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guangtou
sage
Reged: 03/27/10
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Re: Stiff Necks and the Zenith
[Re: Jim Davenport]
#5694107 - 02/22/13 07:23 AM Attachment (18 downloads)
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The hardest part about using a tripod with straight through binoculars to look at the zenith is my neck won't go back 90 degrees. The second hardest part is the tripod gets in the way. One way to overcome the second part is to use a combination of panhead, 410 geared head and ball head to achieve anough distance from the tripod.
As far as overcoming the first part, I suspect that persistence in contorting yourself this way will either break your neck (at which point 90 degrees will be no problem) or convince you that the way to look at the zenith with such binoculars is either lying down on a blanket or sitting in an anti-gravity chair.
Edited by guangtou (02/22/13 07:32 AM)
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Don M
super member
Reged: 10/12/08
Loc: Roseau, Minnesota
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Re: Stiff Necks and the Zenith
[Re: daniel_h]
#5694211 - 02/22/13 08:50 AM
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i can get to 80deg ok with my P-mount...who wants to look directly overhead at scorpio/sagittarius in the cool of winter anyway?? 
oops my bad - i forgot they are low down for you guys
Remember - with continental drift that is going to change!!
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Sarkikos
Postmaster
   
Reged: 12/18/07
Loc: Suburban Maryland, USA
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Re: Stiff Necks and the Zenith
[Re: Don M]
#5694241 - 02/22/13 09:09 AM
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I can't wait that long.
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Jon Isaacs
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Reged: 06/16/04
Loc: San Diego and Boulevard, CA
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Re: Stiff Necks and the Zenith
[Re: GlennLeDrew]
#5694251 - 02/22/13 09:19 AM
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One aspect of this configuration to bear in mind, particularly if desiring to obtain wide fields with 2" eyepieces, is the need to employ a larger diagonal in the 'under' tube. This might require a 2.6" m.a., certainly not a 'standard' 2" diagonal, for shorter f/ratio objectives.
I am thinking if I use a short drawtube, a moderate focal ratio and limit the range of focus, it all should work with 2 inch diagonals which have about 42mm-44mm of clear aperture. The big optical disadvantage of this configuration is that the images are reversed right to left, for commercial use, this is probably unacceptable. For me, I prefer it...
This is a retirement project, probably start with ST-80s, if that works satisfactorily, then move on to the Orion 100mm F/6...
Here is a way out there design... totally asymmetrical.. I wonder if anyone has ever done this.. I am strongly left eye dominant, that is probably one reason I am more interested in mono-vision than bino-vision. How about binoculars with full aperture on one side, reduced aperture on the other side, just to provide that eye with something to look at... Say an 80mm F/6 on one side, a 40mm F/12 on the other...
Jon
Edited by Jon Isaacs (02/22/13 09:25 AM)
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Andresin150
Pooh-Bah
Reged: 08/14/07
Loc: Bogotá - La Calera / Colombia
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Re: Stiff Necks and the Zenith
[Re: Sarkikos]
#5694272 - 02/22/13 09:29 AM
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I like the idea of using 90 deg diagonals, but not too much of using 2" size. In my experience, 2" eps are just too fat to accomodate my eyes comfirtably. I remember that the Chinese 150bt was only comfortable when using the 1 1/4" Denkmeier eps. The big Fujis are just on the limit of ep fatness I can take, and also they have acceptable long er (the 40x not so much but acceptable). Thats why I declined in buying the Ethos at that time... And thats why I've been interested in the Delos and their long ER, (the Naglers have also short ER for bino viewing, of course all are excellent for mono..) The Docter EPs are incredibly comfortable, thin enough for all users and everyone should be able to see the whole Fov, if I where on a project such as Glen's, thats the eyepieces I'll consider...
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Vondragonnoggin
Post Laureate
   
Reged: 02/21/10
Loc: Southern CA, USA
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Re: Stiff Necks and the Zenith
[Re: Andresin150]
#5694285 - 02/22/13 09:36 AM
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Aggghh, some of these pics in this thread make my neck ache just looking at them. Realistically speaking for me, if straight through bins, it is max 45 degree and for short runs. Anything higher and I'm reserved to several minutes max. Loungechair almost flat is great. My 90 degree bins are great.
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Jon Isaacs
Postmaster
   
Reged: 06/16/04
Loc: San Diego and Boulevard, CA
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Re: Stiff Necks and the Zenith
[Re: Andresin150]
#5694369 - 02/22/13 10:17 AM
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In my experience, 2" eps are just too fat to accomodate my eyes comfirtably.
I agree most are.. that is why I specified the 32mm TV Widefield. It's not the 35mm Panoptic or the 31mm Nagler but it provides quite pleasing widefield views and is 55mm in diameter which means with careful design, about anyone could use it.
The other reason to use 2 inch diagonals is that they can be further down the optical path because of their greater clear aperture, less vignetting than with 1.25 inch diagonals.
Jon
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Mr. Bill
Postmaster
   
Reged: 02/09/05
Loc: Northeastern Cal
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Re: Stiff Necks and the Zenith
[Re: GlennLeDrew]
#5694488 - 02/22/13 11:25 AM
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A fellow at the Golden State SP last year saw my BinoBox and showed me his over/under design using 5 inch Jeager objectives.
If I hadn't already built my side by side, I would seriously consider this design alternative. The main issue would be an adjustable IPD.
OBTW, my BinoBox is featured in the April S&T Telescope Workshop column....I received a copy of the article from a fellow in Europe. I guess they get early delivery since my issue hasn't shown up yet.
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hallelujah
Post Laureate
   
Reged: 07/14/06
Loc: Colorado Rocky Mountains
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Re: Stiff Necks and the Zenith
[Re: Mr. Bill]
#5694574 - 02/22/13 12:10 PM
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OBTW, my BinoBox is featured in the April S&T Telescope Workshop column....I received a copy of the article from a fellow in Europe. I guess they get early delivery since my issue hasn't shown up yet.
http://www.garyseronik.com/?q=node/208
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Special Ed
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Reged: 05/18/03
Loc: Greenbrier Co., WV 38N, 80W
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Re: Stiff Necks and the Zenith
[Re: Tony Flanders]
#5695686 - 02/22/13 09:34 PM
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I found that viewing objects close to the zenith was more confortable using a p-gram mount. The pic is from Green Bank StarQuest 4 ....
That kind of parallelogram mount helps me not at all. It lets you move your chair back away from the tripod, but you still have to bend your neck exactly the same as if you were sitting under the tripod.
My UniMount is another story. Because that allows viewing at right angles to the p-gram arm, it makes it possible to view from a reclining chair in perfect comfort. The downside is that it's more cumbersome to carry around than a mid-sized telescope.
Tony,
Backing away from the tripod legs is a good thing which makes the p-gram mount part of the solution.
If you want to view near the zenith in comfort, the unimount system is one excellent solution. The amount of gear to deal with is an individual judgement.
My astronomy experience (and I'm sure yours, too) requires a certain amount of contortionism at least some of the time. If you don't want to bend your neck to view near the zenith, the only alternative is to lay on your back.
My most confortable zenith observing (by far) includes an anti-grav chair and image stabilised binoculars.
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Mr. Bill
Postmaster
   
Reged: 02/09/05
Loc: Northeastern Cal
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Re: Stiff Necks and the Zenith
[Re: Special Ed]
#5696525 - 02/23/13 12:35 PM
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I think Tony's technique of leaning back with a tripod is probably the simplist effective way of using small straight through binoculars while observing near the zenith.
I use a p-mount which is another level of equipment to fiddle with.
Lately, I've enjoyed my mirror mount shown on an earlier post.
Lots of options...
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