C9. 25 - opinions

[markclaire50]

Hi. 

How would people rate this scope? I'm not interested in the edge version. Too expensive! But I'm sure secondhand versions of the starbrite ones are around. 

Particularly, what are your experiences with it on doubles and planetary? 

Has anyone compared them to 10" newts? 

Basically, any interesting stories would be welcome. 

Thanks. 

Mark

[Paz]

I've got a C8 which is the same type but a bit smaller. On doubles it will resolve well due to the aperture but star images are a bit softer than I've seen in refractors, newtonians, and maksutovs.

[RT65CB-SWL]

For lunar and planetary viewing, I would say it would be a good choice. The only downsides of catadioptric OTA's are the cool downs, they are dew-magnets and narrow field of view. 

[kirkster501]

^^^^

All the above.

I have one.  It is a superb instrument for planets, the moon and deep-sky smaller objects.  It is useless for wide fields.

You may want to read this article by Damian Peach.  If he says it's good, then it's good.  Mine is in my observatory and is always at temperature and ready to go.  Collimation is straightforward and easy

http://www.damianpeach.com/c925review.htm

Edited February 19, 2019 by kirkster501

[dweller25]

Sadly the C9.25 I used to have was the second worst scope I ever had - it gave very soft planetary views, was hard to cool down and dewed up for fun.

I think with hindsight I had a lemon as the C8 I bought years later was a superb planetary scope - very sharp and contrasty. The C6 I currently own is also excellent.

The Skywatcher 10" Newtonian I had was a real winner - it would thermally equilibriate much sooner than the C9.25, did not dew up, was much cheaper and had  more clear aperture - so better on the planets - BUT you can get into some awkward angles when viewing. Had to sell it though as I have a bad back - not the scopes fault.

Edited February 19, 2019 by dweller25

[markclaire50]

42 minutes ago, dweller25 said:

Sadly the C9.25 I used to have was the second worst scope I ever had - it gave very soft planetary views, was hard to cool down and dewed up for fun.

I think with hindsight I had a lemon as the C8 I bought years later was a superb planetary scope - very sharp and contrasty. The C6 I currently own is also excellent.

The Skywatcher 10" Newtonian I had was a real winner - it would thermally equilibriate much sooner than the C9.25, did not dew up, was much cheaper and had  more clear aperture - so better on the planets - BUT you can get into some awkward angles when viewing. Had to sell it though as I have a bad back - not the scopes fault.

Thanks. I'm having a real case of analysis paralysis over future acquisition. Ideally I'd like to get one scope to rule them all (like in Lord of the Scopes?), which would show real improvements over my 80mm  ed and 127mm mak. I'd like to do AP and ideally(!) see features on ganymede (yes, it is a very specific objective!). A good mount, prob heq5, is definitely on the list, but which scope? I've dallied with the idea of 180mm mak and a skywatcher 200pds (or OO VX8) - the mak for planets and double stars (Sirius is on my hit list, as well as e f stars in trap) and the newt for the wider views with AP potential. But then I read a 130p can do brilliant AP, as can the 80ed I have already. It's more the imaging cam, guiding, processing, filters and mount that matter than scope aperture, for DSO. But I love planets too. So, I thought mmm, what about a bigger sct. Compact ess is important for storage, travel etc. I've heard other variable reviews of C9. 25.Ive read Damian Peaches review. But I read reviews about lemons too, too frequently! It would be easy to go insane, trying to make right choice!

[John]

"... features on ganymede ..."

When you say features I assume you mean the very subtle albedo changes that it is possible, under superb seeing conditions, to detect when using a really good 8 inch or larger aperture scope ?

Many scopes are capable of showing the 4 brightest Jovian moons as disks but seeing brightness variations on those disks ....... well thats a different level of observation

[markclaire50]

13 minutes ago, John said:

"... features on ganymede ..."

When you say features I assume you mean the very subtle albedo changes that it is possible, under superb seeing conditions, to detect when using a really good 8 inch or larger aperture scope ?

Many scopes are capable of showing the 4 brightest Jovian moons as disks but seeing brightness variations on those disks ....... well thats a different level of observation

Hi John. I guess albedo difference rather than linear features which I've seen in some superb OO VX8 photos on astrobin. The other thing of course is seeing. I'm based near Nottingham and I'm not experienced enough to know good and bad seeing yet. Is there an upper limit on aperture beyond which our UK weather makes it rather pointless to get a larger aperture for planets? I have a suspicion that 8" might be near to that size limit, as I'm told that our skies don't often allow sub-1" details? So 8" aperture at Rayleigh limit of 0.7" can cover that plus nights of slightly better than average seeing for planets? 

I welcome your suggestions. 

Thank s 

Mark 

[John]

I have a 12" OO F/5.3 with a 21% central obstruction and a good quality primary in it. It can show really superb planetary images when the seeing is good. When the seeing is average to fair (ie: more often !) it still does well but my 120mm and 130mm refractors get mighty close despite the big aperture difference.

A lot of what can be seen through a scope is about the seeing conditions and the experience of the observer in teasing out the detail. When you identify the factors that contribute to the quality of the image your observe, the scope and eyepiece are lower down the list in terms of impact, generally.

Look at what one of our members here can see with just 3.9 inches of aperture:

 

[kirkster501]

1 hour ago, John said:

"... features on ganymede ..."

When you say features I assume you mean the very subtle albedo changes that it is possible, under superb seeing conditions, to detect when using a really good 8 inch or larger aperture scope ?

Many scopes are capable of showing the 4 brightest Jovian moons as disks but seeing brightness variations on those disks ....... well thats a different level of observation

Indeed.  Extremely good seeing - which we hardly ever get anymore in the UK -  and precise collimation are what is required to see such details.

[Mr Spock]

I went from a 10" Newt to a C9.25. There are differences; the Newt had more contrast but the C9.25 is more easy to handle, collimates better and is easier to push to higher magnification.

While not having the tight stars of a frac or a Mak, the C9.25 splits really close doubles easily. Something like an 0.7" double is a wide split.

If you think they take long to cool down then you are keeping them in the wrong place!

[markclaire50]

55 minutes ago, John said:

I have a 12" OO F/5.3 with a 21% central obstruction and a good quality primary in it. It can show really superb planetary images when the seeing is good. When the seeing is average to fair (ie: more often !) it still does well but my 120mm and 130mm refractors get mighty close despite the big aperture difference.

A lot of what can be seen through a scope is about the seeing conditions and the experience of the observer in teasing out the detail. When you identify the factors that contribute to the quality of the image your observe, the scope and eyepiece are lower down the list in terms of impact, generally.

Look at what one of our members here can see with just 3.9 inches of aperture:

 

Thanks John. Pretty certain 7-10" will be aperture I go for. But it's the specific type of scope I'm ruminating over. Newt, mak or sct. Won't be a frac. 

[dannybgoode]

Secondhand with Starbright you say

https://www.rothervalleyoptics.co.uk/second-hand-celestron-c925-xlt-optical-tube-assembly-vixen-bar.html

As an observation, I have the Meade 10” SCT so physically very similar with almost the same focal length. 

Pros - I like the fact you can use big, wide eyepieces and still get a reasonable magnification. Physically a 10” SCT is pretty manageable for one person as well. Robust as well. 

Cons - (and this may be the Meade as opposed to SCT’s in general) but I find it optically very acceptable but not special. A bit dull at times and not much depth. If the corrector does fog kiss goodbye to your evening - I keep mine in a (very dry) garage and there’s been time in the very cold weather it’s still misted up when mounted and it would not clear. The focal length is sometimes too much as well - means buying longer focal length eyepieces that may not get used much but you’ll want them to hand. 

Overall a very nice scope but wouldn’t have it as my only weapon by any means. 

[John]

4 hours ago, markclaire50 said:

Thanks John. Pretty certain 7-10" will be aperture I go for. But it's the specific type of scope I'm ruminating over. Newt, mak or sct. Won't be a frac. 

If you get a 7-10" frac be sure to post lots of pictures

More seriously though, much above 130mm and I would be looking at a high spec newtonian I think - something like an F/6 with top quality mirrors and a relatively small central obstruction. Mak-newtonians are good as well - very "frac like" images

[markclaire50]

7 hours ago, Mr Spock said:

I went from a 10" Newt to a C9.25. There are differences; the Newt had more contrast but the C9.25 is more easy to handle, collimates better and is easier to push to higher magnification.

While not having the tight stars of a frac or a Mak, the C9.25 splits really close doubles easily. Something like an 0.7" double is a wide split.

If you think they take long to cool down then you are keeping them in the wrong place!

Hi Mr Spock ( good name!) 

Thank you for your comments. So, if you had to choose 7"mak over the 9.25" sct for planetary and double stars, which would you go for? I'm aware of aperture is king rule. If both were in your garage or wherever you keep scopes, which one would you reach for, if the planets were out? Or you wanted to have a go at e f stars in trap or the pup? 

Thanks 

Mark

[markclaire50]

2 hours ago, John said:

If you get a 7-10" frac be sure to post lots of pictures

More seriously though, much above 130mm and I would be looking at a high spec newtonian I think - something like an F/6 with top quality mirrors and a relatively small central obstruction. Mak-newtonians are good as well - very "frac like" images

If I bought a 7_10 inch frac, I'd also send lots of photos from down under in my newly acquired aussie mansion from the same lottery win needed. ?

At the moment, being realistic, the following permutations are possible:

1. 180 mm mak - planets, doubles, lunar

And skywatcher 200 mm F5 (aka 200p, not pds: the p has smaller secondary). 

These are close together aperture-wise, but I anticipate different viewing experience? I've seen both scopes at reasonable prices secondhand, especially the newt! 

2. The Mak And a vx10 from OOUk. Choice of 1/8 or1/10wave to be decided. Mak likely secondhand. But I see very few OO newts secondhand. 

3. C9.25" only. Good balance of aperture, but possibly not as good on planets as mak or as good for wide fields as newt. Also it's compact. 

In all cases, I currently plan to get a heq5 as I believe this is important for AP with my 80mm ed but also I believe it will handle any of the scopes above for visual. It could handke the mak and 8" newt for AP too I think. 

If I had lots of money, I wouldn't be so careful, but I haven't. So the right long term choice is needed: I think many of us have gone through this thought process. I also remember you saying how a 6" scope could see DSO at a dark site that you couldn't see with your 10" (or 12"?) newt in your more LP backyard, which I thought was a very interesting point. So, my set up needs portability potential too. I Suspect a 8" F5 newt would show lots more than I can see here, if in a dark site and be easier to take and store in my garage. 

Thanks

Mark

Edited February 20, 2019 by markclaire50

[Mr Spock]

5 hours ago, markclaire50 said:

Thank you for your comments. So, if you had to choose 7"mak over the 9.25" sct for planetary and double stars, which would you go for? I'm aware of aperture is king rule. If both were in your garage or wherever you keep scopes, which one would you reach for, if the planets were out? Or you wanted to have a go at e f stars in trap or the pup? 

For planets I'd go for the C9.25 - it's what it's made for, especially imaging. Look up Damian Peach's images taken with a C9.25. Maybe he has used ideal seeing conditions but it still shows what the scope is made of.

If I was doing doubles only, probably a 180 Mak. The tighter stars and better contrast would make the difference.

I've not used a 180 Mak, only a 140. That couldn't see the pup but the C9.25 shows it easily - e and f in the trap are easy too, as they were in the 250 Newt.

[markclaire50]

2 hours ago, Mr Spock said:

For planets I'd go for the C9.25 - it's what it's made for, especially imaging. Look up Damian Peach's images taken with a C9.25. Maybe he has used ideal seeing conditions but it still shows what the scope is made of.

If I was doing doubles only, probably a 180 Mak. The tighter stars and better contrast would make the difference.

I've not used a 180 Mak, only a 140. That couldn't see the pup but the C9.25 shows it easily - e and f in the trap are easy too, as they were in the 250 Newt.

Hi. Thank you for this useful information, especially the info on e f stars and pup. This of course raises the question _ what latitude are you at? I'm about 52° N in uk. So, if you can see pup at similar latitude, that is a big positive for the 9.25!

Thanks 

Mark

[John]

Mr Spock must have better eyes than I have !

I'd never call seeing the Pup star an "easy spot" in any scope that I've seen it in. There are some very experienced double star observers with large scopes who have failed to see Sirus B so I don't think it ever falls into the "easy" category, from the UK at least.

I had the Pup in view (to my eye) with my 12" dob last year at a Society star party but none of my club member colleagues (some experienced observers) could see it at all

Mind you, they did not have the Vulcan eyesight

I'm not against the 9.25 SCT's though - they can be superb scopes if you get a good one.

[markclaire50]

Does anyone here have experience with imaging using the C9. 25 on a HEQ5 Pro mount? 

If yes, how did it perform on:

Planetary

DSO 

I would really prefer not having to factor in a heavier EQ mount! ??, as I want option to be able to go to a dark site, without breaking my back. 

I could ask the imaging lounge, but my last post fell on deaf ears there. ?

Thanks

Mark

Edited February 20, 2019 by markclaire50

[markclaire50]

Hi. Next question ?

Do you think that a 200p would compliment a C9.25? By compliment, I don't mean that the 200p would be congratulating the C9.25 for a superb night's viewing. ?

With similar apertures, resolution and light gathering will be similar, but viewing experience is what I'm interested in. 

Thanks

Mark

[paul mc c]

5 hours ago, markclaire50 said:

Does anyone here have experience with imaging using the C9. 25 on a HEQ5 Pro mount? 

If yes, how did it perform on:

Planetary

DSO 

I would really prefer not having to factor in a heavier EQ mount! ??, as I want option to be able to go to a dark site, without breaking my back. 

I could ask the imaging lounge, but my last post fell on deaf ears there. ?

Thanks

Mark

Taken with a c9.24 only on a NEQ6,taken when the planets wer at a fairly low altitude.

[JeremyS]

I love my Celestron C9.25, which I use instead of my Takahashi FS102 when I need a bit more light grasp. With 2-inch eyepieces it gives wonderful views of deep sky objects. It also gives very decent high mag views of planets. I sometimes take it to star parties as the OTA is easy to transport by car; a bit easier to handle than a 10-inch Dob at least that's what I wound.

Highly recommended.

[AKB]

6 hours ago, markclaire50 said:

Does anyone here have experience with imaging using the C9. 25 on a HEQ5 Pro mount?

Well, yes.  Here's what it looks like on the mount...

 

This is its planetary configuration with a flip mirror for photography, where atmospheric disturbance is really more of an issue than mount tracking.  I've also used it with a Hyperstar configuration, so, again, tracking less of an issue, but actually it worked very well.  This is with a Rowan belt mod, which I'd deem essential.

 

[markclaire50]

On 19/02/2019 at 14:37, kirkster501 said:

^^^^

All the above.

I have one.  It is a superb instrument for planets, the moon and deep-sky smaller objects.  It is useless for wide fields.

You may want to read this article by Damian Peach.  If he says it's good, then it's good.  Mine is in my observatory and is always at temperature and ready to go.  Collimation is straightforward and easy

http://www.damianpeach.com/c925review.htm

Hi

Do you have any problems with seeing the E and F stars in the trapezium using your C9.25? 

Cheers

Mark