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old C8 vs new C8

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#26 watcher

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Posted 22 February 2013 - 06:12 PM

I think, if this is going to be your only scope, you might consider an Edge 8 CPC. Passive cooling would be beneficial in your climate. The fork mounts are more comfortable to view with, and I haven't seen a single report of anything but great optical quality in any Edge scope. besides that, you will get the best coatings available. :) I just think if your only going to have one scope to do it all, it's worth spending a little extra.

#27 rflinn68

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Posted 22 February 2013 - 06:29 PM

Post Deleted by rflinn68

#28 Julio

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Posted 22 February 2013 - 07:31 PM

Optical figure trumps everything, some have tested their C8-C14s and have found that they surpass 1/8 PV. While not common, such a SCT of mass production is in the excellent to superb category and an outstanding value and worthy of reacoating.

#29 mike174

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Posted 22 February 2013 - 08:14 PM

Magnus,

If your C8 has very good optics, that quality will have a profound impact on high power detail and contrast. No modern coating can make up for that. Only if the modern sample has similar high quality optics, than the coatings will add a little extra. Make sure you test any new C8 side-side with your old C8 at identical magnifications with identical eyepieces and diagonals. The coatings will do good on very low power views. As soon as you go to 150x and up, the quality of the optics will reveal themselves. Not only in the level of detail, but also in the steadiness of observable detail. Like the better scope has better seeing, while in fact it has better optics under similar seeing.


I noticed that when viewing the moon through a Mewlon 250 a few towns away under typical NJ skies. The sharpness of the optics was easily seen through the seeing. My 2007/2008 C11 seems to loose sharpness when I go eyepieces smaller than 20mm.

My Orange C8 seems to be almost the same on either side of focus unlike my C11.

MIke

#30 Bill Barlow

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Posted 22 February 2013 - 08:22 PM

Seems hard to believe that your C8 can show dimmer and brighter stars than a C11. Did you do the side by side using similar magnifications or the same focal length eyepiece in each? This would make the C11 use a higher magnification given it's longer focal length. The much higher light grasp of the C11 should be noticeable versus the C8 I would think.

Bill

#31 Brian Risley

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Posted 22 February 2013 - 11:06 PM

Just 2 C-8's? I have 3 and also the club's CPC-800 along with my Meade 10! :) :) :)
Brian

I have a mid-90's black tube C8 and I wouldnt trade it for anything other than an EdgeHD (8" vs 8"). Mine compared better than a friends similar model C8 and every bit as good as a brand new dark orange tube 8SE. I might even sell my 10" Meade SCT someday soon and buy the EdgeHD and keep my black tube C8. I like it that much! But I like my Meade too! :lol: Maybe I'll keep them both and just buy the EdgeHD! Everbody needs two 8" SCT's and a 10" SCT. Right? :grin:



#32 rflinn68

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Posted 23 February 2013 - 12:06 AM

Just 2 C-8's? I have 3 and also the club's CPC-800 along with my Meade 10! :) :) :)
Brian

I have a mid-90's black tube C8 and I wouldnt trade it for anything other than an EdgeHD (8" vs 8"). Mine compared better than a friends similar model C8 and every bit as good as a brand new dark orange tube 8SE. I might even sell my 10" Meade SCT someday soon and buy the EdgeHD and keep my black tube C8. I like it that much! But I like my Meade too! :lol: Maybe I'll keep them both and just buy the EdgeHD! Everbody needs two 8" SCT's and a 10" SCT. Right? :grin:


:roflmao: The more the merrier, right?

#33 jrbarnett

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Posted 23 February 2013 - 10:38 PM

Better still, you can get used, recent C8s for $350. They depreciate a lot.

- Jim

#34 greedyshark

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Posted 24 February 2013 - 08:26 PM

I recommend that you find some one local that has the Newer C8 that you are thinking of purchasing and see for yourself how your old C8 compares in a one to one showdown, directly with that scope using the same eyepiece and same diagonal. It might not be as big a jump as you might be anticipating...Bob


I agree with Bob 100%. I own an early '80s orange tube...outstanding optics! I will pass this one to my boy.

Charles

#35 rfic1

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Posted 24 February 2013 - 08:41 PM

I owned a 1976 Celestron Pacific C8 that I felt had outstanding optics. It almost always provided better planetary views than multiple 5" APO's I owned. I purchased a TEC 200MC and that is the reason why I parted with it. Yes the TEC is better, but at 7 times the cost. Plus it is not as portable and requires a substantial mount. I still miss that scope. One that I wish I never let go.

#36 Greg Boynton

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Posted 25 February 2013 - 06:57 PM

I also had an orange 70's C8 that had really sharp views. I didn't appreciate how good it was though and sold it in a fit of aperture fever. After looking through a whole bunch of SCT's since and getting educated, I realized that I screwed up. I do agree that the newer scopes seem to be more consistently good, but I wouldn't count on any given sample as being an upgrade.

I guess the lesson is: Never sell a scope which gives great views unless you are dang sure the replacement is actually better for you.

#37 orion61

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Posted 25 February 2013 - 07:41 PM

I have a C8 that was made for former Celestron VP of sales Leo Henzl, there are hand written notes on the back of the mirror in blue marker and it describes the extra figuring process and his name.
With my F 6.3 FF/FR I cant imagine anything sharper! I have owned C8's since the 70's this one is sure a keeper,
Even at the price I got it for.
I am debating sending the mirrors in for enhanced coatings.
The stock ones look good with no pin holes..
I just don't know what to do...

#38 bob midiri

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Posted 25 February 2013 - 07:59 PM

Larry why mess with perfection!!! Enjoy that scope, how much can really be gained by the coatings. use a 99% reflective diagonal to increase a little light going to your eyepiece...if you don't already!! Bob

#39 magnus

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Posted 27 February 2013 - 09:46 PM

This evening, before moonrise,I used my friend`s C8 XLT to see how it performes vs my old orange C8 Pacific -73. My friend Roger (sunrutas) is also a CN member but he is 100% imaginer, mostly planets. Now and than he visits solar system imagening forum to show his amazing Jupiter/Saturn pictures taken with his C8XLT & C925XLT.

Anyway this evening I got the chance to have a look tru`his C8XLT from his balcony, were he has a very solid pier & an CG-5 mount on top of it. I also often observe from my balcony so the conditions were very similar. I had taken my eypieces, diagonal & focalreducer with me to use on Rogers scope.

I had a look at Jupiter, Rigel, Alnitak, Trapezium, Sigma Orionis, gamma Leo. All in all I could not notice any distinct difference. Jupiter looked pretty much the same as in my old C8; details and contrast very much the same. Possibly J. was a bit whiter & brighter in XLT but I am not certain. No e or f star in Trapizium but not often I see those in my C8 either. (M42 don`t get high over horizion up here)More easy in my 8" f/6 OOUK Newt. But the four "original" Trap. stars were defenitely more distinct & pinpont in my C8. Strange! The C component in Sigma Ori. was harder to see in the C8XLT than in my C8.Even more strange!! I could not notice any difference when observing Rigel, Alnitak & gamma Leo.

A quick startest gave pretty much the same result in both scopes; not perfect but pretty good.

I am very surprised & glad how extremely well my classic C8 hold up against a brand new XLT. Tom Johnsson had certainly done his homework before starting massproducing the C8 1970!

A test C8 vs C8 XLT on a dark place with no moon might have tipped the advantage over to the C8XLT but I very much doubt it, not in a
dramatical way, anyway.

I will keep my beutiful 40 (!!) year old orange C8 Pacific & take good care of it & use it as much as I can.

Best Regards,
Magnus 57N.

PS Seeing was: ca. 5/10 P.

#40 bob midiri

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Posted 27 February 2013 - 10:09 PM

Nice report Magnus, :bow: Im glad you saw for yourself... Bob

#41 magnus

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Posted 27 February 2013 - 11:30 PM

Bob!

Thanks for advicing me to compare a new C8XLT vs my old C8; luckily I have a local friend with the C8XLT to compare with!

Back home this late night I had marvelous observation of Saturn at 240X, despite it was just 17 degrees above horizon and gamma Virgo was wide open at 411X.
Seeing had improved!

Now it`s time for bed!

/Magnus 57N.

#42 Eddgie

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Posted 28 February 2013 - 11:37 AM

While I agree on this point, I am unsure that you have to make this an "Either/Or" proposition.

The C8s seem to me to enjoy the best consistency in terms of high quality optics of all the Celstron SCTs I have ever owned.

There may have been some Comet lemons out there, but I have never star tested a Celestron C8 that did not show very good to excellent optics.

I also agree that it would be very hard to see the difference between a older SCT or a Starbright SCT, or comparing a Starbright SCT to an XLT SCT, but in each case, the steps are minor.

The XLT also introduced the use of water white glass, so this is not at all a coating change.

The step in transmission between a pre-starbright and XLT SCT is on the order of 12% or so.

People on the eyepiece forum routinely report seeing transmission differences half of that.

Ah, but you would have to look for it.... This amount of transmission difference will only be readily apparent when doing limiting magnitude tests.

I also think a serious planetary observer that routinely uses very small exit pupils (.8mm or smaller) would indeed notice the light falloff because the image would dim sooner in the old scope.

So, for the most demanding usage, I think it is very likely that the difference would be detectable for anyone that was demanding enough to see it.
But for casual use, it could be ignored.

#43 bob midiri

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Posted 28 February 2013 - 03:18 PM

To me the money he saved by keeping the old C8 with great optics, compared to the minimal gain he might have achieved purchasing the C8XLT, he now is in position to purchase some excellent eyepieces and even a Di-electric diagonal to further increase his enjoyment of that wonderful classic scope. I own a Super C8 orange and a classic Orange C14, and I would NOT trade them in. I enjoy them too much....bob

#44 rflinn68

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Posted 01 March 2013 - 06:24 PM

I've heard that the reflectivity will decrease 1% per year. My near 20 year old C8 compared well to a brand new 8SE of a friends but I did think the image in his was a little brighter. Not sure if it was 20% brighter though :shrug:

#45 vct123

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Posted 02 March 2013 - 06:04 PM

I just picked up a black tube Starbright c8, I actually traded my buddy for my 8"dob.
This is a good one with excellent optics and very little image shift.
To me the difference from the starbright to the xlt coatings
is minimal at best on most objects.
I have had many c8's and I just think its a great scope to have at hand.

#46 magnus

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Posted 03 March 2013 - 07:19 PM

Bob!

A TV 24 Panoptic will be nice to have + a binowiever with matching eypieces :)

/Magnus 57N.

#47 bob midiri

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Posted 03 March 2013 - 07:23 PM

I hear you Magnus!! :bow: BTW post some pictures of that Classic C8 , I know I for one would love to see your scope. Clear skies. bob

#48 magnus

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Posted 03 March 2013 - 07:46 PM

Bob!
I will see if my astrofriend Roger can help me with that. Promise!
/Magnus 57N.

#49 orion61

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Posted 03 March 2013 - 10:39 PM

I thought that was for an open tube?
I have a 70's C8 that used to belong to Leo Henzl Jr.
Some of the pics in the old Celestron Sales catalogs were
taken through it!
Nice deal tho.
There is a Coulter 8 Dob on Shop Goodwill.com with a &5.00 bid on it right now...

#50 magnus

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Posted 04 March 2013 - 05:55 AM

Mine has lost 40% reflectivity if 1% loss a year is correct for a closed SCT :shocked:
/Magnus 57N.






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