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kingjamez
scholastic sledgehammer


Reged: 10/03/06
Posts: 996
Loc: Washington D.C.
Surplus Shed 110mm Jaegers Achromat.
      #1418219 - 02/11/07 03:44 PM

110mm Jaegers

Think this is a good deal? Antares has a 127mm mounted in a collimate-able lens for less. However, I don't know the quality of either. Think it's worth a try?

-Jim

--------------------
C8 on Atlas with EQMOD
ETX125 UHTC
Celestron Onyx 80mm
Meade Walmart 60mm guide scope
Canon Xsi Modified w/IDAS LPR
Gen 3 NightVision Eyepiece
Aspiring Optician
Watch my Wiimote control Atlas:
http://www.youtube.com/watch?v=PnmkygmGNiM


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John Jarosz
Astro Gearhead


Reged: 04/25/04
Posts: 3026
Loc: Chicago area, IL
Re: Surplus Shed 110mm Jaegers Achromat. new [Re: kingjamez]
      #1418482 - 02/11/07 05:58 PM

The only Antares lens I found was one for over $300. Can you post a link to the Antares?

John

--------------------
6" F4.6(w/Paracorr) Reflector , 8" F11 Dall Relay Scope ,
6" F5 RFT Refractor w/Istar Obj , G11 Mount Gemini1 Level 4


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Biff
Carpal Tunnel


Reged: 09/04/05
Posts: 2562
Loc: Tampa, FL
Re: Surplus Shed 110mm Jaegers Achromat. new [Re: John Jarosz]
      #1418572 - 02/11/07 06:31 PM

They have some edge chips, some staining, some light scratches, may need some polishing....

Doesn't sound to great to me but if you're into restoring lenses then it might work out pretty good.

--------------------
Ryan


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Art Bianconi
Post Laureate


Reged: 03/06/06
Posts: 4659
Loc: Delaware River Valley, New Jer...
Re: Surplus Shed 110mm Jaegers Achromat. new [Re: kingjamez]
      #1418734 - 02/11/07 07:45 PM

Jaegers is a repected name in optics and has been so for many decades.

The strings that you've seen me initiate here at CN are for the purpose of getting knowledgeable in the design and construction of defractors ( What? ). This will be my very first. ( Any of you ever build a defractor? Or am I the first? ) I've a set of the 110 x 1096 on their way from SS as I speak.

I have never, ever gotten stuck with anything I have ever purchased from SS.

Quality and personalized service and good prices.

Art

Edited by Art Bianconi (02/11/07 11:13 PM)


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fxxm747
professor emeritus


Reged: 05/26/04
Posts: 696
Loc: Milwaukie, Oregon
Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1419074 - 02/11/07 11:06 PM

Art, worst case scenario you'll end up with some minor blems that will only be an annoyance because you know they are there. You won't see any difference from the eyepiece though and you should have an awesome well corrected achromat. I don't know if it makes a difference but I'm always gracious and humble dealing with SS. After which a request for a hand picked nice one has either worked, I was lucky, or all they had was exceptional. They may also just put up the disclaimer to protect themselves. Let us know how it goes!

--------------------
* Jim *
80mm f15 Refractor
Meade Research Grade 8" Newt
Meade Starfinder 10" EQ
Homemade 12.5" Fork Mount Newt


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Art Bianconi
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Reged: 03/06/06
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: fxxm747]
      #1419097 - 02/11/07 11:20 PM

Jim,

They are a great bunch and go out of their way to satisfy customers. Their warehouse has stuff that's not listed on their web site. I throw a set of saddle bags on the bike for a quick trip on the interstate on Saturday's and simply rummage.

I've stockpiled mirror blanks, LED's, KE tester parts and have enough finished now and ready for coating than I will ever get to, all from SS.

I wish they sold aircraft parts!

Art

--------------------
“Everything is on its way to somewhere. . . . . everything!"

____________________ George Malley (John Travolta)
________________________ "Phenomenon"


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fxxm747
professor emeritus


Reged: 05/26/04
Posts: 696
Loc: Milwaukie, Oregon
Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1419133 - 02/11/07 11:40 PM

Boy I wish I could browse their warehouse, of course they'd probably be kicking me out come closing time. Now if they would get the f20 lenses in I've been looking for. Anyone know of a source for 60mm to 100mm f20 achromats? I really want to make a long tube refractor.

--------------------
* Jim *
80mm f15 Refractor
Meade Research Grade 8" Newt
Meade Starfinder 10" EQ
Homemade 12.5" Fork Mount Newt


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BillB9430
super member


Reged: 12/02/06
Posts: 172
Loc: Illinois
Re: Surplus Shed 110mm Jaegers Achromat. new [Re: fxxm747]
      #1419252 - 02/12/07 01:48 AM

Art,
I agree that Surplus Shed has some great lenses. I hope you get a good one. Since you said this was your first refractor ( I love that comment about building the first defractor!), please forgive me if you already know the ideas in my comments that follow:
1. Since the 110/1069 lens is apparently not coated, you will lose some light from surface reflection. This is not a big deal, but you can minimize the loss from reflection on the inner surfaces of the lens by cementing the lens. I have done a number of 3" achromats using Norland Products NOA61 Optical Adhesive. It is UV curing and ATMers can cure it just by putting the lens in sunlight. SS also sells Canada balsam, but I have not tried that yet. The the cemented Jaegers lenses that SS sells seem not to be cemented with balsam. I got one that was cloudy. Heat would not separate it. I soaked it over a week in methylene chloride before it finally separated. I re-cemented it and it is perfect now. I use a little mercury vapor light to reflect off the assembled lens pair and rotate the crown over the flint (be sure no grit is between them!) until the interference fringes are widest. That matches the curves the best. The Jaegers SS lenses I have received have not had alignment marks on them. This may not be very critical, as the differences are usually slight.
2. Your diagram in post #147154 2/11/07 2:45 AM shows a cone of light with its apex point just in front of the eyepiece. I think you want to diagram a focal plane rather than a focal point. The excellent diagrams of Mike Jones and Nils Olaf Carlin show this focal plane correctly. If photography is the goal, the glare stops should be arranged so that the focal plane is fully illuminated. If the scope is set up for visual use, the field lens of the widest eyepiece need NOT be fully illuminated. This is because the human eye is more sensitive off axis (recall using averted vision!). So the size of the focal plane allowed by your glare stops and constriction of your focuser tube should be a compromise based on the eyepieces you intend to use.
3. Jaegers Optical is back in business. Their website catalog is at www.ajaegers.com They have a cell to fit your 110 mm dia. lens as well as tubing. You may want to use PVC pipe and fittings to keep costs down, however.
4. The best reference I've ever seen for ATM assembling of refractors is Fawcett "How To Book" # 454, Amateur Astronomy Handbook, by Lloyd Mallan, Published in 1960! I bought my copy in 1960 off a grocery store magazine rack. I was a freshman in high school at the time! Anyway, there's a chapter on glare stops for refractors and numerous articles about building various telescopes - some astronomical, some with prism erecting systems. The plans for the popular Jaegers 5" RFT comprise one chapter. Besides information on laying out glare stop sizes, the book describes and illustrates a nifty way to make a simple razor blade compass to cut the stops from posterboard. The stops are then cemented in a cylinder rolled from screen wire and the whole thing spray painted flat black. The flat black screen cylinder really breaks up reflections from the tube walls and makes it easy to hold the glare stops precisely in position. If the scope is likely to be used in daytime or with a bright moon, there can be multiple reflections from tube walls, not just the single ones that have been shown in glare stop diagrams in other posts. The book suggests that you can hardly overdo the number of glare stops to minimize these reflections. The only downside to added stops is the small amount of time needed to make and position them. I made a Jaegers 5" RFT using these techniques in 1971 and am still using it. I'm currently making a spotting scope using a SS/Jaegers 80mm lens and a SS 7 x 50 military binocular prism cluster as an erector. I will use it to watch bears, mountain goats, and other critters in Montana. The coated version of the Jaegers 110/1069 lens you bought listed for $67.50 in the 1967 Jaegers catalog. Correcting for inflation, that cost would be equivalent to $407.43 in today's money! Building a quality refractor has never been cheaper, thanks to Surplus Shed.

Hope some of this helps in your project. - Bill


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Art Bianconi
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Reged: 03/06/06
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: BillB9430]
      #1419294 - 02/12/07 02:54 AM

Bill! What a generous post! I love it thanks!

Your wrote: "1. Since the 110/1069 lens is apparently not coated, you will lose some light from surface reflection."

I believe that in addition to coating astronautical mirrors. Jeff Decker at Majestic coatings, also coats lenses. I'm not sure and haven't a clue what cost, if any is involved.

I've heard many positive things about coating lenses it worth the expense for this entry level scope?

You wrote: "I use a little mercury vapor light to reflect off the assembled lens pair and rotate the crown over the flint (be sure no grit is between them!) until the interference fringes are widest. That matches the curves the best."

That sounds almost identical to the system I used (Dave Groski's) A lamp with a high mercury spectrum (fluorescent probably), projected through a green filter.

My two Schief mirrors, one convex, the other concave, both spherical and and their RC's matched closely. The test was used in between each lap but my memory was that as the two mirrors came closer to matching, the line straightened out and got closer together.

My memory is NOT to be trusted however but the test does sound a lot like one I have done before.

You wrote: " 2. Your diagram in post #147154 2/11/07 2:45 AM shows a cone of light with its apex point just in front of the eyepiece."

That was deliberate Bill, done hastily only to make certain that there was no vignetting of the eyepiece, not for the purpose of defining system spacial relationships.

Someone had cautioned that there might be vignetting and while I wanted to define a real plane, I was uncertain what diameter I should pick. I was in too much a rush to go find out and for that test, what I did appeared to be sufficient. Thanks for pointing that out.

You wrote: "You may want to use PVC pipe and fittings to keep costs down, however."

It's too late to bring the sectioned drawing over to this system. I'll do that tomorrow. I have, however, done just: that used PVC. We've this game going on here at CN where guys like Mike Jones throw friendly challenges at me: "See if you can design THIS with toilet plumbing from Home Depot!"

At some point, likely in mid March, I'll have finished machining the steel I purchased for building a Slip Roll machine. That will be used for forming sheets up to 1/8" thick (36" wide throat). When that's up and running, then I'll have three options for tubes: sheet metal, mil spec Kraft rocket air frames from Public Missiles and my favorite, foam cored composite.

There's a lot in your post to digest. That one got cut and pasted off line! I appreciate your commitment to supporting me and other others here and the extent of your experience.

Thanks!

Art

--------------------
“Everything is on its way to somewhere. . . . . everything!"

____________________ George Malley (John Travolta)
________________________ "Phenomenon"


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astroN00B
sage


Reged: 10/21/06
Posts: 393
Loc: Bakersfield, CA
Re: Surplus Shed 110mm Jaegers Achromat. new [Re: John Jarosz]
      #1419362 - 02/12/07 05:06 AM

Quote:

The only Antares lens I found was one for over $300. Can you post a link to the Antares?

John




Try Island Eyepiece & Telescope under PRODUCT LIST/ATM PARTS/OBJECTIVE LENSES and go to the second page. They have an Antares "Refractor Objective Fraunhofer Type Diameter=127mm F=1000 with Multi-Coatings and adjustable lens cell with hood" for $125.95 USD.

--------------------
SV 80/9D 10:1 focuser
WO 66mm SD APO
100mm f/5 ATM achro refractor
WO TR-188 tripod
Modified DS-2000 goto mount
Orion AZ-3
Vixen Polaris
Meade 5000 1.25" EPs, Telextender
GTO 7mm-22mm zoom


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BillB9430
super member


Reged: 12/02/06
Posts: 172
Loc: Illinois
Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1419855 - 02/12/07 12:19 PM

Art and others,
I Googled Majestic Coatings and it looks like magnesium fluoride coatings begin at $150, so perhaps are not cost effective on a surplus lens. The NOA61 adhesive is $25 or so for enough to do many lenses and will reduce reflection loss by near 50% (2 surfaces rather than 4). They advertise a one year shelf life, but my bottle is nearly two years old and still usable. Got to keep it in the dark, though! OTOH, your image may not be noticably degraded if you just air space the elements. Maybe try it and see.
You have a Scheif! I have a 4 1/4 " Scheifspeigler primary sitting in a drawer that I ground and polished in college, but got too busy to finish. I'm now retired so hopefully will have time to finish it. I made a 4 1/4" f/5 reflector RFT 40 years ago, but am a real novice glass pusher compared to you and most on this board. I will undoubtedly have questions for you! I used to have my high school physics students measure the thickness of a hair by interference with two flat glass plates arranged as an air wedge with the hair at one end. Between each fringe, the distance between plates increases by half a wavelength, so I think fewer fringes would mean a better match of the surfaces of the flint and crown. The most common fringe appearance with the SS Jaegers lenses is a bullseye pattern, meaning the R of C of the lenses are just slightly different. I did get one pair from SS that did not match. (ie. MANY fringes) I tried cementing them anyway, using a LOT of cement, but the image was poor. If I ever get another like that I'll send it back.
With regard to the problem of planning a focuser with no vignetting of the eyepiece, I think that you still may need to put in your desired image plane diameter, since that would increase the size of the light cone that your focusing tube must admit.
Your slip roll sounds great. Just what you need for custom tubes. I've got an old South Bend lathe in the basement and have made spiral focuser tubes using the 4 tpi gearing, but I really like the idea of using off the shelf plumbing fittngs. It would be great if you could describe how to do that here so folks who don't have access to machining could make a precision focuser without much cost. - Bill


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Art Bianconi
Post Laureate


Reged: 03/06/06
Posts: 4659
Loc: Delaware River Valley, New Jer...
Re: Surplus Shed 110mm Jaegers Achromat. new [Re: BillB9430]
      #1419865 - 02/12/07 12:23 PM Attachment (95 downloads)

Bill, here is what I came up with thus far.

I'm canvassing my ATM friends to see if they have those books you suggested.

Thanks

Art

Attachment


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BillB9430
super member


Reged: 12/02/06
Posts: 172
Loc: Illinois
Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1419917 - 02/12/07 12:46 PM

Art,
Your cell diagram is great! I am amazed at your abilities. I checked and see that you are a mechanical designer. It shows! Thanks for all that you share with the rest of us. Bill


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Biff
Carpal Tunnel


Reged: 09/04/05
Posts: 2562
Loc: Tampa, FL
Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1421801 - 02/13/07 11:04 AM

Quote:

Jaegers is a repected name in optics and has been so for many decades.

I have never, ever gotten stuck with anything I have ever purchased from SS.

Quality and personalized service and good prices.

Art




I wasn't saying anything against Jaegers optics as I know they are a very respected name and I wasn't saying anything against SS either, if that's the impression you got. I've had many good dealings with them myself.

I have found they are very honest and upfront about about their product, which is very good. So I'd expect to receive exactly what they say you will receive, though there is the possibility you may be pleasantly surprised.

--------------------
Ryan


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Art Bianconi
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: kingjamez]
      #1439532 - 02/21/07 10:05 PM Attachment (50 downloads)

Although I received a post from SS saying the 110mm lens had been shipped, it has not yet arrived.

The component parts needed to assemble it are all but done. I have put off making the machined, collimatable cell. Instead I have opted for something simple so I can bring it to the Mirror Making event at the end of February. Dave Groski will have an interference testing rig there and I hope to use that to optimize the glass.

Art

Attachment


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Vesper818
Astronomess


Reged: 11/21/05
Posts: 2785
Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1439576 - 02/21/07 10:30 PM

Simple?
Sure is, Art!
I got my lens in the mail at work today. The ony "flaw" I could find was a "lint shadow" on the back if the back lens.
Between customers, I drew out the light cone on taped together graph paper.
A trip to the hardware, and the basic OTA is almost premade--
2 4" abs Joiners- perfect fit with no machining.
A 3 foot section galvanaized stove pipe fit the cell perfectly, and its even the right length. The liner pipe can be easily removed, and the steel is lighter than the pvc I already had. I'm almost tempted not to paint it as the smooth frost pattern on it is actually quite attractive.
For the tail piece, a 3x4 and a 2x3 abs " general purpose drain", screwed back to back, will set the foundation for the focuser..


This is way too fun!
Siderea

Edited by Siderea (02/21/07 10:34 PM)


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Vesper818
Astronomess


Reged: 11/21/05
Posts: 2785
Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Vesper818]
      #1439592 - 02/21/07 10:39 PM

Oh, BTW, the Jaegers site sells the 110 mm lens, coated , for over 600.oo... Yipes!
LCC


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Art Bianconi
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Reged: 03/06/06
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Vesper818]
      #1439884 - 02/22/07 03:05 AM Attachment (70 downloads)

The lens has arrived!

It was my fault that the lens was not shipped promptly, not SS! I had also ordered a high resolution 4.25 F/10 but told Brian not to ship yet as I was looking for more at their site.

I've most everything ready. I even sprayed that Truck Bed Paint on some of the parts. Fantastic!

I also figured out a cheapo fork mount, all with PVC parts from Home Depot. If it costs 8 bucks, I'm saying a lot.

I ordered some new threaded inserts from McMasters. I should have this thing running by weekend.

Art

Nuts!

Art

Attachment

--------------------
“Everything is on its way to somewhere. . . . . everything!"

____________________ George Malley (John Travolta)
________________________ "Phenomenon"


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Art Bianconi
Post Laureate


Reged: 03/06/06
Posts: 4659
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1439886 - 02/22/07 03:10 AM Attachment (69 downloads)

Here's the mount for the Flush Valve Helical Focuser.

I've made a composite: one shows the unit with an exaggerated move so you can see how the sandwiching assembly works. Of course it could never move that much in real life.

The outside diameter of the two aluminum plates is smaller than the inside diameter of the cap by only about 0.375".

That's not a lot, but enough to collimate the focuser with the objective lens. If that's not enough, then it's best I hang it the tools and start washing dishes for a living!

Art


Attachment


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Mike I. Jones
Carpal Tunnel


Reged: 07/02/06
Posts: 2874
Loc: Fort Worth TX
Re: Surplus Shed 110mm Jaegers Achromat. new [Re: BillB9430]
      #1440058 - 02/22/07 07:13 AM

Bill,
Welcome to the world of Bianconi-Land! Art is our Norman Rockwell and Dalhart Windberg of CAD as well as being our own telescope Mythbusters shop, and a little John Belushi thrown in now and then, all rolled into one. This guy can draw, and then build, anything.

Your posts make it clear you've been around the block once or twice yourself. Glad to have you here.
Mike

--------------------
56 mirrors, lenses, 16" f/6 Newt, 6" f/10 refractor, TOA-130S, Tinsley 5" f/15 Mak, 6" f/4 RFT, Coronado PST. Still to build: 24" f/10 Modified Dall-Kirkham, 10" f/26 Mak, 8" f/12 apo, spectrohelioscope, Herrig, Schupmann, and others.


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Art Bianconi
Post Laureate


Reged: 03/06/06
Posts: 4659
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: kingjamez]
      #1452302 - 02/28/07 04:12 AM Attachment (70 downloads)

Well, it's all over but the shouting.

Here's what 110mm looks like in the engineering software. I need to buy about $5 worth of PVC fittings to correct an assembly mistake I made.

Everything you see here, EVERYTHING is from Home Depot and ran about $30.oo

It's all done but a small connection on the fork mount I must do over.

Photo's and more after I get some sleep!

Art

Attachment

--------------------
“Everything is on its way to somewhere. . . . . everything!"

____________________ George Malley (John Travolta)
________________________ "Phenomenon"


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vmsguy
sage


Reged: 01/09/07
Posts: 237
Loc: West Virginia
Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1456822 - 03/02/07 11:01 AM

Hi all,

I just received in the mail, what apparently was the last 110mm Jaegers lens from SS. However, this last lens has a significant chip on the back surface of the flint.

The chip is about 1/8" x 1/8" about 1" in from the edge (about half way to the center of the lens). Everything else looks clean and clear. I've spoken with SS and they say I can return the lens for a full refund. I've also heard that this area could be blackened out.

If I blackened out this chip, how would that affect the quality? I primarily will use this for astrophotography.

Thanks for any insight,

Brent
http://astrogazer.us/

--------------------
Brent Maynard
Canon T1i (modded), T2i, refurbed T3i (mod pending), Nikkor 180 ED f2.8, Nikkor 105 f2.5, C8,and a couple of DIY refractors from old achromats, Orion Sirius mount.


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Vesper818
Astronomess


Reged: 11/21/05
Posts: 2785
Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1457008 - 03/02/07 12:34 PM

Boy, you are quick, Art!
You're done, and I'm still assembling parts for mine. Determined this time to do a reall all-metal scope, instead of plastic..and my "machining" tools are a hacksaw and a dremel...
Your ingenuity is inspiring!
LCC

Edited by Siderea (03/02/07 12:44 PM)


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Mike I. Jones
Carpal Tunnel


Reged: 07/02/06
Posts: 2874
Loc: Fort Worth TX
Re: Surplus Shed 110mm Jaegers Achromat. new [Re: vmsguy]
      #1457653 - 03/02/07 06:14 PM

Hi Brent,
The only way that chip could cause you any problems is if it launched any traveling cracks, just like a windshield. Those would be fairly evident just by visual inspection, naked eye and with a loupe or eyepiece. If you see any, you don't want it, and return it to SS for you refund and keep looking for another lens.

If you don't see any cracks extending away from the chip, it's probably a closed chip and will remain stable. Paint the chip black to keep light from scattering through it to your image. From the size of the chip you describe, blackening it will essentially have no effect on your image. It's much smaller than any typical Newtonian diagonal and has much less linear scattering length than any spider, straight or curved.

Pop the lens with its blackened chip in a tube and look through it and see if you like what you see. You may have swap directions to see which way it's supposed to be oriented.

Hope it's a goodun.
Mike


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Art Bianconi
Post Laureate


Reged: 03/06/06
Posts: 4659
Loc: Delaware River Valley, New Jer...
Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1462898 - 03/05/07 08:17 AM

Surplus Shed 110mm Jaegers disappointing.

I brought the 110 OTA with me to the Delmarva Star Gazers annual mirror making event. The plan was to have Dave Groski optimize the lens orientation and then install it.

Dave put it under the monochromatic light source and found the combination to have a serious astigmatism problem.

One lens had a small chip when it arrived from SS but nothing serious so I delayed making any judgements until Dave's test.

I should have delayed investing all that work building a refractor without having tested the optics first.

If I am going to be playing with 2 piece achromats, I should invest the time in building a monochromatic light source.

That's yet one more thing to build added to an already overwhelming list.

I'll return the 110 to SS, store all the components in a cluttered attic and perhaps invest in a set of 80 x 400 lenses instead for some future project.

The other option is to bring a monochromatic light source to SS and sit down with their boxes of lenses. I can mix and match them until I find a pair that work to my expectations.

Another thing that frustrated this project was the mistake of machining a cell on the basis of the advertised dimensions. That wasn't too smart of me. The diameter of the lenses turned out to be 108mm, not 110 and their combined thickness turned out to be 75 not 86mm. The result was a very sloppy lens cell. Efforts to correct that proved unsuccessful as well.

Some suggested that since there was plenty of hot pitch ready to be poured, I should make a lap and take a few minutes at polishing and fitting the lenses to perfection. I chose not to. I am barely treading water making mirrors.

In spite of the outcome, I am not disappointed. Many of the problems I encountered were created by me and a result of my impatience. I learned a great deal from the experience so all is well.

SS and its staff are a great bunch of guys; the products are as advertised and I will continue to purchase optics from them.

Art

--------------------
“Everything is on its way to somewhere. . . . . everything!"

____________________ George Malley (John Travolta)
________________________ "Phenomenon"


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netwolf
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1462977 - 03/05/07 09:12 AM

Art from where I am standing you added value to yourself and the ATM community in doing this project. There is much interest in the SS lens's and your design and process are a great resource. I would think it would be worthwhile to suggest to SS that they might want to keep a monochromatic light source to test the lens's themselves. This would avoid them having to deal with returns. And improve on a an already excellent service they provide to the ATM community.

Perhaps someone could build a light source for them and show em how to use it.

Regards

Edited by netwolf (03/05/07 09:15 AM)


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Art Bianconi
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: netwolf]
      #1463092 - 03/05/07 10:38 AM

Those who I have spoken to at SS are knowledgeable. I doubt they need to be taught how to build or use a monochromatic interference tester.

As for them testing each pair that goes out, I think that might be asking a bit much.

Remember that these are less than perfect, uncoated, surplus lenses of questionable history and far below the prices asked by Jaeger's for current production.

If I were SS and someone were asking me to do what you suggested (test each pair) I'd want a surcharge for doing so.

I still believe that the 110 Achro Jaeger is a bargain at what SS is asking for them. This particular one simply was not up to what I want from a refractor.

Art


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Vesper818
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1463365 - 03/05/07 12:42 PM

Tough luck with objective, Art. Possibly SS has a replacement . The two Jaegers objectives I've used from them have proved excellent, though uncoated... Before construction starts on my 110 Ota, this calls for a tape up , to star test and see if its worth the effort. Many reasons a lens could be "seconded" from serious fault, to cosmetic blemish...
Good luck with the rest of your projets!


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vmsguy
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1465259 - 03/06/07 11:24 AM Attachment (54 downloads)


I'm totally in uncharted waters here, but here goes.

Last night I wanted to test my 110mm Jaegers to see if I would experience the same astigmatism as Art did.

I rigged up a monochromatic light source by using a laser level and a cheap 80mm cemented achromat. Shining the beam on the edge of the 80mm lens diffused the laser well. I could then take my hand or a sheet of paper to illuminate the 110mm lens.

I had air spaced the lens using the stamp method, but I could not get any diffraction fringes, no matter what I tried.

I removed the stamp spacers and made sure the crown and flint were as clean as possible and placed them together.

The diffraction fringes appeared immediately, but not like I thought they would. They were slightly curved lines, not rings.

The crown was floating on the flint, like it was oil spaced. I could not detect any glass to glass contact.

The crown easily moved like a puck on an air hockey table.
I could slide the crown off to one side and it would slowly slide back towards center on its own.

I slowly rotated the crown to see if that would give me the rings I thought I needed to see. But all I got were the curved lines.

I left it sitting there for 5 to 10 minutes while I searched google. When I came back, the rings were now visible. My guess is that more air had escaped from between the flint and crown. I again slowly rotated the crown until the rings were and concentric as possible.

Attached is a picture showing the results.

My question is: Is this 110mm Jaegers worth keeping?

Attachment

--------------------
Brent Maynard
Canon T1i (modded), T2i, refurbed T3i (mod pending), Nikkor 180 ED f2.8, Nikkor 105 f2.5, C8,and a couple of DIY refractors from old achromats, Orion Sirius mount.


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vmsguy
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: vmsguy]
      #1465272 - 03/06/07 11:30 AM Attachment (54 downloads)

More pictures:

Offset crown

Attachment

--------------------
Brent Maynard
Canon T1i (modded), T2i, refurbed T3i (mod pending), Nikkor 180 ED f2.8, Nikkor 105 f2.5, C8,and a couple of DIY refractors from old achromats, Orion Sirius mount.


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vmsguy
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: vmsguy]
      #1465273 - 03/06/07 11:31 AM Attachment (48 downloads)

One more picture:

Air spaced no spacers, crown seems to float on layer
of air.

Attachment

--------------------
Brent Maynard
Canon T1i (modded), T2i, refurbed T3i (mod pending), Nikkor 180 ED f2.8, Nikkor 105 f2.5, C8,and a couple of DIY refractors from old achromats, Orion Sirius mount.


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vmsguy
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: vmsguy]
      #1465280 - 03/06/07 11:34 AM


I do appreciate this forum, I've learned alot over the past few weeks.

Thanks,
Brent
http://astrogazer.us/

--------------------
Brent Maynard
Canon T1i (modded), T2i, refurbed T3i (mod pending), Nikkor 180 ED f2.8, Nikkor 105 f2.5, C8,and a couple of DIY refractors from old achromats, Orion Sirius mount.


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DAVIDG
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: vmsguy]
      #1465307 - 03/06/07 11:51 AM

You have a very good match between the two inner radii of the lens and there looks to be no astigmatism. This is only one test that would need to be done to determine if the lens is good or not. Mounting it and doing star test and/or an autocollimation test under monochrome light would be good test of the complete system.
When I tested Art's lens in this manner, all I could get was very oval shaped rings that rotated with the concave element, indicating astigmatism in this element.

- Dave

--------------------
Homemade 'scopes 8"f/7,6" f/5", 6"f/4, 4.25" Schiefspiegler,60mm Coronagraph,60mm H-alpha system, 4.25" White-light Solar Newtonian,solar spectroscope, 4" f/12, 4.5" f/16 & 6" f/12 Schupmann Medial refractors, 4" Celestar, 19 Stellafane awards 9 in optics

Engineering = Taking what you have and making what you need.


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Vesper818
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: DAVIDG]
      #1466131 - 03/06/07 05:50 PM

This is so interesting... how would someone with no experience and no equipment test the objectice, other than to paste up into a cardboard tube, star test and check for CA, coma, spherical aberation simply by sight?
V, could you post a pic how you set up the lazer leverl and objective, please? I'd like to try this with my 110 mm Jaegers as well...
Several times I have taken apart someone's "lowsy refractor, and greatly improved perfomance by simply rotating the elements till it gave the best view.Beyond that, this is all new to me.
Any suggesstions?

Edited by Siderea (03/06/07 05:56 PM)


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vmsguy
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Vesper818]
      #1466197 - 03/06/07 06:18 PM Attachment (52 downloads)


Here is my very un-scientific setup.

The laser is pointing up. The cheap 80mm achromat is hanging over the edge slightly, just enough to catch the beam. The 110mm Jaegers is sitting on some black craft foam. I turn out the lights and use my hand or a piece of paper to deflect some light over the 110mm objective.

BTW, laser levels seem to be significantly brighter than laser pointers.

Brent

Attachment

--------------------
Brent Maynard
Canon T1i (modded), T2i, refurbed T3i (mod pending), Nikkor 180 ED f2.8, Nikkor 105 f2.5, C8,and a couple of DIY refractors from old achromats, Orion Sirius mount.


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Vesper818
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: vmsguy]
      #1466269 - 03/06/07 06:50 PM

Thank you very much, I will test mine out tonight....

one of many Carols here


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Art Bianconi
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: vmsguy]
      #1466612 - 03/06/07 08:44 PM

Brent, I'm in the midst of building a monochromatic light source using ultra violet lamps and a green filter.

That's what Dave used to verify my Schiefspiegler mirrors last year. It's also what he used when examining my 110mm achromat last weekend.

I'm trying to follow your description of the test apparatus you described but I am having some difficulty.

What purpose does the other lens serve.

Thanks

Art

--------------------
“Everything is on its way to somewhere. . . . . everything!"

____________________ George Malley (John Travolta)
________________________ "Phenomenon"


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vmsguy
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1466847 - 03/06/07 10:31 PM Attachment (41 downloads)

Hi Art,

I'm going to attach more images that might help give more
detail.

I used the smaller lens to diffuse the laser light. Shining the laser perpendicular to the frosted edge worked well.

This would probably work better if setup on a table instead of using a speaker like I did. (my table was too messy).

Attachment

--------------------
Brent Maynard
Canon T1i (modded), T2i, refurbed T3i (mod pending), Nikkor 180 ED f2.8, Nikkor 105 f2.5, C8,and a couple of DIY refractors from old achromats, Orion Sirius mount.


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vmsguy
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: vmsguy]
      #1466857 - 03/06/07 10:35 PM Attachment (46 downloads)

Here is a picture I accidently took with the flash on.

The paper was used to "bounce" the light onto the 110mm lens.

Attachment

--------------------
Brent Maynard
Canon T1i (modded), T2i, refurbed T3i (mod pending), Nikkor 180 ED f2.8, Nikkor 105 f2.5, C8,and a couple of DIY refractors from old achromats, Orion Sirius mount.


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gregj888
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: vmsguy]
      #1466976 - 03/06/07 11:27 PM

You can use an F15T8BL fluorescent tube and fixture. No filter is needed but a diffuser helps.

Greg

--------------------
Greg

8" f/4.2 Houghton
6" f/15 Trischiespiegler
20" cas (under construction)


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Art Bianconi
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: vmsguy]
      #1467183 - 03/07/07 02:02 AM

Tanks Brent.

I went downstairs to the shop, lenses, camera and 2 lasers (red and Green)

I tried everything in an attempt to replicate the images you got. Even put on a set of welding goggles.

The closest I got was by accident. Very faint rings, the same egg shape Dave Groski got, were barely visable in the reflected light from the fluorescent lights over the bench. I'll another attempt today.

Surplus Shed has responded as I expected. Return it for a full refund or they'll test and try to find a good set. No questions asked. I like those guys.

I also surfed the "Internets" (thanks George!) looking for black lights with the BL designator. Found lots of bulbs, very little on fixtures but did manage to come a cross a nice hand held unit powered by 4 AA batteries. It's not nearly as bright as the others and with only 4 small batteries to run, it can't stay on very long me thinks. But, it does fit in your shirt pocket and it does use the 5 Inch white "BL" black light bulb. $9.95 at Amazon plus about $4 shipping.

If I go this route at all, I'll likely put two fixtures and 8 inch long bulbs inside a steel case with a frosted diffusion glass. I must admit however, that the brightness and clarity of those red lit rings you got was mind blowing!

Thanks for what you did. I keep learning and I like that a lot.

Art

--------------------
“Everything is on its way to somewhere. . . . . everything!"

____________________ George Malley (John Travolta)
________________________ "Phenomenon"


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John Carruthers
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1467274 - 03/07/07 05:36 AM

A good source of tubes/bulbs is our local aquarist, all manner of uv and 'high red' tubes and bulbs.Just looking at the various tubes in our house gave a surpring array of discrete spectra. For diffusers we used to use fibreglass mat in the DG unit shop along with some acid etched sheet.

--------------------
Jc

ATM 10" F6.1, 1/25th wave spec (max wavefront error +/- 1/12.6 in zone 4 of 6, sodium light )
6" F7 spec
127mm F9.4 Refractor
Criterion DX8
10 x 50 bin
SP mount/Synscan goto.
ETX80 (finder)
Canon 20D
PST
DSI 1
Butenschön 125mm F13.4 refractor
diy spectroscope
and curiosity



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DAVIDG
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: gregj888]
      #1467477 - 03/07/07 08:52 AM

Just understand that this type of bulb is emitting UVA which has it's problems. By using a plastic green filter and diffuser, the UVA is removed and only the mercury line at 546nm is transmitted making it safe.

- Dave
Quote:

You can use an F15T8BL fluorescent tube and fixture. No filter is needed but a diffuser helps.

Greg




--------------------
Homemade 'scopes 8"f/7,6" f/5", 6"f/4, 4.25" Schiefspiegler,60mm Coronagraph,60mm H-alpha system, 4.25" White-light Solar Newtonian,solar spectroscope, 4" f/12, 4.5" f/16 & 6" f/12 Schupmann Medial refractors, 4" Celestar, 19 Stellafane awards 9 in optics

Engineering = Taking what you have and making what you need.


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Art Bianconi
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: DAVIDG]
      #1467563 - 03/07/07 09:40 AM

Dave makes a good point. Many of the web sites I visited while looking for the right bulbs had caveats about long term exposure.

These UV Light bulbs are used in medicine for treating certain skin ailments. That appears to be why they do not have the blue coating: so those rays can get out.

The properties that treat the illness, can, if not used properly, cause harm over time.

Art

--------------------
“Everything is on its way to somewhere. . . . . everything!"

____________________ George Malley (John Travolta)
________________________ "Phenomenon"


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vmsguy
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1467598 - 03/07/07 09:52 AM

Hi Art,

I think the reason that my rings showed up so well was due to the intensity of the laser level beam. It is easily 2-3 times brighter than and standard laser pointer. The reason I think it so much brighter is because there is a beam splitter that you can flip over to create a crosshair that will cover the side of a house.

I only paid $9.00 for it a few years back at our local Krogers grocery store. It was in a Christmas gift idea display.

It has turned out to be a great little all around gadget.
Good luck on getting your tester working.


Brent
http://astrogazer.us/

--------------------
Brent Maynard
Canon T1i (modded), T2i, refurbed T3i (mod pending), Nikkor 180 ED f2.8, Nikkor 105 f2.5, C8,and a couple of DIY refractors from old achromats, Orion Sirius mount.


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gregj888
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: DAVIDG]
      #1467736 - 03/07/07 10:50 AM

Dave,

As far as I know this is a long wave UV (basic black light) and is safe for general use. If you have an output spectrum I would love to see it (I did check, but just in case). No question that the green filter would help but the fringes are easily visible as is.

Quote:

Just understand that this type of bulb is emitting UVA which has it's problems. By using a plastic green filter and diffuser, the UVA is removed and only the mercury line at 546nm is transmitted making it safe.

- Dave





--------------------
Greg

8" f/4.2 Houghton
6" f/15 Trischiespiegler
20" cas (under construction)


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Art Bianconi
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: gregj888]
      #1472468 - 03/09/07 08:29 PM Attachment (47 downloads)

I just returned from Home Depot with a GE fluorescent 10" long light fixture which uses the 9" long F6T5 bulb. It cost me $14.

I've located a number of suppliers that sell the 9" F6T5BL bulb for less than $2.0 a piece (they rape your wallet on shipping however).

I chose this length because the 10" fixture will fit nicely into the steel NEMA junction box case (12 x 12 x 4). It's overkill as a housing but it's on the shelf collecting dust so why not? The flat plate that covers it can be replaced with a sheet of green. The light fixture has a prismatic diffuser that should prove adequate. If not I can always take some light sandpaper to it or leave it out completely.

Of equal value is the fact that there is room in there for at least 3 more lamps should the amount of light from one fixture prove inadequate.

I got an unexpected education in light bulbs from the electrical department employee who stunned me by guessing correctly what I was building! "Are you testing optics?" In Home Depot yet!

He then took me to the air and water purification inventory all the while talking about the distinctions between ozone and chlorine methods of purification!

Turns out that those systems have some really big UV lamps. Clear ones; no coating at all. The problem is those bulbs were needlessly expensive for my applucation ($57.00) so I passed.

The 110 mm Achromat that started all this is on it's way back to SS. When I get caught up with all the OTA's that I have in process, then I'll order another set. I suspect it will be a while!

In the meantime, a friend is building a 4.25" Schiefspiegler and must match the RC of both mirrors exactly. I'll let him borrow my light box. If it works as planned, it should produce something like this:

Art

Attachment

--------------------
“Everything is on its way to somewhere. . . . . everything!"

____________________ George Malley (John Travolta)
________________________ "Phenomenon"


Edited by MMICKELS (03/10/07 10:39 AM)


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DAVIDG
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1473388 - 03/10/07 12:27 PM

Art,
The Home Depot lamps used for air and water purification emit UVB very strongly. This bulbs will give you a nasty sunburn very quickly. One would need very good filtering to use them for optical testing. There is no need to use such a bulb in the first place since cheaper and much more safer ones are easily obtained.
The picture you posted in your last reply was taking by me. It is of my Schiefspiegler secondary being testing against the primary before I cored it to size. The light source is a commerical Edmund Scientific monochrome unit. It use a "BL" type black light with a diffuser and green plastic filter to isolate the mercury emission line at 546nm. I believe the bulb is rated at 5 watts and gives very bright interference lines. My picture was taken in my kitchen with all the lightS on. So one of the 9" bulbs you purchased should be plenty bright.

- Dave

--------------------
Homemade 'scopes 8"f/7,6" f/5", 6"f/4, 4.25" Schiefspiegler,60mm Coronagraph,60mm H-alpha system, 4.25" White-light Solar Newtonian,solar spectroscope, 4" f/12, 4.5" f/16 & 6" f/12 Schupmann Medial refractors, 4" Celestar, 19 Stellafane awards 9 in optics

Engineering = Taking what you have and making what you need.

Edited by DAVIDG (03/10/07 02:16 PM)


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Art Bianconi
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: DAVIDG]
      #1473528 - 03/10/07 01:44 PM

Hi Dave!

I sent you an e-mail with the link to Rosco and asked for you to suggest which filtration sheet to get.

Thanks

Art


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DAVIDG
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1473637 - 03/10/07 02:44 PM

Art,
Any green filter that has a high transmission around 546nm and drops off on each side will work fine. You don't have to filter the light source, you can use a small filter in front of your eye like a #56 green eyepiece filter.
My desk lamp has an IKEA energy saver bulb. I just tried it with a two optical flat and the red and green fringes are easily visible without any aditional filtering. Using a piece of red plastic that I use on my lap top screen, improves the contrast.

- Dave

--------------------
Homemade 'scopes 8"f/7,6" f/5", 6"f/4, 4.25" Schiefspiegler,60mm Coronagraph,60mm H-alpha system, 4.25" White-light Solar Newtonian,solar spectroscope, 4" f/12, 4.5" f/16 & 6" f/12 Schupmann Medial refractors, 4" Celestar, 19 Stellafane awards 9 in optics

Engineering = Taking what you have and making what you need.


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Art Bianconi
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: DAVIDG]
      #1474186 - 03/10/07 09:04 PM

The Rosco films were just that: flimsy sheets that would have required lamination between two sheets of acrylic. So instead I purchased a 12" x 12" x 1/4" green translucent acrylic sheet from:

Delvies Plastics It's on it's way. I could only guess-estimate the degree of transmittal: about 40%. It has a UV inhibitor which is a plus.

I chose to purchase two F6T58Bl bulbs locally. At $7.00 a piece thats 2-1/2 times the Internet price but there is no $10.oo shipping cost so I am ahead of the game.

If one bulb gets the job done, great! If not I can always stick a second fixture in the housing. Remember this is a big unit 12" x 12" x 4".

I'll supply images when it's done.

For those who might be interested in a hand held, battery operated unit, you can find one in Home Depot with a regular white bulb for only about $7.00. Assuming you must pay $7.00 for the short BL bulb you'll have a portable tester that will fit in your shirt pocket for about $15.00 and you'll only need to supply sun glasses with green lenses to use it.

These thin bulbs require a 48 volt power supply. The hand held uses 4 AA batteries. There has to be an oscilator and circuitry to bump the voltage from DC to AC and from 6 Volts to 48. With only those 4 AA batteries pushing the process it's unlikely that they will last more than a few hours of continuous use.

However, given the intermittent nature of this test application, they should last lots longer. While not as powerful as it's bigger brother, the amount of light should be adequate.

I'll know how mine performs in about a week and report back.

Art

Edited by Art Bianconi (03/12/07 04:38 PM)


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Mike I. Jones
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1474420 - 03/11/07 12:33 AM Attachment (37 downloads)

I built a good Newton's tester using an 18W low-pressure sodium light (about $60), a piece of 50/50 office window glass (shiny side down) for about $35, and scrap 1/2" plywood. Here's a side shot of it. I'd be glad to post the construction plans for it if anyone's interested.
Mike

Attachment


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Mike I. Jones
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1474421 - 03/11/07 12:34 AM Attachment (35 downloads)

Here's the front view of the sodium light tester with a 6" flat and not-so-good 5" test part. I can get a 24" diameter part into the tester.
Mike

Attachment


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Mike I. Jones
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1474424 - 03/11/07 12:37 AM Attachment (37 downloads)

And here are the interference fringes. That's a 6" master flat I have in contact with a 5" Pyrex mirror blank with a dummy shined back surface. Not a very good surface but it shows the fringes nicely.
Mike

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Art Bianconi
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Reged: 03/06/06
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Mike I. Jones]
      #1474446 - 03/11/07 01:11 AM

Your images are almost as bright as Brents! I'm not too sure what to expect using UV bulbs and a green filter but if I can get the same results as shown on Dave's green test of his Schief, I'll be content.

Do you realize that I came very close to building this tester exclusively with Home Depot components?

While I was in the store, they announced over the PA system that Home Depot is looking for personal human interest stories from customers. Should I?

I can see it now: "The Bathroom Astronomer"!

Art

--------------------
“Everything is on its way to somewhere. . . . . everything!"

____________________ George Malley (John Travolta)
________________________ "Phenomenon"


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Mike I. Jones
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Reged: 07/02/06
Posts: 2874
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1475633 - 03/11/07 05:24 PM

Yes, Art, I think ya should. Home Depot has plumbed the depths of America looking for guys like you.

You should answer Nature's Call and do a personal interest story for them on how everything to make a telescope but the optical components is within their hallowed walls.

Now if Home Depot merged with Newport Glass and Ash-Dome, Bianconi would eventually forget where his actual home is (in like four days) and just set up his optical lavatory right there in Dome Depot

Mike

PS: You really could make a Newton interferometer totally from Dome Depot materials. The mercury "security" lights we all prefer to refer to as "targets" actually make pretty good fringes if viewed through green plastic, or even just green sunglasses. But the 18W low-pressure sodium light runs a lot cooler, needs no filtering, and makes nice contrasty tiger-stripe fringes.


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Vesper818
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Mike I. Jones]
      #1475773 - 03/11/07 06:31 PM

Quote:



Now if Home Depot merged with Newport Glass and Ash-Dome, Bianconi would eventually forget where his actual home is (in like four days) and just set up his optical lavatory right there in Dome Depot

Mike







How about an observatory from a Rubbermaid shed, with folding screens from PVC pipe and black poly?


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Art Bianconi
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Mike I. Jones]
      #1476075 - 03/11/07 09:16 PM

Mike wrote: ". . .Home Depot has plumbed the depths. . "




Didn't look for Low Sodium but I am aware of their use in this application. They are lots more expensive.

Not sure what you mean by security lights. Could you shed some light on that (sic!)?

Art

--------------------
“Everything is on its way to somewhere. . . . . everything!"

____________________ George Malley (John Travolta)
________________________ "Phenomenon"


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vmsguy
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: kingjamez]
      #1477002 - 03/12/07 11:09 AM


All,

I've got the parts from lowes/home depot to put together
the 110mm project. (I do get some odd stares from
folks while I'm holding lenses up to PVC fittings)

I have another question though. Should I airspace the 110mm
lens using the stamp method, or just tape them together.

The two surfaces seem almost perfectly matched, the glass surfaces don't seem touch, the flint just floats on whatever air remains between the two.

Thanks for any advice,
Brent
http://astrogazer.us/

--------------------
Brent Maynard
Canon T1i (modded), T2i, refurbed T3i (mod pending), Nikkor 180 ED f2.8, Nikkor 105 f2.5, C8,and a couple of DIY refractors from old achromats, Orion Sirius mount.


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BCB
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Vesper818]
      #1477536 - 03/12/07 04:22 PM

Quote:

Quote:



Now if Home Depot merged with Newport Glass and Ash-Dome, Bianconi would eventually forget where his actual home is (in like four days) and just set up his optical lavatory right there in Dome Depot

Mike







How about an observatory from a Rubbermaid shed, with folding screens from PVC pipe and black poly?




Already been done by me..

Check the thread in my sig line just above my clear sky clock..

--------------------
Mark

Lost in thought. Please send search party!!!

Astro-Tech 111EDT
Orion 8" F5 Newt w/Moonlight CR-2 focuser
CGEM EQ mount
Treeline Observatory



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Pedestal
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: vmsguy]
      #1477670 - 03/12/07 05:32 PM

Maybe they're supposed to be oil spaced????
Hubert

--------------------

Hubert
---------------------------------
www.smoggybottom.org





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Art Bianconi
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Pedestal]
      #1477797 - 03/12/07 06:57 PM

There are special lens adhesives made purposefully for bonding achromats. In so doing they are said to eliminate reflections from two of the four surfaces. Since the 110 combo is uncoated, and subject to reflections, I viewed the adhesive as the way to go.

I asked Dave if he had any I could use and why. He responded telling me he did not have any lens adhesive but that the lens should be air spaced anyway.

From what has been discussed here, the use of 3 pieces of a postage stamp at the edge, spaced 120 degrees, appears to be the best method.

Art

--------------------
“Everything is on its way to somewhere. . . . . everything!"

____________________ George Malley (John Travolta)
________________________ "Phenomenon"


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vmsguy
sage


Reged: 01/09/07
Posts: 237
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1478034 - 03/12/07 08:49 PM

Thanks Art,

I will go the air-spaced-stamp route.

Hopefully in a few days I'll get first light.

Brent

--------------------
Brent Maynard
Canon T1i (modded), T2i, refurbed T3i (mod pending), Nikkor 180 ED f2.8, Nikkor 105 f2.5, C8,and a couple of DIY refractors from old achromats, Orion Sirius mount.


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Mike I. Jones
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Posts: 2874
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1478060 - 03/12/07 08:57 PM

Dome Depot sells mercury lights and fixtures you put up on your garage, the front of your house, etc. so you can feel "secure". Or more accurately, light your house up so a burglar can more conveniently see where to break in or attack you, when you're not home, etc.

These lights are way way too bright for optical testing, as the bulbs are typically over 100 watts. I bought my 18W low-pressure sodium light, socket and ballast at an electrical supply house, and paid about $60 for it (much cheaper than the Dome Depot mercury light). It takes about 10-15 minutes to warm up and reach full brightness, and when it does, it is so bright it hurts to look at. But when you knock down the brightness with the white Plexiglass diffuser, then with the 50/50 office window glass beamsplitter, it's just the right brightness. And it doesn't put out much heat so the enclosure can be made light-tight.

Sodium fringes have high contrast because almost 100% of the light is radiated strictly at the two sodium emission lines (D1 at 0.589592 µm and D2 at 0.588995 µm). The lines are roughly the same intensity, so the fringes visually appear to form at the average wavelength of 0.5892935 µm.

Mike


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DAVIDG
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: Art Bianconi]
      #1478106 - 03/12/07 09:18 PM

Quote:

There are special lens adhesives made purposefully for bonding achromats. In so doing they are said to eliminate reflections from two of the four surfaces. Since the 110 combo is uncoated, and subject to reflections, I viewed the adhesive as the way to go.

I asked Dave if he had any I could use and why. He responded telling me he did not have any lens adhesive but that the lens should be air spaced anyway.

From what has been discussed here, the use of 3 pieces of a postage stamp at the edge, spaced 120 degrees, appears to be the best method.

Art




Art,
I stated that the spacing between the lens elements is used to adjust the color correction of a typical achromat, not that air spacing is the way to go. Without knowing the design one can not assume that these lens should be air spaced, cemented or oiled. If air spacing is what is called for ,the proper spacing would need to be determined by either raytracing the design or by testing the lens under the stars or with a monochrome tester in autocollimation setup. Plus or minus a 0.0001" in some design makes a big difference. It's also unknown if everyone is getting the same lens design so what works for one might not work for others.
Postage stamps as spacers was the method used by lens makers like Alvan Clark in the 1880's. They designer some of their lenses to use US postage stamps as spacers since the US government was very careful in making stamps with uniform and constant thickness. The thickness of stamps has changed since the 1880's and collectors of Clark telescopes sometimes purchase old US stamps of that vintage just to use them of as spacers of the correct thickness.

- Dave

--------------------
Homemade 'scopes 8"f/7,6" f/5", 6"f/4, 4.25" Schiefspiegler,60mm Coronagraph,60mm H-alpha system, 4.25" White-light Solar Newtonian,solar spectroscope, 4" f/12, 4.5" f/16 & 6" f/12 Schupmann Medial refractors, 4" Celestar, 19 Stellafane awards 9 in optics

Engineering = Taking what you have and making what you need.


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Art Bianconi
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Re: Surplus Shed 110mm Jaegers Achromat. new [Re: DAVIDG]
      #1478407 - 03/12/07 11:31 PM

Dave wote: "I stated that the spacing between the lens elements is used to adjust the color correction of a typical achromat, not that air spacing is the way to go."

Whoops! Sorry Brent!

Thanks Dave. Another reminder not to trust my memory.

Brent, I am uncertain how well the interference test will resolve this issue. If it were a mirror I'd look at it through a Ronchi screen but I am not sure if that will work.

I'm not sure how to optimize those two lenses.

Art


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