Telescope Reviews: 127mm f/5.5 binocular

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Equipment Discussions >> Binoculars

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Smithfr2000
member

Reged: 09/12/09

Loc: Nantes - France

Re: 127mm f/5.5 binocular new

[Re: Mr. Bill]
#5295922 - 06/30/12 06:29 AM

Very interesting work ! Well done !

I do not understand how you achieve collimation with knobs inside the box ? Any explication ?
Thanks a lot.

Post Extras:

GlennLeDrew
Postmaster

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada

Re: 127mm f/5.5 binocular new

[Re: Smithfr2000]
#5296254 - 06/30/12 11:54 AM

What's the weight? My 1996 version of the 5" weighed 27 pounds, and I want to shave a fair bit off the 2012 re-do.

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Mr. Bill
Postmaster

Reged: 02/09/05

Loc: Northeastern Cal

Re: 127mm f/5.5 binocular new

[Re: GlennLeDrew]
#5296410 - 06/30/12 02:00 PM

Looks like just under 30 pounds, Glenn.

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Mr. Bill
Postmaster

Reged: 02/09/05

Loc: Northeastern Cal

Re: 127mm f/5.5 binocular new

[Re: Mr. Bill]
#5296894 - 06/30/12 08:11 PM Attachment (91 downloads)

Received second 3.1 mirror by priority mail today.

Achieved near perfect binocular collimation centering a telephone pole 1 mile distant while maintaining reasonable intrabarrel collimation.

Once figured out what I was doing it was easy and alignments very robust.

Next step, star test.

Focusers work perfect in position shown and will result in very little change in position during altitude rotation. Should be able to sit and sweep from horizon to zenith without much if any seat adjustment.

Note: found helical threading to be too sloppy to precise maintain collimation alignment....used Teflon pipe tape on drawtube to provide stiffness and friction without stiction.

Edited by Mr. Bill (07/01/12 03:15 PM)

Post Extras:

Mr. Bill
Postmaster

Reged: 02/09/05

Loc: Northeastern Cal

Re: 127mm f/5.5 binocular new

[Re: Mr. Bill]
#5297117 - 06/30/12 11:22 PM

Another interesting thing now that collimation is achieved is there is a 3-4mm difference in ep height when fine focused with the same eye.

I assume that is the difference in focal length between objectives.

That's around 1/2% so I guess that's probably normal.

I could put a shim on the long barrel to even out the ep height.

Post Extras:

Mr. Bill
Postmaster

Reged: 02/09/05

Loc: Northeastern Cal

Re: 127mm f/5.5 binocular new

[Re: Mr. Bill]
#5297647 - 07/01/12 10:39 AM Attachment (80 downloads)

First light this morning between moonset and first light of dawn (3:00-4:00 AM)

"My God, it's full of stars."

This is going to be the "killer app" of Milky Way cruising machines. Panoptic 19 seems to be a perfect match for this...37x and 3.5mm exit pupil.

Much more to do...flocking, staining, varnishing but optical design proved.

Contrast even without flocking is excellent and dark nebulae and starclouds are breathtaking...even better than my trusty BT100s.

Maybe someday I'll be able to compare side by side with the Fuji 25x100s.

Total cost without eyepieces was around $2200.

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marcelof
sage

Reged: 05/24/10

Loc: Necochea,Bs As,Argentina

Re: 127mm f/5.5 binocular new

[Re: Mr. Bill]
#5297710 - 07/01/12 11:20 AM

That advantages has this disposition versus place only four diagonals going out on the later part?
(Besides saving both biggest mirrors.)

Anyhow remain the eyepieces vertical to up, achieving the 90 º of inclination so looked.

Edited by marcelof (07/01/12 11:24 AM)

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Rich V.
Post Laureate

Reged: 01/02/05

Loc: Lake Tahoe area, Nevada, USA

Re: 127mm f/5.5 binocular new

[Re: marcelof]
#5297757 - 07/01/12 11:48 AM

Marcelo, if I understand you correctly, using two diagonals attached to the rear of the box so as to allow 90° viewing would present images 180° rotated relative to each other. One side would have the image rotated right 90° and the other side rotated left 90°.

Using the larger first mirrors to orient the images 90° initially allows the two diagonals on each side to mimic a rhomb which creates no rotational error as they are turned for IPD adjustment.

Rich

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GlennLeDrew
Postmaster

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada

Re: 127mm f/5.5 binocular new

[Re: Rich V.]
#5297797 - 07/01/12 12:15 PM

I knew you'd succeed, Bill! And talk about short order, too--it came together mighty quickly. I'm not surprised to see that even non-blackened, the contrast is good. This is due in part to the fact that unlike a 'streamlined' bino, wherein the main tubes closely follow the converging light cone and thus too easily allow scattered light to do harm, your box has its walls, for the most part, well removed from the image-forming light cone. And the self-shadowing provided by the back side of the front board and lens cells is a big contributor, too.

Making your own binocular isn't so hard, is it? The very first astro instrument I built was a 5" bino, too. If one gets over the needless fear of super precision being required, it's not much harder than designing a Dobsonian scope.

Post Extras:

Mr. Bill
Postmaster

Reged: 02/09/05

Loc: Northeastern Cal

Re: 127mm f/5.5 binocular new

[Re: GlennLeDrew]
#5298010 - 07/01/12 02:35 PM Attachment (55 downloads)

Quote:

I knew you'd succeed, Bill! And talk about short order, too--it came together mighty quickly. I'm not surprised to see that even non-blackened, the contrast is good. This is due in part to the fact that unlike a 'streamlined' bino, wherein the main tubes closely follow the converging light cone and thus too easily allow scattered light to do harm, your box has its walls, for the most part, well removed from the image-forming light cone. And the self-shadowing provided by the back side of the front board and lens cells is a big contributor, too.

Making your own binocular isn't so hard, is it? The very first astro instrument I built was a 5" bino, too. If one gets over the needless fear of super precision being required, it's not much harder than designing a Dobsonian scope.

That's about right....

Preparation before cutting pieces is essential. Raytracing and measuring backfocus of components like diagonals will prevent surprises.

Making the box refractor before this allowed me to hone up my woodworking skills but one slip and....

This was done using only a radial arm saw and floor drill press. I would not attempt this project without them; the precision of cuts is beyond hand tools and Skil saws.

Taking a break today from project...my 80 trees are hollering for a deep watering!

Edited by Mr. Bill (07/01/12 10:22 PM)

Post Extras:

Mr. Bill
Postmaster

Reged: 02/09/05

Loc: Northeastern Cal

Re: 127mm f/5.5 binocular new

[Re: Mr. Bill]
#5298036 - 07/01/12 02:48 PM

Hey, just made Postmaster.....only took 7 1/2 years.

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marcelof
sage

Reged: 05/24/10

Loc: Necochea,Bs As,Argentina

Re: 127mm f/5.5 binocular new

[Re: Rich V.]
#5298040 - 07/01/12 02:51 PM

It is difficult to express with words.
I refer to this:

Only that constructed with the materials used by Mr. Bill.
I counted badly or only it uses two diagonal mirrors????

Post Extras:

Rich V.
Post Laureate

Reged: 01/02/05

Loc: Lake Tahoe area, Nevada, USA

Re: 127mm f/5.5 binocular new

[Re: marcelof]
#5298058 - 07/01/12 03:06 PM

Marcelo, what you are talking about is the Matsumoto EMS mirror system. It's the ultimate solution for a bino back. Matsumoto uses an elegant 2-mirror system that produces a correct image. There's a lot more engineering and precision fabrication to it than using 2- 90° factory diagonals together as Bill has done, though.

Matsumoto EMS

Rich

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Mr. Bill
Postmaster

Reged: 02/09/05

Loc: Northeastern Cal

Re: 127mm f/5.5 binocular new

[Re: Rich V.]
#5298085 - 07/01/12 03:27 PM Attachment (69 downloads)

My understanding is that the EMS system only works well with relatively slow f ratios such as f/7 and higher.

My setup provides no vignetting and outstanding edge of field illumination on fast refractors using f/5 or in my case here f/5.5.

Here's a 6 inch f/8 Tak tubes system using the EMS. I took this last year at the Okie-Tex SP. Only cost $28K.

Edited by Mr. Bill (07/01/12 03:47 PM)

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Wes James
Postmaster

Reged: 04/12/06

Re: 127mm f/5.5 binocular new

[Re: Mr. Bill]
#5298492 - 07/01/12 08:33 PM

...*drool*...

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Wes James
Postmaster

Reged: 04/12/06

Re: 127mm f/5.5 binocular new

[Re: Wes James]
#5298493 - 07/01/12 08:33 PM

You've got an impressive project going here, Bill- Impressive!!

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marcelof
sage

Reged: 05/24/10

Loc: Necochea,Bs As,Argentina

Re: 127mm f/5.5 binocular new

[Re: Wes James]
#5298580 - 07/01/12 09:47 PM

I supposed that eliminating the elliptical mirrors the beams they follow his path, placing then diagonals in the back part. The box should be little long mas. I do not have the elements to experiment, because of it I ask.
My experience says to me that eliminating the prisms a binocular remains much more luminous. Will it be more luminous than the fuji 150? Or maybe equal?

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mercedes_sl1970
professor emeritus

Reged: 12/02/05

Loc: Canberra, Oz

Re: 127mm f/5.5 binocular new

[Re: Wes James]
#5298749 - 07/02/12 12:01 AM

Quote:

You've got an impressive project going here, Bill- Impressive!!

You'd think he would have it finished by now. It really is only a fairly trivial project....! (Yeah, right).

Andrew

ps I bet the bet the views will be fabulous

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GlennLeDrew
Postmaster

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada

Re: 127mm f/5.5 binocular new

[Re: mercedes_sl1970]
#5298958 - 07/02/12 06:46 AM

The elegance of the Matsumoto system lies only in the fact that that two mirrors deliver a normal, non mirror-reversed view. In other respects the system leaves much to be desired due to the fact that it requires the user to tweak things in order to have the eyepieces be parallel. That the erection/folding system effectively 'hangs out there' like a plumber's nightmare just waiting to be bumped and hence knocked out of collimation gives me the heebie-jeebies! This is NOT robust, by my engineering standards.

Post Extras:

Rich V.
Post Laureate

Reged: 01/02/05

Loc: Lake Tahoe area, Nevada, USA

Re: 127mm f/5.5 binocular [Re: GlennLeDrew]
#5299169 - 07/02/12 10:35 AM

Amen to that, Glenn! There's a whole lot going on mechanically with the EMS design compared to the sheer simplicity of this three mirror design.

I'm looking forward to looking through Bill's Bino Box!

Rich

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