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Mega-mod thread for Zhumell dobs

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#51 Enig

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Posted 02 November 2010 - 10:01 PM

Improve your laser
[*] Collimate your laser.
[*] Add an aperture stop to your laser.


Got this done tonight. I had previously collimated the laser, but I really wanted to squeeze that beam into a tighter dot, so I did the mod exactly as shown in the thread you linked, then re-collimated to a tighter tolerance. All of this had *exactly* the results described... and then my batteries were depleted, so I will be forced into going to Wal Mart, tomorrow I suppose. I think I'll get a goodly supply (maybe three sets) to insure that it will be a decent while before it happens again, and maybe when I get down to one set left I can wait till my wife is going and get her to get them while *she's* there!

Anyway, thanks *very* much for these helpful instructions, everyone involved! I think my next upgrade from this thread will be the Rigel QuikFinder... I too like the idea of it being able to fit between the focuser and finder, and I also like the built in pulse, and the higher profile which should require less neck / head contortion, no?

#52 Sarkikos

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Posted 02 November 2010 - 10:06 PM

Tim,

Yep, you've put the counterweight in the right place. That way you'll balance the scope horizontally and vertically. Putting the weight along the top of the OTA is not the best solution. I use a sports pack (fanny pack) containing lead weights. I strap the sports pack around the OTA.

Mike

#53 Tim L

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Posted 02 November 2010 - 10:40 PM

I think my next upgrade from this thread will be the Rigel QuikFinder... I too like the idea of it being able to fit between the focuser and finder, and I also like the built in pulse, and the higher profile which should require less neck / head contortion, no?


Hey Enig,

I think it's only a fraction of an inch taller than a Telrad in actuality, so there are still some contortions needed if viewing near zenith. But, I do like the small footprint that lets it tuck in close to the finder / focuser.

During the blazing summer heat, my double-sided tape loosened in the garage, and the Rigel fell off once. No damage done, but I'm taking it off after each use now.

Glad the laser mod worked for you. I burned up a set of batteries when I first collimated it as well, but now a set lasts a good long time, and collimation of the laser, if needed, is much quicker.

Clear skies! :rainbow:

#54 Enig

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Posted 02 November 2010 - 10:44 PM

I'm taking it off after each use now.


:john:

Does that not put the fear of the dreaded tab breakage issue into you?

#55 Tim L

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Posted 02 November 2010 - 10:55 PM

Not since I've seen Rigel offer to fix broken tabs for free! :grin:

I do try to be very careful when removing it, however. I suppose the smart thing to do would be to just replace the tape. :smirk:

#56 VikingRaider

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Posted 03 November 2010 - 04:04 PM

I'll throw in my hat here...I've used a lot of these tips on my new Z8 (well, new as in July...) especially the ones about focusing with the Crayford (those little thumbscrews on the bottom had me stymied for a few days) and the finderscope focusing trick.

I've since added a Telrad in between the focuser and the RA finder, but a little futher back down the tube. I find there's no real problem sighting on the Telrad, because the tube is so long to begin with it doesn't feel awkward. I took some black nylon "zip-ties" I had picked up at Home Depot for another project and put 5 together, head to tail to make on big one. They're the standard 12" or so variety.

This I threaded betwen the base and the Telrad itself. One at the front and one at the rear and tighten. The Telrad doesn't move AT ALL and there's no harm to the paint's finish on the OTA. I decided to do it this way because in the middle of the summer my garage can get pretty hot when it's 110 outside. In fact, it was hot enough to melt the glue on the four little felt pads that are around the edge of the OTA cover. A dab of superglue on each fixed that.

Also, speaking of the cover, I drilled a small hole and bought a wooden ball from an arts and crafts store, of a size comfortable to my hand. It was flat on one side and had a pre-drilled hole. This I painted about 3 times with dollar store paint, let dry and attached to the cover with a screw and some wood glue in the ball. Now my cover has a convenient and very secure grip to pull the cover off without groping for the edge in the dark.

Also, I like the way the Orion scopes had a little knob on the front of the OTA by the opening to allow for easier positioning of the OTA during your viewing session. I felt real nervous about drilling a hole in the OTA so I used some more of the zip-ties (I guess they're technically called cable ties) and cut a piece of 1" black PVC in half. Next, I bought a clearance cabint knob from the Depot for .59 (already black!) and drilled a hole in the slice of pipe. Attach the "handle" to the OTA with cable ties and I now have a very secure handle for moving the OTA around while viewing without getting fingerprints all over the tube (or sticking my fingers around the lip of the opening).

Next up, flocking!
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#57 Enig

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Posted 03 November 2010 - 06:36 PM

four little felt pads that are around the edge of the OTA cover.


??? There are felt pads on yours? Curious... mine is just a plastic disc with little "bumps" around the edge that just sorta friction fits... evidently they've made some sort of change. A pic would be great, also of where you have mounted your Telrad and your wooden OTA lid handle!

Laser Batteries

Went to Wal Mart to get replacements... they are $5 and some change for 3 of them... *but*, if yours is like mine, up in one of the checkout lane impulse items they have little laser pointer keychains for about $2.40 that have a set of three inside them, *plus* an extra set of three in the package... I bought three lights for $7 and change which provided 6 sets of batteries (total of 18).

#58 VikingRaider

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Posted 05 November 2010 - 03:09 PM

??? There are felt pads on yours? Curious... mine is just a plastic disc with little "bumps" around the edge that just sorta friction fits... evidently they've made some sort of change. A pic would be great, also of where you have mounted your Telrad and your wooden OTA lid handle!


Sure thing. I'll have to do it as attachments one at a time though. Okay:

"felt.jpg" this is a picture of the little square patch of felt that was glued at 4 spots around the inside rim of the "lid".

Attached Thumbnails

  • 4165846-felt.jpg


#59 VikingRaider

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Posted 05 November 2010 - 03:11 PM

This is a picture of the underside of the lid, showing a few of the pads I reglued, and the screw and some washers holding the handle on the other side.

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  • 4165852-inside-lid.jpg

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#60 VikingRaider

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Posted 05 November 2010 - 03:12 PM

This is a shot of the ball I painted and attached to the outside of the lid. Makes putting that lid on REAL easy now. The washers have the added benefit of giving the lid just a bit of weight---just enough to keep it in place when I'm observing and a slight breeze blows up (which is pretty often where I live...no trees or anything to block that ever present Texas wind).

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  • 4165856-lid.jpg

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#61 VikingRaider

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Posted 05 November 2010 - 03:13 PM

Sorry about all the posts guys but I can't seem to get more than one picture per post....please forgive

This is the little clearance cabinet knob I got at Home Depot, attached to a cut piece of 1" black PVC pipe (again from the Depot). All held together with cable ties. Nice and secure, all pre-painted black and no marring to the paint on the OTA.

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  • 4165860-handle.jpg

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#62 VikingRaider

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Posted 05 November 2010 - 03:14 PM

The Telrad base, strapped on with cable ties...that way I don't have to worry about the glue on the adhesive strips giving way when stored in the garage in the summer.

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  • 4165862-telrad-base.jpg


#63 VikingRaider

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Posted 05 November 2010 - 03:16 PM

And the Telrad installed... Still plenty of room on this thing for me to take a peek up the barrel. I find I end up with my head somewhere over the altitude brakes or a little further up. I'm 6'3" and it doesn't seem to bother me all that much because I built a base on casters to wheel this baby in and out of the garage...next post has a picture.

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  • 4165867-telrad.jpg


#64 VikingRaider

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Posted 05 November 2010 - 03:21 PM

Here's my homemade base built of scrap 2x4s and other bits of wood I had laying around. Cost me $3 in paint (contractor 99 cents a can paint at Depot), $18 in casters (two 3-inch casters $3 ea., and two 3-inch swivel casters $6 ea.) and $2 for a pair of hinges. Has a little table on a hinge that lowers when it's stored in the garage out of the way. My wife thinks it looks like a black hot water heater in the corner of the garage (I store OTA vertical). Crude but it serves it's purpose. I'm fixin to upgrade the hard plastic casters with some rubber or pneumatic wheels from Harbor Freight by Christmas. The casters tend to give a rougher ride than I thought on smooth concrete and like to get stuck in the grooves of my driveway. No big deal, but a minor annoyance that's easy to fix so why not?

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  • 4165878-yard-cannon.jpg

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#65 Tim L

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Posted 05 November 2010 - 05:19 PM

Steve,

Thanks for including the pics. Those are great ideas!

Like Enig said above, mine doesn't have those felt pads in the lid, either.

I like your ideas for attaching knobs. :waytogo:

#66 Enig

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Posted 06 November 2010 - 05:26 AM

I'm fixin to


Yep... he's one of *us*... (blows Dixie horn)!

Man, those are some *awesome* mods you've done! That's definitely a different OTA tube lid... I wonder what caused them to go to the trouble of changing *that*?

That sure is a neat base roller thang you've made there... so you observe standing? Does that alter the length of your viewing sessions? That definitely makes the Telrad position seem more ok than it might from my seated observations... it looks like I'd have to twist and contort back a bit much for that.
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#67 VikingRaider

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Posted 06 November 2010 - 03:47 PM

Yeah, I stand...I find it easier to grab my sketchbook, pencil, lights, EPs, etc., than sitting. Plus, thanks to 7 years in retail, sitting just isn't as comfortable as standing. Not to mention it's way easier to swat the bugs (or stamp my feet in the winter).

Yep...he's one of *us*...(blows Dixie horn)!

Would you believe I was born in Delaware? :grin:

I've been reading the other mod threads and I have another I'll do maybe tomorrow or Monday. I'm going to fashion a pad on the front of the rocker box to cushion the OTA should the alt locks give out and the tube come down. I have some pipe insulation I'm going to line the rocker box with. Simple and should do the trick (now that I've added all the extra weight to the front of the OTA).

Soon I'm going to add counterweights because she's a bit topheavy.

#68 Adam Mendelson

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Posted 08 November 2010 - 10:13 AM

VikingRaider,
I really like the push to knob addition. I have been thinking about this since I picked up my Z12 a few weeks ago. Looks like this is the route for me!

#69 VikingRaider

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Posted 11 November 2010 - 07:50 AM

It was actually very easy----the only thing I had to do was use a hack saw to trim the length of the little bolt that came with the cabinet knob. It was obviously designed to go through wood, not 1/8" of PVC.

#70 graffias79

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Posted 14 November 2010 - 12:01 PM

Regarding the fans that come attached to the back of the Z dobs, is it possible to use an alternative battery pack with them? Has anyone done this? Perhaps one of the rechargeable camping batteries with the cigarette lighter style plugs? I don't fancy buying loads of D batteries. To me it's just not economically feasible or ecologically responsible. Besides, I will want to use the camping battery to power other devices as well.

#71 Sarkikos

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Posted 14 November 2010 - 01:09 PM

graffias79,

Try the battery pack first and see how long the D batteries will last for you. I have a 10" Newt Dob with which I use a Orion battery pack that contains eight D batteries. I bought it over two years ago. I probably use the scope and battery pack at least a half-dozen time a month. I think I've only had to replace a D battery once or twice in all that time. If the Zhumell battery pack is similar to the Orion - and it probably is - you won't have to replace the batteries very often. Just buy an extra pack of D batteries for when you need to replace any, which might not be for well over a year.

Also, it's a good idea to check the batteries in the pack before you take the scope out. It only takes a couple minutes.

Mike

#72 Tim L

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Posted 14 November 2010 - 03:23 PM

Regarding the fans that come attached to the back of the Z dobs, is it possible to use an alternative battery pack with them? Has anyone done this? Perhaps one of the rechargeable camping batteries with the cigarette lighter style plugs? I don't fancy buying loads of D batteries. To me it's just not economically feasible or ecologically responsible. Besides, I will want to use the camping battery to power other devices as well.


Graffias,

Mine came with a battery pack for AA batteries (8 of them = 12v) to run the fan. I think as long as you're getting the same voltage you could probably use other power sources for the fan. A 9v battery might be a little low on airflow.

I've been thinking of putting some kind of regulator on mine to control how much power the fan gets, so I can turn it down once it's close to ambient, but still have a little air flowing down the tube.

#73 capstain

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Posted 03 December 2010 - 04:26 PM

Just bought my first DOB and chose the Z10 because of price and accessories included. I also own a Meade AR6 refractor so this is my first experience with Collimation and am slowly learning the ropes.

One question I have is regarding the collimation of the collimator. Do I put it on a stable stand and then rotate it in a circle in one place with the beam on a wall, adjusting the screws until it doesn't create a circle during the entire 360 degree rotation?

Does anyone in this thread have pictures of this procedure? Sorry for my obvious confusion. I'm really excited about the viewing through a bigger scope and want to make sure I have everything set up correctly.

Also, has anyone had an issue with getting an object in the center of the crosshairs on the finder scope? No matter how much I turn the adjustment screws the best I can do is get the object about a half inch below and then compensate with the OTA. Thank you.

#74 jimbo216

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Posted 03 December 2010 - 06:13 PM

Does anyone know the polarity (tip) of the battery pack for the fan is for the Z10 ?

#75 Tim L

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Posted 04 December 2010 - 03:57 PM

One question I have is regarding the collimation of the collimator. Do I put it on a stable stand and then rotate it in a circle in one place with the beam on a wall, adjusting the screws until it doesn't create a circle during the entire 360 degree rotation?

Does anyone in this thread have pictures of this procedure?


Capstain,

You've got it right--point the laser at the wall and rotate it in a secure holder.

Scroll up in this thread to posts #3633302 and 3633318. There's a little more "how to" in those posts.

Jason D also posted a diagram early in this thread showing how you can use your OTA as a jig.

Best to you!


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