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need information on C11

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#1 DSobserver

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Posted 07 November 2013 - 01:28 PM

I'm looking to purchase a 2nd hand OTA

If the C11 is a hyperstar one, the surface treatment is always XLT? If I know the serial number can I know how old is the telescope?

Thanks for your help!

#2 freestar8n

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Posted 07 November 2013 - 01:35 PM

I don't know the various possible combinations, but I have a carbon fiber c11 that is hyperstar compatible but is before XLT. It came with one of the early cge1100's.

Frank

#3 WarmWeatherGuy

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Posted 07 November 2013 - 01:37 PM

When I was looking for a used C11 I came across some new ones that were cheap and bought one for $500 off the normal price.

http://www.highpoint...n-C11-SCT-Al...

#4 Eddgie

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Posted 07 November 2013 - 01:55 PM

Well, there is almost always a sticker that will say either "Starbright" or "XLT."

Have you asked the seller if either one of these stickers is present on the scope?

That would be the easiest way to know.

The XLT sticker is also Laser Holographic as well to keep it from being easily counterfitted.

But there is almost always a sticker.

#5 mclewis1

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Posted 07 November 2013 - 02:04 PM

I'm looking to purchase a 2nd hand OTA. If the C11 is a hyperstar one, the surface treatment is always XLT? If I know the serial number can I know how old is the telescope?

I don't think you can tell the age directly from the serial number but you might find someone who has a similar number which should tell you roughly how old it is.

It would also be helpful to describe the ota, color of the tube, the type of secondary holder, the style of the rear cell, the style of the focuser knob, dovetail bar, finderscope, etc.

If the ota has XLT coatings there will be an XLT sticker on the ota. If there is no XLT sticker then it will likely have StarBright coatings.

With a little more of a description of the ota I'm sure a few of the more experienced folks around here could tell you more about the possible age of the ota.

#6 DSobserver

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Posted 07 November 2013 - 03:13 PM

it's a carbon ota with a completely flat rear cell and one handle.

#7 jrcrilly

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Posted 07 November 2013 - 03:21 PM

it's a carbon ota with a completely flat rear cell and one handle.


I owned one just like that. It was Fastar compatible but did not have XLT (which, I guess, answers one of the questions in your initial post).

#8 DSobserver

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Posted 07 November 2013 - 03:28 PM

and when did you owned it?

is xlt treatment really interesting for visual use?

#9 jrcrilly

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Posted 07 November 2013 - 03:38 PM

and when did you owned it?

is xlt treatment really interesting for visual use?


It was when the CF tubes first came out on the Nexstar 11GPS; 2002 or thereabouts. XLT came along as an option a couple of years later and eventually became standard equipment..

#10 David Pavlich

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Posted 07 November 2013 - 04:17 PM

and when did you owned it?

is xlt treatment really interesting for visual use?


I forget the percentage of light passage increase of XLT over Starbright, but it is a fair amount. If push comes to shove, I'd always try to find the XLT version.

David

#11 mclewis1

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Posted 08 November 2013 - 10:05 AM

The transmission was something like just under 10% for visual work, and just over 10% for a wider spectrum response (appropriate for CCD imaging) and when everything was taken into account Celestron advertised a 16% difference. When XLT was released folks who viewed them side by side (new StarBright vs. new XLT) generally reported no real brightness difference but quite often there was a difference in contrast noticed.

http://www.celestron...starbright-xlt/

#12 DSobserver

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Posted 10 November 2013 - 01:30 PM

I just get a reply from celestron : it's not possible for them to know with the serial number when the scope was produce....

I can't understand the sense of this number...

Like you they ask me for pictures to estimate production date....






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