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Equipment Discussions >> ATM, Optics and DIY Forum

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dawsonian2000
Carpal Tunnel
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Reged: 07/26/06

Loc: Riverview, FL, USA
Re: Jaegers GJD 6" f/10 Refractor Build (VSC) new [Re: martym]
      #5248710 - 05/31/12 11:34 AM

Excellent suggestion, Marty! I think I will do that for the main tube. At present, I have the painted lens and focuser components in my garage, which gets quite hot here in FL between noon and dusk. So, doing as you suggest, I will put the tube in attic for faster curing and out gassing once I paint it.


Mel


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martym
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Reged: 02/15/10

Re: Jaegers GJD 6" f/10 Refractor Build (VSC) new [Re: dawsonian2000]
      #5252604 - 06/02/12 09:16 PM

Well, as long as your making the OTA to fit the lens F/L you may consider giving yourself enough in-travel to use a pair of binos in the future. My Denk II's have about 121mm of optical path lenght inside the device, plus the optical path that a 2" diagonal will use up. Most off-the-shelf refractors don't have enough in travel to use binos in a diagonal without requiring an extra lens to extend the prime focus; and binos in a refractor without a 90 degree diagonal just isn't going to be pleasant. My 6" lens has plenty of light to feed my binos to my complete satisfaction. So as long as your cutting your own tube, it's a lot easier to make an extra long 2" draw tube to go into the focuser to reach focus using one eyepiece and then use a much shorter drawtube to use with a diagonal and binos. If you spend some time viewing through a good pair of perfectly collimated binos, you may not want to return to single eye viewing again. I like my Denks, but Earthwin is making binos as good or better and less cost.

marty


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gmazza
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Reged: 03/10/09

Loc: RS, Brazil, 29S 51W
Re: Jaegers GJD 6" f/10 Refractor Build (VSC) new [Re: martym]
      #5276116 - 06/17/12 07:58 PM

Just a question:

Seeing your cell design looks you used 0.150 inch = 3.81 millimeters for the flanges to retain the lens.

is it really necessary to lose all of this aperture for a good support ?


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Jim Curry
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Re: Jaegers GJD 6" f/10 Refractor Build (VSC) new [Re: martym]
      #5278460 - 06/19/12 09:16 AM

Mel:

I've been following your build since this thread started. You're doing a great job.

On cutting the tube to length, on two OTA's I built I made up a sled similar to what you did. I use second hand focusers, in my case Astro Physics 2.7" with 4" of travel and mount it on a backplate and rotating ring as if I were going to mount to tube OTA. Not having an interest in bino's I set the focuser with diagonal and eyepiece on the sled with the focuser tube in the mid position ie: 2" of travel either way. I slide that focuser assembly to focus on something 1/4 mile away and measure from the back of the lens mounting ring to the front of the backplate. That's the length I cut my OTA to. I'm wondering if a focuser with 4" of travel would allow you find a position to use a bino or a diagonal without extensions?

Regards,
Jim


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dawsonian2000
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Reged: 07/26/06

Loc: Riverview, FL, USA
Re: Jaegers GJD 6" f/10 Refractor Build (VSC) new [Re: martym]
      #5281404 - 06/20/12 09:50 PM

Hey Marty,

Sorry I am just getting back to the thread to read your notes. I will have to strongly consider incorporating a binoviewer in the scheme of my build. Switching between the two setups is an easy proposition.

I was hoping to get the race trace done of recent, but other family matters took precedence. So, once I get the opportunity to resume, my plans may ultimately change to a binoviewer setup.

Mel


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dawsonian2000
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Reged: 07/26/06

Loc: Riverview, FL, USA
Re: Jaegers GJD 6" f/10 Refractor Build (VSC) new [Re: Jim Curry]
      #5281423 - 06/20/12 10:02 PM

Hi Jim!

Thanks for the kind words! Great points and notes, as well!

A binoviewer is still a tossup effort in my mind. But the idea is certainly calling me. For the moment, my project is on hold until I get through some home front matters. In any case, I like the method you used for determining your tube length.

I see that you will be using an Astro Physics 2.7" focuser! I have one of these focusers too, but I will be using mine for a 6" f/5 refractor project; to be executed after the 6" f/10 build.

Mel


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dawsonian2000
Carpal Tunnel
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Reged: 07/26/06

Loc: Riverview, FL, USA
Re: Jaegers GJD 6" f/10 Refractor Build (VSC) new [Re: gmazza]
      #5281429 - 06/20/12 10:09 PM

Hey gmazza!

Is this a question for me or Marty?

Mel


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gmazza
sage


Reged: 03/10/09

Loc: RS, Brazil, 29S 51W
Re: Jaegers GJD 6" f/10 Refractor Build (VSC) new [Re: dawsonian2000]
      #5281830 - 06/21/12 06:24 AM

Quote:

Hey gmazza!

Is this a question for me or Marty?

Mel




Hi Mel,

The question is for you, I am buiding a cell for the 108mm 8.5 and don't know the measure to be used in the retaining ring.

Best

Gustavo


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Jeff B
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Reged: 12/30/06

Re: Jaegers GJD 6" f/10 Refractor Build (VSC) new [Re: Jim Curry]
      #5283636 - 06/22/12 11:02 AM

Quote:

. I'm wondering if a focuser with 4" of travel would allow you find a position to use a bino or a diagonal without extensions?

Regards,
Jim




Yes it will but you have to measure everything very accurately and have a binoviewer/diagonal combination with a reasonnable optical path length.

Notice that when you unscrew the 2" adapter from the end of the AP's draw tube and rack it all the way in, the end of the draw tube will retract at least an inch into the body of the focuser. That allows you to add one of AP's threaded extensions to the draw tube to maximize the amount of travel to ~5.5". The Denks with the power switch consumes about 5" of optical path length. That's enough total travel to allow allow me to use my Denk II with the power switch and the AP diagonal without the need for a seperate extension tube. However, that does not leave a whole lot of room for extra in and out travel, which, in turn, may limit your eyepiece selection.

The Lumicon mirror and Baeder prisim diagonals have a shorter shorter path lengths than the AP diagonal and can provide a bit more travel capability.

Hope this is usefull.

Jeff


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dawsonian2000
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Reged: 07/26/06

Loc: Riverview, FL, USA
Re: Jaegers GJD 6" f/10 Refractor Build (VSC) new [Re: gmazza]
      #5284458 - 06/22/12 09:20 PM

Quote:

Quote:

Hey gmazza!

Is this a question for me or Marty?

Mel




Hi Mel,

The question is for you, I am buiding a cell for the 108mm 8.5 and don't know the measure to be used in the retaining ring.

Best

Gustavo




Hi Gustavo,

Actually, if you were to divide the .150" in half, you would get .075", which will translate into being the retainer intrusion supporting the edge of the objective. And my clear aperture will be 6" exactly. This is the same measurements as built into the standard Jaegers cells. I hope this clarifies the matter.

As for your 108mm f/8.5 objective, I would think that a .050" to .075" retainer lip would work for you.

Mel


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gmazza
sage


Reged: 03/10/09

Loc: RS, Brazil, 29S 51W
Re: Jaegers GJD 6" f/10 Refractor Build (VSC) new [Re: dawsonian2000]
      #5284871 - 06/23/12 07:55 AM

thank you, that question was being difficult to find.

Best

Gustavo


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dawsonian2000
Carpal Tunnel
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Reged: 07/26/06

Loc: Riverview, FL, USA
Re: Jaegers GJD 6" f/10 Refractor Build (VSC) new [Re: dawsonian2000]
      #5386466 - 08/25/12 02:49 PM Attachment (43 downloads)

With much of my major family matters out of the way, I was able to resume work on the Jaegers GJD 6" f/10 refractor. I won't bore you with all of the intricate steps I went through to get to this point, for it will be covered on my website once the project is complete.

As you may recall, the last thing I posted on my efforts was the painting of the lens cell and focuser support components.

Skipping over much of the fluff on how I got to this point, here is a photo of the main tube being cut. The method I used produces a very smooth and perpendicular edge, even though I cut it with a hacksaw.

Mel


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dawsonian2000
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Reged: 07/26/06

Loc: Riverview, FL, USA
Re: Jaegers GJD 6" f/10 Refractor Build (VSC) new [Re: dawsonian2000]
      #5386478 - 08/25/12 02:55 PM Attachment (36 downloads)

After the main tube and dew shield were cut to size, I drilled all of the holes to attached the lens cell and focuser support components. I then performed a test fit of the parts for the OTA to surmise the end result; to a degree. Here is a shot of that effort.

Mel


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dawsonian2000
Carpal Tunnel
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Reged: 07/26/06

Loc: Riverview, FL, USA
Re: Jaegers GJD 6" f/10 Refractor Build (VSC) new [Re: dawsonian2000]
      #5386487 - 08/25/12 03:02 PM Attachment (45 downloads)

The test fit went off without a hitch. Next, I established the location of the baffles and then drew them onto the race trace, as seen in the photo below. I plan to cut the baffles out on tomorrow, weather permitting. With Tropical Storm Isaac on its way, I do not know for sure which direction it may take. So the baffle cutting on tomorrow is tentative, to say the least.

Mel


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dawsonian2000
Carpal Tunnel
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Reged: 07/26/06

Loc: Riverview, FL, USA
Re: Jaegers GJD 6" f/10 Refractor Build (VSC) new [Re: dawsonian2000]
      #5386693 - 08/25/12 05:14 PM Attachment (38 downloads)

We have lost a legend in the annals of space exploration. Neil Armstrong passed on today at the age of 82. He will be honored and missed greatly.

Rest in piece, Mr. Armstrong! May your footsteps in heaven be as fulfilling as those you have placed on the moon.

Mel


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martym
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Reged: 02/15/10

Re: Jaegers GJD 6" f/10 Refractor Build (VSC) new [Re: dawsonian2000]
      #5387107 - 08/25/12 09:56 PM

That's a nice aestheic lenght on that dew shield, Mel.

marty


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dawsonian2000
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Reged: 07/26/06

Loc: Riverview, FL, USA
Re: Jaegers GJD 6" f/10 Refractor Build (VSC) new [Re: martym]
      #5387241 - 08/25/12 11:46 PM

Quote:

That's a nice aestheic lenght on that dew shield, Mel.

marty




Hey Marty,

The camera actually made the dew shield look quite long in comparison to the main tube. But not by a great amount. The next photo I take, I hope it portray the scope in true proportion. I believe my point-n-shoot has some pin-cushioning.

Mel


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dawsonian2000
Carpal Tunnel
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Reged: 07/26/06

Loc: Riverview, FL, USA
Re: Jaegers GJD 6" f/10 Refractor Build (VSC) [Re: dawsonian2000]
      #5400174 - 09/02/12 08:49 PM Attachment (38 downloads)

Today, I completed the baffle rack for the Jaegers GJD 6" f/10 refractor. Below is a photo. It just has to be flocked. Being different from most other baffle racks, it is unique in that the individual baffles were cut from a sheet of .250" thick Lexan (polycarbonate); which I purchased on eBay for a fantastic price. Typically, most ATM's make theirs from aluminum sheet. Lexan is very tough. It is also lighter than aluminum.

The four baffles were fabricated with a Bosch model 1608 laminate trimmer. The trimmer is basically a small router. In conjunction with the trimmer, I used two different Jasper router circle guides to make accurate cuts. A model 200 jig was used to cut out the circumference of each baffle from the sheet of Lexan, and the model 400 to cut out the knife-edge inner circles using a carbide v-groove router bit.

Edited by dawsonian2000 (09/02/12 09:29 PM)


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martym
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Re: Jaegers GJD 6" f/10 Refractor Build (VSC) [Re: dawsonian2000]
      #5400951 - 09/03/12 12:01 PM

Very nice Mel,

I wanted to FYI that you can get a 6 foot 1/4"-20 threaded aluminum rod from McMaster-Carr for $8.91. Or 5/16"-18 aluminum rod for $14.07.
Matching aluminum nuts and washers are also available from the same source.
McMaster-Carr never exploits the customer on shipping costs and usally ships same day. They are located in Atlanta, GA.
I have bought a lot of stuff from them over the years for both ATM and other machining projects; never been unhappy with the shipping costs or service, web site is very user friendly, much easier to navigate than Grainger.

marty


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BarabinoSr
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Re: Jaegers GJD 6" f/10 Refractor Build (VSC) [Re: martym]
      #5401041 - 09/03/12 12:55 PM

Doc, that baffle assembly is first rate. I'm looking into baffling my 12" f/5 reflector with a set of four to be mounted inside the tube. That looks to be an exceptional piece of work. Another great instrument in the making! Bambina! :

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