Celestron G 9.25
Posted 12 November 2012 - 04:22 PM
I have an old C-8 Orange that has yet to float my boat. I bought it used 18 years ago. M-13 is beautiful, planetary views not so much. It could be that the seeing where I live leaves my small aperture refractors relatively unmolested compared to raising havoc with my C-8. Maybe the collimation is always off. It has been collimated and checked before by Cat people, even sent it back to Celestron for a tune up but I never have noticed any difference in image quality. I believe the D.O.B. of this scope is 1980. My next size scope is a vintage Criterion RV-6. Then refractors 4" - 2". I seldom acclimate the refractors to the outside air, but I have given generous cool down periods for the reflectors. The RV-6 has given great planetary views.
So I'm skeptical about Cats but still want to like 'em, love 'em really. Would some of you please share your experience with the C-9.25 scope? The owner says they purchased it for $1500 and only used it a few times. It's gonna be awhile before it clears here so a test viewing may not be possible before deciding to buy or not.
In general how were the optics regarded?
Were the mounts sufficient for this OTA?
When were these produced? Were there "bad" years?
If condition is practically unused what would be a fair offer?
Posted 12 November 2012 - 05:16 PM
Posted 12 November 2012 - 06:31 PM
Posted 12 November 2012 - 06:52 PM
I expected views in the C9.25 to best the RV6 in every respect. While it certainly out performs on deep sky objects and dim fuzzies it is hit and miss with planetary views of Mars and Saturn. The bigger Cat is considerably more sensitive to our seeing conditions here in north central Texas. There were nights when the C9.25 views of Saturn knocked my socks off, and other nights when the views in the two scopes were comparable if you take into account the 100 in to 48 in focal lenght difference.
I have found that the C9.25 needs a long cool down or warm up time going from indoor temps to outside. I have found that even after an hour or so of cool down, star tests show evidence of tube currents.
In the past few week, I have been setting up during dusk and observing Jupiter around midnight with very good results.
I have never owned a decent refractor, but I can say the the close tube Cats need more care and feeding than an old reliable Newt.
Posted 12 November 2012 - 07:47 PM
Posted 12 November 2012 - 07:54 PM
New manufacture C9s may be consistently better than they used to be.
But I had an MN61 that also put up better planetary images than the C9.25 I owned, so I guess it depends on the specific sample.
I am no great fan of the C9 personally. I think its reputation is a bit outsized. I did not like it for planets. The C11 was much better and the first SCT that I found to be a capable planetary performer.
And yes, I have owned two C5s, three C8s (one is an EdgeHD), A C9.25, a C11, and a C14.
The C9.25 was actaully the only one that disappointed me. I had expected something special, and it was better than the C8, but only a tiny bit.
Again, new ones may have better optics than in the past, and perhaps if your C8 has only so-so optics, maybe you would indeed see a meaningful improvement.
A CG5 ASGT may hold it ok unless you do a lot of high power observing.
If it was made in the last 2 or 3 years, it seems like the quality has been running consistently very good to excellent in this time frame.
My own C9 was a black tube made around 2001 and the optics were so-so. Celestron was struggling financially at the time, and my guess is that quality suffered as a result.
Rohr has tested a few of these and the quality of the ones he tested was quite variable. One had a Strehl of about .89 (I would say "Good" but nothing special. One was about .93 would would be very good, and one was I think .95 which would be at the bottom of the "Excellent" range.
One test was posted on a Japanese web site about 6 or 7 years ago, and it was in the "Very Good" catagory.
Posted 12 November 2012 - 09:33 PM
I don't know what mount (s) these were supplied with originally. This scope is being sold by a "not a telescope kind of guy" for his mother-in-law. I have a Tak 102 on a CG-5 mount. Very solid for the Takahashi. It came with some controllers that I've never tried. Were these G9.25 sold on CG-5 mounts or SP mounts? Were the SP mounts the only ones with wood tripods? All I've seen is a fuzzy photo of the brochure/instruction manual. I can't even tell if the tripod is wood or metal. It does appear to be adjustible for height unlike my C-8. The asking price is $600 OBO. Seems like a lot of telescope for the bucks but I'm more used to collectibles and paying collectible premiums. Of course there is always a concern when someone says they have an awesome telescope used like twice! Why??? I think it is usually because they are overwhelmed but it does cause one to pause.
Are the CG-5 mounts and this OTA more difficult to use than if it were fork mounted?
Atlas mount and Cat cooler eh? Is the Atlas mount way beefier than the CG-5? And where is the best place to cool my cat?
Your knocking off of socks on the right nights sounds great. I have dark skies but am often under the jet stream. Some nights are OMG! and some are just OH NO! I'm concerned I won't use this telescope enough to justify the expense after a string of OH NOs. What about faint fuzzies does the seeing really affect globulars and galaxies? I'm asking seriously as I really haven't had anything large enough to enjoy those very distant views. There are plenty of times there is no moon and no planets and a sky full of wonders that are out of reach with the small stuff. Do you think a 9.25 fills the gap?
What is the vintage of your scope?
You believe Celestron optics are improving? When I contact the owner I'll try to pin down the purchase date. Thank you for that heads-up!
Posted 12 November 2012 - 09:38 PM
Posted 12 November 2012 - 09:43 PM
Posted 13 November 2012 - 12:27 AM
Posted 13 November 2012 - 12:46 AM
Posted 13 November 2012 - 09:36 AM
Posted 13 November 2012 - 02:53 PM
Criterion RV-6 that I also brought new in 1963. My wife allows me to get a new scope every 50 years or so.
50 YEARS or so!
Sounds like you picked well... both scopes and wife!
I am mostly concerned that my local seeing conditions will limit my use of this scope. Things can get pretty bubbly from my site. Thanks for the help. I'm psyching up to go take a look, which most likely means buy it. If the mount seems heavier than the CG-5 (although I doubt it) it will be an easier decision.
Again thanks for all of your input.
Posted 13 November 2012 - 04:58 PM
I bought mine second hand but am pretty sure it is an '05 or '06 model based on what the original owner said at the time.
Posted 18 November 2012 - 01:16 PM
If its a G9.25 as the header says, it comes with a losmandy GM8 mount that was rebranded for Celestron. If this is the case, you best jump all, over this and hire a lawyer 'cause this is a steal of a deal......
The "G-9" was actually a mix of GM8 and G11 parts and a fairly good mount. The down side was the tripod which was the same aluminum slide rule type sold under the early CG-5 with an adapter plate for the Losmandy fitted. The good news is that you can pull the adapter plate and move it to a Celestron HD field tripod like was done here:
Posted 01 January 2013 - 05:03 AM