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127mm f/5.5 binocular

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#76 Smithfr2000

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Posted 05 July 2012 - 03:23 PM

Very nice !
Thanks a lot for the pictures and the explanations about collimation. :D

#77 Smithfr2000

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Posted 05 July 2012 - 03:24 PM

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#78 Joad

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Posted 05 July 2012 - 06:52 PM

I'm more than a little amazed at how fast you completed this project! :bigshock:

#79 Mr. Bill

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Posted 05 July 2012 - 09:52 PM

I'm more than a little amazed at how fast you completed this project! :bigshock:


My wife's on holiday in Ireland so I have been working without distractions to finish in time for the Golden State SP coming up in two weeks.

Will be giving a PowerPoint presentation on this project at GSSP.

:cool:



#80 JMW

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Posted 05 July 2012 - 11:48 PM

Just stumbled across this. Looks awesome. I will definitely mossy on over for a view through your new creation at the GSSP. There may be a line.

Bill, I still appreciate the tours of the dark stuff when I camped next to you at the 2009 GSSP. Seeing the dark nebula is one of the things I look forward to after viewing for several months within an hour of Reno's light dome.

#81 mercedes_sl1970

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Posted 06 July 2012 - 08:47 AM

Very impressive. Look forward to hearing about the views.

Andrew

#82 Mr. Bill

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Posted 06 July 2012 - 09:34 PM

Ready for night trials...

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#83 Mr. Bill

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Posted 06 July 2012 - 09:36 PM

Another...

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#84 Rich V.

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Posted 06 July 2012 - 09:51 PM

Wishing you a good night, Bill!
:D

Rich

#85 Mr. Bill

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Posted 07 July 2012 - 03:24 AM

I remember Klipchhorn speakers....my first $75 bottle of pinot noir wine....

Looking through these at M24 gives me the same sensation of the next level...

Maybe mirrors instead of prisms is the way to go...

With the 24mm Pans, pinpoint stars to the edge of the fieldstop and the contrast is definitely better than the BTs which are very, very good.

#86 Smithfr2000

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Posted 07 July 2012 - 07:21 AM

A question about collimation : Do you tweak the mirrors alone ?
Or, do you tweak also the lenses cells ?
And what about the diagonal's mirrors ?
Thanks.

#87 Rich V.

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Posted 07 July 2012 - 10:37 AM

Looking through these at M24 gives me the same sensation of the next level...

With the 24mm Pans, pinpoint stars to the edge of the fieldstop and the contrast is definitely better than the BTs which are very, very good.


I take it you were duly impressed?...... ;)

Rich

#88 Mr. Bill

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Posted 07 July 2012 - 10:37 AM

The lens cells are fixed; all collimation is done with the diagonals.

There are three adjustments...rotation, tilt, and yaw.

The 1 1/4 diagonal is adjusted with a precision square to be precisely parallel to the 2 inch diagonal to eliminate field rotation.

Each barrel is adjusted for best collimation, then I tweek the right barrel (my non dominate eye) to correct the inter collimation.

I use my focused/defocused barrel technique on a star to do final collimation.

#89 Mr. Bill

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Posted 07 July 2012 - 10:42 AM

Looking through these at M24 gives me the same sensation of the next level...

With the 24mm Pans, pinpoint stars to the edge of the fieldstop and the contrast is definitely better than the BTs which are very, very good.


I take it you were duly impressed?...... ;)

Rich


They'll do.... :grin:

#90 hallelujah

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Posted 07 July 2012 - 11:05 AM

They'll do.... :grin:


It is 'acceptable' to be enthusiastic over your excellent piece of workmanship! :bounce:

We won't hold it against you.

GREEN with Envy is another thing.

Stan

#91 GlennLeDrew

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Posted 07 July 2012 - 11:56 AM

Bill,
I'd be curious to see a pic looking into the objective from one side, with eyepiece installed, and another of the exit pupil...

#92 Mr. Bill

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Posted 07 July 2012 - 12:28 PM

Here they are, Glenn...24mm Pan (4.35mm ep) on left, 19mm Pan (3.45mm ep) right.

:cool:

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#93 Mr. Bill

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Posted 07 July 2012 - 12:29 PM

Edge of field illumination with 24mm Pan in place...tracing out on a piece of paper placed over monitor and adding missing part, I would say 70%.

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#94 Gordon Rayner

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Posted 07 July 2012 - 01:21 PM

You found that there was enough looseness in the focusers' threads that you needed to use Teflon plumber's tape applied over the male threads. Stellarvue is not alone in this shortcoming. The advertising buzzword use of "CNC" does not make up for lack of proper design, manufacture, and fitting quality control .

A good threaded helical focuser should use truncated Acme or similar shallow thread profile ( inserts are available from Seco Snap-Tap, or their successor or buyout, and no doubt several other threading bit sources) rather than a standard vee. That allows optimal use of the wall thickness allowed in the spacing budget for this portion of a binocular instrument.
For a monocular telescope, wall thicknesses are much less constrained, but that is not an excuse for sloppy thread fits and non-optimal thread profiles, and lack of multiple threads, "CNC" or not.

For a given IPD, there are limits on the glass diameter and the wall thicknesses of the metal parts of the eyepieces . That is why multiple lead/"multiple start"/ multiple threads are used in professionally manufactured binocular instruments ( and in many common food and drink containers).

For a given wall thickness, multiple threads allow more axial motion per turn. That is important in optical focusing. The material savings in production of millions of PETE beverage bottles must be substantial.

#95 Mr. Bill

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Posted 07 July 2012 - 01:38 PM

Gordon...helical focusers are not Stellervue's.

Bought these several years ago (anticipating this project) and cannot remember vendor or manufacturer...no markings.

I will comment on one problem with the 2 inch Stellervue diagonals....the drawtube barrels are baffled with grooving but the finish was shiny anodizing.

I discovered this when I was observing the moon and moved off axis about 20 degrees when the fov became flooded with light where there should have been none. Turned out the diagonal drawtube was the cause in spite (and probably a result of) of the grooved baffling.

That just ticks me off that manufacturers just don't get it...my Moonlite focuser had the same issue and when I called Ron at Moonlite he didn't think it was a big deal.

A few shots of Krylon Ultra Flat Black solved the problem on both items.

Curiously,the Stellervue 1 1/4 inch diagonal drawtube barrels were both grooved and properly blackened. Probably different manufacturers.

:foreheadslap:

#96 Rich V.

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Posted 07 July 2012 - 01:44 PM

What is the source of the intrusion into the light path? To fuzzy to tell...

Looks great!

I had to paint the inside of my SV 2" diagonal as well. That in addition to the shiny 2" Feathertouch drawtube baffles bothered me. You'd think this would be considered. UFB paint made a big difference.

Rich

#97 Mr. Bill

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Posted 07 July 2012 - 01:59 PM

What is the source of the intrusion into the light path? To fuzzy to tell...

Rich


Hi Rich

the bottom of the helical drawtube.

#98 GlennLeDrew

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Posted 07 July 2012 - 02:29 PM

Good field illumination, and certainly no prism-induced 'fingernail' extra-pupil reflections to send unwanted light into the eyes. The area immediately surrounding the exit pupil looks well enough 'black', and so the only light of any consequence making it through to the retina is that forming the image.

Have you tried bumping up the magnification, on one side only if tyis is all you can do, to see how the image holds up? I should think a 1mm exit pupil, or around 130X, is useable. Of course, in bino mode this will place pretty tight constraints on collimation. This is why I implemented external up-down and left-right adjustment knobs for easy and instant on-the-fly tweaking. Such things as loose focusers and wiggling eyepieces (primarily due to slight differences in barrel diameters) can be accounted for the instant collimation drifts as the bino is moved about.

#99 Mr. Bill

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Posted 07 July 2012 - 03:10 PM

I would say for a binocular where 50% edge illumination is considered good (a la EdZ) that 70% is very good.

My monocular 6 inch f/5 box refractor is about 80%, but it doesn't have two diagonals in the light path to deal with.

#100 RichD

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Posted 07 July 2012 - 04:55 PM

I'd say 70% is at least very good and probably excellent! I bet you can't wait for winter and M42...


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