the sweet spot for what I want. Since it's for visual only the regular one would do just fine. Found the CatCooler worked really well.

John

[A40farinagolf]

I have a CPC925 and would thoroughly recommend the OTA - bang for bucks it's hard to beat from a visual use point of view.

I leave the French doors on my dining room open for a couple of hours (with the scope positioned just inside the opening) before use and then simply carry it outside in 2 pieces - tripod and then forks / OTA, level the tripod, align after using the inbuilt GPS and I can track and locate virtually anything I want to in a few minutes. Much simpler than my frac and AZEQ6.

I get told off though if I leave the other internal doors open as the house becomes freezing in no time.

[nmoushon]

I have a 9.25 edge and love it. With my weather and travel I haven't got to use it very much but when I have I haven't any problem. It's light enough I can put it on the mount by myself and don't worry about dropping it. So size wise it is perfet...for a sct anyways. I usually put the tube outside while I cook and eat dinner and by the time Im done and get everything ready it's plenty cooled for the evening. You will want a dew shield and heated would be prefered.

There can be problem with tube currents but there are several ways the get rid of them or reduce them a good bit. The standard vents do help but since there no fan on them it's not a huge help.

I can't say if there is a better scope than the sct but there are other options in that price range. You can look at some fast newts in the 10-12" range. You could get a decent sized frac as well. Apo doublet would still be in your range or go to an achro and get a larger aperture. The newer achros have a lot better correction than they use to.