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Equipment Discussions >> Eyepieces

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BillP
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Reged: 11/26/06

Loc: Vienna, VA
Exposed Brandon
      #5639605 - 01/23/13 09:43 PM Attachment (93 downloads)

I finally got around to taking apart my Brandon. These are the elements of the 8mm Brandon. The scale above is .025" per line...ever 4 lines are 1/10th of an inch.

Eye lens is on the left and field lens on the right. The spacer between them is to the right of the lenses. The curvature radius of the two inward facing lenses appears the same with an approximate radius of 9.2mm.

The first surface of the eye lens on the far left is very slightly convex. The thickness of the 2nd element of the eye-doublet is approx. 1.6mm. The thickness of the 4th element or field lens is approx. 2.2mm. When the lenses are assembled the approximate distance between the centers of the two convex inward facing lenses is approximately 0.3mm.

Bottom line is that it looks to be three different lens types making the two doublets not symmetrical. The two inward facing convex lenses however appear to be identical (they only look slightly different in the pic because one is slightly leaning).


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MRNUTTY
Carpal Tunnel
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Reged: 11/22/11

Loc: Mendon, MA
Re: Exposed Brandon new [Re: BillP]
      #5639615 - 01/23/13 09:54 PM

So is it a Plossl Bill? Or at least 'symmetrical'.

Edited by MRNUTTY (01/23/13 09:56 PM)


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Moonglum
professor emeritus


Reged: 06/01/08

Re: Exposed Brandon new [Re: BillP]
      #5639621 - 01/23/13 09:56 PM

Hey! Gonna blacken the edges with a sharpie before you put them back in? Are these easy to take apart and put back together? (I want to blacken mine...) I ordered mine with no fieldstops because I'm alt/az at F20. I'm gonna try cutting my own fieldstops out of a soft black plastic waste-basket. Getting the holes perfectly centre for merging with binos will be the tricky part.

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Rick Woods
Postmaster
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Reged: 01/27/05

Loc: Inner Solar System
Re: Exposed Brandon new [Re: MRNUTTY]
      #5639819 - 01/24/13 12:03 AM

Quote:

So is it a Plossl Bill? Or at least 'symmetrical'.




It's a Brandon.


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rogerandgarf
sage
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Reged: 06/01/05

Loc: Arlington, Wa
Re: Exposed Brandon new [Re: BillP]
      #5639894 - 01/24/13 01:11 AM

So what tool did you choose to remove the element housing? Is the housing aluminum?

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leonard
scholastic sledgehammer
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Reged: 10/19/07

Loc: West Virginia
Re: Exposed Brandon new [Re: BillP]
      #5639898 - 01/24/13 01:16 AM

Hello ,

Thanks for posting Bill .

I wonder if the 24mm and the 48mm are the same design or a slight design modification ?
I only ask this because these two are the ones that are different from the rest is some way , anyone know for sure ???????????

Leonard


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MRNUTTY
Carpal Tunnel
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Reged: 11/22/11

Loc: Mendon, MA
Re: Exposed Brandon new [Re: Rick Woods]
      #5640150 - 01/24/13 08:08 AM

Quote:

Quote:

So is it a Plossl Bill? Or at least 'symmetrical'.




It's a Brandon.




:-) doh! I was trying to compare it to other lens configurations. Unfortunately, I elected the lazy way out and chose Wikipedia for my info. Today, I used a better source ( Lens configurations ) and withdraw that question. It is very close.

Edited by MRNUTTY (01/24/13 08:12 AM)


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Jeff Morgan
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Reged: 09/28/03

Loc: Prescott, AZ
Re: Exposed Brandon new [Re: leonard]
      #5640232 - 01/24/13 09:14 AM

Quote:

Hello ,

Thanks for posting Bill .

I wonder if the 24mm and the 48mm are the same design or a slight design modification ?
I only ask this because these two are the ones that are different from the rest is some way , anyone know for sure ???????????

Leonard





A few years back quite a few people were asking about a 36 mm focal length in a 2" barrel. In a telephone conversation with Don Yier regarding my 48 mm on order he claimed the design was scaled, and he could produce them in any desired focal length.

One other item to note is that the glass types vary - possibly three or four types. One of the reasons for the infrequent offerings of the 48 mm was limited runs from Schott in sizes large enough for the 3rd element. Whether that was the third from the right or left I don't know, and Don doesn't let many details go.

Glass availability may explain why the rumored 36 Brandon never appeared. That and Vernonscope is quite busy with military orders.

Edited by Jeff Morgan (01/24/13 09:18 AM)


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BillP
Postmaster
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Reged: 11/26/06

Loc: Vienna, VA
Re: Exposed Brandon new [Re: Jeff Morgan]
      #5640288 - 01/24/13 09:50 AM

All,

-> They are definitely not symmetrical as each doublet is unique having different lens thickness and outward facing curves.

-> Is it a Plossl? I would say no...although I've never really seen an actual patent or technical diagram of a "true" asymmetrical Plossl. However, popular wisdom on a true Plossl design is that the diameters of each doublet are different, which as can be seen on these that they are not. So not a Plossl and not a Symmetrical.

-> The way it comes apart is that the tube structure from underneath actually unscrews. So you grip that and unscrew while holding the eyepiece upright. Then slowly remove it and the lenses simply sit in that with the eye lens doublet protruding.

-> As far as tools...I'm sure Don has a special one, but I just got some needle nose pliers, then wrapped the tips with electrical tape, then grabbed the edge of that tube housing to unscrew. Did not take much of any force, and once loose just did the rest by hand.

-> Yes, I want to blacken the lens edges...but also want to blacken the interior of the spacer as that is gloss black Before I do that though am thinking of trying to borrow another 8mm from someone (yellow coatings) so I can do a side-by-side observation with them before and after to see if any obviouse improvements occur to the views.

-> While similar in some respects to a 1915 Konig design, it is still different so yes, it is a Brandon


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leonard
scholastic sledgehammer
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Reged: 10/19/07

Loc: West Virginia
Re: Exposed Brandon new [Re: Jeff Morgan]
      #5640849 - 01/24/13 02:40 PM

Hello ,

So we know they are scaled up or down and it seems the glass availability would be the limiting factor .
Thanks Jeff .

From what BillP has shown here Rick Wood has been correct ,a Brandon is a Brandon and only a Brandon !!!

I would still like to know just what this narrow FOV eyepiece , with its restricted eye relief is used for in the military. It must be some kind of non-critical piece of equipment as far as combat goes as its hard to beleave in the 21st such an antiquated design would be used on the field of battle .
It would be interesting to read something by someone who in real time used this eyepiece in the military and just what they did with it , and show pic or web sites where anyone could go and see for themself.
Aside from that there is only speculation as to its use .


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csrlice12
Postmaster
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Reged: 05/22/12

Loc: Denver, CO
Re: Exposed Brandon new [Re: leonard]
      #5640888 - 01/24/13 03:03 PM

Erfles were used for bomb sights....why not a Brandon?

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jrbarnett
Eyepiece Hooligan
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Reged: 02/28/06

Loc: Petaluma, CA
Re: Exposed Brandon new [Re: leonard]
      #5640901 - 01/24/13 03:16 PM

I suspect they go in the surveillance scopes the military buys from Questar.

- Jim


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t.r.
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Reged: 02/14/08

Loc: Upstate NY
Re: Exposed Brandon new [Re: csrlice12]
      #5640928 - 01/24/13 03:30 PM

Quote:

I would still like to know just what this narrow FOV eyepiece , with its restricted eye relief is used for in the military. It must be some kind of non-critical piece of equipment as far as combat goes as its hard to beleave in the 21st such an antiquated design would be used on the field of battle .
It would be interesting to read something by someone who in real time used this eyepiece in the military and just what they did with it , and show pic or web sites where anyone could go and see for themself.
Aside from that there is only speculation as to its use .




Personally, I simply believe that the Questar Brandons are used in conjunction with the Questar scopes as a system for military/surveillance purpose. I believe I have seen these in the field (targeting ranges) in use. The other military connection that could be misconstrued is that the actual manufacturer of the lens sets, also has military contracts (fact) and that when they have a run of optics for them, Vernonscope is put on hold, until they are free to run the Brandon lenses again. However, I as well as others have heard Don state that, he (Vernonscope) was providing Brandons for military orders and when that occurs, we amatures are delayed. Actually, there is little left to speculate about.


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Jeff Morgan
Postmaster
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Reged: 09/28/03

Loc: Prescott, AZ
Re: Exposed Brandon new [Re: leonard]
      #5640937 - 01/24/13 03:38 PM

Quote:

Hello ,

So we know they are scaled up or down and it seems the glass availability would be the limiting factor .
Thanks Jeff .

From what BillP has shown here Rick Wood has been correct ,a Brandon is a Brandon and only a Brandon !!!

I would still like to know just what this narrow FOV eyepiece , with its restricted eye relief is used for in the military. It must be some kind of non-critical piece of equipment as far as combat goes as its hard to beleave in the 21st such an antiquated design would be used on the field of battle .
It would be interesting to read something by someone who in real time used this eyepiece in the military and just what they did with it , and show pic or web sites where anyone could go and see for themself.
Aside from that there is only speculation as to its use .





Equating age of a design to usefulness or performance is a big mistake. Many popular military designs are old but still well-suited to the job. For example:

- M16 rifle, early, 50+ years;
- B52 bomber, 60+ years; and
- 1911 pistol, 100+ years.

As you mentioned, we don't know what the military does with them. It could be something very specialized and low volume - it doesn't take much to keep what is essentially a one-man operation busy.

Eye relief of course varies by focal length. I find the 24 to be comparable to the Delos. The 16 should be fine for wide variety of uses. The 12 and shorter begin getting tight and take some time to get used to.

Closer to the point for astronomers the Ortho, Plossl, and Newtonian designs are also "antiquated" but perform superbly.


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leonard
scholastic sledgehammer
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Reged: 10/19/07

Loc: West Virginia
Re: Exposed Brandon new [Re: jrbarnett]
      #5641138 - 01/24/13 05:46 PM

Hi Jim ,


I think your correct , if its true the military is using Questars for surveilance and as range spotting scopes then the Brandons would go along as sort of a captive accessory since it uses threads instead of slip fit.

Leonard


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leonard
scholastic sledgehammer
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Reged: 10/19/07

Loc: West Virginia
Re: Exposed Brandon new [Re: t.r.]
      #5641164 - 01/24/13 05:59 PM

Hello tr ,

>>>>> I believe I have seen these in the field (targeting ranges) in use. <<<<<<<<

Now were getting somewhere , I feel you and Jim are correct in that spotting scope use is the purpose . But you have no first hand experience and cannot point me to any web site that shows the eyepiece in action .


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George N
Carpal Tunnel
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Reged: 05/19/06

Loc: Binghamton & Indian Lake NY
Re: Exposed Brandon new [Re: leonard]
      #5641204 - 01/24/13 06:27 PM

The military uses a modified 7-inch Questar Mak as the spotting scope for sniper teams. They don’t use the screw-in Brandon’s, but rather the 1.25-inch, because sniper teams don’t have the time to fool around screwing in stuff. The troops keep losing them – which keeps Don busy making them. The military versions don’t have the brand names on them.

I’ve visited Don’s shop on a number of occasions (we’ve been friends since the mid 1980’s) and have watched him make the military eyepieces. There is a big DoD “stay out” sign on the outside of his shop. He told me “They make me put that up. Just ignore it.” The last time I was there he took me on a tour and I got to see piles of parts from old VERNONscope products, and a goodly number of antique telescopes and such, including two brass 18th Century scopes, all waiting for another of his famous auctions.

Don made me a pair of matched 16mm ‘blems’ for bino-viewing using lenses he picked out of the rig holding the military ones. He checked a few “to make sure that the focal length is exactly matched”. He provided ‘blems’ by taking a pair of barrels and putting a little scratch on each – and sold me the pair for a very low price (which he was also offering at NEAF). Actually, one of the ‘blem’ barrels has a little scratch. The white paint filling the lettering is not complete on the other.

I also note that this thread started with a picture of a disassembled Brandon. At NEAF last time Don told me that “proper assembly is as important as the actual components of an eyepiece. The only other person who can assemble these things as well as I can is my son, but he’s not interested in taking over the business. I’m still working on him, but he prefers working at his cabinet making business.”


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Ed Kessler
Pooh-Bah
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Reged: 05/17/06

Loc: Millersburg, PA
Re: Exposed Brandon new [Re: BillP]
      #5641215 - 01/24/13 06:35 PM

Thanks Bill. That was quite interesting. I'm using Brandon's with a Vernonscope binoviewer for much of my observing these days.

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Ed Kessler
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Reged: 05/17/06

Loc: Millersburg, PA
Re: Exposed Brandon new [Re: BillP]
      #5641226 - 01/24/13 06:41 PM

Quote:

-> Yes, I want to blacken the lens edges...but also want to blacken the interior of the spacer as that is gloss black Before I do that though am thinking of trying to borrow another 8mm from someone (yellow coatings) so I can do a side-by-side observation with them before and after to see if any obviouse improvements occur to the views.





I wonder why they're not already blackened?


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leonard
scholastic sledgehammer
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Reged: 10/19/07

Loc: West Virginia
Re: Exposed Brandon [Re: Jeff Morgan]
      #5641231 - 01/24/13 06:42 PM

Hi Jeff ,


>>>> Equating age of a design to usefulness or performance is a big mistake. <<<<<

I don't think so .

- M16 rifle, early, 50+ years;
Great combat rifle , is it the last word I don't think so . Prone to dirt and grit flowing , at least it used to be .

- B52 bomber, 60+ years; and

On the slow side now and up-graded many times . The only reason its still used is bombers are somewhat out dated . It shows up on radar like a bright flash light at night .

- 1911 pistol, 100+ years.

Great pistol , may be as good and auto. as ever designed .

>>>>> It could be something very specialized and low volume <<<<<<<

I know your kidding here .


>>>> Eye relief of course varies by focal length. I find the 24 to be comparable to the Delos. <<<<<

Lets see , the Delos has 20mm of ER . The 24mm Brandon has 8mm of useable ER . Jeff you must have special eyes .

Closer to the point for astronomers the Ortho, Plossl, and Newtonian designs are also "antiquated" but perform superbly.
The Newtonian was modified from first design .
Plossl , yes the TelVue Plossl would be to me the better pick for older designs for use in the Questar spotting scope .
Its useless to get anything like real proof .

Leonard


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