a-l-e-x
scholastic sledgehammer
Reged: 12/25/07
Posts: 820
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Hi all,
Scanning through the internet, Ive found some reports of a few people needing to have their sct primaries recoated, and it being something that needed to be done "at the factory" because the primary is glued to the back of the cell. Im thinking of getting an 8" sct as my portable "large" aperture scope and Im wondering, short of quality control issues, how long would one have to go between mirror recoats? Thanks!
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Nexstar 8SE SCT
Meade DSI-3
90mm refractor
10x50 binoculars
Starry Night Pro Plus 6.4.3
900x Microscope
My site:
http://originsoftheomniverse.shutterfly.com/
http://supermanalexthegreat.shutterfly.com
http://supermanalexthegreat.wordpress.com
http://Alex_the_GREAT.photoshop.com
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firestar
Born to be Mild
Reged: 10/18/06
Posts: 3942
Loc: Cleveland Ohio USA
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Both my SCT's are near 20 years old and throw up great views.
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Eastlake Ohio
Lots of cheap Asian glass  
Antares 12" Dob,Antares 8" Dob
Meade 8" SCT, Celestron C8 SCT
Zhumell 152 mm F8,Antares 127 mm f9.4
Orion short tube 90 F5.6,Celestron 80 ED F7.5
Imaging Source DMK 21AU04 ccd camera
Stellarvue bv3's with 32,26,23,21,9 mm pairs
Olivon 42,35,28mm,siebert 21,12.5,7mm,GSO superview 20mm,Meade swa 13.8mm,Hyperion 13mm
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Randy Roy
sage
Reged: 10/07/05
Posts: 443
Loc: Tennessee
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Assuming you:
- don't remove the corrector plate more than every 2-3 years or so for a cleaning
- don't use an active cooling device (I do use one)
- don't store the scope in a damp environment
- don't store it in an area with lots of spiders
- don't normally use the scope in a very dusty/sandy environment
-do use adequate dew control so that the primary does not dew up very badly very frequently:
Then, my own experience is at least 15-20 years.
All of these caveats above have some effect, but perhaps not as much as they sound like they may. I've had lots of SCTs over the past 25 years under some of all the conditions above and have never had a recoat on any of them. The worst gremlin, IMO, is mold/mildew which can occur from storing the scope in a damp area.
Randy Roy
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a-l-e-x
scholastic sledgehammer
Reged: 12/25/07
Posts: 820
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Wow, thats a long time, much longer than I expected actually. Does being close to a big city or the ocean significantly reduce that or would you still say at least 15 years, especially with the special coatings that both meade and celestron provide their scopes? Im trying to decide between the lxd75 mounted 8" meade and its counterpart celestron, and they both seem to have great coatings and similar image quality from what I can tell.
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Nexstar 8SE SCT
Meade DSI-3
90mm refractor
10x50 binoculars
Starry Night Pro Plus 6.4.3
900x Microscope
My site:
http://originsoftheomniverse.shutterfly.com/
http://supermanalexthegreat.shutterfly.com
http://supermanalexthegreat.wordpress.com
http://Alex_the_GREAT.photoshop.com
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4Texans
super member
Reged: 12/08/07
Posts: 121
Loc: TX
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I have a 1984 Meade 826 newtonian reflector that has the original coatings. They still work fine. The big factor is avoid storing in a moist environment. Also, do not store a telescope in a garage with pool chemicals. Chlorine is very corrosive. I had a C8 for seven years and the coatings were like new when I sold it.
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Meade LXD-75 8" S/N
Meade 826C
Meade ETX90EC
7x50 binoculars
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Randy Roy
sage
Reged: 10/07/05
Posts: 443
Loc: Tennessee
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I have not lived near the coast, so cannot comment on that. I would say that if I listed all the criteria that was important to me to decide between two scopes, the coatings would be near the bottom of the list. Most modern scopes have excellent and durable coatings that make this a non-issue, IMO. You are correct that both M and C provide excellent coatings.
You can tell from all the M vs C threads on various newsgroups over the years, that supplier selection is mostly a matter of choice with each company having its loyal supporters. Most 8" SCTs these days are very good optically. You should be happy with either.
Randy Roy
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a-l-e-x
scholastic sledgehammer
Reged: 12/25/07
Posts: 820
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I think Ive found something I want. Nice aperture, very portable, has goto and wont break my back... or the bank! :P
Nexstar 8se... what do you guys think?
If I do astrophotography, its going to be of the 30sec-1min type, and I'll just stack images with registax. I hope I found the right big aperture compact!
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Nexstar 8SE SCT
Meade DSI-3
90mm refractor
10x50 binoculars
Starry Night Pro Plus 6.4.3
900x Microscope
My site:
http://originsoftheomniverse.shutterfly.com/
http://supermanalexthegreat.shutterfly.com
http://supermanalexthegreat.wordpress.com
http://Alex_the_GREAT.photoshop.com
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edl
professor emeritus
Reged: 06/24/04
Posts: 581
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I have the same Meade 826, also circa 1984. The primary still looks great with no coating issues.
Best,
Ed L.
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w orchid
Pooh-Bah
Reged: 04/23/07
Posts: 1137
Loc: Tampa, Fl
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C8 circa 1981, all is well.
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Celestron C8 orange tube circa 1979
Stellarvue SV102ED
SBIG ST8300C
http://www.astrophotogallery.org/u378-man-of-constant-sorrow.html
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Stelios
Pooh-Bah
Reged: 10/04/03
Posts: 1484
Loc: West Hills, CA
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Good choice of scope. Excellent combination of portability and aperture. For AP, the CG8-GT would be better, but less of a Grab-n-Go package.
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APM/TMB 115/805 APO
9.25S - GT
Naglers: 17T4, 13T6, 3-6 zoom
UWANs: 28mm, 7mm
Pentax 10XW, 10mm Radian
Misc EP: 50mm Parks, 42mm GSO, 2x TV Barlow
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a-l-e-x
scholastic sledgehammer
Reged: 12/25/07
Posts: 820
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Thanks Stelios. Afer looking at the various 8" sct packages from both Celestron and Meade, I figured that this is the most portable form of the scope. As far as accessories are concerned, would you say the focal reducer and the carrying case are most important? I already have a set of EPs (Orion Highlight Plossl 40mm, Meade Super Plossls Series 4000 26mm and 9.7mm and TMB 7mm, along with an Orion Shorty Barlow 2x) planetary filters, O-3 filter, broadband filter, OPT diagonal... Im thinking I should get the carrying case and the f/6.3 focal reducer. Does this scope have a dust seal on the back? Cant think of anything else to get now except maybe the ac adapter or power tank. I dont think my AA 2500 mah rechargeables can put up with more than a couple of hours of work.
--------------------
Nexstar 8SE SCT
Meade DSI-3
90mm refractor
10x50 binoculars
Starry Night Pro Plus 6.4.3
900x Microscope
My site:
http://originsoftheomniverse.shutterfly.com/
http://supermanalexthegreat.shutterfly.com
http://supermanalexthegreat.wordpress.com
http://Alex_the_GREAT.photoshop.com
Edited by a-l-e-x (12/29/07 07:37 PM)
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