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g__day
14-10-2006, 10:06 AM
Well it feels like welcome to the bigs (after 6 years with Newtonians, a year with a MAK, 3 months with a ED 80), I finally "invested" in a decent size SCT.

I choose the C9.25 for a few reasons:

1) it has fairly stellar reviews
2) its a tad bigger than the 8" so there is more light reach (about 30%)
3) its not "too big" to piggy back a Megrez 80mm on a CG5 goto mount (though I'm pushing it I'd guess)

I selected the carbon fibre (CF) version as I figured it would retain focus through significant thermal variation - and that it certainly does. As an added bonus it certainly feels light and looks way cool!

Now I selected the CF verison, but I wanted to match it to the CG5 mount - which is were the first challenge came from - the first of three challenges actually. The CF version is only supplied with the CGE mount fitting - which is twice as wide as a CG5 fitting. It took quite a number of e-mails and calls to several retailers and the importer to confirm you simply needed to purchase a CG5 mount fitting - No Celestron won't sell the CF version with a CG5 fitted - go figure!

My first worry - the scope mount bar appears to have two holes at the rear (spaced about 4cm apart) and one at the front to attach a CGE bar - how was I to attach a CG5 bar? Solution - after unscrewing the bar I was relieved to find the scope has four holes at the rear (two blocked by allen key threaded screws - easy to remove) - two for the CGE bar and two for the CG5 - so fitting a CG5 bar to this scope is trivial!

Challenge two - mount the Megrez! I had it mounted with 5" rings to a bar to 4" rings to connect the MAK to the Megrez. I asked Bintel if they could sell me a longer bar - but they correctly informed me the bar was too narrow for the CG5 / CGE holes at the rear. Think, think, think...

I realise the CGE bar would be perfect to mount the Megrez too, by moving it to the top of the scope, and simply drilling two holes where the 4" rings need to go - easy peasey!

Challenge 3 - finding screws to mount the CGE bar at the top. The screws supplied are way too short! This was the hardest puzzle. The bottom bar attaches with simple 3/16" screws - the top uses speciality screws. I took one to the local hardware store and it left them bam-boozled, they tried everything. So eventually they refered me to E&I fitters in Gladesville. Who were able to tell me they thought it was it was American 10 / 32 NSF threaded - but there bolts and nuts of that size wouldn't work. So they sent me to Lee's in North Parramatta - a total Godsend! Lee's told me it was actually 8 / 32 NSF threaded (8 guage (thread thickness) * 32 threads per inch) and they had plenty in stock in stainless steel - so $7 later I am in action. Cut them down a centrimetre and its good to go!

Except now the scope at the top weights too much - so I sandwich an old 5kg weight from my dumbells between two 5kgs weights on the bar. Huston we have lift off!

A bit of figuring to align the scopes - and its magic.

But I crash at 9pm exhausted from too many long days. Anyway I wake at 3am and look at M42 - and am blown away!I tested the scope with a Vixen LVW 22mm lens on Orion, NGC 1890, Sirius, Betelgeuse, M45, 46, 48 50 and 93 - my god I am impressed. The difference between the C9.25 and a 5" MAK is simply incredible. The focus is a bit more challenging on my CG5 mount - a slight bit of vibration - need to weld supports on my pier! I definitely think a motorised, computer controllable focuser is my next purchase.

Anyway a huge thanks to Steve at MyAstroShop Harbord, who offered excellent service - price matched my best price and really went above and beyond to get me going. All round I'm stoked and know who I'm getting more of my gear from!

Dennis
14-10-2006, 10:14 AM
Welcome to the world of the C9.25, dovetail rails, mounting bars, threaded fasteners, balancing, etc!

Cheers

Dennis

matt
14-10-2006, 10:22 AM
Did you buy the CF 9.25 from MyAstroShop?

I'm sure you'll enjoy the scope:thumbsup:

g__day
14-10-2006, 12:17 PM
Yes,

Andrews had a great price, and I've bought many eye pieces, binoviewers, my CG5 mount and binoculars from him. Astronomy Online where fairly good - I got my MAK from them and my O rings, they were very friendly but a slow getting back to me via e-mail and at the high end of the price curve. Steve at MyAstroShop I've bought lens from before, was exceptionally helpful and professional. Steve also was willing to match Andrews price.

So I choose Steve at MyAstroShop and I'm completely happy with his service and the quality of the mount. He even told me how to fix the finderscope - which is kinda underwhelming until you do the adjustment to focus it. But the SCT I feel well deserves its reputation!


So it ca

Dennis
14-10-2006, 12:26 PM
I'll be flocking my C9.25 soon, to (hopefully) reduce the scattered light that was so apparent when I was imaging Uranus as it approached the Moon leading up to the occultation of 8th Sept.

I contacted Protostar (http://www.fpi-protostar.com/flock02.htm) who are going to quote me on shipping. Their standard international shipping rate appears to be US$28.00 on sheets of the flocking material that cost US$10.00 per sheet.

The Protostar (http://www.fpi-protostar.com/flock02.htm) die cut sheets with the stronger adhesive backing are 20 x 30 inches. A quick measure of the ID of my OTA reads about 10inches, so π x d (pi x d) gives (3.142 x 10) = 31 inches.

The C9.25 OTA is 22 inches long according to the Celestron specs, so it looks like I’ll have to order 2 sheets.

Cheers

Dennis

matt
14-10-2006, 12:33 PM
Dennis

If you want to do the math and work out how much you'll need to do 2 scopes I'd be happy to share the cost with you:)

Only if it works out better for you to order a few more sheets???

Dennis
14-10-2006, 01:34 PM
What a great idea Matt - I'll start a new thread, when I get the details, to give anyone interested the opportunity to reduce costs.

Thanks!

Dennis

jase
15-10-2006, 09:43 PM
You missed the No.1 reason to buy a 9.25 - the secondary has a lower magnification resulting in a more flater field of view. Great for astro photos. :)
However the downside to this is the scope is a little slower (F/11) @ 2350mm compared to a C11 that is (F/10) @ 2800mm. Though its nothing a focal reduce can't fix. ;)

Just an observation from your pics - the CG5 looks taxed with the OTA of this size. Celestron are a little shy at providing stats on the CG5's load capacity. In fact I couldn't find them at all. I searched some forums to find the mount was rated to carry 35lb (15kg). The 9.25 is a 20lb (9kg) OTA along with the Megrez 80 at 5.9lb (2.7kg). Certainly getting close. Of course these are purely figures. Like the Takahashi mounts, most if not all can be overloaded and still track well.

I'm sure you'll enjoy what the 9.25 has to offer.:thumbsup:

g__day
15-10-2006, 11:01 PM
Jase - as you say - that's a taxed mount at the moment - and it will be the next major component to be upgraded when funds become available! Tracking seems surperb at the moment. Pick a star, leave it for 2 hours and its wandered about 30% from the centre of a low magnification eye-piece so I am continually drift aligning this rig. A pro would have this sorted weeks ago, but I'm learning!

I didn't talk about the flatter field because I've heard it but I don't really understand it in laymens terms yet!

To my thinking my upgrade path is likely to go:

1. Weld extra supports to scope pier to reduce vibration
2. Add motor / robo focuser to SCT
3. Possibly convert Megrez to APO and install a 10:1 fine focuser
4. Get focal reducers
5. Maybe get a Canon 400D for astro photography
6. Add more computing resources to the astro lab
7. Motorise the dome roof and slew it to the telescope's movements
8. Get a premium mount (Atlux, Tak, CGE or a G11 in that preference order).

So this might take 18 months or 4 years to afford - or never - who can tell? But at present I have alot to learn before I have the skills to use this rig anywhere near its capability, but God its fun learning each night!

TV76
16-10-2006, 08:04 PM
Congradulations on the C9.25". You state you got it from MyAstroShop - I had a quick look I can't see it advertised on there website - I guess you have to contact the shop and ask?

Thanks,

Alec

g__day
16-10-2006, 09:01 PM
Yes TV76, Given Steve at MyAstroShop sells most Celestron gear I assummed he as an authorised seller (and Steve at ExtraVision - the distributor confirmed this) I asked if he could and he said absolutely!

TV76
18-10-2006, 09:21 PM
Thanks for confirming that. Im still trying to decide if a C9.25" is in my future or save my pennies for a 5" refractor hmmmm......

Alec

g__day
19-10-2006, 02:27 PM
I'm impressed by my 80mm refractor (Megrez - 2nd hand). For widefield on bright objects (e.g. M7) is great, I'll have to wait some more to compare my Meg vs MAK vs SCT for planetary - Jupiter is too low - I'll have to wait for Saturn, and I'm not an early morning person! But a serious 5" refractor (like strongmanmike used I'd note) is costly and high performance.

My next splurge will be focusers then eventually a much better mount.