SBrian
super member
Reged: 09/04/10
Loc: New Hampshire USA
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Re: Tinkering Beachchairbill
[Re: EdZ]
#4346881 - 01/28/11 04:43 PM
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Snow...LOL Yah I just clean 2 feet off my deck so can drag the DOB out when the clouds finally clear out. Bill the two lens are most likely sandwiched together the only way to see the two is from the side.
Edited by SBrian (01/28/11 04:45 PM)
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SBrian
super member
Reged: 09/04/10
Loc: New Hampshire USA
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Re: Tinkering Beachchairbill
[Re: SBrian]
#4346900 - 01/28/11 04:48 PM
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I was going to attach a photo but for some reason the capability to attach a photo is gone.
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Jawaid I. Abbasi
Carpal Tunnel
Reged: 06/19/07
Loc: LEVITTOWN, PA
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Re: Tinkering Beachchairbill
[Re: EdZ]
#4346929 - 01/28/11 04:58 PM
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I strongly agreed unless you have some kind of special paint that not in the "CAN spry"
Brian,
add cloudynights.com in the trusted site if using IE then enable "applet"
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SBrian
super member
Reged: 09/04/10
Loc: New Hampshire USA
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Re: Tinkering Beachchairbill
[Re: Jawaid I. Abbasi]
#4346956 - 01/28/11 05:08 PM
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I agree as well... I just test the paint using a green laser and the gray paint does absorb the light quite well. 
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EdZ
Professor EdZ
Reged: 02/15/02
Loc: Cumberland, R I , USA42N71.4W
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Re: Tinkering Beachchairbill
[Re: SBrian]
#4347005 - 01/28/11 05:29 PM
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if you have a green laser you can shine that thru the lens and easily see the number of elements in the lens
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SBrian
super member
Reged: 09/04/10
Loc: New Hampshire USA
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Re: Tinkering Beachchairbill
[Re: EdZ]
#4347061 - 01/28/11 05:54 PM
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Ed, well I'm no expert but my APMs are advertised as having Doublets, but when I ran the laser over the optics it revealed two lens as expected but with a large air gap between the two. I would have thought they would have been sandwiched together.
Edited by SBrian (01/28/11 05:55 PM)
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pcad
Carpal Tunnel
Reged: 01/17/05
Loc: Connecticut
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Re: Tinkering Beachchairbill
[Re: SBrian]
#4347160 - 01/28/11 06:47 PM
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Either an air gap or a big piece of fluorite is sitting between the lenses. In this case it's most likely air.
A lot of smaller binos have cemented doublets, but there are all sorts of objective designs out there. If there's an air gap I'd be leary of disassembling the objective.
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EdZ
Professor EdZ
Reged: 02/15/02
Loc: Cumberland, R I , USA42N71.4W
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Re: Tinkering Beachchairbill
[Re: pcad]
#4347344 - 01/28/11 08:06 PM
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The Oberwerk BT100 straight thru is a triplet with a small airgap (1/8"?) between the outer and mid elements and a big (1/2"?) airgap between the mid and inside lens.
The WO 22x70 Semi-Apo is an air spaced doublet.
the Fujinon 16x70 is a cemented doublet.
The Garrett 22x85 Signature is an air spaced doublet.
Both the Oberwerk Ultra 15x70 and the 10.5x70 are from the same family as the GO22x85 yet they are both cemented doublets.
The Garrett Optical Gemini 20x80 TWP looks like a cemented triplet. It's specified as 3 elements/2 groups. The outer two elements are definitely cemented. The air space must be extremely thin between that outer doublet and the inner element.
The Celestron Regal LX 8x42 Roof is a triplet made up of a cemented doublet outer lens then an 1/8" air space and a single inside lens.
The Zen Ray ZRS Summit 10x42 Roof is a triplet made up of a single outer lens with a thin 1/8" air space and then a cemented doublet.
The Nikon SE 12x50 is a cemented doublet and BTW, the insides of the barrels are grey.
edz
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Jawaid I. Abbasi
Carpal Tunnel
Reged: 06/19/07
Loc: LEVITTOWN, PA
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Re: Tinkering Beachchairbill
[Re: EdZ]
#4347453 - 01/28/11 09:25 PM
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Brian,
Here is the specification:
Prism type= Orthorhombic
Lens Element- 10 pieces in 6 group -0.2% reflectivity.
I will send you the diagram if you want.
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beachchairbill
Pooh-Bah
Reged: 11/06/08
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Re: Tinkering Beachchairbill
[Re: Jawaid I. Abbasi]
#4347630 - 01/28/11 11:24 PM
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Ed,
I will take your advice and not paint them, however, I will clean the the inner tube. Since I do not have a green laser is their another way to check to see if their are two lenses. Right now I see only one large one, would anything else work.
Any suggestion on what I should use to clean the inner tube?
Beachchairbill
Jaeaid, post your d here, Thanks
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Joad
Wordsmith
Reged: 03/22/05
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Re: Tinkering Beachchairbill
[Re: beachchairbill]
#4347658 - 01/28/11 11:51 PM
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I think you can use a process of elimination on deciding the lens number.
Achromatic optics have objective doublets of one kind or another. It was the doubling of the objective lens that invented achromatic refractor optics in the first place.
Achromats can also have triplet objectives, but triplets are much heavier. As EdZ has said, the Oberwerk 100mm BT is a triplet, and that is part of its weight. I do not believe that the APM could be so much lighter than the BT if it was a triplet.
It certainly isn't a Petzval (two doublets).
It really has to be a doublet.
In cleaning the inner tube I would advise only a VERY careful daubing away of any globs of grease with a dry Q-tip. That grease probably isn't having any effect on optical performance anyway. You don't want to risk introducing any corrosive cleansers into your tube. Having it open and apart like this is already a risk. Screwing everything back in exactly right (and the tolerances are pretty darn tight) is going to be enough of a challenge.
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beachchairbill
Pooh-Bah
Reged: 11/06/08
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Re: Tinkering Beachchairbill
[Re: Joad]
#4347760 - 01/29/11 01:58 AM
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Joad,
Thanks for the additional information and for your information, these tubes have been worked on before when I sent them back to Garrett clean the tubes that were a mess.
Here is a question that I have with regard to having two lenses, how thick should each lens be and how far appart are they usually. In looking through the front Obj lens it appears to be only one lens. When I look at it from the back side it only looks like one lens. For now, I'm trying not to unscrew the cone that holds it or them together. I know that the cone does unscrews but prefer to leave it alone for now. Here is my measurement from front to back. Never mind the measurement I just unscrewd the the cone and their are two lenses and the look to be of different sizes. Will measure them and post it here with a picture.
BB
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EdZ
Professor EdZ
Reged: 02/15/02
Loc: Cumberland, R I , USA42N71.4W
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Re: Tinkering Beachchairbill
[Re: beachchairbill]
#4347992 - 01/29/11 07:48 AM
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If you note from the samples I provided in my post above, there is no set spacing distance. It can vary from a mm to a half inch.
The thickness of each lens varies across the lens from center to edge. As one lens of the doublet gets thinner the complimentary lens is often seen to get thicker.
This is pretty simple lens design. You'd be far better off reading about this in a book than taking your lens apart.
No doublet lens should ever be taken apart without first marking the edges with a match point. If the lens pair has had any quality control, the lenses were turned (or tuned would also be a good word) to match with respect to each other, and then they were mounted in their cell. Changing the position of one element with respect to the other in a doublet can and probably will introduce some aberration.
edz
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SBrian
super member
Reged: 09/04/10
Loc: New Hampshire USA
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Re: Tinkering Beachchairbill
[Re: EdZ]
#4348003 - 01/29/11 08:05 AM
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JAWAID where did you get the information on the prism? and yes send me the drawing.
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SBrian
super member
Reged: 09/04/10
Loc: New Hampshire USA
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Re: Tinkering Beachchairbill
[Re: SBrian]
#4348012 - 01/29/11 08:17 AM
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Well Bill it sounds like you're going for the Full Monty with regards to your GBT.
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Goodchild
scholastic sledgehammer
Reged: 12/31/08
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Re: Tinkering Beachchairbill
[Re: SBrian]
#4348138 - 01/29/11 09:44 AM
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I gotta say this, Bill, you have a lot of nerve (or a lot of money).  Good luck, as we are all watching this thread with interest.
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Jawaid I. Abbasi
Carpal Tunnel
Reged: 06/19/07
Loc: LEVITTOWN, PA
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Re: Tinkering Beachchairbill
[Re: SBrian]
#4348392 - 01/29/11 12:14 PM
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Quote:
JAWAID where did you get the information on the prism? and yes send me the drawing.
APM telescope sent me the information. As soon the printer is able to scan, I shall send you the drawing.
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beachchairbill
Pooh-Bah
Reged: 11/06/08
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Re: Tinkering Beachchairbill
[Re: Jawaid I. Abbasi]
#4348686 - 01/29/11 02:43 PM
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Here is some additional information, the inside lens is 88mm in width and 12mm thick. There are no rostu screws or broken ones either. I have noted that their are smudges on this glass and it did not come from me, I'm using white gloves. I will clean it before I put it back. The distance between the two lenses is 1 1/8 inch.
Picture to follow.
Ed, which books do you recommend and is their anything online that I can read.
Thanks
BB
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beachchairbill
Pooh-Bah
Reged: 11/06/08
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Re: Tinkering Beachchairbill
[Re: beachchairbill]
#4348917 - 01/29/11 04:49 PM Attachment (32 downloads)
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Here are three additional pictures
BB
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beachchairbill
Pooh-Bah
Reged: 11/06/08
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Re: Tinkering Beachchairbill
[Re: beachchairbill]
#4348919 - 01/29/11 04:50 PM Attachment (27 downloads)
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