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The big reverse binoculars

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#26 dustyc

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Posted 20 October 2020 - 01:29 PM

I see the usual quasi-valid negatives are coming in, which is fine.

 

By similar arguments, one would opt to keep the pony, rather than drive a car because: it's too complicated to steer, accelerate and brake... a car is bigger than a pony... a car won't fit in my stable stall... the buggy whip would become obsolete... a car costs too much... The last one is actually ~driving~ the decision; the others are just justifications. Then you eventually get to Loch Lomond and find cars and tents filling the lush pasture afore ye arrived.

 

Chorus
O ye’ll tak’ the pony and I’ll tak’ the Chevy,
And I’ll be in Scotland afore ye.
But me and my true love will never meet again,
On the bonnie, bonnie banks o’ Loch Lomond        Tom

Every time Tom brings up pics of these binos, I ask myself "I wonder if he could only keep one, would he keep the 36" dob or the 16" double barrel?"


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#27 TOMDEY

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Posted 20 October 2020 - 03:48 PM

Every time Tom brings up pics of these binos, I ask myself "I wonder if he could only keep one, would he keep the 36" dob or the 16" double barrel?"

Another option is to get another 36-inch mirror and turn that into a true binoscope. I have noticed that it would actually fit into the dome... and both barrels could (just barely) peer out through the 84-inch-wide slot, without vignetting! Hmmm... Not healthy. I would then be able to sell off the 16-inchers, to help defray the cost. I'll go into the kitchen and present this proposal to my wife...

 

I'm back... She replied, "The last time you presented a proposal to me was forty-eight years ago... and look where that's gotten me!" I sprinted back into this Computer Room and slammed the door... She was holding a cast iron frying pan in one fist and a marble rolling pin in the other. Retreat was my only prudent option. I'm an expert at interpreting subliminal body-language.  Tom

 

~click on~ >>>

Attached Thumbnails

  • 95 Tom's 24-foot dome opening wide enough for 36-inch bino or 50-inch mono.jpg

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#28 PEterW

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Posted 20 October 2020 - 04:58 PM

I think a quiet call to Mr Lockwood for a pair of “sensible sized”, crazy quick mirrors might be a better option. Better for NV and better for finding low contrast stuff. Sometimes it’s not size that matters....

Peter

#29 faackanders2

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Posted 20 October 2020 - 05:53 PM

My JMI RB-16 shown there only takes 1.25-inch eyepieces, so the available field is about 1.7 times the diameter of the moon, when using e.g. a pair of TeleVue 24mm Panoptic Eyepieces The advantage is the brightness, contrast and presence of even the most subtle deep sky objects... things that you wouldn't see at all with a lesser instrument. I use the pair of ITT Gen 3 Night Vision Eyepieces shown in the previous picture for Globulars. Even the extremely remote ones, deemed near impossible with ~regular~ telescopes become objects of major interest... not only looking good, but also resolved into stars. The brighter, closer showcase globulars are almost too bright to look at. Using the Night Vision with narrowband Hydrogen Alpha filters... the Horsehead Nebula is in your face obvious and distinct --- looking just like in the pictures we see in the literature.   Tom

 

Here's a picture that I took with a different telescope... but it gives some idea of how it looks. >>>    Tom

16" Binoscope with two night vision eyepieces!  WOW!


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#30 faackanders2

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Posted 20 October 2020 - 05:58 PM

nother pic

What was just the cost of just the 16" JMI binoscope and year you bought it?



#31 TOMDEY

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Posted 20 October 2020 - 06:36 PM

16" Binoscope with two night vision eyepieces!  WOW!

Yeah, indeed extravagent... and a true pleasure to use.    Tom

 

What was just the cost of just the 16" JMI binoscope and year you bought it?

Around $15K base price, around six years ago... and double with all the extras >>> SkyWizard, Encoders, crating and shipping, custom matched Fullum Primary Mirrors,  premium OWL enhanced coatings and certifications, premium Secondary Folding Flats, Premium Tertiary Star Diagonals, Amish 8x10 Custom Shed, Site Prep, 220VAC underground run, permits, inspections, research, communications, contacts, logistics, etc. etc.    Tom

 

[General Comment: It's prudent to roughly double your estimate on any aggressive custom building project ($$$, time, difficulty, aggravation) to keep out of trouble and calibrate your decision whether to proceed. It takes a combination of realistic expectations and dogged determination to pull off the tough ones. Start with ~little~ projects and work up, always building on successes and failures. And the biggest consul of all --- save up the avocational expense $$$ before starting. That's painful, when you're hot to trot, but then the execution becomes a reward, rather than a dreaded commitment to what might turn out to be unaffordable!]   Tom



#32 ButterFly

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Posted 21 October 2020 - 12:22 AM

I'll go into the kitchen and present this proposal to my wife...

Wrong room.  Try again when you're holding toilet paper or a dry towel.

 

 

I think a quiet call to Mr Lockwood for a pair of “sensible sized”, crazy quick mirrors might be a better option. Better for NV and better for finding low contrast stuff. Sometimes it’s not size that matters....

Peter

In a few years, when the Tom Dey Space Telescope Institute opens for operations, once again, the only thing that matters will be: location, location, location.  Just think of all that half-observing he's done with all those wasted daylight hours!



#33 Mitrovarr

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Posted 21 October 2020 - 01:10 AM

This is definitely getting filed under the category of "Things I'm never even going to get to see in the field", kind of like that 10" Astro-Physics Maksutov.


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#34 faackanders2

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Posted 21 October 2020 - 04:18 PM

This is definitely getting filed under the category of "Things I'm never even going to get to see in the field", kind of like that 10" Astro-Physics Maksutov.

If Tom Dey ever takes this to a star party I may go and take a look, for that Hubble like experience!

 

Too bad JMI is no longer making these; but $15K 6 years ago may be $30K with inflation today (for the base 16" model).



#35 edwincjones

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Posted 22 October 2020 - 05:22 AM

This is definitely getting filed under the category of "Things I'm never even going to get to see in the field", kind of like that 10" Astro-Physics Maksutov.

and that 25" dob, 6" AP refractor, 20x60 zeiss IS, 22x60 Tak astronomers, and many others

 

frown.gif frown.gif


Edited by edwincjones, 22 October 2020 - 05:23 AM.


#36 Tony Flanders

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Posted 22 October 2020 - 05:40 AM

Would you choose to look up at the night sky with one eye closed, because a monocle is smaller and cheaper than binocular eyeglasses? Give it a try; that shows what you're forfeiting, each and every time you bring only one eye to your monoscope, and deprive the other, envious eye! Obstacles are created to be overcome; convenience is what you make it. When the goin' gets tough, the tough make it easy... and then reap the benefits, evermore... each time they open both eyes to the Universe, as Nature intended. Why settle for half of that?


Because for me, merging the two images in binoculars is always somewhat of a strain. Granted, it's often worth the effort, but I find one-eyed observing much more relaxing.

 

With a monocular scope, I have moments when I feel that my eye placement is spot-on and the focus is perfect. Rare, but it does happen. With binoculars, the chances that both eyes will be placed perfectly and the focus will be perfect in both -- all four at the same moment -- are zero.
 
For similar reasons -- but more extreme -- my wife usually closes one eye when using binoculars. She says she dislikes using my 2x54 binoculars at night because unlike with regular binos, she finds it impossible to ignore the image through her non-dominant eye.

But in purely practical terms, the reason that large binocular telescopes are so rare is that for the same price, weight, and bulk, you could buy a telescope with twice the aperture. Which would yield even more of a boost in viewing power than using two eyes.

 

Really can't argue about this one -- it's a very individual thing.
 



#37 Xilman

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Posted 22 October 2020 - 05:57 AM

The only reasons some people recommend against them is because they can't afford them.

At least one other person, me, wouldn't buy them is because I have different degrees of myopia and astigmatism in each eye and, much the most important, I need differing degrees of prism in each lens of my spectacles to point my gaze in the right direction. Hardly ever can I fuse the views in a pair of binoculars and then only by straining.

 

When I use binoculars for astronomy, which is moderately often, I leave one eyepiece lens cap in place and use the other side as a monocular. When that one becomes steamed up from my eye, I swap the cap over and use the other side with the other eye.



#38 salico

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Posted 22 October 2020 - 06:00 AM

I also have eye sight issues, but fortunatelly they don't stop me from using binos - and the difference to mono is day and night like often



#39 clivemilne

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Posted 22 October 2020 - 07:05 AM

 I just wonder if someone who has one of these monsters, would like to comment on the views that these things give.

 It's interesting...

 

The real advantage of large Newtonian binoculars under a pristine sky is seldom expressed in a way that truly conveys it.

 

It's not so much that you see more (quantitative)

 

Rather, it is qualitative...  it's the difference between seeing Niagara Falls on a movie screen

versus standing on the river edge feeling the rumble in your bones and the fine mist on your face.

 

It becomes real, you are there, in space, staring out of a porthole window...

 

I recall comparing my 20" bino's to a friend's 25" mono.  

There really wasn't much difference in how much you could see.

In all fairness, the 25" probably just had a slight edge, even so... the only thought that entered my head was:   Hmmm, maybe I need to build a bigger bino.

 

Basing your decision wrt large bino's on advice from people who can't achieve stereopsis

is like asking a deaf man about HIFI.

 

~c


Edited by clivemilne, 22 October 2020 - 07:20 AM.

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#40 salico

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Posted 22 October 2020 - 07:09 AM

true, it's hard to discribe, if you don't see it - when I close one eye while using one of my BTs it feels like the magic is gone



#41 Charles Funk

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Posted 22 October 2020 - 08:36 AM

I was at a star party once where one of those JMI reverse scope/binos were setup. The 3D view of M8 still haunts me to this day. Magnificent!


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#42 TOMDEY

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Posted 22 October 2020 - 09:43 AM

Interesting Discussion!

 

There are myriad good reasons to opt for mono: Debilitating physical restrictions are high on the list. Difficulty or impossibility merging one's eyes is certainly front and center. Those personals are the three angular accommodations of convergence, divergence and the two dipvergences ( ˃˂ , ˂˃ , ˄˅, ˅˄ ). The JMI RBs motorized push-button controls effortlessly finesse those in while looking. Then there's the lateral accommodation of IPD, which we here are quite familiar with (why ~regular~ binos have that hinge). And uncorrected personal near or farsightedness, which is the familiar (left and right) focus knobs or buttons. And uncorrected personal astigmatisms (magnitudes and clockings) which we can correct with two Dioptrx, Lasik, PRK, or eye lens implants. Note that all of those are addressable, but at the expense of time and money. The surgeries are the gold standard repairs, but involve some minor risk for those life-altering improvements. My brother terribly scratched his right cornea, a few years ago. He just left it that way because he fears surgery. He often covers that eye "to see better". Friends shrug and wink.    Tom

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#43 PEterW

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Posted 22 October 2020 - 11:20 AM

The image is much calmer and fainter stars are visible with two eyes. Massive scopes just change the image scale (which can help the vsisjbility depending on the apparent angular size), but exit pupil is an important point. Same exit pupil, same brightness (for extended objects). Mel bartels operates a one eyepiece many scopes approach keeping the exit pupil the same. He’s moving to binocukars now.

Peter

#44 Mitrovarr

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Posted 22 October 2020 - 02:57 PM

and that 25" dob, 6" AP refractor, 20x60 zeiss IS, 22x60 Tak astronomers, and many others

frown.giffrown.gif


People forget how rare some of this equipment actually is. In 20+ years of this and going to many star parties, I'm not sure I've ever seen a Takahashi of any kind. Definitely never looked through one. I think I've see one Astro-Physics scope, a 6" I actually got to look through (no planets though, so it didn't leave much of an impression). I have gotten to look through huge dobs, thankfully.

Our club seems to be very newt and SCT focused. Lately though people are starting to go more to refractors so we actually have some showing up to star parties (including my own SW150ED).

#45 dustyc

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Posted 22 October 2020 - 07:05 PM

Every time I have an eye exam I'm reminded about why I like using binoculars. Taking the chart test with left eye then right eye always is difficult. Then the doc says to read with both eyes, "ah that's better", and I can fire off the letters more confidently too. 

There's always the scope cost factor (2 of everything), but the satisfaction always seems to be worth it. 

 

Kinda like listening to surround sound, much more satisfying than stereo, but ya need 5 of everything! 



#46 Tyson M

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Posted 22 October 2020 - 07:24 PM

Is JMI still in business? I might be interested in either the RB10 or even 16 sometime for my darksite. Not sure exactly when though, as I'd like an observatory that could house it first.

#47 TOMDEY

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Posted 22 October 2020 - 08:00 PM

Is JMI still in business? I might be interested in either the RB10 or even 16 sometime for my darksite. Not sure exactly when though, as I'd like an observatory that could house it first.

The site is there, but it points you to Farpoint. I get the feeling that the JMI RB's are no longer being built... but you might as well call and ask. I believe the RB-66 (six inch) were produced at least a few at a time... but seemed like the bigger ones were made to order. I have no idea how many big ones are out there in the field... probably only a few. It does indeed seem to be a very limited interest market --- in the sense that piles of amateur astronomers imagine how nice it would be --- but are reluctant to build or pay for the really giant binos. Similarity: There are plenty of 4-inch (45o and 90o) Astro Binos out there... but precious few 6-inchers. The cost precipice seems to be a few $K. As much as amateurs want giants... it is the cost that they choke on... and then explain that they really didn't want them anyway... too heavy, too awkward, etc. But it's really the price.    Tom


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#48 Dave Mitsky

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Posted 22 October 2020 - 09:45 PM

FINAL TRANSFER
At the end of July, 2018, Farpoint / Optical Structures, Inc. (OSI) will assume production of all JMI MOTOFOCUS and MOTODEC products. Therefore, Jim's Mobile will be accepting new orders only until 5:00 pm Mountain Daylight Time on Monday, July 23.  This will complete the transfer of JMI products to Farpoint Astro.

 

AFTER 5:00 pm MDT on Monday July 23, 2018
ALL ORDERS FOR JMI PRODUCTS
SHOULD BE DIRECTED TO FARPOINT ASTRO.
(See information below)

 

Jim's Mobile will continue to manufacture and sell the
Reverse Binocular Telescope.

 

http://www.jimsmobile.com/


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#49 ihf

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Posted 22 October 2020 - 10:38 PM

As much as amateurs want giants... it is the cost that they choke on... and then explain that they really didn't want them anyway... too heavy, too awkward, etc. But it's really the price.    Tom

I always wondered, why are rich people not interested in binoculars? Is it that they can't enjoy the simple pleasures with their refined tastes?



#50 TOMDEY

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Posted 22 October 2020 - 11:42 PM

I always wondered, why are rich people not interested in binoculars? Is it that they can't enjoy the simple pleasures with their refined tastes?

Oh, they're out there, alright, but they make a point of not bragging about it. At a certain astronomical price-point, the (admittedly few) buyers commission custom builds, with the contractors sworn to secrecy. Word more often leaks out on such expected bobbles as jewelry, clothing, cars, yachts, houses... but not telescopes... even though some astonishing toys are out there and being enjoyed. B&L produced some magnificent one of a kind custom hobby telescopes and microscopes for private customers in the early years.

 

Hypothetical example: Suppose you were some notable TV mogul, interested in astronomy, and wanted a nifty 36-inch Maksutov Telescope in a dome at your remote vacation estate. Would you brag about it, or just modestly admit to your aw shucks little commercial scope? Hard to imagine, but there is a level at which they choose to not flaunt their toys.    Tom


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