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1976 Edscorp 4" f/15 with Manual

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#101 Bomber Bob

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Posted 16 December 2017 - 08:39 PM

It's gonna sound selfish (I guess), but I'm glad that lots of refractor fans want APOs.  It means less competition for these long & cumbersome achromatics, and helps keep the costs down for us old timers.  I mean:  Gotos, N-Ks, Swifts, & Unitrons (among others) have shown up on the Goodwill site.  The Goodwill!   It gives folks a chance to snag a great optic at a low price.  Some of these are seriously under-valued, and show up in our Finds thread.

 

Has anyone compared an Edmund 3" with a Jaegers?  I assume Edmund used Japan-made optics, while the Jaegers were made in-house.


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#102 clamchip

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Posted 16 December 2017 - 08:53 PM

I think the 3 inch dew cap is a little longer in it's length-diameter ratio than the 4 inch.

I have the dew caps positioned so right where the cap flares out is the end of the lens

cell.

I had them both out today because it was a good high-power resolution day, target: the

perforated thingy on the cell tower 2-1/2 miles from my house.

The cylinder is perforated with venting and it very difficult to resolve the perforations.

This photo is with a 8 inch Cave reflector, the perforations are not visible in this photo

because its out of focus. I'll see if I have a better photo, I don't think I do.

 

post-50896-0-34253100-1492899837_thumb.jpg

 

 

 

 

 


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#103 clamchip

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Posted 16 December 2017 - 09:15 PM

Here's a better picture of the tower, but again, cylinder perforations unresolved.

I've never been able to photograph the perforations.

The Edmund 4 is a champion at resolving these perforations. And on a good day

the 3 inch Edmund can do it.

Another difficult thing to see is the wire snaking its way up the center of the mast

upward from the perforated thingy. 

This photo is with Zeiss a 63mm.

 

Z 138.jpg


Edited by actionhac, 16 December 2017 - 09:56 PM.

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#104 clamchip

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Posted 16 December 2017 - 09:31 PM

This one I think you can begin to see the perforations if you click on the photo.

8 inch f/7 Cave again.

I don't remember the magnification but the cell tower is 2-1/2 miles from

my house.

 

fifties Cave 151.jpg


Edited by actionhac, 16 December 2017 - 09:33 PM.

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#105 terraclarke

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Posted 17 December 2017 - 12:02 AM

This thread is worth re-reading.


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#106 highfnum

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Posted 17 December 2017 - 01:35 AM

Mmm I got a 3 inch jeagers as well as 3 inch edmund 

f numbers are a bit different 

15 vs 11



#107 terraclarke

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Posted 17 December 2017 - 10:05 AM

This thread is worth re-reading.

Woops, we were partying a bit too hearty earlier last night! I forgot to attach the link! lol.gif

 

https://www.cloudyni...-who-made-what/


Edited by terraclarke, 17 December 2017 - 11:18 PM.

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#108 Paul Rini

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Posted 19 December 2017 - 01:44 PM

The Edmund 4" objective lenses are unstoppable! yay.gif

One day with excellent seeing and a good friend, did some testing /scope comparison with an Edmund 4" f/15 and a Brandon 94mm refractor and it was very close when viewing Jupiter...really close at 575X until I up the power on the Edmund 4" to 625X and the contender conceded to the superior. Couldn't believe the details in the cloud structures.


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#109 clamchip

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Posted 19 December 2017 - 04:24 PM

I've always considered my Edmund 4 inch 'The Regulator', highly accurate and which all others are compared to. 

When I owned my 1st one I couldn't stand owning more than one telescope and I would bring home new scopes

now and then to compare to the Edmund just to see if there was a greener pasture out there. The Edmund was

always on top.

I still do the same thing only its my 4th Edmund 4 inch and somehow I gave up on the only one telescope business.

Still one wife though!

 

Robert 


Edited by actionhac, 19 December 2017 - 04:32 PM.

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#110 Paul Rini

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Posted 23 December 2017 - 09:03 AM

It's gonna sound selfish (I guess), but I'm glad that lots of refractor fans want APOs.  It means less competition for these long & cumbersome achromatics, and helps keep the costs down for us old timers.  I mean:  Gotos, N-Ks, Swifts, & Unitrons (among others) have shown up on the Goodwill site.  The Goodwill!   It gives folks a chance to snag a great optic at a low price.  Some of these are seriously under-valued, and show up in our Finds thread.

 

Has anyone compared an Edmund 3" with a Jaegers?  I assume Edmund used Japan-made optics, while the Jaegers were made in-house.

Not to over quote but Edmund Scientific made their optics in their optical lab in Barrington, New Jersey. This included their well know achromats of 63mm diameter F/6, 3" F/15, 4" F/15, 5" F/14. Their very rarely items listed for sale included 127mm X 600mm Focal Length doublet (Japan) plus a few others which had a short lifespan like the 3" F/11 and a few others. Also, a lot of the smaller achromats included Military Surplus which were shown in Edmund's 1960-1970 catalogs.

 

For those Edmund Scientific 4" F/15 refractor enthusiasts: while helping Edmund clean/clear out 3 of their warehouses in the Barrington, NJ store of lenses they weren't using (warehouse space is very expensive and not appropriate for minimum quantity used lenses), one of the boxes which I got had this optical lab specification sheet at the bottom of a box of mixed lenses. This will help complete your authentication for your Edmund 4" F/15 Telescope.

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#111 Paul Rini

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Posted 14 March 2018 - 12:40 AM

First and only owner since 1976

 

Edscorp, Barrington New Jersey no. 85,038  Air-Spaced (foil spacers) 4" Achromat 60" Focal Length (f/15) First Crown/Second Flint Objective

With manual dated 5/74

Edscorp no. 85,034 Equatorial Mount with Oak tripod legs.

With manual dated 5/74

Edscorp no. 40,477 Barlow

With manual dated 5/72

Edscorp Lens:

  25mm Kelner

  1/2" Ramsden

  1/4" Ramsden

 

 

How to use YOUR TELESCOPE no. 9055,  Copyright 1972

TIME in Astronomy no. 9054,  Copyright 1966 

 

Really so much fun to dig these out of the closet again.

Going to try the scope out on the CGE mount soon!

Would you know the length of the original Edmund Scientific 4.00" outside diameter X 3.875" inside diameter aluminum tube used on the Edmund 4" F/15 doubet refractor specifically with the white tube? Thanks in advance.



#112 clamchip

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Posted 14 March 2018 - 09:59 AM

Would you know the length of the original Edmund Scientific 4.00" outside diameter X 3.875" inside diameter aluminum tube used on the Edmund 4" F/15 doubet refractor specifically with the white tube? Thanks in advance.

I have that dimension, the tube alone is 49" inches.

 

Robert



#113 apfever

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Posted 14 March 2018 - 11:12 AM

My bare tube is 51"

#114 clamchip

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Posted 14 March 2018 - 11:16 AM

Wow! there's that much variation, interesting.



#115 Paul Rini

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Posted 15 March 2018 - 12:08 PM

Thanks for the total length measurement....Edmund must have kept the basic 9"-10" (on their 3" f/15 a 35" tube is noted) back focal length distance available for the prism image erector. Thanks again and clear skies, Paul



#116 kaymann

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Posted 15 March 2018 - 03:47 PM

OK measuring only my mount only white I get 46".

I have not physically removed the Dew shield since it was attached and do not believe I can remove it...

The black primary lens holder adds 2 1/2 inches and probably another 1/2 inch under the dew shield.

That puts it at 49".

 

Randall


Edited by kaymann, 15 March 2018 - 03:48 PM.


#117 apfever

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Posted 18 March 2018 - 11:02 AM

OK Randall,

How I did it. (Books that were never written: "How I did it between the Bushes" by Bill Clinton) ("How I Did It" by Dr. Frankenstein, Mel Brooks from the movie)

The raw bare metal tube is not threaded. The focuser skirt slips IN the tube and is held by screws. The lens cell slips OVER the tube and is held by screws.
The tube goes INTO the lens cell quite a ways - 3".

The tube is square cut end to end, 51" long.

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Edited by apfever, 18 March 2018 - 11:03 AM.

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#118 apfever

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Posted 18 March 2018 - 11:18 AM

The lens cell has the optics very close to the front, about 1/4" clear for the threaded retaining ring. There is no dew shield, didn't get one, the original textured finish is to the end of the cell. The front cap is also original, made the first day after masking tape was discovered (ok, IMO, just always gave me that impression).

The focuser is official Edmund 2" but I need a new star shaped brass rod piece long enough to go through it. Can't remember about the original, too short or messed up or cut or something, I think sources are out there. There's some chunks downstairs, full regular size 1.25 but nothing long enough for this focuser.
The focuser goes in flush from the back face of the tube to the back face of the focuser. It makes a nice looking finish, and for projects in front of it there is only 2 or maybe 3 dozen, so...

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#119 nowhere

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Posted 18 March 2018 - 11:54 PM

"I'm glad that lots of refractor fans want APOs"

 

Me too, otherwise I wouldn't have had the chance to buy a used Skylight 4" f15 at an irresistible price last year! I hated to have to give up the Polarex 3" that I had spent years looking for and years looking through (couldn't afford to have both) but it was worth it. I had been keeping my eye out for a 4" Unitron/Polarex at a price I could afford for a while but it seemed like it wasn't going to happen. If I had known about these Edmund 4" before this thread came up I would have been looking for one of these too.


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#120 Paul Rini

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Posted 19 March 2018 - 05:58 AM

The lens cell has the optics very close to the front, about 1/4" clear for the threaded retaining ring. There is no dew shield, didn't get one, the original textured finish is to the end of the cell. The front cap is also original, made the first day after masking tape was discovered (ok, IMO, just always gave me that impression).

The focuser is official Edmund 2" but I need a new star shaped brass rod piece long enough to go through it. Can't remember about the original, too short or messed up or cut or something, I think sources are out there. There's some chunks downstairs, full regular size 1.25 but nothing long enough for this focuser.
The focuser goes in flush from the back face of the tube to the back face of the focuser. It makes a nice looking finish, and for projects in front of it there is only 2 or maybe 3 dozen, so...

As for that star shaped item you might be referring to the pinion gear which meshes against the rack attached to the focuser tube. Check its diameter and want ad on CN or just drill and tape one end (or both) and add a bolt...you will need to add diameter to this Bolt(s) to fit the original focuser knobs. Main object is to have the pinion meshing with the rack. That focuser tube is chromed machined brass as is the original pinion.



#121 kaymann

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Posted 19 March 2018 - 10:42 AM

Greetings, I would love to have 2" focus, to match my SCT, but more importantly I need a 4" ring set to mount it to my new to me CGEM DX... No worries the original mount is staying in the family as long as the scope is!

 

On another note for anyone to chime in, my white paint is in fantastic shape but I was wondering what people use to polish them up. Car finish products?

 

My 1981 Meade SCT deep blue paint is in real good condition but could use buffing up.




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