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Mega-mod thread for Zhumell dobs

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#276 fnowat

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Posted 08 December 2012 - 08:57 PM

Thank you for the lead/link to cool mods for our "Z" telescopes! Here in the gap between the Midwest and the Northeast it is way-too often cold and cloudy. The Mrs and I did a simple thing, we gave our Dob 'pajamas' (aka-sweat pants) just to lessen the frost build-up. We leave the fan on under her to keep the mirror ambient.


I like the idea! Is it really just a pair of sweat pants big enough for the tube or did you use some other material?


Sorry Tim, It was just a pair of xxxl sweat pants and then ripped out the seam. The pull string waist band is on the bottom, and the pockets hold my 4 "AAA" battery pack (also helps balance when using larger TV ep/s. Cut the rubber band on the ankle/bottoms and then tied each leg together and it is positioned above the thumb screws (spider vane screw) for preventing slipping down on the tube. I often have to guide the pants off of the bearings when setting the OTA onto the bearings. Total cost $1.99 from Goodwill/Salvation Army thrift store. Not pretty department store look...but it is dark when she is wearing

#277 kfiscus

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Posted 09 December 2012 - 01:41 AM

Bought a new-to-me Z12 and had the seller ship it to me without the HEAVY particle board mount. I had him strip every part off the mount and send the parts. I used my buddy's stock Z12 base's parts as my patterns and then built my shorter, lighter, and prettier base. I needed to get rid of the stock mount's extra height because I'm only 5'8" and the scope rides on a dedicated Atomic EQ platform (no groundboard at all). The EP is right at my eye at the zenith.

Other mods done by me or previous owner: Refigured primary(OMI), premium slightly-smaller secondary, Telrad & dew shield at top of tube- right by focuser, straight 8x50 finder adjacent to telrad. Fully-flocked tube.
Next big mod: Astrocrumb original(?) filter slide and rotated spider.

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#278 Tim L

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Posted 10 December 2012 - 10:54 AM

kfiscus,

Wow--I love that front panel! :waytogo:

#279 pftarch

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Posted 10 December 2012 - 01:36 PM

That base DEFINITELY fall into the "way cool" category. Beautiful job.

Peter T.

#280 echoes1961

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Posted 10 December 2012 - 02:42 PM

If you want more freedom adjusting the focuser. I removed the 4 focuser screw & nuts and the focuser on my Z10. Then I took a 1/4" drill and carefully "slotted" the holes up and down (top to bottom) thereby giving the focuser freedom to be moved slightly up or down the tube, whatever the adjustment called for.

I did this because I could never get the final collamation right and it seemed that the whole focuser needed to be moved a little towards the primary mirror. And it worked in my case. :)

#281 kfiscus

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Posted 10 December 2012 - 09:09 PM

Thank you. Here's the side. It's an homage(?) to M-31 and friends. The small top hole is also functional. It holds a C-5 OTA for solar events with a glass filter and digital EP going into a monitor for group viewing. The lowest hole (M 110?) is the handle.

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#282 Tim L

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Posted 11 December 2012 - 04:25 PM

Here's the side. It's an homage(?) to M-31 and friends.


Just when I thought it couldn't get any cooler... :cool:

#283 rlmxracer

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Posted 12 December 2012 - 08:05 PM

Awsome job Ken the best I've seen.

#284 Scanning4Comets

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Posted 14 December 2012 - 07:17 AM

Yea! Super nice looking mount with nice touches Ken! :bow:

#285 rlmxracer

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Posted 16 December 2012 - 01:12 PM

Me again ... 8 posts and I'm already a "journeyman". Wow ... talk about your easy forums.

_______

Finished up the altitude gauge/weight slider today. As promised ... pics!

Here's a closeup of the slider with the Wixey mounted up. The magnetic base of the gauge holds tight to the mount, and just loosen the thumb screws to slide it up and down the OTA. The rail has to be sturdy and lock tight for a good read on the gauge, so that's 3M taped AND bolted to the OTA. It ain't never goin' nowhere. I lined the bottom of the slider with the fuzzy velcro, and with any kind of luck, that should keep the paint nice. I did nick the rail in a couple places during assembly (probably wouldn't have been an issue if I let the paint set for a day or so longer), but a quick dab with a Sharpy and you can't see it. Gotta love black.

Posted Image

Here's the rail itself. Runs all the way from the base of the OTA to the pivots, so there's a LOT of adjustment range.

Posted Image

I also added reinforcement rails to all the addons inside the tube. No worries about stressing holes and such. None of the screws stick out any more than the OEM stuff, so I don't expect any interference. Next step is flogging ... er flopping ... uh ... flocking the tube, so the shiny parts aren't an issue. You can also see the knob I mounted at the top of the OTA to help move it about when viewing.

Posted Image

Last (for now anyway) but not least, a corner shot of the slider rail and the handles I added above the pivots to help when dropping the OTA into the rocker box.

Posted Image

All in all, quite happy with way it's all working out so far ... Now that it's done and I've been playing around with it some, I'm thinking I may make another slider for the rail for the battery pack. With the rail as close to the center pivots as it is, I should be able to still balance the OTA easily.


Skizoid, where did you find those rails? I am looking to do a similar setup for a counter balance on my new to me dob.

#286 Gastrol

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Posted 16 December 2012 - 01:38 PM

That Wixey weighing almost nothing, does it really make much difference using it as an adjustable counterweight?

#287 kfiscus

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Posted 29 December 2012 - 09:06 PM

Currently scopeless- no matter, clouds forever. I have my Z12 completely taken apart. Tube is ready for flocking. I've drilled 4 new holes for the spider. It'll accomodate the Astrocrumb filter slide (original type) I'm getting. Measuring and drilling the holes took about 30 minutes.

Anyone else have an Astrocrumb installed already?

#288 simpleisbetter

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Posted 29 December 2012 - 11:24 PM

rlmxracer, checkout ScopeStuff for the rail and balance kit you're looking for - Dob counterbalance kits

#289 Sarkikos

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Posted 30 December 2012 - 10:08 AM

An easy, inexpensive and highly adaptable counterbalance is a sports pack loaded with lead shot. (Pour the lead shot into small zip-lock baggies before placing in the sports packs!) I use these on my 10", 8" and 5" Dobs to achieve very smooth balance and motion.

For the 10" Dob, I have a lower pack for longitudinal balance, and an upper smaller pack for lateral balance.

Mike

#290 Sarkikos

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Posted 30 December 2012 - 10:10 AM

Lead makes the most sense for a counterbalance material. It has the highest weight in the least space for any nonradioactive element.

Mike

#291 Sarkikos

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Posted 30 December 2012 - 10:12 AM

Happy Birthday, Ken!

:band: :rimshot:

Mike

#292 Sarkikos

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Posted 30 December 2012 - 10:20 AM

The type of packs I use for counterbalance might not be sold anymore. But here is something similar:

Sportline Run Lite Pack

The hole in the pack for an audio lead can be used for a power cord from batteries in the pack to a fan for the primary mirror.

Mike

#293 Jaimo!

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Posted 30 December 2012 - 05:28 PM

Lead makes the most sense for a counterbalance material. It has the highest weight in the least space for any nonradioactive element.

Mike


http://en.wikipedia.org/wiki/Tungsten

Jaimo! :grin:

#294 Sarkikos

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Posted 30 December 2012 - 09:22 PM

Lead makes the most sense for a counterbalance material. It has the highest weight in the least space for any nonradioactive element.

Mike


http://en.wikipedia.org/wiki/Tungsten

Jaimo! :grin:


I think you might have gotten me there, Jaimo! I was assuming - we shouldn't do that, should we? - that since lead has a larger atomic number (82) and atomic weight (207.2) than tungsten (74 and 183.8 respectively), lead must be heavier than tungsten here in the macro world. The article you cite says that the density of tungsten is "much higher (about 1.7 times) than that of lead." So that must mean there is more mass per unit volume of tungsten than of lead, regardless of the mass of individual atoms. I didn't even consider the density of the elements.

On the other hand, is tungsten as readily available and as cheap as lead shot? If it is, tell me where I can get some for my counterweights!

:grin:
Mike

#295 Sarkikos

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Posted 30 December 2012 - 09:34 PM

For fun, I looked up the density of some other non-radioactive elements we could use in our counterweights. Here they are listed in order of increasing density measured in g/cm^3:

Iron 7.86
Copper 8.96
Silver 10.49
Lead 11.34
Tungsten 19.25
Gold 19.3

Densities of the Elements

It appears that Gold beat out Tungsten by a hair, Jaimo! You've got to admit, Gold would make some really impressive counterweights!

Iron is not so hot at only 7.86. But its strong points are that it's cheap and can be magnetized.

I think lead wins the prize as most practical and effective counterweight material, since it is cheap, readily available and nearly 1.5 times denser than iron. If there are other materials that are denser than lead and not much more expensive, I'd like to know.

Mike

#296 simpleisbetter

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Posted 30 December 2012 - 09:38 PM

I was going to say I thought gold had lead beat. Then again, I don't see anyone counterweighting their dobs with gold...

#297 Sarkikos

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Posted 30 December 2012 - 09:46 PM

Gold even has tungsten beat! I think some of these deep pockets strutting around Cloudy Nights could well afford gold counterweights. Maybe someone should start a business... Talk about pimping your Dob! :ubetcha:

:grin:
Mike

#298 Jaimo!

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Posted 30 December 2012 - 10:46 PM

I think Tungsten is a more affordable alternative than gold...

http://weddingengage...r-value-than...

Jaimo! :grin:

#299 kfiscus

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Posted 02 January 2013 - 02:02 AM

Spent 18 hours obsessing over flocking and darkening my Z12's OTA. I used Protostar flocking board inside the whole tube using the fittings' hardware to secure the flocking up top and at the altitude bearings. Used the primo 2-sided exterior mounting tape with the red release plastic along edges. Hand painted flat black fast-drying paint on all metal objects not covered by flocking including the entire inside of the top tube ring. Used some very old ScopeStuff adhesive flocking for the 8"x9" EXTERIOR around the focuser. I put dark gray shrink tubing on the 5 knurled knobs around the focuser.

Note in the photo that I have made 4 new holes for my spider. I rotated the spider 45 degrees to accomodate the Astrocrumb filter slide (original style) that I'm ordering.

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#300 kfiscus

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Posted 02 January 2013 - 02:06 AM

Here's a shot of the focuser area. I used a TON of light to show details in the photo. There should be very little glare near the EP when actually in use. The discoloration around the edge of the felt is the contact cement that I used to guarantee it never peels.

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