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ryanr256
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Reged: 04/21/09

Loc: Southwest Ohio
My 103mm Jaegers build
      #6133500 - 10/12/13 05:49 PM

I was able to pick up a 103mm lens set from Surplus Shed at the beginning of the year. My plan is to buil a 103mm, f15 refractor.

I picked up some aluminum tubing from Velocity Air, had Dan at Crawmach make me a custom cell and bought a GSO 2 inch Crayford focuser. I also got in on the Meade 2 inch diagonal and 24mm eyepiece deal.

Then the project stalled for a while.

But I am able to spend some time on it now and I put together this test mule:


My plan is to use it to determine the overall length of the aluminum tubing. Once the tube is cut, I will work on the baffles. My plan for them is to make them out of aluminum sheet and epoxy them to the inside of the tube.

I'm using this as a guide:


Wish me luck.

-Bob


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magic612
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Re: My 103mm Jaegers build new [Re: ryanr256]
      #6133853 - 10/12/13 08:55 PM

Good luck! I have the same lens, and so will be subscribing to this thread as you updated it. I'll be building my own lens cell from plywood for now, but was going to go the Velocity-Air tube route like you. I have an inexpensive focuser to use initially, but would replace with something better later on.

Please let me know how the views are in yours - I'm very much looking forward to getting mine together one of these days.


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ryanr256
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Re: My 103mm Jaegers build new [Re: magic612]
      #6134019 - 10/12/13 10:58 PM

Tonight was somewhat of a success. Of course the PVC pipe is not flocked or otherwise baffled. Lots of internal reflections, plus it wasn't completely dark yet.

Having said all that, I was able to get my 30mm SWA eyepiece to focus on the moon before the clouds rolled in. The focuser tube is marked in millimeter increments and I was just over the 30mm (3cm) mark with my tube at 52.25 (52 1/4) inches.

I want to use less of the focuser tube travel with the 38mm so I'm going to add .5 (1/2 of an inch) to my tube length. I will cut my aluminum tube to be 52.75 inches long. The 38mm will focus within the first 15mm to 20mm of focuser travel and shorter length eyepieces should have plenty of travel.

I think my thought process is correct? I think I'm going the proper way with my dimensions. Long FL eyepieces need less focuser travel than short FL eyepieces, correct?


Thanks,

-Bob


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ryanr256
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Re: My 103mm Jaegers build new [Re: ryanr256]
      #6143581 - 10/17/13 07:35 PM

My plan was to have the baffles cut by now. I did try cutting them freehand but it didn't work out too well. So no pretty pictures of concentric circles tonight.

I am going out of town for a week and will continue on the baffles when I return. I am making them out of some left over .032 6061 aluminum sheet from another project. I do need to get some struts though. My first plan was to epoxy the baffles directly to the OTA, but after reading the posts on the forum, I am going to make a fame for them that I can then insert into the OTA.

-Bob


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ryanr256
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Re: My 103mm Jaegers build new [Re: ryanr256]
      #6165437 - 10/29/13 09:54 PM

I've cut the baffles. I had an issue with what would be the first one (largest opening). I couldn't keep the ring from deforming while being cut. So instead of a 3.75 inch opening, I will use a 3.00 one. Also, I am using a shorter tube than the one in the Jaegers diagram for the 'scope. The smallest baffle will have an opening of 2.00 inches.

I will do the math, or diagram the light cone, and come up with the placement of the baffles. Once I know the dimensions, I will build a frame and paint it flat black and then insert it into the OTA.

Here are the baffles I cut:



Oh, and I have a correction to a previous post. I used a 38mm SWA eyepiece when determining the length of the tube, not a 30mm.

-Bob

Edited by ryanr256 (10/29/13 10:20 PM)


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Jeff B
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Re: My 103mm Jaegers build new [Re: ryanr256]
      #6166037 - 10/30/13 09:48 AM

Bob, nice looking baffles. I was going to suggest you ditch the last one as three with such a slow F stop is all that's really needed.

Also, I suggest using only the middle baffle to set the actual fully illuminated field size and position the others slightly further down the light path than the drawing would suggest. This way only the center edge of the middle baffle actually intersects the primary light cone and diffracts that light. The other baffles, being now set further down the light cone, don't touch the primary light cone and therefore don't diffract light from it.

A baffles job is to reduce stray light, and not generate it. Positioning the baffles this way reduces to a minimum any stray light their inner edges may generate.

Of course, I'd bet a months pay, such diffracted light scatter would be difficult to measure, let alone see, however, why not eliminate it if you can. It's soooooo easy to do and keeps with the idea of maximizing contrast, which is a refractors strong suit to begin with.

Jeff


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ryanr256
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Reged: 04/21/09

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Re: My 103mm Jaegers build new [Re: Jeff B]
      #6178432 - 11/05/13 11:58 PM

Quote:

Bob, nice looking baffles. I was going to suggest you ditch the last one as three with such a slow F stop is all that's really needed.

Also, I suggest using only the middle baffle to set the actual fully illuminated field size and position the others slightly further down the light path than the drawing would suggest. This way only the center edge of the middle baffle actually intersects the primary light cone and diffracts that light. The other baffles, being now set further down the light cone, don't touch the primary light cone and therefore don't diffract light from it.

A baffles job is to reduce stray light, and not generate it. Positioning the baffles this way reduces to a minimum any stray light their inner edges may generate.

Of course, I'd bet a months pay, such diffracted light scatter would be difficult to measure, let alone see, however, why not eliminate it if you can. It's soooooo easy to do and keeps with the idea of maximizing contrast, which is a refractors strong suit to begin with.

Jeff




Thanks for the tips. I've computed the spacing of the baffles and have decided that I want a baffle closer to the objective. I am going to try to cut one from a slightly thicker piece of aluminum sheet which should give some stability to the resulting ring and minimize the distortion.

I've scheduled time this weekend to do the cutting.

-Bob


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m. allan noah
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Reged: 08/14/09

Loc: Virginia, USA
Re: My 103mm Jaegers build new [Re: ryanr256]
      #6178697 - 11/06/13 07:18 AM

Superglue the baffle to a thicker block before you cut it. A little heat will pop it off.

allan


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oldtimer
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Re: My 103mm Jaegers build new [Re: m. allan noah]
      #6179306 - 11/06/13 01:43 PM

I also recently completed a 4" F15 scope but with a rare Ebay find of a Edmund lens and cell. I used 4" PVC for the tube and baffles were fashioned from 3" pipe couplings, one by itelf and one with a 2" pipe coupling insert. Nice thing about these is that they are a 'jam" fit down the 4" tube.

To stablize the long tube I fashioned a 'Hargrave" strut.

To make the lens colimatable I placed it in two 4" PVC pipe couplings with one set of three drilled and tapped holes in each. The Edmund metal cell fits loosly in the pipe couplings and is colimated by six allen screws.

I opted for a nice old all metal 1.25" focuser from an old Tasco as a 2" focuser is rather unneeded for a long focus planetary scope.

Edited by oldtimer (11/06/13 02:00 PM)


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ryanr256
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Loc: Southwest Ohio
Re: My 103mm Jaegers build new [Re: oldtimer]
      #6210577 - 11/23/13 12:56 AM

Quote:

I also recently completed a 4" F15 scope but with a rare Ebay find of a Edmund lens and cell. I used 4" PVC for the tube and baffles were fashioned from 3" pipe couplings, one by itelf and one with a 2" pipe coupling insert. Nice thing about these is that they are a 'jam" fit down the 4" tube.

To stablize the long tube I fashioned a 'Hargrave" strut.

To make the lens colimatable I placed it in two 4" PVC pipe couplings with one set of three drilled and tapped holes in each. The Edmund metal cell fits loosly in the pipe couplings and is colimated by six allen screws.

I opted for a nice old all metal 1.25" focuser from an old Tasco as a 2" focuser is rather unneeded for a long focus planetary scope.




Sounds interesting. You should start a thread and post pics of it. I'd be interested in seeing them.

I've started building the baffle frame. Here's a couple of pics:





I haven't installed the first, thin baffle yet. I am going to wait until the epoxy cures on the other ones before I do the last one and cut the struts.

My goal for this weekend is to finish the baffle assembly, paint it and the inside of the OTA and then install the baffles in the OTA. I've already cut the OTA to its final length (52 5/8 inches). Once the baffles are installed, I will mark and drill the holes for the lens cell and focuser.

If things go well for me, I just may be able to complete everything this weekend and have a functioning Jaegers 103mm/f15 telescope!

-Bob


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BillB9430
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Re: My 103mm Jaegers build new [Re: ryanr256]
      #6210908 - 11/23/13 09:33 AM

Bob, you wrote: " . . . I think my thought process is correct? I think I'm going the proper way with my dimensions. Long FL eyepieces need less focuser travel than short FL eyepieces, correct?"

I don't think you can generalize that. It depends on where the eyepiece field stop (AKA "eyepiece focal plane") is located relative to the barrel flange that abuts the focuser tube. Some eyepieces of different focal lengths are parfocal, having no travel needed between them. Garrett SWA's of 20mm, 26mm, 32mm. and 38 mm are like this and have their field stop inside the barrel at the same position as the flange outside the barrel. (Those are also the same eyepiece series as the Orion Q70 and the Agena SWA.) In comparison, I have an Edmund orthoscopic 6 mm that needs 7.9 mm more "in" focus than the Garrett SWA's and a Galoc 16.3 mm FL that needs 21.4 mm more "out" focus than the SWA's. Best measure the eyepieces you plan to use. and make sure you have the focuser travel range to accommodate them. Check with a Barlow, too, if you plan to use one. Televue lists this information for their eyepieces in a table on their website, but most ocular manufacturers don't. It is pretty simple to measure if you have another finished scope on hand, though. For eyepieces with the focal plane below the field lens, you can even make this measurement without a telescope by pushing a thin strip cut from a note card up from the bottom of the eyepiece until its upper edge is focused sharply. (Don't use a ruler or anything that might damage the field lens!) Then transfer that distance from the bottom of the eyepiece to the outer barrel (mark temporarily with a soft pencil) and measure how far the mark is from the flange. This method does not work with many complex wide field eyepieces like Naglers, Ethoi, Pentax XW, etc, because they have the field stop between lenses where it is not accessible for measurement. Do those by comparison of focus position with other eyepieces in a finished scope.

Hope this helps. There's nothing any more frustrating than building a scope and then finding out there's not enough "in" focus to allow use of some of your favorite eyepieces. - Bill


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ryanr256
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Reged: 04/21/09

Loc: Southwest Ohio
Re: My 103mm Jaegers build new [Re: BillB9430]
      #6222556 - 11/28/13 11:39 PM

Quote:

Bob, you wrote: " . . . I think my thought process is correct? I think I'm going the proper way with my dimensions. Long FL eyepieces need less focuser travel than short FL eyepieces, correct?"

I don't think you can generalize that. It depends on where the eyepiece field stop (AKA "eyepiece focal plane") is located relative to the barrel flange that abuts the focuser tube. Some eyepieces of different focal lengths are parfocal, having no travel needed between them. Garrett SWA's of 20mm, 26mm, 32mm. and 38 mm are like this and have their field stop inside the barrel at the same position as the flange outside the barrel. (Those are also the same eyepiece series as the Orion Q70 and the Agena SWA.) In comparison, I have an Edmund orthoscopic 6 mm that needs 7.9 mm more "in" focus than the Garrett SWA's and a Galoc 16.3 mm FL that needs 21.4 mm more "out" focus than the SWA's. Best measure the eyepieces you plan to use. and make sure you have the focuser travel range to accommodate them. Check with a Barlow, too, if you plan to use one. Televue lists this information for their eyepieces in a table on their website, but most ocular manufacturers don't. It is pretty simple to measure if you have another finished scope on hand, though. For eyepieces with the focal plane below the field lens, you can even make this measurement without a telescope by pushing a thin strip cut from a note card up from the bottom of the eyepiece until its upper edge is focused sharply. (Don't use a ruler or anything that might damage the field lens!) Then transfer that distance from the bottom of the eyepiece to the outer barrel (mark temporarily with a soft pencil) and measure how far the mark is from the flange. This method does not work with many complex wide field eyepieces like Naglers, Ethoi, Pentax XW, etc, because they have the field stop between lenses where it is not accessible for measurement. Do those by comparison of focus position with other eyepieces in a finished scope.

Hope this helps. There's nothing any more frustrating than building a scope and then finding out there's not enough "in" focus to allow use of some of your favorite eyepieces. - Bill




I realized after I posted, and thought more about it, that I was generalizing too much. I did try a variety of eyepieces in my test mule before actually determining the final length of the OTA.

I was able to finish the baffles and paint them:





I also painted the inside of the tube. Here's a pic from one end. No flash, before baffle install:



Here's one with flash:



The flash makes it look gray, but it's really, really black. I'm very surprised how it came out.

I should have everything completed this weekend. Unfortunately, I have to work on Friday and won't make much progress.

And, yes, I touched up the edge before I installed the baffle frame in the tube.

-Bob

Edited by ryanr256 (11/28/13 11:44 PM)


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ryanr256
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Re: My 103mm Jaegers build - COMPLETED! new [Re: BillB9430]
      #6225586 - 11/30/13 05:21 PM

I was able to spend some quality time last night and today to complete the Jaegers 103mm build. I still need to make a dew shield and find some sort of lens cap for it. Here's a few pics:

The OTA:


On the C5-ASGT:




The business end:


First light will probably be tonight. I will report back on how it performs.

I'd like to thank everyone for their advice and suggestions. I'm pleased with how things turned out. It's really pretty impressive when set up. My hope is that the views are as impressive.

Oh, that's not a carbon fiber tube. A tube of that size in carbon fiber would have been prohibitively expensive for me. So, I did the next best thing. A vinyl wrap on the aluminum tube.

I've dumped the pics into a Picasaweb album:

Jaegers 103mm build

-Bob

Edited by ryanr256 (11/30/13 05:24 PM)


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KevinS
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Re: My 103mm Jaegers build - COMPLETED! new [Re: ryanr256]
      #6230896 - 12/03/13 08:02 AM

Very Nice! Hope to see some planet pics soon.
I am finishing a 128mm F5.5 project and painting that darned tube is turning out to be the hardest thing. I may eventually do a wrap (work smarter not harder) like you did. It looks great.


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ryanr256
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Re: My 103mm Jaegers build - COMPLETED! new [Re: KevinS]
      #6234407 - 12/04/13 11:00 PM

Quote:

Very Nice! Hope to see some planet pics soon.
I am finishing a 128mm F5.5 project and painting that darned tube is turning out to be the hardest thing. I may eventually do a wrap (work smarter not harder) like you did. It looks great.




Unfortunately, my mount has decided to not co-operate with my efforts.

Evidently, it's an encoder issue on the DEC drive.

I won't be able to do much until it gets fixed.



-Bob


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KevinS
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Reged: 12/27/11

Re: My 103mm Jaegers build - COMPLETED! new [Re: ryanr256]
      #6234936 - 12/05/13 09:21 AM

So sorry about the dec encoder. Is that a CG5?
I have had good luck with the AVX I bought this Spring but should I worry about encoder issues? They are probably the same motor/encoder.


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ryanr256
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Re: My 103mm Jaegers build - COMPLETED! new [Re: KevinS]
      #6235934 - 12/05/13 06:13 PM

Quote:

So sorry about the dec encoder. Is that a CG5?
I have had good luck with the AVX I bought this Spring but should I worry about encoder issues? They are probably the same motor/encoder.




Yes, it's a CG5-ASGT. I don't know if you should worry. I don't think it's that common of an issue though.

-Bob


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dawsonian2000
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Re: My 103mm Jaegers build - COMPLETED! new [Re: ryanr256]
      #6243866 - 12/09/13 11:25 PM

Congratulations on the completion of your Jaegers 103/1545, Bob! Very impressive with its carbon fiber tube. You should be very proud of this auspicious accomplishment. I have one to build myself. It is going to be interesting to compare it to the Carton 100/1300 I previously built.

Sorry to read about the ills of your EQ. I hope you can get it operational as soon as possible. In the interim, I wish you a successful First Light session. Look forward to reading your report.

Mel


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ryanr256
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Re: My 103mm Jaegers build - COMPLETED! new [Re: dawsonian2000]
      #6246049 - 12/10/13 11:20 PM

Quote:

Congratulations on the completion of your Jaegers 103/1545, Bob! Very impressive with its carbon fiber tube. You should be very proud of this auspicious accomplishment. I have one to build myself. It is going to be interesting to compare it to the Carton 100/1300 I previously built.

Sorry to read about the ills of your EQ. I hope you can get it operational as soon as possible. In the interim, I wish you a successful First Light session. Look forward to reading your report.

Mel




The tube is not carbon fiber. It's plain old 6063 aluminum. I didn't feel like doing all the sanding, filling, sanding again, etc., etc. steps to get a good looking tube.

So I went with the vinyl wrap. Because the tube is longer than the stock width of the wrap, I had to go with a really large piece and cut it down. I went with 3M Gloss Black DI-NOC Flex Wrap.

The wrapping went ok. At first I thought I was going to mess it up but it worked out eventually. You just have to make sure the edges of the piece of vinyl are square.

The replacement encoder diode is on its way to me. If I can't replace the one I have and get the new one working I will order a replacement motor/encoder assembly directly from Celestron.

-Bob


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Z28500
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Reged: 02/27/12

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Re: My 103mm Jaegers build - COMPLETED! new [Re: ryanr256]
      #6246564 - 12/11/13 09:01 AM

Hi Bob,
I just came across this thread by accident and saw your Jaegers 103 thread, and since I just finished building one myself over the last 2 years:
http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5140754/page...
and custom making over 350 parts (including the custom made screws) I thought I'd get on here and wish you luck on the performance of your new scope. If it does as well as the one I built for my son, then you'll have a lot of fun with it. The lens we got was not a second since I bought it over 2 years ago, but I believe even the seconds perform as well as the first's? Is that what I should call an un-second?! Not really sure about that one. Anyway, edge to edge focus is crystal clear using any eyepiece, with or without the prism star diagonal also. It's definitely a "planet killer" and a "star splitter", bright - midrange galaxies also. And since it's a 4", CA's hardly noticeable, as a matter of fact, after a lot of studying, I've found that 4" is what you might call the "cut off" point for low CA in achromats. Of course, different lenses have something to do with that also, not to mention opinion. We can point his scope at black sky, look through the EP, and hundreds of perfect stars appear, most with no CA at all, and all of them, all the way to the edge of the lens, crystal clear, as I already stated. The same thing goes for pointing it at "visible by the naked eye" objects as well, edge to edge clear with hardly any or none at all CA. Sirius of course, does have some CA, but it's not that bad, another advantage of an F/15, less CA than shorter FL's
The highest magnification we've gotten so far is with a 6mm Ep putting the mag at 262.5. I tried putting in the 4mm but the focal length was too long and I couldn't achieve focus. Maybe next time we take it out, we'll take off the star dia. and try it. I don't see why it won't work even though the mag will be at around 393 - quite a bit. On the other side of the coin, we have the most fun with the lower mag EP's like the 38mm.
So far, the objective is still uncoated, but since it performs so well, I see no reason to make any changes in that department.
Therefore, all in all, what an awesome lens, I wish I could buy another. I have talked to Surplus Shed about more, and they said they also have all of Jaegers spec's and plan on having lenses ground. They won't be "Jaegers" but they will be clones, and supposedly, just like the old Jaegers.
That vinyl wrap kind of reminds me of the Monocoat we use on radio control aircraft, hmm, now there's a thought, might try it on a small scope I'm building. Guncoat ( www.guncoat.com ) works good too, out & inside the tube if flocking paper isn't used, since besides many bright colors, it comes in super flat black too. It's an epoxy, spec't at over 100,000 draws out of a holster. Wonder if that means we can take the scope out of the box over 100,000 times!? Since finding that stuff, I don't use spray paint anymore, epoxy's far superior, especially in a dew shield.
You know, that 103mm Jaegers seems to be popular, quite a few people are building with them, including Mel, who made a contribution on this thread. He's also finished some awesome scopes himself, one of them's even in a magazine!
So anyway, good luck with your new scope, it looks great, and I know it's going to be a lot of fun, there's really nothing like an F/15!

Z


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