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Equipment Discussions >> ATM, Optics and DIY Forum

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bremms
Carpal Tunnel
*****

Reged: 08/31/12

Loc: SC
Re: Jaegers Lens spacers new [Re: Perseus_m45]
      #5616434 - 01/10/13 10:46 PM

My 4" F15 SS lens showed a good bit of undercorrection with the 1/8" spacer. With 0.002" of foil spacers the lens is much better, still a little undercorrection but it is minimal. The effect of the spacer is spherical and color correction. Ghosting and edge to edge focus won't be effected too much by the spacing. You need to do intra and extrafocal ring star tests. ( use a green filter for accurate results)

Edited by bremms (01/10/13 11:02 PM)


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Z28500
sage


Reged: 02/27/12

Loc: N. 30.1 W.-95.6 Texas
Re: Jaegers Lens spacers new [Re: Perseus_m45]
      #5636339 - 01/22/13 07:37 AM

Turned out great, here is a few threads of the scope One is another forum and you have to have a user name & password:

http://www.cloudynights.com/ubbthreads/showflat.php?Cat=0&Board=atm&N...

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5140754/page...

http://www.astronomyforum.net/atm-diy-telescope-making-forum/152008-soon-maga...

Z


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Z28500
sage


Reged: 02/27/12

Loc: N. 30.1 W.-95.6 Texas
Re: Jaegers Lens spacers new [Re: Z28500]
      #5636349 - 01/22/13 07:49 AM

Also I have zero "ghosting" and the edge to edge image is exactly the same as it is in the center. Surplus Shed gave me a really good set (they weren't the seconds) I have a 90mm meade I bought cheap from EBay, and when the image gets to the edge it starts to get a little blurry, not with this Jaegers! The only thing the lenses do have is a little chromatic aberration, but all achromats have that problem. The bigger the lens, the more CA. I've read some reviews and a common point seems to be that CA isn't that noticable with lenses 4 inches and smaller, yet another point is how much does CA really bother a person anyway. I really don't care and I have an Apo (6 inch)! But back to the F/15-Star Test was perfect, I guess if I was going to recommend anything it would be collimation, objective lens and focuser. A good place to get those two items is where I got mine:

http://crawmach.com/home

Dan is the guy that builds them and mine were built perfect.
I got my tube from speedymetals.com and then turned it down on a lathe to .050". They also have all kinds of other alum & brass.
I also built a mock-up out of green PVC 1st to get the length right and also to see how the lens worked.
Good luck.
Z


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Napersky
Carpal Tunnel
*****

Reged: 01/27/10

Loc: Chicagoland
Re: Jaegers Lens spacers new [Re: Z28500]
      #5637167 - 01/22/13 03:35 PM

PM Sean Cunneen as he knows everything about spacing and building lens cells for the Jaegers.

Mark


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BarabinoSr
Pooh-Bah
*****

Reged: 11/17/05

Loc: Slidell La
Re: Jaegers Lens spacers new [Re: Napersky]
      #5637276 - 01/22/13 04:22 PM Attachment (14 downloads)

When I got the objective for my 4.5" Jaegers, I obtained some air-conditioning duct tape. This is the kind that has some adhesive on the back and aluminum finish on the front. I was able to cut some very tiny rectangles out, place them in position using a pair of tweezers in between the elements .I also had owned previously a 6" f/15 Jaegers and did this before, so I know it will work! I also took the time to make sure that the spacers (3) were spaced equidistant from each other before putting back in the convex lens. The tape pieces did not move during this action due to the adhesive, and I don't think that the tiny amount would harm the elements.Regular aluminum foil pieces would not stay in position for me.
After this was done and later in the evening after the optics acclimated,I took the scope out for an observing session and grabbed a neat lunar shot:


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BarabinoSr
Pooh-Bah
*****

Reged: 11/17/05

Loc: Slidell La
Re: Jaegers Lens spacers new [Re: BarabinoSr]
      #5637282 - 01/22/13 04:26 PM Attachment (17 downloads)

Moonshot!

Edited by BarabinoSr (01/22/13 04:30 PM)


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