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Riser for TeleVue Gibraltar

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#1 Mike Holland

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Posted 15 March 2009 - 09:00 AM

Does anyone know if there is a riser available for the TeleVue Gibraltar mount, i.e., something to put under the fork to raise it a few inches? The diagonal hits the tripod legs when you get anywhere near the zenith, and I'm looking for a way around that. Thanks!

Mike

#2 MacRoberts

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Posted 15 March 2009 - 04:52 PM

Hi, Mike-

A short riser or pillar would be great. I immediately remembered meeting the owner of KB Systems, the company than manufactures the Gibralter tripod for TV. He seemed very willing to consider changes to the-then product line and we talked for a good 20 minutes or so. Very likable.

So I took a look at the KB System site after reading your post and now see a couple extensions that might just be what you're looking for. If not, you could give them a call - there is contact information listed on their site, here.

I would be interested in knowing what you come up with, Mike. Good luck!

#3 Mike Holland

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Posted 16 March 2009 - 08:16 PM

Hi Jim,

That looks like a good contact. I went to their site and saw the extension that they have listed, and hope that is something that can help. I will send them an email and then let you know what they say.

Thanks very much for the response!

Mike

#4 Mike Holland

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Posted 01 April 2009 - 05:51 PM

I would like to post some pictures that show this problem, but can't find any guidelines regarding appropriate image sizes for CN posts. Anyone know where I can find those? Thanks!

Mike

#5 Mike Holland

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Posted 01 April 2009 - 05:58 PM

Jim,

I'm sorry to get back with you so late on this, but it took me a while to produce images that I think are needed to fully describe the problem. Once I have those posted, I'll call KB Systems. I did phone them once already, and the man that answered was very nice and interested in the problem. I want him to see my photos so that he'll know exactly what I'm talking about. Thanks!

Mike

#6 mes

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Posted 01 April 2009 - 08:44 PM

I had experienced the same problem and found that with a little bit of work and some spare wood I was able to build one. Basically I cut out 5 - 3" squares of oak from a oak 2x4, stacked them and glued them together, drilled a 7/16" hole down the middle, and trimmed off the corners on the tablesaw so that the I end up with a octogonal column. I then bought a 12" 3/8" thread rod from the hardward store for a couple of dollars and replaced the thread rod that came with the Gibraltar head. The rod is long enough to reach all the way through the column and through the head of the Gibraltar tripod so it can be attached with the washer and winged nut that came with the setup.

Note that I also used another piece of 2" oak to build a plate that sits on the tripod head to give me 3 1/2" flat surface for the column to rest on.

For me this works great. There is a little more shake because of the extension (I use a NP101), but things settle down in about a second.

Overall, the project took about 3 hours of my time and about $5 of materials. The only thing I watch out for is that the wood expands so I loosen the nut when not in use just to be safe.

I should also say that with the column installed I can view all the way up to the zenith.

#7 MacRoberts

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Posted 01 April 2009 - 10:43 PM

I would like to post some pictures that show this problem, but can't find any guidelines regarding appropriate image sizes for CN posts. Anyone know where I can find those? Thanks!



Mike, "Image Posting Guidelines" is a permananent thread at the top of this forum listing, here. The limit is 800x800 pixels and 100K.

Another permanent thread gives a link to tips on image resizing and size verification, here. I'm looking forward to the pictures and hearing what KB Systems might do.

#8 Mike Holland

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Posted 02 April 2009 - 08:06 PM

Ok, here we go ... :jump:

The first image shows what is actually happening: the focuser hits the top of the tripod legs when the scope is pointed up, preventing the tube from being pointed straight up (although the problem is slightly exaggerated because my driveway slopes downward).

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#9 Mike Holland

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Posted 02 April 2009 - 08:07 PM

The second image shows that the legs are close enough together at that point that the focuser can't simply fit between them.

Some kind of extension might be the answer, i.e., something that would raise the fork--and consequently the tube--a few inches.

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#10 Mike Holland

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Posted 02 April 2009 - 08:11 PM

Can you post an image of what you've done? It sounds good. Thanks!

Mike

#11 mes

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Posted 03 April 2009 - 09:33 PM

Here is a close up picture of the riser.

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#12 mes

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Posted 03 April 2009 - 09:35 PM

Here is a picture of my scope pointing at the zenith

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#13 mes

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Posted 03 April 2009 - 09:38 PM

To reach the zenith, I had to add a 3/8" space under the scope to 'move it out' a little. I just used a piece of aluminum I had lying around...drilled a couple of holes...added some longer threaded rods to the scope to go through the spacer and the mount bottom. I still secure the mount with the wing nuts supplied with the scope.

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#14 mes

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Posted 03 April 2009 - 09:49 PM

One last entry...I promise.

The other modification I had to make was to grind a little bit of aluminum off the eyepiece caddy to allow my focusmate focuser a bit more room so it didn't hit the caddy.

The last modification I made to the mount was to use the drilled and threaded hole that is normally used to attach the encoders to add a knob with a plastic stopper (which I just made out of whatever was lying around). This works great as a 'brake' that I tighten when I'm changing eyepieces. Using this means that I do not have to change the tension on the mount supplied brass knobs....I could never get them right again after I tightened then to change an eyepiece.

Also if you would like any pictures of the wood base that the riser rest on then let me know. Basically all I did for this was drill out a hole using a fostner bit and then use a wood chisel to shape it to fit snugly over the tripod head. My initial carving lacked a bit of precision so some felt added to the inside of the carving gave a snug fit.

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#15 Mike Holland

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Posted 04 April 2009 - 07:22 AM

Thanks for the responses, Mes. It must be nice to be so handy with tools! :grin:

I wonder if the stability issue is why TeleVue doesn't put out a riser like this (or something similar).

Mike

#16 mes

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Posted 04 April 2009 - 07:58 AM

Trust me, there isn't a lot of skill involved...just patient, time, and a couple of simple tools (a drill, a small tablesaw, a wood chisel, and a clamp...all things I have around to service my needy home) If you have the tools then I recommend you give it a try. Worst case is that you will waste a couple of hours and about $5.

Personally I don't find the stability a problem. The damping time is only slightly more than it was without the riser and the benefits of using the riser far outweigh the negatives. Also, having the riser allows me to not extend the tripod legs as much which makes it a much more solid platform for everything to sit. This likely helps keep the damping time down.

I hope some of this info was helpful and good luck with finding a riser that works for you.

#17 Mike Holland

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Posted 05 April 2009 - 07:52 AM

Thanks, Mes. I'll post again after I've come up with something.

Mike






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