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Mega-mod thread for Zhumell dobs

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#401 AlBoning

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Posted 25 September 2013 - 09:13 AM

I've done that, use a Sharpie to blacken the bevel of the primary mirror, and I took it a bit further. I made an annular baffle from a plastic divider for a 3-ring binder, covered it with adhesive backed flocking paper, and mounted it on top of the mirror clips. Can't say if it made any difference, it certainly didn't change the star test any. Which leads me to conclude there is no turned down edge. Next time I remove the primary I'll likely remove the baffle.

#402 Tim L

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Posted 26 September 2013 - 10:50 AM

Welcome, Wingryder, and enjoy the new scope! :jump:

#403 Scanning4Comets

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Posted 29 September 2013 - 11:49 AM

I replaced the focuser tension screw with a hex screw because I kept tightening and loosening the wrong one when viewing.


You could have just removed the bottom thumb screw from your Crayford focuser altogether, (which is a focus lock screw), rather than replace the top thumb screw, (which makes the focusing tight or loose), instead.

I have the bottom one on mine right off.

#404 George Methvin

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Posted 02 October 2013 - 03:50 PM

I do most of my viewing from my driveway so I just roll my Z-12 out of the grage where I keep it. I have my Z-12 on rollers so it just rolls out and back in when I am done for the night. When setting up for a night of viewing I set a old box fan behind my scope and turn it on low so it cools my scope down in no time flat, I keep the fan on it most of the night. This is really a very nice scope and very easy to setup and use now my other two scope get use very little. Thanks to all you folks, you are great and very helpful clear skys.

#405 George Methvin

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Posted 03 October 2013 - 09:40 AM

Well I just order a EZCBP equatorial platform for my Z-12 dob, can't wait to get it going.....NICE.

#406 Spyke

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Posted 05 October 2013 - 11:12 AM

I'm inches away from placing an order for a GSO 10" f5 Dob, which I assume is going to be very similar in construction to these Zhumell Dobs. I like a lot of the mechanical modifications made - the secondary collimation screws, the milk jug washer for secondary, flocking, replacement of collimation springs, etc...

But I would very much like to keep the cost of these "add-ons" to an absolute minimum. I'll read through all the posts again to see what I can pick up, but I'd like to know the cheapest options with the biggest paybacks.

Also, when using the secondary milk jug washer mod, how exactly is it placed? I presume the secondary mirror is removed completely - are there any problems with doing this?

Thanks,

Ant

#407 StarCurious

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Posted 05 October 2013 - 12:45 PM

For my Z10 with a 22 inch base, I had a 24 inch setting circle printed and laminated at Staples. A setting circle same size as the base would have meant cutting the base.

I put Velcro tape on the quadrant of the mount to allow me to move around an LED light/paper clip pointer combo. The square base allows me to roughly align quickly to the North. Then I have an OTA mounted 10 inch tablet with Sky Safari Plus to tell me the actual coordinates of an "alignment star", and move the pointer to the more accurate position.

Together with an inclinometer, also with a tiny LED flash light attached with magnet, this set up is my PUSHTO.

I would like to thank CN contributors for the may great ideas, especially on this thread.

#408 StarCurious

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Posted 05 October 2013 - 05:23 PM

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#409 Tom Andrews

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Posted 06 October 2013 - 08:59 PM

For my Z10 with a 22 inch base, I had a 24 inch setting circle printed and laminated at Staples. A setting circle same size as the base would have meant cutting the base.

I put Velcro tape on the quadrant of the mount to allow me to move around an LED light/paper clip pointer combo. The square base allows me to roughly align quickly to the North. Then I have an OTA mounted 10 inch tablet with Sky Safari Plus to tell me the actual coordinates of an "alignment star", and move the pointer to the more accurate position.

Together with an inclinometer, also with a tiny LED flash light attached with magnet, this set up is my PUSHTO.

I would like to thank CN contributors for the may great ideas, especially on this thread.


Great idea! Makes things so easy and no damage to the scope. Good use of your brain/imagination.

#410 woodscavenger

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Posted 08 October 2013 - 09:48 PM

I added a rotating removable tabletop. You can see the details in this post. Rotating tabletop

#411 VikingRaider

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Posted 19 October 2013 - 10:47 AM

I posted this over in the ATM forum but I had to attach it here as well, if nothing else than to give the thread a bump :)

I built a hiss drive my 8" Zhumell this week (and as of yet haven't been able to test it because of... you guessed it...cloudy nights) as my (hopefully) triumphant return to astronomy and woodworking after a back injury that sidelined me for the last almost three months.

Only, I added wheels to make the drive (and the telescope on top) mobile, so I can wheel it out of my garage and observe, and hopefully be able to track objects with it. The project has been in on the back burner for about a year ever since I came across Tom Fangrow's webpage about his(from 1985!). Best part was, it only added 2" to the overall height of the base+scope that I have been observing with for the last few years.

I have since been able to find a few other forums talking about it and a handful of pictures, but honestly there's not much out there that I can find. So I decided to make my own and document every step so that someone like me can come along after me and have a little more info.

Since hurting my back, I have come to realize the appeal of smaller SCTs with goto mounts but even the Nexstars are out of my price range. One day....

This whole project cost me less than $50, using wood leftover from other projects and tools I already had. I had to purchase a bicycle pump, aquarium supplies (hose, valves, etc) and an inner-tube. I scavenged some of the wood and the wheels from the old yard canon base.

It was a fun build, and I still have some tweaking to do (as explained in the blog entires) but it's about 95% done and ready for testing, as soon as the skies clear. Right now it's mid-morning and there is a crystal clear sky out there teasing me. Hopefully it holds until sunset!

For your convenience, I've linked the blog entries in order below if you want to check it out. Rest assured that once I give it a whirl I'll report back and let you know if all the effort and planning and dreaming was worth it lol

Part I: Hiss Drive Rover

Part II: Back to the Drawing Board

Part III: Version 2.0

Part IV: Adding Support and Wheels

Part V: Attaching the Top Half

Part VI: The Lever, and Attaching the Top Half, Part Deux

Part VII: Assembling the Drive

Thanks for looking.

Attached Files



#412 Sarkikos

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Posted 19 October 2013 - 02:52 PM

So you don't sit while observing?

Mike

#413 VikingRaider

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Posted 20 October 2013 - 08:09 AM

Mike,

No, not generally---it's a sort of trade off for me. I find that on it's old mount the scope was perfectly suited for me to stand. After a decade of retail management, I'm used to standing for 12 hours a day. Sitting down has actually gotten less comfortable (unless I'm on a couch on game day) over the years.

Combine that with a recent back injury this summer and sitting down is now downright painful---albeit a LOT less so than three months ago.

With this thing on wheels, I can pull it out quickly and easily. I can let it sit and cool down, then come out later and get right to it, without dragging a chair along. Plus I am just tall enough that in a chair, unless I'm looking at the zenith (or near it) I have to hunch over to comfortably view in the eyepeice. I figured, if I have to build a base to raise the scope, why not make one so I can stand? Additionally, with the unpredictability of my kids (4 and 2 and 1 in the oven) I sometimes (read that often) have to abort a session to comfort, clean, or feed someone in the wee hours before dawn (my only real observing time), requiring me to very quickly bring the scope inside. With it's wheeled base, I just grab it and roll. Thanks to my back, bending over to pick up the scope is right out. At least for the foreseeable future.

My solution is really a goto sct in the 6-8" range. Quick set up, quick cool down, no messing around with nudging and star hopping....I get such little time to observe and need to make the most of it. Alas, that is not in the stars. Too expensive on a one salary home.

So...LOL in a word, the answer to your question is yes. Got a little long winded there...

#414 Scanning4Comets

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Posted 24 October 2013 - 03:39 AM

So you don't sit while observing?

Mike


I don't either.

#415 Damo636

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Posted 25 October 2013 - 11:00 AM

I'm inches away from placing an order for a GSO 10" f5 Dob, which I assume is going to be very similar in construction to these Zhumell Dobs. I like a lot of the mechanical modifications made - the secondary collimation screws, the milk jug washer for secondary, flocking, replacement of collimation springs, etc...

But I would very much like to keep the cost of these "add-ons" to an absolute minimum. I'll read through all the posts again to see what I can pick up, but I'd like to know the cheapest options with the biggest paybacks.

Also, when using the secondary milk jug washer mod, how exactly is it placed? I presume the secondary mirror is removed completely - are there any problems with doing this?

Thanks,

Ant


Hi Ant

I removed the secondary to install the milk jug washer but it can be done without dismantling. Jason's diagram in this thread shows how....


http://www.cloudynig...5854490/Main...

I also modified the primary cell to allow the mirror to float unrestrained and allow easier removal...

http://stargazerslou...l-improvements/

#416 Dakota1

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Posted 25 October 2013 - 12:35 PM

Counter weights for heavy eyepieces and added goodies to focuser area. I will have an Apertura AD12 first of the year and am going to install a Scope stuff rail system with a sliding counter weight to off set heavy eyepieces etc. I have had the system on several of my dobs and it really works good. They have a rail 24 inches long that attaches with two sided tape to the scope. You can get a 1 or 2 pound weight that is mounted to a rail car that moves up & down the track. You can get the rail car by itself and add your own weight. It is a clean looking system and it works.
Thanks

Bill

#417 kfiscus

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Posted 25 October 2013 - 04:24 PM

I have quite a bit of accessorizing done on my Z12 and have not had to do any weight rail. The adjustable bearings are very good and I still have about a quarter inch left to slide the tube rearward. (I have a Telrad, 2" Telrad riser, 9x50 finder, filter slide, filters, and full flocking that all add weight forward of the bearings.) You may not need a rail unless you're binoviewing. I've had no troubles even when using a 13 Ethos.

#418 kfiscus

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Posted 17 November 2013 - 11:55 PM

Bump. This thread was getting buried.

#419 DonY

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Posted 18 November 2013 - 07:17 AM

For my Z10 I use a 2# soft weight from my SCUBA gear tucked under a bungee cord wrapped around the mirror end of the scope. I need this when using my heaviest eyepiece. My scope has a Telrad, the 5x view finder and an inclinometer on the scope. I couldn't obtain perfect balance with the adjustable pivot point/friction adjustment with all EP combos and/or viewing altitudes so trade off was to set pivot point to balance with my lighter EPs for viewing above 30*. If I'd set balance for heaviest EPs then lighter EPs would have required counter weighting on the EP end of scope which I didn't want to do.

#420 kfiscus

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Posted 18 November 2013 - 12:42 PM

Don, how well do you like your Halo? I'm thinking of getting one for a push-to rig. It would go on my buddy's stock Z12.

#421 DonY

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Posted 18 November 2013 - 12:51 PM

I love it and highly recommend it. Much cheaper than digital setting circles and combined with a digital level is just as accurate.

#422 bevelhead

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Posted 05 December 2013 - 01:58 PM

The extra holes in the primary mount on the AD12 are 8x1.25mm. I added bolts and pressed on some bottle caps filled with sticky tack putty for feet to protect the primary adjusters. I also used tack putty to mount my GLP. Butting it up against the focuser mount lines it up well enough to get whatever it's pointing at in the finderscope.
Posted Image
Posted Image

#423 Elroy

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Posted 09 December 2013 - 11:28 AM

Looks like I'm next!
This thread is great. Thanks to all you kind and knowledgeable people for sharing your ideas and work for the rest of us to learn from.

:bow:

#424 petrus45

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Posted 14 December 2013 - 04:59 PM

Anyone found a really ideal focuser upgrade for the Z10?
I have an older Z10, originally with single speed crayford, replaced with dual speed, but I find it's still a bit wobbly feeling with heavier EPs. I've tried John Isaac's suggested method of holding the EP flange flush against the focuser insert while tightening the screw, but I still can wobble the EP just a bit in the collar (single screw compression ring). Also, I noticed the barlowed laser will move off center pretty easily if I "tug" on the focuser, imitating the effect of a heavier EP. Perhaps I need to tighten the screws holding the focuser to the OTA, or is this an issue of inherent focuser stability? Any suggestions?

#425 Sarkikos

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Posted 14 December 2013 - 05:08 PM

I've upgraded the focuser in my C10NGT - a Celestron f/4.8 Dob OTA similar to the Z10 - with a low-profile, two-speed Crayford Moonlite focuser. Solid as a rock. And now nearly all my eyepieces come to focus when I use my 1.25" or 2" filter wheels.* Well worth the money.

*The TV Nag T5 31, Leica ASPH and ES 100 20 are the only ones among my eyepieces that do not have enough in-focus in the 2" filter wheel. The ES 82 30 does come to focus. I've sold the ES 100 20.

Mike






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