
Mega-mod thread for Zhumell dobs
#101
Posted 13 January 2011 - 02:34 PM
(I'm Polish. That sort of stuff happens to me all the time ...)
If I were to attempt removing the mirror, I think I'd try a heat gun first. Looks like there's a bit of a gap around the edges of the barrel, so once the adhesive fails (somewhere around 300F if I remember right), the mirror should drop right out ... theoretically of course. I'm sure the mirror would survive, but depending on how they silver their glass, that could be a problem at those temps. Try it out on some sacrificial glass first. Reattachment is another thumb twiddler - I'd be tempted to try using a bit of that rope caulk 3M makes for seating windshields. Just happen to have a roll of that in the workshop. You can spread that real thin, and you're talking 100% coverage with superior bonding. A good wipe with isopropyl alcohol first of course. As in, no mirrors falling off and denting the primary.
(Did I mention I was Polish?) <G>
I was also interested in the "DewGuard" tech that Kendrick offers on some of their heaters. Supposed to take the guesswork right out of it and fire the heater only when needed. That'd certainly reduce power drain. Sent an email last night - already got a response. How's THAT for tech support?
Unfortunately, they're not currently planning to offer that option on the wraparound heaters. They did say I could run one in series with one of their DigiFire controllers - starting at around $170. NOT including a power supply. Yeowch. That IS a four channel unit, so if you're right serious about dew, I supposed it'd be a good investment. I might have to wait till I hit the MegaBall numbers tho. I figure I'd have more into heaters than I've got into the entire setup at this point.
* I'm gonna email them back and volunteer to test a protype DewGuard barrel heater for them. Hey, why not? Also plan to ask specifically about the 3M tape and potential heat conduction issues. That's pretty thin stuff, but we're also talking really low current thru the heater.
<EDIT>
Holy carp! Already got a response on the heat conduction issue - in a word ... not a problem.
OK - that's three words. My bad.
</EDIT>
#102
Posted 13 January 2011 - 02:57 PM

Still looking around for a nice bubble level for the base. I've got a digital level for elevation - I suppose I could use that, but a bubble would be much easier for setting the rocker box on all axes simultaneously.
#103
Posted 13 January 2011 - 03:17 PM
Pretty slick little unit. No backlight, but that's a good thing, right? Easy to read under red light, and that's the important thing. If I have a complaint, it's that there's no automatic power down. Not a biggie. It uses a standard CR2032 battery that you can get most anywhere.
Thing is also surprisingly heavy for it's size. I figure to mount it on a slide on the OTA and get bonus value as a counterweight.
Cloudy Nights TOS does not allow reproducing images from other web sites. Image removed by moderator.
Ah. Missed that part. Must have been between the blah de blahs and the wa wa wawawa wa's ... my bad. <G>
Worth a pic tho. Here's my certified personal photo, complete with the 9mm 1¼" supplied with the Z8 as a reference for size. Like I said, compact lil devil, it is. Two inch square, 1¼" deep.

Just got done fabbing and painting the slide for the OTA. I'll post up a pic of that when I git er done.
#104
Posted 13 January 2011 - 08:06 PM
#105
Posted 13 January 2011 - 10:55 PM
Good catch - I've melted plastic with my heat gun before. I saw the metal mirror clip and base plate on the mount barrel and just assUmed the body was metal. Proof positive I haven't a clue what I'm doing here ... <G>
Looks like PLAN A is going with the wraparound heater.
Or Plan B? I'll eventually park the scope out in a shed so it stays more or less ambient temp. If I leave the fan on all the time running on a 12v wall wart, would dew even be an issue?
#106
Posted 14 January 2011 - 07:05 PM
If I do decide to go with both, preferred mounting location? Reason I ask now is the tube is still torn down and now would be a good time to add mounting holes if needed.
#107
Posted 14 January 2011 - 08:26 PM
I think the best finder setup is an illuminated optical finder with a RACI diagonal and a Telrad. I use the Telrad to get me in the general area of the object, use geometrical orientation, or to sight on the nearest obvious star. Then I use the optical finder and a star atlas to center the object more precisely before I view it in the telescope. I prefer the Sky & Telescope Pocket Sky Atlas. Who needs goto or DSCs?

Mike
- oddlad likes this
#108
Posted 14 January 2011 - 09:03 PM
Next step is flocking. I'm going with ProtoStar's new FlockBoard. No adhesive, so if I do need to get in there again, it's easy enough to remove and make any necessary changes. Stuff's just held in place with spring tension. Also good if I were to decide to add some other doodad down the road.
The Sky & Telescope Pocket Sky Atlas sounds like it'd make a nice addition to my library. I did pick up on Nightwatch and Michigan Starwatch at the recommendation of a friend. Between those, I should be able to muddle thru.
* PS ... I sent an email to ProtoStar when I was researching materials - they tell me they now have complete tube liners for all the GSO scopes. They're still working on the manuals and haven't listed them on the website, but will supply just the tube if anyone's interested. The 8" version is $84 shipped.
#109
Posted 15 January 2011 - 07:31 PM
_______
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.

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.

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.

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.

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.
#110
Posted 15 January 2011 - 09:07 PM
Looking good. Nice work.
Your giving me mod fever. I will soon be installing handles and a battery pack holder. Flocking in the future.
Thanks for sharing...
John in Oregon
#111
Posted 15 January 2011 - 09:22 PM

#112
Posted 16 January 2011 - 12:50 AM
This here is just me getting the silly out of my system. Amazing what you can find laying about when you're digging thru the parts bins ...

Seemed somehow appropriate - the people's telescope, and all that ... <G>
#113
Posted 16 January 2011 - 01:02 AM

Had to complement the girl on the desk for their fantastic collection of telescope parts. Got one of THOSE looks ...

- NickInSac likes this
#114
Posted 16 January 2011 - 01:44 AM

Here's how the circle goes together ...

The circle goes on first, followed by the plexiglas protector, and then the first bearing surface. I cut the plexi from a 18"x24" poster frame I got at the big box store for $8. Nice and thin. Cut that at 18" to overlap the circle for protection. Word of warning - that stuff is VERY brittle and had a tendency to chip and crack a bit when I was cutting the circle. Not a biggie - I'm the only one that will ever see it. (OOps ... until now anyway). Same thing with cutting the paper - more or less round is good enough. The bearing seemed dry to me, so I swiped each roller with some blue lithium before adding the top bearing plate.
Now for the hole. Doesn't do much good if you can't see it.
Lay it out ...

I went with 1¼" for the hole diameter. Ran it thru with a hole saw, then rounded the corners with a router. Cut a slot with a dremel and hot glued a piece of 22 guage telephone wire in for a reticule.

Last step was adding a dress up ring on the top of the circle. Got that out of the lamp parts aisle. Just pops right in. All that, and this is what you see ...

- buddyjesus and CharlesB like this
#115
Posted 16 January 2011 - 08:53 AM
BIG THANKS TO THE ORIGINAL POSTER I didn't. Know you could rotate your focuser
#116
Posted 16 January 2011 - 12:00 PM
Power tools ... they make life easy
Power tools ... they make life fun!
(Let me guess - I'm the only Planet P fan out here)
OK then ... something original. Hmmmmm. Well ... I DID straighten out the "Z". Talk about your lousy quality control!

#117
Posted 16 January 2011 - 02:32 PM
Half Degree Base Mod--Finally Finished
#118
Posted 16 January 2011 - 03:32 PM
Real easy to replace the circle I'm using, but I'm having to do some serious resizing in photoshop to make yours fit my Z8. Mine ends up half the size of the original, so the degree markers are correspondingly closer. Here's an actual size section to show what I end up with. This is a jpeg - I saved the resized image as bmp to reduce any chance of artifacts, and that's a step or two clearer than this ...

(Hardly finished my mod and now I gotta mod it) <G>
Killer resolution, so I'm definitely going to get one professionally printed. My home laser is black and white, and my trusty old ink jet will never handle that resolution gracefully.
I do have a small lens that fits the hole on mine. Seemed a bit overkill for the scale I was using, but I can see where it could be a big advantage going with the half degree marks. I <may> also have to reduce the size of the reticule to take advantage of the finer resolution - easy as stripping the same size wire I'm currently using and painting it red. I'll have to see what the actual circle looks like when done.
Thanx for the link!
#119
Posted 16 January 2011 - 03:53 PM
#120
Posted 16 January 2011 - 03:58 PM
#122
Posted 16 January 2011 - 05:21 PM
The JPG you posted is actually quite clear, but the higher quality pic would be greatly appreciated. I saved that to BMP (lossless) so there's no degradation. JPEGs typically hold up fairly well thru second generation anyway. After that, it's progressively worse. Just the nature of the beast. If you look close at the section I posted, you can see some ghosting on the lines - none of that in the BMP version I was planning to work with, even after resizing. At half the original print size, that weighs in at about six megs ...
#123
Posted 16 January 2011 - 06:30 PM
#125
Posted 17 January 2011 - 10:56 AM