dobsoscope
member
Reged: 05/24/06
Posts: 48
Loc: MT
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Hi all,
I just swept my 150mm solar filter from Thsnd.Oaks off the table  
It did not shatter however, but a number of cracks in the glass appeared, leaving quite largish areas unaffected.
Given its price (!!) I was going to paint in black paint, over the crack lines to make sure no sunlight passes through them.. what do you think?
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Ralph Marantino
Postmaster
Reged: 05/01/05
Posts: 5256
Loc: Old Bridge, New Jersey
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Post deleted by Ralph Marantino
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Lunt H-alpha LS200THaDS with 3200 blocker (Pre- ordered)Xmas Maybe?
Rockland Astronomy Club
Member BAA Solar Section
Central Appalachian Astronomy Club(Greenbank NRAO)
Astronomical League
DSPST,PST & 70mm Coronado Cal K telescope.2.2A 500mm FL 1200 blocker
14.5 inch f 3.74 Starmaster Zambuto Dob
2 inch APM Herschel wedge LUNT Cal K Module in a80mm Brandon 500mm FL 2.4A 1200 blocker...
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darkstar528
Post Laureate
Reged: 03/06/07
Posts: 4761
Loc: Hodgenville, Kentucky, USA
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OUCHIWAWA, that sucks...Sorry to read that...
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Blue skies,
Stephen "Darkstar" Ames
PST, VIXEN 8-24mm,CEMAX 2x Barlow, Thousand Oaks White Light Filter and a Meade Elec EP
CFI, CFII, MEI, working on EIEIO!
BAA Member
My solar site:
http://seemysunspot.com
Live solarcams from around the world:
http://www.seemysunspot.com/live_sun.html
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Jim Rosenstock
Carpal Tunnel
Reged: 07/14/05
Posts: 2408
Loc: MD, south of the DC Nebula
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I'm gonna be conservative and caution that you shouldn't take ANY chance of turning a small disaster into a BIG one.
The integrity of the glass is compromised. Should it crack some more when exposed to the Sun, and have a chunk fall out...I wouldn't want to be at the eyepiece!
Call me paranoid, but filters can be replaced more cheaply than eyes.
Jim
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Ralph Marantino
Postmaster
Reged: 05/01/05
Posts: 5256
Loc: Old Bridge, New Jersey
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I changed my mind on the side of caution chuck it!PLEASE
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Lunt H-alpha LS200THaDS with 3200 blocker (Pre- ordered)Xmas Maybe?
Rockland Astronomy Club
Member BAA Solar Section
Central Appalachian Astronomy Club(Greenbank NRAO)
Astronomical League
DSPST,PST & 70mm Coronado Cal K telescope.2.2A 500mm FL 1200 blocker
14.5 inch f 3.74 Starmaster Zambuto Dob
2 inch APM Herschel wedge LUNT Cal K Module in a80mm Brandon 500mm FL 2.4A 1200 blocker...
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stephenramsden
sage
Reged: 08/17/07
Posts: 481
Loc: Atlanta, GA--USA
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That's crazy man. Forget that thing and call Ken at Thousand Oaks. Maybe he will work with you on a swap at a reduced cost since he can use the frame again.
A pinhole maybe but a crack...no way! Ever heard of expansion and contraction because of temperature?
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Stephen W. Ramsden
Atlanta, GA--USA
www.solarastrophotography.com
www.stephenramsden.com
WAYYY too much Solar stuff according to my new wife..
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Daniel
scholastic sledgehammer
Reged: 06/16/05
Posts: 757
Loc: Roscoe,IL
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R U NUTZ???? Toss it, no way no how would I try to PAINT a filter to fix it.. just because of money. I would rather go without until I could afford a new one.
If ANYTHING, take a large piece of it and make a smaller app. filter to fit over your larger app scope... Ya Know what I mean???
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Meade 8" Starfinder w/ EQ mount, Magellan II
ETX 70mm,F5
Coronado PST(Original Gold Coatings!),on smaller Meade EQ / motorized Mount
Bushnell 7-21x40 bino's
Barska 20x80mm Bino's
(CCD)LPI,Meade Video Eyepiece
Canon A-E1 SLR,Canon EOS ElanII
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dobsoscope
member
Reged: 05/24/06
Posts: 48
Loc: MT
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Yes you're right guys...! absolutely...
For the time being I'll break out all the glass and put some Baader filter material instead.
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--
Astrozap 152mm f/8 refractor
Minolta 10x50 WA binoculars
CG5-ASGT
Edited by dobsoscope (10/01/08 08:37 AM)
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Zoomster
professor emeritus
Reged: 01/30/05
Posts: 670
Loc: Tampa FL
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Good choice, I was going to suggest that!
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Celestron CPC 1100 aka "The Marino"
Moonlite Dual Rate Focuser
WO Dielecric Diagonal
Denkmeier "Big Easy" Binos and assorted eyepieces.
Coranado PST
SPC900NC...not modded...yet. (eh-eh)
Is God willing to prevent evil, but not able? Then he is not omnipotent. Is he able, but not willing? Then he is malevolent. Is he both able and willing? Then whence cometh evil? Is he neither able nor willing? Then why call him God?
Epicurus
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BYoesle
scholastic sledgehammer
Reged: 06/12/04
Posts: 876
Loc: Goldendale, WA USA
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The Baader filter material will be just as good, if not better. And it's so inexpensive, you wont have to worry about replacing it should you accidently damage it...
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Bob 
You are a child of the universe,
no less than the trees and the stars...
And whether or not it is clear to you,
no doubt the universe is unfolding as it should.
Desiderata
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GlennM
member
Reged: 09/29/08
Posts: 63
Loc: Grimsby, ON, Canada
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I have a full-size Baader filter for my 150mm reflector and the resolution of details is as good as any I've seen for white light.
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colinsk
Pooh-Bah
Reged: 01/17/08
Posts: 1234
Loc: CA
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All materials have a quality called "The Work of Fracture". It is expressed in a critical crack length. If a crack exceeds the critical crack length for the material we are talking about then the crack will self propegate. Glass has one of the shortest critical crack lengths of any material (less than 1mm if I rememeber right) we commonly use. Have you ever seen the small crack in your windshield spread over time to a long crack?
In addition to the large cracks what you have now is hundreds of cracks that are very small and exceed the critical crack length. They can and will spread. At some point a large piece of the glass will just drop out. I think you have a Dob, this piece will not only damage the mirror but it will image a bright portion of the sun on your retnia causing permanant damage.
Don't risk it. Baader is cheap and good. And you already have a cell for your scope. Make sure to not try to stretch the Baader tight when you make your new filter. It can't have any tension but a couple of wrinkles are OK.
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Mahalo,
Colin Kaminski
Coulter 10.1" Dobsonian
PST
TV-76/Baader White Light Filter/LS50F/BF1200
LS60T/DS50/FT/BF1200
DSM
LXD-75
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Tom and Beth
sage
Reged: 01/08/07
Posts: 434
Loc: Tucson, AZ
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As others have already said, consider the glass "TOAST" and just use the frame with Baader Solar Film.
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BobH1357
super member
Reged: 01/15/05
Posts: 122
Loc: San Jose, CA
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Why not put the Baader filter over the broken glass one? I don't know how well the combination works, but the Baader film would protect you if the glass breaks further.
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BYoesle
scholastic sledgehammer
Reged: 06/12/04
Posts: 876
Loc: Goldendale, WA USA
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This would be the equivalent of "stacking" two white light filters, and the image would be invisably dim.
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Bob
You are a child of the universe,
no less than the trees and the stars...
And whether or not it is clear to you,
no doubt the universe is unfolding as it should.
Desiderata
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dobsoscope
member
Reged: 05/24/06
Posts: 48
Loc: MT
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I'll go with just the Baader instead /;)
The nice warm yellow image was great though in the glass filter... !
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--
Astrozap 152mm f/8 refractor
Minolta 10x50 WA binoculars
CG5-ASGT
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Ralph Marantino
Postmaster
Reged: 05/01/05
Posts: 5256
Loc: Old Bridge, New Jersey
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just insert a cheap yellow filter in your eyepiece.
--------------------
Lunt H-alpha LS200THaDS with 3200 blocker (Pre- ordered)Xmas Maybe?
Rockland Astronomy Club
Member BAA Solar Section
Central Appalachian Astronomy Club(Greenbank NRAO)
Astronomical League
DSPST,PST & 70mm Coronado Cal K telescope.2.2A 500mm FL 1200 blocker
14.5 inch f 3.74 Starmaster Zambuto Dob
2 inch APM Herschel wedge LUNT Cal K Module in a80mm Brandon 500mm FL 2.4A 1200 blocker...
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blackhaz
Carpal Tunnel
Reged: 05/20/06
Posts: 1564
Loc: Prague, Czech Republic
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At least with Baader you can see the Sun in it's natural color and not artifical yellow. 
Baader film has the most uniform flat visible light transmission curve among popular WL filters. And the quality just rocks. I do not even know what Herschel wedges are here for. Despite I have one from APM that is much more expensive than a piece of Baader film, the quality through the film is superior.
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Max,
10" Aries MCT AP900GTO, C11-SGT XLT, WO ZenithStar 66ED, 90mm <1Å H-a, <2.2Å CaIIK Solar Achromats
Photos and Projects: http://www.bcsatellite.net/bao/
ČAS Solar Section
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colinsk
Pooh-Bah
Reged: 01/17/08
Posts: 1234
Loc: CA
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Max, You are the first person I have heard say the quality of the film is better than a wedge. With the extreme resolution of your work it says a lot. Hmmm....
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Mahalo,
Colin Kaminski
Coulter 10.1" Dobsonian
PST
TV-76/Baader White Light Filter/LS50F/BF1200
LS60T/DS50/FT/BF1200
DSM
LXD-75
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Alan Friedman
sage
Reged: 08/30/07
Posts: 352
Loc: Buffalo, NY
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It is a rare day for most when the seeing is not the limiting factor to viewing the sun in white light. An advantage of the Baader film, however, is that it can be used with a reflector or cassegrain - allowing use of a large aperture if the seeing is good.
cheers,
Alan
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Alan Friedman
www.avertedimagination.com
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