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Finally! an alt-az I can live with and maybe love

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#1 PJ Anway

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Posted 01 June 2013 - 03:40 PM

For some time now(years), I have been looking for an alt-az mount for solar observing. I am a big fan of a driven equatorial, but there is something to say for a quick grab-and-go, especially for low-power solar views where nudging is infrequent. In the past I've used a standard video head on a tripod, but was never satisfied. I have also tried various alt-az mounts, including a Unitron, Takahashi/lapides, Discmount & others. Recently, I found a used Wimberley Gimbal mount at a decent price and thought I might as well give it a try. After all, they receive high praise from photographers that use long/big telephoto lenses (and they should at $600).
Anyway, after putting it through it's paces for a couple of weeks, I'm impressed. Once balanced (which is easy) it stays where you put it, is rock solid and has very smooth movement. So far it's been a dream of a setup. With my Pentax SDHF 75mm, Coronado SM60 and binoviewers onboard, it hardly notices the 9 lb. total load. A lot is said about them by photographers, but you don't see much said about them with regards to astronomy use. It seems to be a hidden jewel of a mount and it looks pretty cool too.

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#2 skullpin

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Posted 01 June 2013 - 06:56 PM

Cool PJ. I have a new one due to be delivered this Tuesday. :)

I will be using it for travel with a lightweight Borg 89ED.

I will need to experiment with it and my Borg 125SD later this summer when I get back home from contract work. It weighs about 12lbs set up with rings, diagonal and largish eyepiece. I wonder if it will give my DiscMount DM4 a run for its money. The DM4 is superbly stable, I can keep my hand on the focuser at higher than 200 powers.

Keith

#3 tomharri

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Posted 01 June 2013 - 10:14 PM

They got'em on ebay for $90 shipped, a cheap copy direct from China !!!

Look under photo tripods.

#4 skullpin

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Posted 02 June 2013 - 05:17 AM

They got'em on ebay for $90 shipped, a cheap copy direct from China !!!

Look under photo tripods.


I especially like the ones with button compasses built into the control knobs (BEIKE brand).

Keith

#5 PJ Anway

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Posted 04 June 2013 - 01:14 PM

Keith,

Let me know what you think of it. Sounds like a great match for the Borg 89!

#6 skullpin

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Posted 04 June 2013 - 06:11 PM

Received in a nice brown box with precisely cut foam. Nice presentation.

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#7 skullpin

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Posted 04 June 2013 - 06:14 PM

Yes, that is a bag of Wimberley branded M&Ms. They are dark brown or white and have "Wimberley" marked on one side and "M&M" marked on the other. I have not opened the package yet, but expect a full field report soon.

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#8 skullpin

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Posted 04 June 2013 - 06:17 PM

One view. Those knobs are of a rubbery coated plastic variety and seem to be of good quality. The crinkle finish on the mount is quite thick and textured, reminiscent of vintage microscopes. Neat: the mount is warm to the touch, not cold anodized aluminum; I presume the thickness of the crinkle finish is responsible for this.

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#9 Goodchild

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Posted 04 June 2013 - 06:18 PM

Yes, that is a bag of Wimberley branded M&Ms. They are dark brown or white and have "Wimberley" marked on one side and "M&M" marked on the other. I have not opened the package yet, but expect a full field report soon.



Now that's funny! :rofl2:

#10 skullpin

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Posted 04 June 2013 - 06:22 PM

Different angle. The Arca-Swiss style clamp is done to a very high fit and finish, giving even high-end astronomy equipment a run for the money. I decided to get an Arca-Swiss dovetail plate for my scope as it would be cheaper and easier than sourcing a vixen type clamp. Additionally, Arca-Swiss dovetails are a little lighter in weight; grams count for travel. And, they slide a little bit easier in the clamp than vixen dovetails; good for rebalancing.

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#11 skullpin

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Posted 04 June 2013 - 06:34 PM

I did test this mount out in the living room with my scope attached. Photos forthcoming. Here are my initial impressions:

1. Cost was high, but fit and finish do not disappoint.

2. Movement is very fluid on both axes with no looseness observed.

3. The lock knobs are very positive, only about 1/2 - 3/4 of a turn to go from fully locked to fully loose.

4. It is possible to tune the friction so movement is smooth and the scope does not nosedive when imperfectly balanced. In fact, I had the tension set so I could take out and reinsert a 600g eyepiece from my short refractor without any scope movement, and movement was still smooth and easy. Reminiscent of my DiscMount.

5. Reiterating points 3 and 4, while it is possible to set ideal tension, it does involve some pretty small tweaks to the tension knobs.

6. Tension seemed to be retained well as the scope was moved around.

7. I did not notice any stiction when tension was employed.

Those are living room impressions, I hope to get it out tonight.

Keith

#12 mountain monk

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Posted 04 June 2013 - 07:54 PM

Hummmm...Very nice, Do you think it would handle a NP-101?

Dark skies.

Jack

#13 ryderc1

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Posted 04 June 2013 - 08:26 PM

Note that PJ's Wimberley has an adjustable platform so the scope can be raised or lowered in order to properly balance the scope at its center of gravity -- a design concept also found in Half Hitch mounts. With the Wimberley version without the adjustable platform this isn't possible.

I have the same Wimberley version as PJ's and have used it to carry 60, 80, 92, 105, and even 130mm scopes with excellent results with the only limitation being the inability to point all the way up to zenith ( a common issue with these types of mounts). Movements are smooth and the ability to balance the scope along both axes holds the scope in any position as if floating in mid air.

Paul Schroeder authored an excellent review of the Wimberley that can be found here on CN in the Reviews section.

#14 mountain monk

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Posted 04 June 2013 - 09:57 PM

Thanks for the information and the reference.

Dark skies.

Jack

#15 skullpin

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Posted 05 June 2013 - 05:07 AM

Wimberley still sells the adjustable platform version. And, the version I have can be upgraded to the full gimbal platform.

I opted for this one because it is lighter and cheaper. And, I thought I would first check if a little friction can null out minor imbalance issues. So far, so good.

Keith

#16 PJ Anway

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Posted 06 June 2013 - 07:57 AM

Keith,

Very nice! I'll be very interested to see how the Side-Mount version works for you.

A further note: Because I have Zeiss scopes, I use Asro-Physics (DOVE08) dovetail clamp on my mounts because it works well with the Zeiss dovetail. On non-Zeiss scopes/rings, I use the Asro-Physics 7" dovetail sliding bar (SB0800) to keep things compatible. It matches the Zeiss dovetail perfectly. Anyway, I wondered if I would need a DOVE08 for the Wimberley, but I happy to say I didn't. The Arca-Swiss clamp on the Wimberley also works well with the Astro-Physics and Zeiss dovetails. So, the Wimberley was an all-around winner for me.

#17 Tamiji Homma

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Posted 06 June 2013 - 12:14 PM

Hi PJ,

I have something similar to yours.

This particular configuration (TMB 80SS f/6.3) could not clear zenith (up to 60 degree I think). It is good for spotting scope. After lock down alt/az, you can grab a whole thing and walk around :)

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Tammy

#18 PJ Anway

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Posted 06 June 2013 - 01:18 PM

Tammy,

Very nice!
With the Pentax 75SDHF/Wimberley setup I can get almost 80°. That works great for my purposes, because at my latitude (46.4°) the sun never climbs above 68°.

#19 tomharri

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Posted 07 June 2013 - 09:51 PM

Here's my cheap chinese copy, from a warehouse in New Jersey full of these. Holds the Jaegers-Borg Clone 75mm f/5.

Vertical arm looks a little shorter than the actual Wimberley, and the horizontal plate that clamps the arca-swiss dovetail does not slide in-out, so kinda limited to tube size. Would have to make adapter plate to mount vixen dovetail out from arca clamp/dovetail to mount a little bigger tube.

Probable scope limit 90mm f/7 at 7 pounds for this style mount.

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#20 tomharri

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Posted 08 June 2013 - 11:17 AM

Here it is with no-name 90mm triple also from China, had to drill and tap 2 holes to attach arca-swiss dovetail to the vixen sized one, tube and rings do clear mount head. Mount movement feels like it is gonna work and not overloaded.

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#21 tomharri

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Posted 08 June 2013 - 11:39 AM

Size comparison next to 5" Istar f/8 R30.
90mm tripod came from usa seller on ebay and is much sturdier and cheaper at $119 than anything the astro sellers have, also china sourced.

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#22 skullpin

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Posted 09 June 2013 - 05:23 AM

Keith,

Very nice! I'll be very interested to see how the Side-Mount version works for you.


Finally got out tonight to test the Wimberley Side-Mount. Very transparent skies and pleasurable viewing. My findings with a Borg 89ED...

1. Very stable. I got a new Gitzo series 3 aluminum tripod that helps out on this account.

2. Very smooth.

3. Completely loose in altitude was tricky, as balance changed with scope angle.

4. Friction was not difficult to apply in the right amount to overcome balance issues, and tracking at high power was easy. Nice, but not as simple as my DiscMount.

5. Axis lock is positive. The scope does not move when axes are locked. Even when severely unbalanced.

6. The M&Ms made for a better observing experience.

7. They did not melt in my hands and make the knobs sticky.

8. The white ones were the easiest to eat in the dark, and I lost one dark one. Makes me wish eyepiece caps were standard in white.

Overall I would rate it as the most expensive candy I have ever eaten. And, the mount is pretty swell too.

Keith

#23 Mike E.

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Posted 09 June 2013 - 10:58 AM

For white eyepiece caps of the 2" variety, I found that the lids from "Gaviscon" antacid tablet containers are a perfect fit.

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#24 obin robinson

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Posted 09 June 2013 - 11:00 AM

These mounts look very interesting and promising for a quick grab-and-go setup. Does anyone feel that an ST-80 could be mounted to one of these and easily clear zenith?

obin :question:

#25 skullpin

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Posted 09 June 2013 - 06:12 PM

Oh yeh, one more observation: with the Borg 89ED maximum altitude was about 75-80 degrees. A little annoying when I was trying to, but could not, get the Great Cluster of Hercules which was almost overhead. I am not too concerned as I do not go much above 75 degrees normally with any alt-az mount as tracking and pointing becomes non-intuitive and progressively more difficult.

Keith






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