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Jaegers 6" f/15 Question

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#51 Defenderslideguitar

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Posted 22 December 2021 - 09:59 PM

WOW   nice score    Im late to the thread but   after having 2 C 8s   and eventually selling them both   I am taking a break from SCT's   we can always run in to another C8    and you were selling yours anyway       SCT's  they have their place  but  I would do the deal in a New York minute......and it is a great project for you......sweet

 

I have the 4 inch F 15.5 Jaegers  and I love it     a 6 inch f 15 would be sweet



#52 YourNotSirius

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Posted 22 December 2021 - 10:13 PM

I may be off the mark here but, that mount looks to have a lot like a Bill Scheafer GEM!. Now THAT'S a SCORE!

 

You hit this one out of the ball park. We are so envious of you! The old man is drooling over just the thought of restoring this thing! WOW! Lucky!!!

 

By the way, if you find that you do need foil to replace the spacers, just peel some of it from the wrapper of Wrigley's gum. We peeled the foil away from the paper and use it and it was perfect! Very close to no color at all even on Sirius and Vega. A bit of blue but, it wasn't nearly as bad as before we cleaned and re-spaced the elements.

 

Darn it! You are going to have us out in the shop restoring those darned Jeagers scopes and making up some new mounts just to show that they aren't as ungainly as those whiners claim! BHWAHAHAHAHAHA!!! Go big or go home! LOL

 

FWIW

 

Q


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#53 Jeff B

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Posted 22 December 2021 - 11:08 PM

Lens cell removed from the scope. Upon closer inspection, the foil spacers are gone, but the adhesive remains, as you can see right through where they are. The lens elements aren't touching, but I assume I'll need to add some spacers. Side of lenses had index marks, matching serials and a date of 12/2/69.

Ok, you got me thinking on this one.  

 

Have you run the scope as-is through DPAC?

 

Jeff



#54 jragsdale

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Posted 22 December 2021 - 11:26 PM

Ok, you got me thinking on this one.  

 

Have you run the scope as-is through DPAC?

That's the next step, and if it shows as undercorrected I'll add some cricut foil and try again. Rinse/repeat.


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#55 jragsdale

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Posted 23 December 2021 - 12:31 AM

I may be off the mark here but, that mount looks to have a lot like a Bill Scheafer GEM!. Now THAT'S a SCORE!

 

I think you're right! I looked through a bunch of pics and it's a dead ringer for an older AT-7. This one has the Byers 7" RA gear on it. It seems that Bill Schaefer never made the same mount twice, lots of incremental improvements. Thanks for that info, that will come in handy! Now just to figure out how all these motors work, there's 2 on the RA and 1 on a tangent arm on the DEC.


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#56 YourNotSirius

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Posted 23 December 2021 - 08:57 AM

You are welcome.

 

If I were to take a guess, I would submit that the two motors on the RA axle turn in opposite directions to significantly reduce backlash. I could be wrong but, it kind of makes sense since electronic/digital control was not yet available. Alternately, and not so likely, one would turn normally and the other would be engaged when trying to slew or correct in the opposite direction. That would be done my switches activating each motor when needed and turning off the other one when not needed. I know it sounds silly but, think about it.

 

They are all synchronous motors that run on 1110/120VAC and are probably 1rpm. Those Hurst motors are beasts! They are easily capable of swinging those OTAs around the sky without complaining. There are plenty of articles on CN about how to wire up these motors. Don't worry about goto stuff and all. It's way overrated for instruments of this nature. It already has nice setting circles which should work just fine.

 

A thought: Save yourself the aggravation of getting involved with imaging with this scope. For planetary it would do just fine but, for DSOs, not so well. Especially, when you consider that most of the time spent with that stuff is at the computer trying to make sense of it all. We tried that imaging shenanigans and it was far more work than interesting. It you want pretty pictures then the Hubble has already done it. Just use your eyes and enjoy the show in real time. LOL

 

Q



#57 tim53

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Posted 23 December 2021 - 09:41 AM

The dual motors on C-8 spur gear drives run in the same direction such that they take up the backlash in the gear train by one motor being slightly ahead of the other.  That idea probably wouldn't work so well with a worm gear, unless the worm is directly driven by the motors without spur gear reduction.

 

Another possibility is that there's a differential gear train between the motors and the worm.  The Cave Observatory mount has such a setup, such that you don't need a drive corrector to guide or manually pan around the field of view.  The motors can't run fast enough for slewing.


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#58 jragsdale

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Posted 23 December 2021 - 10:24 AM

A thought: Save yourself the aggravation of getting involved with imaging with this scope. For planetary it would do just fine but, for DSOs, not so well. Especially, when you consider that most of the time spent with that stuff is at the computer trying to make sense of it all. We tried that imaging shenanigans and it was far more work than interesting. It you want pretty pictures then the Hubble has already done it. Just use your eyes and enjoy the show in real time. LOL

 

Q

Yeah, I've got my imaging rig down with a 4" triplet on an EQ6-R Pro with the works of mono cam, autofocuser and guiding. This one will definitely be for mostly fun, visual and maybe planetary imaging.


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#59 Terra Nova

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Posted 23 December 2021 - 10:38 AM

Congratulations! I think you made an excellent trade. I’m looking forward to hearing how it does under the stars and seeing it restored.


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#60 barbie

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Posted 23 December 2021 - 11:51 AM

I had a Jaegers 6" f15 from 1985-1991 and it was a very capable instrument with a well figured lens.
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#61 tim53

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Posted 23 December 2021 - 02:04 PM

I took a few deep sky images with a 6" f/10 Jaegers I once owned.  At prime focus, color fringing isn't too bad.  Mars was gorgeous, but it's mostly red.  Jupiter looks funny, with yellow and purple belts that are hard to compensate for.

 

My 6" f/15 is spectacular for visual, and decent for planetary imaging, though Jupiter still looks a tad funny.  I never shot deep sky with it, but I bet it would do well.  I haven't used it in many years, because the tube is so long.  I am somewhat tempted to fold it.  In half, like Gerry Logan brought up to the last RTMC in 2019, one could mount the focuser in such a way that it's pointed at the flat, so a star diagonal lets you point the eyepiece to either side of the OTA, and rotating rings aren't needed.  His tube was rectangular in cross-section.

 

I also have a 6" f//5 Jaegers, built by a late friend of mine about 30 years ago.  That thing, with a 31mm Nagler and a black cloth over your head in a dark sky is just AMAZING.  I actually tried imaging with it once.  Blue channel stars were HUGE, so I gave up.


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#62 tim53

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Posted 23 December 2021 - 02:10 PM

Here's the tube for my f//15 as I was building it, using 1/4" Walnut plywood.  I had it mounted on my Tak NJP mount for testing and use, but it was a lot to set up and take down, which is why I haven't used it in a long time.

 

post-6788-14072963883177_thumb.jpg

 

post-6788-14072963933345_thumb.jpg

 

post-6788-1407296427142_thumb.jpg


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#63 apfever

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Posted 23 December 2021 - 04:12 PM

It looks like it matches the mount in the last picture very well. :)



#64 jragsdale

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Posted 23 December 2021 - 08:09 PM

Today I got the 2.7" focuser squared away, stripped all the  white paint off the whole thing (4 rounds of citri strip). It came off the bakelite knobs nicely without messing with the red color. Got the rack and pinion cleaned and regreased. I'll still paint the black in a wrinkle finish when I get further along, but at least now it has that Jaegers charm.

 

I can't find a way to add tension to the R&P though, any tips? It is VERY loose, I think it'll slide out pretty easy with any weight. Also, any leads on a 2.7" to 2" adapter? I'd like to use some 2" diagonals and EPs.

 

I mounted it up very carefully on a CGEM just for testing purposes, no serious movements or observations.

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Edited by jragsdale, 23 December 2021 - 08:10 PM.

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#65 SkipW

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Posted 23 December 2021 - 09:01 PM

The dual motors on C-8 spur gear drives run in the same direction such that they take up the backlash in the gear train by one motor being slightly ahead of the other.  That idea probably wouldn't work so well with a worm gear, unless the worm is directly driven by the motors without spur gear reduction.

 

Another possibility is that there's a differential gear train between the motors and the worm.  The Cave Observatory mount has such a setup, such that you don't need a drive corrector to guide or manually pan around the field of view.  The motors can't run fast enough for slewing.

I'm wondering what's inside the box the motors are attached to. Here's a Byers differential - those things are really cool! Maybe that's what is in there. If that's what you have, one of the motors should run continuously the same direction for sidereal tracking and the other should be reversible for east or west slow motion. The two motors are are probably geared for different speeds, and the differential input gearing may also be different, so pay attention to which motor goes where if you take this stuff apart.

 

ByersDifferential_50c.jpg

 

Those Hurst CA synchronous motors are discontinued, but maybe yours still work. Hurst still provides specs, wiring, and other reference information for them online.

 

https://www.hurst-mo...om/ca_dd_g.html

 

Each one should have two black wires, one red and one white (assuming they are both CA motors). You will need to connect the two black wires together and put a 0.5 uF nonpolarized capacitor rated for 230 VAC or more between red and white. 

 

Connect one side of your 110V 60 Hz power to the pair of black wires. To run the motor in a clockwise direction, connect the other side to white. To run CCW, connect the other to red. To make one reversible, connect one side of your AC to black and the other side to the common terminal of a SPDT, center-off, switch and connect the switched terminals to red and white. I would recommend connecting the line (hot) side of the AC to black, and neutral to red, white, or the switch. The motor will work with hot on either side and neutral on the other, but running neutral out to whatever handbox or control panel you use seems slightly safer than routing hot out there. Use a polarized power plug and a GFCI-equipped circuit.


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#66 jragsdale

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Posted 23 December 2021 - 09:26 PM

I'm wondering what's inside the box the motors are attached to. Here's a Byers differential - those things are really cool! Maybe that's what is in there. 

Here's what is under the cover, I haven't dug much further. Thanks for all that info, that'll come in handy when I'm wiring this up!

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#67 SkipW

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Posted 23 December 2021 - 09:52 PM

Yuck!

 

I hope that's just white paint and you can tell the colors of the wires coming out of the motors under it.

 

There doesn't look like enough room left for a diff. I wonder what's in there?

 

Can you read the motor RPMs? They're probably stamped on the gear cases.



#68 YourNotSirius

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Posted 23 December 2021 - 10:32 PM

Today I got the 2.7" focuser squared away, stripped all the  white paint off the whole thing (4 rounds of citri strip). It came off the bakelite knobs nicely without messing with the red color. Got the rack and pinion cleaned and regreased. I'll still paint the black in a wrinkle finish when I get further along, but at least now it has that Jaegers charm.

 

I can't find a way to add tension to the R&P though, any tips? It is VERY loose, I think it'll slide out pretty easy with any weight. Also, any leads on a 2.7" to 2" adapter? I'd like to use some 2" diagonals and EPs.

 

I mounted it up very carefully on a CGEM just for testing purposes, no serious movements or observations.

The only way that we found to adjust the tension on the focusing unit is to loosen one of the set screws on the knob and squeeze the two knobs toward each other while tightening the set screw again. If you place a small compressible fiber washer or something similar between one of the knobs and the housing that could work as a form of a clutch by applying pressure to the housing. Again, the tension would be created by the method noted above. I'm certain there are other ways but, they likely would require some machining. One idea that immediately comes to mind is to make a tension device by drilling a hole through the housing and thread it for a small thumb screw. However, unless done properly that could mar the chrome on the tube.

 

Q


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#69 jragsdale

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Posted 23 December 2021 - 11:26 PM

Yuck!

 

I hope that's just white paint and you can tell the colors of the wires coming out of the motors under it.

 

There doesn't look like enough room left for a diff. I wonder what's in there?

 

Can you read the motor RPMs? They're probably stamped on the gear cases.

I think I can scratch off paint and see color on some of the wires. 

 

Here's a pic under that cover plate showing the worm and other gears.

 

Motors are RA: 2x 5W 1/2 RPM, DEC: 5W 2 RPM

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#70 SkipW

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Posted 24 December 2021 - 12:02 AM

I have no idea why there are two motors. Maybe they're the same RPM, turn in opposite directions, and work together to produce the required torque.

 

Since they're synchronous motors they should turn at exactly the same speed and the gearing could produce identical output speeds.



#71 ccwemyss

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Posted 24 December 2021 - 12:08 AM

Today I got the 2.7" focuser squared away, stripped all the  white paint off the whole thing (4 rounds of citri strip). It came off the bakelite knobs nicely without messing with the red color. Got the rack and pinion cleaned and regreased. I'll still paint the black in a wrinkle finish when I get further along, but at least now it has that Jaegers charm.

 

I can't find a way to add tension to the R&P though, any tips? It is VERY loose, I think it'll slide out pretty easy with any weight. Also, any leads on a 2.7" to 2" adapter? I'd like to use some 2" diagonals and EPs.

 

I mounted it up very carefully on a CGEM just for testing purposes, no serious movements or observations.

I seem to recall that the one that originally came on my AP 6” had a nylon screw going through a tapped hole in the top of the housing. I don’t have it anymore. I donated it to a club project to put a refractor in the second dome at the Amherst College observatory. Unfortunately, about a year later, the professor who had an office beneath the dome caused a fire that destroyed it. 
 

 Chip W.



#72 Kasmos

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Posted 24 December 2021 - 05:10 AM

Focuser adjustment.

Like Mr. Sirius mentioned above, loosen a knob and squeeze to the desired tension, but there should be a rubber washer between each knob and and the housing. It looks like they are still there.



#73 jragsdale

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Posted 24 December 2021 - 05:16 AM

Focuser adjustment.

Like Mr. Sirius mentioned above, loosen a knob and squeeze to the desired tension, but there should be a rubber washer between each knob and and the housing. It looks like they are still there.

Yeah, I did that and it seemed to do the trick. Not "smooth" per se, but definitely tight enough to stop slipping. Looks like the original neoprene washers, both are split, but still seem functional. No easy matches at the local hardware store so I'll have to order those online. I might add a teflon washer on both sides to help smooth out the motions but still get the same tension.



#74 davidc135

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Posted 24 December 2021 - 05:49 AM

Focuser adjustment.

Like Mr. Sirius mentioned above, loosen a knob and squeeze to the desired tension, but there should be a rubber washer between each knob and and the housing. It looks like they are still there.

Not Mrs Sirius?  David



#75 YourNotSirius

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Posted 24 December 2021 - 09:25 AM

Not Mrs Sirius?  David

Just call me "Q". Yeah. The parents loved Star Trek and apparently, as I got older, I reminded them of the character on the Next Generation. Who am I to argue with them? LOL

 

Q


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