Mr. Bill
Carpal Tunnel
Reged: 02/09/05
Posts: 2748
Loc: Just passing through.....
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Well, the Vixen 125s are now available; here is the issue.
BT100s with 24 Pan eyepieces....25x with a 68 degree afov and a 2.7 degree real fov and 4mm exit pupil.
Vixen 125s with 24 Pan eyepieces....31.7x with a 68 degree fov and a 2.145 degree real fov and a 4mm exit pupil.
BT100s....$1500 vs $3699 for the Vixen binoculars OTA.
Hummmm.....oh yeah, I already have the BTs.
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10x50 Fujinon FMT-SX binos
15x70 AP binos + Paragon p-mount
Oberwerk 100BT 45 degree + Hercules fork mount
120mm f/5 Orion achromat + Moonlite focuser
140mm f/5.7 Vixen NeoAchro Petzvel refractor
150mm f/6.5 Antares achromat
150mm f/8 homemade achromat....EE Barnard MW Sweeper
8 inch newt with f/5 Swayze mirror
10 inch f/4.7 Orion newt + Paracorr
15 inch f/5 Discovery split tube
35mm Pan, 26mm Nagler, 17mm Nagler, 13mm Ethos, 8mm Ethos
Member IDA
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Joad
Wordsmith
Reged: 03/22/05
Posts: 11900
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Realizing that this is a purely subjective question, I can give you my personal opinion (and opinion all it is): I do not think it is worth the cost. For one thing, I think the solid body, single housing on the BTs produces a more reliable collimation. I own the BT100 and find the dark sky, low power views I use it for are very satisfying, even without Panoptics. With Pans the views must be better still.
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Mr. Bill
Carpal Tunnel
Reged: 02/09/05
Posts: 2748
Loc: Just passing through.....
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The 24 Pans converted a somewhat mediocre binocular with the included eps into a very flat edge correction that complements the triplet objective.
Dare I utter....flatter (and better edge corrected) fov than my 6 inch Fujinons....
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10x50 Fujinon FMT-SX binos
15x70 AP binos + Paragon p-mount
Oberwerk 100BT 45 degree + Hercules fork mount
120mm f/5 Orion achromat + Moonlite focuser
140mm f/5.7 Vixen NeoAchro Petzvel refractor
150mm f/6.5 Antares achromat
150mm f/8 homemade achromat....EE Barnard MW Sweeper
8 inch newt with f/5 Swayze mirror
10 inch f/4.7 Orion newt + Paracorr
15 inch f/5 Discovery split tube
35mm Pan, 26mm Nagler, 17mm Nagler, 13mm Ethos, 8mm Ethos
Member IDA
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OpalescentNebula
member
Reged: 01/11/07
Posts: 52
Loc: Calgary, Alberta
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Why not sell the BT's & buy the Oberwerk 45 deg 120mm binoculars for $2095
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Yours truly,
Bill
"Good friends are like stars...you don't always see them, but you know that they are always there" - unknown
Binos : Zeiss 10x42 FL, Garrett Optical 20x110
telescope: WO Megrez 110 ED
Eyepieces: 13mm Ethos, 5mm Pentax, 28mm WO
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Mr. Bill
Carpal Tunnel
Reged: 02/09/05
Posts: 2748
Loc: Just passing through.....
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My understanding is the 120s use the same prisms so there is some question with the 120s of illuminated edge drop off....
Another issue is the weight of the 120s....38 pounds vs. 24 pounds for the 125s.
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10x50 Fujinon FMT-SX binos
15x70 AP binos + Paragon p-mount
Oberwerk 100BT 45 degree + Hercules fork mount
120mm f/5 Orion achromat + Moonlite focuser
140mm f/5.7 Vixen NeoAchro Petzvel refractor
150mm f/6.5 Antares achromat
150mm f/8 homemade achromat....EE Barnard MW Sweeper
8 inch newt with f/5 Swayze mirror
10 inch f/4.7 Orion newt + Paracorr
15 inch f/5 Discovery split tube
35mm Pan, 26mm Nagler, 17mm Nagler, 13mm Ethos, 8mm Ethos
Member IDA
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Rich V.
scholastic sledgehammer
Reged: 01/02/05
Posts: 967
Loc: Carson Valley, Nevada USA
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Sounds like you might be looking into the land of diminishing returns.
Since you've already had 150mm bins, is it worth 2.5x the price for the 56% greater light gathering of the 125s over your 100s?
Would the larger exit pupil be that much better for the types of objects you view?
Would a minimum of 32x instead of 25x bother you?
How's the CA with the 125mm f6 achro objective? I suspect it will be more than your 100s.
Can the Vixens be "collimated" by the user?
The Vixens weigh about the same as your BT100s; a plus.
Myself, I'm happy with 33x100 with a 66° AFOV / 2° FOV / 3mm exit pupil with my relatively dark skies but I've never looked through 125mm or larger bins. Maybe I don't know what I'm missing!
Good luck with your choice,
Rich V
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Binoculars:
33-150x100 Saturn III, 16x70FMT-SX, 10x50 PCF-V, 10x43 DCF-SP, 10x35 E2, 7x35 E, 8x30 E2, 7x26 Custom, 8x23AS Diplomat, 8x23 Travelite
Scopes:
C9.25, 6" f8 reflector, SV80S
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Mr. Bill
Carpal Tunnel
Reged: 02/09/05
Posts: 2748
Loc: Just passing through.....
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Quote:
Sounds like you might be looking into the land of diminishing returns.
Would the larger exit pupil be that much better for the types of objects you view?
Would a minimum of 32x instead of 25x bother you?
How's the CA with the 125mm f6 achro objective? I suspect it will be more than your 100s.
Can the Vixens be "collimated" by the user?
The Vixens weigh about the same as your BT100s; a plus.
Myself, I'm happy with 33x100 with a 66° AFOV / 2° FOV / 3mm exit pupil with my relatively dark skies but I've never looked through 125mm or larger bins. Maybe I don't know what I'm missing!
Good luck with your choice,
Rich V
Same exit pupil....4mm for both the 125s and the BT100s; that's the rub (they're both f/6). The magnification is what changes.
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10x50 Fujinon FMT-SX binos
15x70 AP binos + Paragon p-mount
Oberwerk 100BT 45 degree + Hercules fork mount
120mm f/5 Orion achromat + Moonlite focuser
140mm f/5.7 Vixen NeoAchro Petzvel refractor
150mm f/6.5 Antares achromat
150mm f/8 homemade achromat....EE Barnard MW Sweeper
8 inch newt with f/5 Swayze mirror
10 inch f/4.7 Orion newt + Paracorr
15 inch f/5 Discovery split tube
35mm Pan, 26mm Nagler, 17mm Nagler, 13mm Ethos, 8mm Ethos
Member IDA
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edwincjones
Post Laureate
Reged: 04/10/04
Posts: 4363
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Quote:
Well, the Vixen 125s are now available; here is the issue.
BT100s with 24 Pan eyepieces....25x with a 68 degree afov and a 2.7 degree real fov and 4mm exit pupil.
Vixen 125s with 24 Pan eyepieces....31.7x with a 68 degree fov and a 2.145 degree real fov and a 4mm exit pupil.
BT100s....$1500 vs $3699 for the Vixen binoculars OTA.
Hummmm.....oh yeah, I already have the BTs.
Mr Bill,
You will not be happy until you get something as good, or better than the big fujis-go ahead and contact Kevin and see if he can get one more Miyauchi 141. It has better optics, but is lighter than the old binoculars.
you know that I am right, you can buy happiness
edj
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n w arkansas
Binocular, Solar, General Amateur Astronomy
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edwincjones
Post Laureate
Reged: 04/10/04
Posts: 4363
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for everyone else,
my guess is if you did a side by side comparsion of the BT100 and Vixen 125s
the BTs would seem like a very good buy,
the Vixens would seen overpriced,
most would not see "that much" difference.
edj
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n w arkansas
Binocular, Solar, General Amateur Astronomy
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Mr. Bill
Carpal Tunnel
Reged: 02/09/05
Posts: 2748
Loc: Just passing through.....
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Quote:
for everyone else,
my guess is if you did a side by side comparsion of the BT100 and Vixen 125s
the BTs would seem like a very good buy,
the Vixens would seen overpriced,
most would not see "that much" difference.
edj
Pretty much what I think but it's always good to hear it from someone else whose opinion I trust.
I'm also wondering if the edge to edge sharpness of the BTs wouldn't be superior with the third objective lens for field flattening.
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10x50 Fujinon FMT-SX binos
15x70 AP binos + Paragon p-mount
Oberwerk 100BT 45 degree + Hercules fork mount
120mm f/5 Orion achromat + Moonlite focuser
140mm f/5.7 Vixen NeoAchro Petzvel refractor
150mm f/6.5 Antares achromat
150mm f/8 homemade achromat....EE Barnard MW Sweeper
8 inch newt with f/5 Swayze mirror
10 inch f/4.7 Orion newt + Paracorr
15 inch f/5 Discovery split tube
35mm Pan, 26mm Nagler, 17mm Nagler, 13mm Ethos, 8mm Ethos
Member IDA
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zx12
super member
Reged: 12/29/05
Posts: 153
Loc: Rhode Island
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Well, I have had the luxury of looking through both instruments for the last two years side by side and can say without any doubt that for me, the BT 125 is clearly superior to the BT 100.
Here's why:
It is better optically. I have looked through three BT 100's and my particular BT 125 is sharper and shows less color than the BT 100.
The BT 100 is okay on planet viewing, but struggles with mags higher than 75x while the BT 125 easily cruises up to 125x.
There is the slight but noticeable increase in brightness on dim objects.
It has a higher level of fit and finish.
It is lighter by 2lbs and has a better balance.
The tripod and fork are better ergonomically, lighter in weight and are much more user friendly.
It cools down faster.
The eyepiece holders lock the eyepieces in place, which is a plus in cold weather and when using a pair of zooms.
It accepts aperture masks readily. With 100mm masks the performance rivals some of the mid-level apo refractors on the market.
It has held collimation/conditional alignment extremely well and from what I have gathered from fellow CN'r WRose, it is not difficult to adjust if necessary.
The only negatives?
Cost is higher, though it quickly became irrelevant since the BT 125 is my most used piece of equipment.
Focus travel is somewhat limited, but is pretty much a non issue as all of my premium e.p.'s work superbly in the 125.
The longer focal length means a smaller apparent field. I find that a 2 degree field at 32x frames most DSO's perfectly, but this is a subject of personal preference and I have not found that I am missing anything here.
As far as field flatness goes, both perform equally as well given the same eyepieces.
I still like my BT 100, but I love my BT 125.
Was it worth twice the cost? For me, absolutely.
Mike
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AP 160 Starfire/AP 1200GTO
Stellarvue SV809D
Vixen BT 125 HFT-MA
Oberwerk BT 100/45
Tak 22x60 Astronomer
Nikon 10x70 FMT-SX
Leica 8-12x42 Duovid
WO 66mm SD
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Mr. Bill
Carpal Tunnel
Reged: 02/09/05
Posts: 2748
Loc: Just passing through.....
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Thanks for the input Mike...
I guess the real problem is that the best tradeoff in the 1 1/4 eyepiece format for low magnification/apparent and real fov/eye relief is the 24mm Pans. It approaches the maximum 27mm field stop which is all you are going to get.
With an f/6 system (which is what both of these are,) the best you are going to do is a 4mm exit pupil. What I would like is an f/5 system that would give me a 5mm exit pupil which would match my dilated pupil.
I am using binoculars to observe in extremely dark skies and am trying to wring out all I can get in terms of contrast and detecting very faint extended objects.My observing interest is large scale MW structure, especially dark nebulae.
The perfect binocular for this would be 30x150 Fujinons that weigh 26 pounds (instead of 42) which doesn't exist...yet.
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10x50 Fujinon FMT-SX binos
15x70 AP binos + Paragon p-mount
Oberwerk 100BT 45 degree + Hercules fork mount
120mm f/5 Orion achromat + Moonlite focuser
140mm f/5.7 Vixen NeoAchro Petzvel refractor
150mm f/6.5 Antares achromat
150mm f/8 homemade achromat....EE Barnard MW Sweeper
8 inch newt with f/5 Swayze mirror
10 inch f/4.7 Orion newt + Paracorr
15 inch f/5 Discovery split tube
35mm Pan, 26mm Nagler, 17mm Nagler, 13mm Ethos, 8mm Ethos
Member IDA
Edited by Mr. Bill (08/13/08 12:52 AM)
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zx12
super member
Reged: 12/29/05
Posts: 153
Loc: Rhode Island
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I use the 24mm Pan's for most of my low power/wide field viewing, but when I'm searching for really faint extended objects I use a pair of Series 5000 26mm Meade Plossl's.
They Meade's don't perform well in my BT 100's, but are quite impressive in the 125. They are sharp out to 75% from the edge, but have very little pin cushion distortion, and objects just seem to "pop" better in the Meade's.
They also accept filters and still come to focus while many Televue e.p.'s run out of focus travel with a filter.
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AP 160 Starfire/AP 1200GTO
Stellarvue SV809D
Vixen BT 125 HFT-MA
Oberwerk BT 100/45
Tak 22x60 Astronomer
Nikon 10x70 FMT-SX
Leica 8-12x42 Duovid
WO 66mm SD
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Joe Ogiba
Post Laureate
Reged: 02/14/02
Posts: 3342
Loc: NJ USA
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Quote:
I use the 24mm Pan's for most of my low power/wide field viewing, but when I'm searching for really faint extended objects I use a pair of Series 5000 26mm Meade Plossl's.
They Meade's don't perform well in my BT 100's, but are quite impressive in the 125. They are sharp out to 75% from the edge, but have very little pin cushion distortion, and objects just seem to "pop" better in the Meade's.
They also accept filters and still come to focus while many Televue e.p.'s run out of focus travel with a filter.
The Meade 26mm 5000 Plossls work great in my BT80-45's . I removed the eyeguard system from them to fix my nose clearance problem.
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Pentax PF-80ED
Meade 102ED APO
Orion EON 72
120ST
Apex 127
C6 XLT
CR150
C9.25
XT10
Zeiss 7x42 FL
Canon 10x42L IS WP
15x50 IS
12x36 IS II
Garrett Optical 28x110 HD-WP Signature Series
Oberwerk BT-80 45
Apogee RA-88-SA
Denk II Power x Switch binoviewer w/13mm Ethos, 20mm Pentax XW's, 20mm Widescan III's.
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Mr. Bill
Carpal Tunnel
Reged: 02/09/05
Posts: 2748
Loc: Just passing through.....
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Well, I considered TVs 32 Plossl but they only have a 50 degree fov. After using the 68 degree 24 Pans, it would seem like looking through a soda straw. 
Let's see....the 32mm with a 50 degree afov would yield virtually the same real fov as the 24 with a 68 degree afov so that is a wash.
26mm isn't that much different than the 24mms in terms of increasing exit pupil, and the real fov is a wash.
It's really impossible to escape from the constraints of the 1 1/4 inch field stop in terms of the tradeoffs of ep focal length/ eye relief/ fov.
What is really needed is a new class of eyepieces
(and, of course, a new class of binos/binoviewers) especially made for binocular/binoviewer use....say 1 1/2 inch format.
That's what the Fujinon eps on my 150s appeared to be.
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10x50 Fujinon FMT-SX binos
15x70 AP binos + Paragon p-mount
Oberwerk 100BT 45 degree + Hercules fork mount
120mm f/5 Orion achromat + Moonlite focuser
140mm f/5.7 Vixen NeoAchro Petzvel refractor
150mm f/6.5 Antares achromat
150mm f/8 homemade achromat....EE Barnard MW Sweeper
8 inch newt with f/5 Swayze mirror
10 inch f/4.7 Orion newt + Paracorr
15 inch f/5 Discovery split tube
35mm Pan, 26mm Nagler, 17mm Nagler, 13mm Ethos, 8mm Ethos
Member IDA
Edited by Mr. Bill (08/13/08 12:49 PM)
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gaf
member
Reged: 07/13/07
Posts: 35
Loc: Phoenix, Az
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Hi Bill
I have been this thread and read where you thought the prisms in the BT120 were the same size as the BT100. I talked to Kevin at BigBinoculars and he since me these E-mail.
Hi Gary,
No, the BT-120 prisms are actually much larger than the BT-100. The overall width of the BT120 prism is 90mm, the BT-100 is 70mm. See attached pic.
The weights mentioned are correct.
Regards,
Kevin
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gaf
member
Reged: 07/13/07
Posts: 35
Loc: Phoenix, Az
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Sorry about the spelling and missed words.I didn't proof read.
Gaf
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Mr. Bill
Carpal Tunnel
Reged: 02/09/05
Posts: 2748
Loc: Just passing through.....
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Quote:
Hi Bill
I have been this thread and read where you thought the prisms in the BT120 were the same size as the BT100. I talked to Kevin at BigBinoculars and he since me these E-mail.
Hi Gary,
No, the BT-120 prisms are actually much larger than the BT-100. The overall width of the BT120 prism is 90mm, the BT-100 is 70mm. See attached pic.
The weights mentioned are correct.
Regards,
Kevin
Thanks for the info...I was misinformed.
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10x50 Fujinon FMT-SX binos
15x70 AP binos + Paragon p-mount
Oberwerk 100BT 45 degree + Hercules fork mount
120mm f/5 Orion achromat + Moonlite focuser
140mm f/5.7 Vixen NeoAchro Petzvel refractor
150mm f/6.5 Antares achromat
150mm f/8 homemade achromat....EE Barnard MW Sweeper
8 inch newt with f/5 Swayze mirror
10 inch f/4.7 Orion newt + Paracorr
15 inch f/5 Discovery split tube
35mm Pan, 26mm Nagler, 17mm Nagler, 13mm Ethos, 8mm Ethos
Member IDA
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zx12
super member
Reged: 12/29/05
Posts: 153
Loc: Rhode Island
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Your right about the 32mm TV's, they have a confining view compared to the wide field e.p.'s.
I still have my pair for the BT's but they don't see much use.
The closet thing to what you describe seeing in the big Fuji's that I have seen is a pair of 20mm Pentax XW's. In my BT 125 they were sharp and bright with great eye relief. They appeared sharp out to 70-75%.
Unfortunately, they barely came to focus because of the limited focuser travel in the Vixen's. I just could not get myself to machine down the barrels on such high end e.p.'s.
--------------------
AP 160 Starfire/AP 1200GTO
Stellarvue SV809D
Vixen BT 125 HFT-MA
Oberwerk BT 100/45
Tak 22x60 Astronomer
Nikon 10x70 FMT-SX
Leica 8-12x42 Duovid
WO 66mm SD
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Mr. Bill
Carpal Tunnel
Reged: 02/09/05
Posts: 2748
Loc: Just passing through.....
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Quote:
Your right about the 32mm TV's, they have a confining view compared to the wide field e.p.'s.
I still have my pair for the BT's but they don't see much use.
The closet thing to what you describe seeing in the big Fuji's that I have seen is a pair of 20mm Pentax XW's. In my BT 125 they were sharp and bright with great eye relief. They appeared sharp out to 70-75%.
Unfortunately, they barely came to focus because of the limited focuser travel in the Vixen's. I just could not get myself to machine down the barrels on such high end e.p.'s.
Still only 20mm....would only yield a 3.3mm exit pupil with f/6 optics. Going the wrong direction for brightest possible fov. Also, I estimate that the 24 Pans are sharp out to about 90%, so no advantage there for the XWs.
Doing the math, to yield 25x with a 6 inch f/5 optic (750mm) it would require a 30mm eyepiece. This is with a 68-70 degree afov and eye relief I estimated to be about 15mm usable (claimed 18.6) This is clearly not possible with the 1 1/4 inch (27mm max field stop) eps available in the market today.
The oculars on the 150 barely fit between the bridge of my nose which is not abnormally wide and my IPD of 64, so that tells you something of the size of the eyepieces on the Fuji 150....not 2 inch but definitely 1 1/2 or larger.
--------------------
10x50 Fujinon FMT-SX binos
15x70 AP binos + Paragon p-mount
Oberwerk 100BT 45 degree + Hercules fork mount
120mm f/5 Orion achromat + Moonlite focuser
140mm f/5.7 Vixen NeoAchro Petzvel refractor
150mm f/6.5 Antares achromat
150mm f/8 homemade achromat....EE Barnard MW Sweeper
8 inch newt with f/5 Swayze mirror
10 inch f/4.7 Orion newt + Paracorr
15 inch f/5 Discovery split tube
35mm Pan, 26mm Nagler, 17mm Nagler, 13mm Ethos, 8mm Ethos
Member IDA
Edited by Mr. Bill (08/13/08 07:57 PM)
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