RE: [Utah-astronomy] 25x100mm binos
I own a pair of Celestron 25x100's but I never use the silly things because not even my heaviest-duty camera tripod can keep them steady. I've seen parallelogram-type mounts, but they all have maximum weight capacities that are less than the weight of the 25x100 monsters. How do you guys manage these things? Why is just one of them called a "pair of binoculars" and I'm forced to speak of them in the plural? Wouldn't it make more sense to call them a "pair of monoculars?" Just grousing. I really do want to know how big-bino owners manage to use theirs. $170 sounds like a screamin' deal. Maybe the money you save on them can go towards a monster tripod & mount. Seth -----Original Message----- From: utah-astronomy-bounces+sjarvis=slco.org@mailman.xmission.com [mailto:utah-astronomy-bounces+sjarvis=slco.org@mailman.xmission.com] On Behalf Of Chuck Hards Sent: Thursday, October 05, 2006 5:18 PM To: Utah-Astro Subject: [Utah-astronomy] 25x100mm binos Fotar binos (same as Celestron, Apogee) on-sale for $169.99: http://www.heartlandamerica.com/browse/item.asp?product=fotar-25-x-100-binoc ulars&PIN=38295&GUID=E78F6819-F4D7-412A-B921-46B9FDE9D925&BC=S&DL=SEH8 Shipping charges extra. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.utahastronomy.com
Hi Seth (et al): I've never seen a commercial parallelogram that I liked, therefore I build my own. I think I still have a photo of my latest "heavy-duty" unit on my Gallery page, if you care to look it up. It's an in-progress shot but you can get the idea. Designed specifically for the 25x100mm heavy monsters. Utilizes Dobsonian technology. The other shots on my Gallery page show my standard parallelogram which holds up to 80mm units comfortably. The maple unit is my favorite for mid-size binoculars. My biggest gripes on commercial units are those with too-short arms, so they can't be used sitting or reclining unless the tripod is shortened first, and units that only pan by rotating the entire arm assembly around the central tripod pivot. One does a lot of walking in circles with these designs. My designs address both of these shortcomings. The longer arms I use also allow a huge range for height differeces in observers- a great star-party advantage when you may have folks that are 6'-4" alongside some kids that may only be just over 3' tall. Having designed and built both metal and wood parallelograms, I now prefer wood for it's vibration-damping qualities and less icy touch in winter. I am unaware of a commercial parallelogram executed in wood. A "pair of binoculars" is one of those incorrect terms that just made it into the common parlance. I try to use the word "binocular" when talking about a single unit, "binoculars" when talking about the devices as a class of optical instruments, but being not of a highly-practiced accademic demeanor, can sometimes slip. Having troubles with Yahoo today, sorry if this reply is incomplete but it represents multiple attempts to send. Grrr... --- Seth Jarvis <SJarvis@slco.org> wrote:
I own a pair of Celestron 25x100's but I never use the silly things because not even my heaviest-duty camera tripod can keep them steady.
I've seen parallelogram-type mounts, but they all have maximum weight capacities that are less than the weight of the 25x100 monsters.
How do you guys manage these things?
Why is just one of them called a "pair of binoculars" and I'm forced to speak of them in the plural? Wouldn't it make more sense to call them a "pair of monoculars?"
Just grousing. I really do want to know how big-bino owners manage to use theirs.
$170 sounds like a screamin' deal. Maybe the money you save on them can go towards a monster tripod & mount.
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--- Seth Jarvis <SJarvis@slco.org> wrote:
I own a pair of Celestron 25x100's but I never use the silly things because not even my heaviest-duty camera tripod can keep them steady. <snip> How do you guys manage these things?
Bino uberobserver Edz has a good article covering mounts for big binos at Cloudynights.com http://cloudynights.com/item.php?item_id=1344 My experience with 20x70s and a homemade parallelogram mount is that for low-end wood parallelograms, 20x80 is near or over the limit. Even then, a standard base tripod has to be a beefy Bogon or a true astronomical tripod. As a safety anti-tipping precaution, I also lean a sandbag against one of the tripod's feet. The industry solution for 20x100s of having the vertical post mount directly off the tripod doesn't work for astronomical use. It's okay for birding. Most peope have to crowd and stradle the tripod in an uncomfortable neck position. You can get to the bino 30-45 alt degree observing zone, but maintaining it for relaxed astronomical observing just doesn't cut it. Above that, you are looking at a $300 industrial grade metal parallelogram like at Unimount: http://www.bigbinoculars.com/unibasic.htm http://www.bigbinoculars.com/unimount.htm or a more reasonably price-point solution ($100) with a Scopestuff cradle but that has less flexibility in motion: http://www.scopestuff.com/ss_binm.htm My own evolution along these lines was to go to 20x70s with a Bogan tripod, a camera light boom-arm - http://focuscamera.com/prods/964590366.asp - with a precision slow-motion adapter. http://www.telescope.com/shopping/product/detailmain.jsp?itemID=141&itemType... - and a red dot finder: http://members.csolutions.net/fisherka/astronote/observed/Glptst/binos1B.jpg I also have a homemade wood parallelogram. http://members.csolutions.net/fisherka/astronote/observed/Glptst/tripod1.jpg The Bogan boom arm on a swivel head is a not flexible compared to a swivel parallelogram for quickly changing between observers of a differing height in or making wide swings across the sky. But for solo observing, the fine motion adapter head was by far the best $25 I've spent when coupled with the straight bar. It allows you to smoothly track an object for about 15-20 minutes. I doubt the Orion fine motion adapter is beefy enough to handle 100mm bino. The boom arm solution seems near its limit at 20x80mm. I wouldn't expect it to work on 25x100 bino. By this point, I was into it total for $300-400. Two seasons of that exhausted the limits of the bino setup. I was debating whether to upgrade to an astronomical binocular with a 45 deg angle tilt and interchangable eyepieces (to get a range of magnification) mounted in a Scopestuff cradle. The economics of the whole thing stopped making sense relative to the price point of buying a telescope with the a binoviewer. That being said, I still use the 20x70 parallelogram binos along with a telescope. It is useful to have the binos to quickly survey at target field in a wide TFOV in direct view, before star hopping the telescope over to the target. In a group setting, it gives visitors something to do while I am retargeting the scope. - Kurt __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
I suppose it depends on how you define "low end". Without changing the design much, careful choice of materials and attention to details can make a huge difference in both load capacity and performance. I use 1" diameter aluminum tubing with a 1/8" thick wall for my aluminum parallelogram, but a square section of 1-1/8" for my maple parallelogram. The aluminum tube is weakened considerably more by drilling holes for pivot bolt bearings (nylon inserts), than the wood arms. The net result is a lower capacity in terms of weight. A 1/8" overall increase in sectional dimension doesn't sound like much, but the capacity of the maple parallelogram is about 3 times the capactiy of the aluminum one. There's a lot of wood there, and it's strong. My 3-arm parallelogram (which incidentally incorporates a horizontal offset between upper and lower arms, just like my 2-arm design) uses wood arms of a 1-3/8" section. Three arms in a triangle arraingement means that the entire arm assembly is much stiffer in every dimension, than a two-arm assembly. Hardwoods such as maple, oak, and ash are terrifically stronger under both bending and torsional loads than pine, fir, or alder, softwoods typically used by the do-it-yourselfer. My 2-arm maple design holds my 20x80mm units just fine. If I shortened the arms by about 10 inches I'd consider mounting the 100mm units, but not as-is. Most commercial parallelograms use off-the-shelf square extruded aluminum tubing of relatively thin wall. All plates and brackets are similarly made from thin gauge material for ease of fabrication and low cost. The kinematics may sometimes be clever, but the excecution is always insufficient for larger binoculars. The large bino mounts that are substantial enough for heavy loads have ergonomic problems, as Kurt pointed out. Another drawback of all the commercial units is the small diameter of the central azimuth bearing. I use a large, 7" diameter base with Teflon-on-Ebony Star as a central pivot on the 3-arm unit, a 2" diameter on the 2-arm unit. I realize that most people are locked-into having to choose a commercial product- but realize that most of the commercial parallelogram offerings are the results of a cottage industry. I haven't sold any complete parallelograms or kits of the 100mm, 3-arm design- I wanted to use it for a year or so before doing so, but perhaps I can skip the waiting period if there is enough interest. I've never built astronomical items as a business enterprise for profit- my only motivation has always been to just enable certain folks, and keep my hobby self-supporting. I have most of the parts done for a second unit, maybe I can finish it in the next few weeks if someone wants to test drive it this winter? All it needs is a set of 3 tripod legs. Bill Vorce (Telescope Warehouse) sells Meade tripod legs that should suffice. --- Canopus56 <canopus56@yahoo.com> wrote:
My experience with 20x70s and a homemade parallelogram mount is that for low-end wood parallelograms, 20x80 is near or over the limit.
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--- Chuck Hards <chuckhards@yahoo.com> wrote: <snip>
Without changing the design much, careful choice of materials and attention to details can make a huge difference in both load capacity and performance. <snip> The large bino mounts that are substantial enough for heavy loads have ergonomic problems, as Kurt pointed out.
It's the eccentric load that's the killer. I suspect Seth has probably put his 100s on the Orion parallelogram mounts sold by the planetarium and found it to have too high a settling time, if not difficultly in maintaining a firm clasp on heavier 100s in all positions. The UA cradle "U" mount design tries to solve the eccentricity problem for larger binos by holding the weight off to one side, but still close to the central post. The other design solution is to simply make the whole thing beefier, as you do, Chuck. Here's some photos of a beefier parallelogram bino mount that may interest you: http://www.astro-tom.com/projects/binocular_mount.htm - Kurt __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
Here is the solution to your binocular problems. I think the seat and springs are optional. With the right trailer hitch you could haul this anywhere. http://www.jimsmobile.com/images/rb16_prototype1.jpg Quoting Canopus56 <canopus56@yahoo.com>:
--- Chuck Hards <chuckhards@yahoo.com> wrote: <snip>
Without changing the design much, careful choice of materials and attention to details can make a huge difference in both load capacity and performance. <snip> The large bino mounts that are substantial enough for heavy loads have ergonomic problems, as Kurt pointed out.
It's the eccentric load that's the killer. I suspect Seth has probably put his 100s on the Orion parallelogram mounts sold by the planetarium and found it to have too high a settling time, if not difficultly in maintaining a firm clasp on heavier 100s in all positions. The UA cradle "U" mount design tries to solve the eccentricity problem for larger binos by holding the weight off to one side, but still close to the central post.
The other design solution is to simply make the whole thing beefier, as you do, Chuck.
Here's some photos of a beefier parallelogram bino mount that may interest you:
http://www.astro-tom.com/projects/binocular_mount.htm
- Kurt
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I know this is tongue-in-cheek, Guy- it's way out of my league, budget-wise. But a fellow actually did mount twin 8-inch Newtonians on a chair some years ago. It was a featured article in either Amateur Astronomy or ATM Journal; I can't recall which one at this point. And his chair was completely powered, using the guts of two battery-powered drills. The twin truss-tube approach fails near the zenith, as room for the observers body quickly diminishes. "Dobsons hole" strikes again. Remember that binocular telescopes are not the "ultimate binocular" in as much as the FOV is way too small and magnification way too high for RFT viewing. Generally speaking, the larger the aperture, the longer the focal length- you tend to lose the wide-field, low-power aspect in a hurry. But it would be fun to test drive one of those big suckers for a weekend, wouldn't it? --- diveboss@xmission.com wrote:
Here is the solution to your binocular problems. I think the seat and springs are optional. With the right trailer hitch you could haul this anywhere.
http://www.jimsmobile.com/images/rb16_prototype1.jpg
Quoting Canopus56 <canopus56@yahoo.com>:
--- Chuck Hards <chuckhards@yahoo.com> wrote: <snip>
Without changing the design much, careful choice of materials and attention to details can make a huge difference in both load capacity and performance. <snip> The large bino mounts that are substantial enough for heavy loads have ergonomic problems, as Kurt pointed out.
It's the eccentric load that's the killer. I suspect Seth has probably put his 100s on the Orion parallelogram mounts sold by the planetarium and found it to have too high a settling time, if not difficultly in maintaining a firm clasp on heavier 100s in all positions. The UA cradle "U" mount design tries to solve the eccentricity problem for larger binos by holding the weight off to one side, but still close to the central post.
The other design solution is to simply make the whole thing beefier, as you do, Chuck.
Here's some photos of a beefier parallelogram bino mount that may interest you:
http://www.astro-tom.com/projects/binocular_mount.htm
- Kurt
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--- diveboss@xmission.com wrote:
Here is the solution to your binocular problems. I think the seat and springs are optional. <snip>
Yeah, Guy. Like we wouldn't have to beat you back from the eyepiece with a baseball bat if one of us owned this RB16 Jimi. -:) http://www.jimsmobile.com/images/rb16_prototype2.jpg A more elegant composite truss design solution: http://www.foothill.net/~sayre/22-in.%20binocular%202.htm - Kurt __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
Larger bearing diameters can help the damping-time issue a lot, even with undersized arm sections or an undersized unit in general. --- Canopus56 <canopus56@yahoo.com> wrote:
Here's some photos of a beefier parallelogram bino mount that may interest you:
http://www.astro-tom.com/projects/binocular_mount.htm I've seen this one. Again the problem is an out-of-balance condition with the binocular yoke itself- eccentric loads lateral to the plane of the parallelogram. He uses four arms, but as the bino swings from one side of the arm to the other, the whole assembly can twist. I avoided this with a 3-arm arraingement- a triangle is much more resistant to torsional loads than a rectangle. I'm winterizing the house and yard this week, as well as painting a couple of rooms, but as soon as I get the domestic projects out of the way, I'll post some good parallelogram shots on my Gallery page. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
participants (4)
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Canopus56 -
Chuck Hards -
diveboss＠xmission.com -
Seth Jarvis