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Old 03-06-2011, 08:00 PM
Giorgio
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Zhumell Tachyon 25x100 binoculars

Hi

I'm selling a Zhumell Tachyon 25x100 binocular I bought 2 months ago directly from Zhumell in USA (shipped to me by FedEx). Because I bought them directly from Zhumell, it benefits from Zhumell 25-year no-fault warranty, although right now I'm not sure if this warranty can be transfered to you, have to find it out.


I believe this binoculars doesn't have collimation issues (please read my post below in this thread for the explanation).
I see everything in focus edge to edge. Moreover, I don't think there are color aberration issues, but as I never seen one, I can't honestly say about it.

The only details that don't allow me declaring it in perfect conditions are:
* A couple of very small scratches on the aluminum tripod adapter.
* A little bump on one edge of the aluminum hard case the case, that comes with this binocular.
* Inside the hard case, there is a depression, caused by the tripod mount. It was already there and I guess it was required to fit this bino in a case that clearly is not made just for this model.

NOTE That I thought was a tiny scratch on the left front lens, turned out to be just some dirt hence I removed it as one of this bino minus.

This model has the same identical tech specs of the 25x100 binos sold under several brands (eg 1, 2, 3). They all comes from the same few specialized Chinese factories in the Yunnan province (have a look here 1, 2, 3).

I'm regretfully selling it for buying a dob. The view of night sky with this binocular are excellent for deep sky object up to magnification 8, although mag 6 to 8 are very feint. That's why I now need a dob...

You will definitively need a very sturdy tripod with this binocular (4.6 Kg), or make your own support. I made one which I recon is very efficient and relatively inexpensive, I finally uploaded pics of my solution for a mount alternative to a tripod.
(basically the binocular hangs over my chair from a frame, which remove the binocular weight and allow me to use them like a very light binos free hands).

I ask $300 ONO for this binoculars which comes with its aluminum hard case.

I way prefer the buyer coming to check and pick it up. I can also ship it (I have all original box package) at buyer expense (box measures: 56cm, 32cm, 22cm, 8kg).

Giorgio

NOTE: I also added here a review by Phil Harrington published in the Astronomy magazine in March.

~~~~~ Tech data from Zhumell website ~~~~

The Zhumell Tachyon 25×100 Astronomical Binoculars are a top-of-the-line choice for amateurs or industry professionals at a price that needn’t be focused on. The 100mm objective lenses offer an expansive field of view in which to enjoy the huge 25-times magnification. Craters on the moon and rings on planets are easily observed under the right conditions, and constellations will be visible in ways you didn’t think possible with binoculars. And since the Tachyon 25×100 takes 1.25-inch astronomical filters, you can enhance your enjoyment of the Moon, planets, and nebulae. Look up at the sky and see through fully multi-coated lenses with BaK4 prisms housed in a binocular with nitrogen-purged waterproof construction and individual eyepiece focus.

The locking aluminum case allows you to pack it up with confidence, knowing that bumpy roads or careless airline handling won’t damage the optics. Zhumell provides a 25-year no-fault warranty, so you’ve got the security to make an investment in your passion knowing that we stand behind our product.

SPECIFICATIONS:
Weight 164.8 oz.
Size Giant Binoculars
Eye Relief 15.44 mm
Waterproof Yes
Magnification 25x
Objective Lens Diameter 100 mm
Field of View @ 1000 Yards 157 ft.
Focus Type Individual
Close Focusing Distance 80 ft.
Exit Pupil 4 mm
Prism Type Porro
Twilight Factor 50
Best Uses Astronomy, Long Distance Terrestrial Viewing, Shoreline/Oceanfront Viewing
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Last edited by Giorgio; 16-08-2011 at 11:18 PM. Reason: Updated text
  #2  
Old 07-07-2011, 06:06 PM
Giorgio
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Added pics of my mount solution for heavy binos
  #3  
Old 08-07-2011, 09:14 PM
Paduan (Brett)
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hi Giorgio have you discussed with Zhumell the warranty regarding collimation issues and are the easily collimated. are they still for sale? what is the manufacturer like to deal with?
  #4  
Old 09-07-2011, 12:14 PM
Giorgio
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Hi Brett,
I'm going to contact them today for sure.
  #5  
Old 09-07-2011, 04:08 PM
Giorgio
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One should never take decisions while is stressed. Lesson re-learned!

This binoculars, like others models featuring long and heavy barrels, use a central steel(?) bar to ensure binoculars barrels being perfectly aligned.

Today, still wandering why yesterday the binocular was clearly out of collimation, I checked them again. I discovered that both bolts that ensure the central bar being firmly attached to both sides of the barrels being quite lose. Especially that one next to the big frontal lens (highlight 2). The other one (highlight 1) too was still not completely tight, but with less game.

Hence I tighted up both of them and in my opinion if there are still collimation issues now, they must be very little, if any at all.

I surely would like both to have someone else having a look and to know if other owners of similar big binoculars have experienced the same problem.
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Last edited by Giorgio; 09-07-2011 at 06:12 PM.
  #6  
Old 09-07-2011, 06:22 PM
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mental4astro (Alexander)
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Hi all,

Collimating binos is not impossible. Binos that are like these have collimating screws on the prism casing, usually located under the rubber armour. Have binos for long enough, & they will all need some degree of re-collimation due to life's bumps.

The site www.cloudynights.com has several articles on the topic. Do a search there on it. To get it right is a pains taking exercise, but not difficult.

I'd love to get my mits on these binos!
  #7  
Old 10-07-2011, 07:37 PM
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dannat (Daniel)
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Giorgione, Alexander is right, do your bino eyepieces move up in an arc down or side to side to adjust for distance between your eyes?

The problem wi the up down in arc is the Inge provides a third area which needs to be encountered for in the collimation. However if they are used by primarily one user you can get them good enough by making them right just for that user
  #8  
Old 16-07-2011, 09:40 PM
Giorgio
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Like in most porro prism binos, also in this one, you have to bend the barrels up or down to set the oculars distance, which clearly must be the cause of the hinges bolts getting lose enough to create collimation problems.
I couldn't find any obvious hints suggesting where the collimation screw is located under the barrel protecting rubber. Hugh suggested it may lay behind each barrel panel, where oculars lay on the back side. There are 4 or 5 small screws there.
However, as this binos are nitrogen filled, I would try open it, only if I'm sure that's it the right place.
On other hand, I can't see any out of collimation hints anymore, since I tight those bolts, hence I'm not going to touch those panels and I'm pretty sure the problem is solved.
Possibly I will see Hugh next week (we are going to Brisbane Planetarium, which I never visited yet) and I look forward for his feedback about the collimation problem.

Thanks for the advices.
Giorgio
  #9  
Old 31-07-2011, 04:07 PM
brian nordstrom (As avatar)
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Hi Giorgio , are these still for sale ?
 

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