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Celestron C 9.25 - Any Good?

jcm

By jcm
in Discussions - Scopes / Whole setups

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jcm

jcm

Posted
Posted

I just wondered if the C 9.25 would give me a bit more aperture and be fairly compact. How does this scope cope with planetary work?

Is there much variation in the optical quality of these scopes and how do you know you are buying a good un ? Could you ask the supplier to test it for you? or is that too much to ask?

John

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centroid

centroid

Posted
Posted

John

I've known quite a few people that have used the 9.25, and have only heard good reports on it.

Have also seen one or two nice images taken with it.

Most SCT's actually excel at planetary work, as they generally of longer focal ratio than a 'Newt'. Also the larger the aperture, the higher the resolving power.

Dave

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cygnusx1

cygnusx1

Posted
Posted

I have had both the C6 and currently a 9.25.

The 9.25 is much heavier +- 10kg , the C6 easier to load on mount 3-4kg.

Visually when looking at Jupiter i hardly noticed any diff btwn the 9.25 and 6 in size of image.

I will comment on DSO work, as this is my main area of interest.

To be honest, w/out filters and in LP skies you wont see a huge diff visually.

Personally i wasn't gobsmacked with the diff from the C6.

For imaging, you would need at least a mount capable of 10-15kg load for 9.25, i.e HEQ5/EQ6 Pro or Sphinx SXD.

The long focal length also makes imaging much harder, unguided exposures sub 45-60s due to smaller fov @ f/10 - be aware of this.

Many DSOs wont fit into the fov of a f/10.

A f6.3 reducer created a lot of vignetting on my images and was a disappointing result.

All in all, i produced better images with my C6, which is around 1/2 the price.

I intend selling my 9.25 shortly and repurchasing a C6, to compliment my 66mm APO.

Just my 2p, i'm sure others might have different experiences.

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Kai

Kai

Posted
Posted

For Planetery it will be fine,Knock it upto F20 or more and you will get some very nice images.

For Dso i would personally steer clear of Dlsr's and look at a CCD instead,that way you can use reducers etc.If you have a look at some of my images you can get a idea of what you can do at f10,only you will get more resoloution being a 9.25 over my C8.

HTH

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Kaptain Klevtsov

Kaptain Klevtsov

Posted
Posted

There was a review in Practical Astronomer recently. They said it was better for imaging than the other SCTs as the focal ratio of the primary was different or something. I seem to remember they gave it good marks.

(pops off to find said mag.)

The primary is f/2.3 compared to the "normal" f/2 thereby giving a flatter field. There, that's what I meant.

They concluded (among many other things) that "The C9.25 is a very good all round performer, especially for it's compact size. We have seen better planetary detail in similar aperture telescopes but with a smaller central obstruction, and in any case, we were unable to precisely collimate the optics due to seeing conditions. Had we been really patient and waited for those moments of good seeing to acheive good collimation, I have no doubt that the planetary views would have gone up an additional notch."

Vol.2 Issue 6 June 2007 If you can get a back issue.

I must add that I would recommend that you subscribe to PA, before they get cross with me for telling you their secrets.

Kaptain Klevtsov

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CELESCOPE

CELESCOPE

Posted
Posted

Hi John , an all rounder the 9.25 , excellent for Planets mate ,and Lunar

fitting the Celestron 6.3 reducer will give you a super flat field across the frame, no coma what so ever , you have seen my images with the C11 .also guiding is no problem for imaging at F6.3 or i should say a more realistic F7, using the ED 80 for guidescope.

As long as you get the settings right , i use the EQ6 PRO for my C11 takes that plus the ED80 on top using a guide rail , its the best of both worlds really using the larger C11 for planetary ,lunar Galaxies and small nebula, then just switch over to the ED80 for the image scope for wide field , and using the C11 ot 9.25 as the guide scope is easy as well , no probs mate .

Hope that helps

Rog :smiley:

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jcm

jcm

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err I do subscribe to practical astronomer :smiley: I will have a look back at recent issues - I will hunt for the June issue - found it.

Just shows you how much notice I take when I read a magazine :evil:

My plan is to buy an EQ6 ( price drop at the right time) use this to mount the C 9.25/ 130mm APO - not at same time.

Use the HEQ5 as a portable mount - star parties , move round the garden etc.

John

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The Warthog

The Warthog

Posted
Posted

Interesting comments. I am thinking hard about my retirement scope, as I will probably only get one kick at the can, and it will be the last chance I get to spend a lot on a scope. (Retirement is 18 months away.) I'm torn between a C8 and a C9.25 at the moment, but beginning to lean more heavily to the 9.25. Good discussion.

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jcm

jcm

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Interesting comments. I am thinking hard about my retirement scope, as I will probably only get one kick at the can, and it will be the last chance I get to spend a lot on a scope. (Retirement is 18 months away.) I'm torn between a C8 and a C9.25 at the moment, but beginning to lean more heavily to the 9.25. Good discussion.

This is likely to be my last purchase ( the wife thinks the 130mm APO was :smiley: )

Its the extra aperture the C 9.25 gives and you do not need a huge mount for it. ( EQ6 - £200 recent price drop)

Second hand is a good option. The variation in optical quality still worries me a bit. I had a test certificate with the APO.

John

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Stormwatch

Stormwatch

Posted
Posted

I have had both the C6 and currently a 9.25.

The 9.25 is much heavier +- 10kg , the C6 easier to load on mount 3-4kg.

Visually when looking at Jupiter i hardly noticed any diff btwn the 9.25 and 6 in size of image.

I will comment on DSO work, as this is my main area of interest.

To be honest, w/out filters and in LP skies you wont see a huge diff visually.

Personally i wasn't gobsmacked with the diff from the C6.

For imaging, you would need at least a mount capable of 10-15kg load for 9.25, i.e HEQ5/EQ6 Pro or Sphinx SXD.

The long focal length also makes imaging much harder, unguided exposures sub 45-60s due to smaller fov @ f/10 - be aware of this.

Many DSOs wont fit into the fov of a f/10.

A f6.3 reducer created a lot of vignetting on my images and was a disappointing result.

All in all, i produced better images with my C6, which is around 1/2 the price.

I intend selling my 9.25 shortly and repurchasing a C6, to compliment my 66mm APO.

Just my 2p, i'm sure others might have different experiences.

Seriously? This shocks me somewhat. Did you try the two scopes at the same time to see how different they were?

I tried my old 4" refractor one night, then the C8 a day later and was really blown away by the difference. Of course, your 6" would be better to start with than a 4" achro refractor, but still, if you never tried the two close together you may be really disappointed once you get shot of the c9.25 and replace it with another C6.

It's easy to be nostalgic about a smaller scope.

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jcm

jcm

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Thanks for all the interesting comments.

I have pretty much decided to get the C 9.25 it should work well on a EQ6.

If only I could get a test certificate with it similar to the one I received with the 130mm APO. The reason why I mention this is many years ago I had a SCT ( not Celestron) but I sold it because it was optically inferior to others that I had the chance to look through. Since then have been a bit wary about the the variation in optical quality - perhaps things are better now.

John

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jcm

jcm

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If I were you I'd not use a standard dovetail for that but convert the EQ6 to a Losmandy-type fitting. It will be *so* much more secure.

Arthur

Good point Arthur , will be in touch when I make my final decision.

John

PS - I assume I order the scope with the Losmandy fitting and convert the EQ6 to accept that fitting.

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