Jaxdialation
Carpal Tunnel
Reged: 04/01/07
Posts: 1791
Loc: St. Augustine, FL
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Another approach to the spring removal issue
Really long web link that makes everyone scroll left and right
Edited by Don W (12/28/07 01:43 PM)
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pike_fly
sage
Reged: 10/10/07
Posts: 365
Loc: Roxborough Park, Colorado
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I found this link very helpful for figuring out why my finderscope wouldn't focus. Apparently the lock-ring on many of the RAFS are too wide to properly focus. Removing it solved my problem.
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Lee
8" Celestron f6 Dobsonian
10" Zhumell Dobsonian
Class 4 Bortle Scale Backyard Site
View Lee's Gallery
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MtnGoat
scholastic sledgehammer
Reged: 02/18/07
Posts: 922
Loc: Columbia Gorge, WA
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I'm still not sure what to think about my RAFS. It's my first one, and though the image being correct orientation is nice, for some reason I actually found it easier to deal with the reverse image in the straight through versions when it comes to moving the scope around. I'll give it some time and see if it gets easier as I accrue more hours, otherwise I may seek a swap with someone who wants it or try and get a new eyepiece assembly in the straight through configuration.
This is also my first experience with the newfangled "two screws opposite a tensioner" approach to finder alignment, all my other scopes are older ones using the two sets of three screws approach. I was skeptical, but I have to say the new approach is great. True, it's easier to knock it out of whack because the tensioner has some give in it and it never quite returns to exactly the same spot after a bump, but I don't bump it much and dealing with only two screws makes the alignment pretty danged fast. Thumbs up on this idea from me.
On the tensioning springs saga evident in this thread....I bought some 1.5" keyrings that my fingers easily fit into before my scope arrived. I installed them on the springs when I got it, replaced Zhumells spring knob/bolt combo with short bolts of the same thread and a locking nut at the bottom, and this arrangement works fine. The large keyring provides enough leverage to set the springs ok, and the spring eyes slip over the bolt heads OK.
I don't mind setting off to modify factory gear right off the bat, I also fly RC sailplanes and 'improvements' over the factory kits, even preassembled planes, are not only common but expected since everyone has some particular idea of what they want (or not) on their bird. We call it "kit bashing". So I guess I'd call the mods here "scope bashing", but when dealing with an optical instrument this phrase has a much more ominous sound!
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"Ignorant people think it's the noise which fighting cats make that is so aggravating, but it ain't so; it's the sickening grammar they use." Mark Twain
Edited by MtnGoat (01/17/08 12:19 PM)
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Jaxdialation
Carpal Tunnel
Reged: 04/01/07
Posts: 1791
Loc: St. Augustine, FL
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I think you hit the nail on the head, RC stuff, computers, telecopes initially have an intimidation factor. I'd have to say that a Z10 is way more forgiving and easier than opening up a computer for the first time. A real confidence builder when you know you can take the whole thing apart and put it back together again. The next hurdle for me was realizing looks weren't that mportant 'cause its dark when you use them 
Quote:
I don't mind setting off to modify factory gear right off the bat, I also fly RC sailplanes and 'improvements' over the factory kits, even preassembled planes, are not only common but expected since everyone has some particular idea of what they want (or not) on their bird. We call it "kit bashing". So I guess I'd call the mods here "scope bashing", but when dealing with an optical instrument this phrase has a much more ominous sound!
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John
SST/Tak/RCOS/SBIG/CCDWare
I started CCD AP December '07 Why didn't someone stop me?
New Zhumell Owner? Read this: New Zhumell Owner Upgrade Mega Thread
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Tom Andrews
professor emeritus
Reged: 01/25/07
Posts: 605
Loc: Homebase - Albuquerque, NM; c...
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My neighbor has a Z10 and we've been experimenting. We abandoned the primary collimating "locking" bolts, screwed the collimating bolts all the way in as far as possible by hand then backed them out to collimate. The original springs seem to be holding very well and the bolts had to be screwed out very little to collimate. In fact, collimating this way, there was much less movement in the screws overall than screwing them in to collimate. By compressing the springs, they hold collimation better than before. He's had the scope out 2 or 3 times so far and hasn't had to collimate.
If anyone else who hasn't already bought new springs tries this we would appreciate knowing how it worked for you. This could be done even with new springs.
By the way, has anyone tried this already?
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Tom
The Secret To Life:
Focus on what you have, not on what you don't;
Focus on what you can do, not on what you can't.
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MtnGoat
scholastic sledgehammer
Reged: 02/18/07
Posts: 922
Loc: Columbia Gorge, WA
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That's a great idea. I'm going to have to try that.
First, I'd better check out the focus position on all my eyepieces to make sure that changing the mirror position won't put me out of reach of focus on any of them.
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"Ignorant people think it's the noise which fighting cats make that is so aggravating, but it ain't so; it's the sickening grammar they use." Mark Twain
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DaveDog
sage
Reged: 06/15/07
Posts: 301
Loc: near Blue Ridge Mts, VA
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Tom,
Yea, that is pretty much what I did with my primary springs too. I just loosened the "locking screws" altogether, tightened the collimation screws all the way in, then adjusted the primary and have not looked back since. My scope holds collimation just fine, even with the autocollimator. The locking bolts just throw it out of collimation anyhow if you use them.
I never could figure out why everyone wants to replace the primary springs. I never had any trouble with them.
Dave
Z10
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Lucky13
sage
Reged: 10/21/07
Posts: 281
Loc: Ashtabula, Ohio
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I made a thread previously on the tension spring issue, but I figured I would preserve it for posterity 
Here's my solution.
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Sean
A Z10 and some other stuff 
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proud uncle
Pooh-Bah
Reged: 01/22/07
Posts: 1336
Loc: Central Texas
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Tom, I basically did the same thing with the primary collimation screws. I have not removed the locking screws, but just screw them in until I have the slightest resistance. I probably don't need them, but they don't seem to cause any problem so long as I don't tighten them too much.
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Kenneth
Zhumell 10" Dobsonian (f/4.9)
2" 32mm WA eyepiece
9mm, 12.5mm, and 20mm Plossls
6mm TMB/BO Planetary
2" 2x ED Barlow
Nikon 10x50 binocular (6.5 deg FOV)
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Tom Andrews
professor emeritus
Reged: 01/25/07
Posts: 605
Loc: Homebase - Albuquerque, NM; c...
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Last year I modified my 8" Coulter Odessey which was built in 1988 and had no springs for collimating bolts. I made new bolts, bought springs at a fastener shop, tightened the collimating screws all the way down then backed them out for collimating. This was the easiest time I ever had collimating this scope and it stayed in place for months at a time. I told my neighbor about it and we did it to his Z10 a couple of weeks ago and haven't had to touch it since. We had it out again tonight with no collimation required. To me, it's the way to go.
Glad it's working for others also.
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Tom
The Secret To Life:
Focus on what you have, not on what you don't;
Focus on what you can do, not on what you can't.
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pike_fly
sage
Reged: 10/10/07
Posts: 365
Loc: Roxborough Park, Colorado
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So you went backwards? Instead of tightening the bolts ont he primary you loosen them for collimation? How much travel did you have in your collimationg screws? It's an itersting idea, but my 8" dob (1995, not as old as yours) screws have adjustibility of over an inch, and my sweet spot is nearly all the way backed out. I've seen the strength of springs keeps the mirror at the end of the adjustment length and makes a big difference. I'm no collimation pro, but it looks like you have to know your scope when you decide which position to start the adjustments. As a new Z10 owner its good to hear that it may be easier to start with the adjustments all the way in and then back out, but for some scopes it may take longer if you start that way. I guess its really six to one half dozen to another. Does anyone else find the sweet spot closer in? Thanks for the info.
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Lee
8" Celestron f6 Dobsonian
10" Zhumell Dobsonian
Class 4 Bortle Scale Backyard Site
View Lee's Gallery
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proud uncle
Pooh-Bah
Reged: 01/22/07
Posts: 1336
Loc: Central Texas
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Thanks for the point, Tom. After reading all these posts about people needing to replace those springs, I was starting to wonder if I was missing something relative to collimation. For me, I do not transport the Dob any further than between my bedroom and back yard, which is all level -- no stairs or rocks. If I was regularly transporting it some distance in the car, that may make a difference. But, it also makes sense, the closer to fully compressed springs are, the greater likelihood of that tension holding. I'm a believer in "if it's not broke, don't fix it". Though I may change the springs some time in the future, I don't plan to in the near future.
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Kenneth
Zhumell 10" Dobsonian (f/4.9)
2" 32mm WA eyepiece
9mm, 12.5mm, and 20mm Plossls
6mm TMB/BO Planetary
2" 2x ED Barlow
Nikon 10x50 binocular (6.5 deg FOV)
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Tom Andrews
professor emeritus
Reged: 01/25/07
Posts: 605
Loc: Homebase - Albuquerque, NM; c...
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Quote:
So you went backwards? Instead of tightening the bolts ont he primary you loosen them for collimation? How much travel did you have in your collimationg screws? It's an itersting idea, but my 8" dob (1995, not as old as yours) screws have adjustibility of over an inch, and my sweet spot is nearly all the way backed out. I've seen the strength of springs keeps the mirror at the end of the adjustment length and makes a big difference. I'm no collimation pro, but it looks like you have to know your scope when you decide which position to start the adjustments. As a new Z10 owner its good to hear that it may be easier to start with the adjustments all the way in and then back out, but for some scopes it may take longer if you start that way. I guess its really six to one half dozen to another. Does anyone else find the sweet spot closer in? Thanks for the info.
Lee,
It is an experiment because this also changes the position of your focusing tube to get focused though usually insignificantly. In my Coulter however, I added an inch of spring that wasn't there before which changed my focal length and everything else. From decompressed to compressed, bolt travel was about 1/2"-3/4". I have a very long focusing tube and it worked but focusing went from one end of the tube to the other.
I compressed the collimating springs on my 2007 Discovery PDHQ 12.5" scope and collimate backwards and it works very well also. I had about 1/2" travel from decompressed to compressed.
On both mine and my neighbor's Z10, the travel is far less than going the other way. In fact, I found this interesting: on my Discovery and Ron's Z10 we only adjust two bolts; one is not turned at all. On my Discovery almost all the adjustment is on one bolt, the other is between 1/8-1/4 turn. On Ron's Z10, the two that are adjusted are adjusted approx. equally. This isn't the case on my Coulter, I have to use all 3 for collimation.
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Tom
The Secret To Life:
Focus on what you have, not on what you don't;
Focus on what you can do, not on what you can't.
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Tom Andrews
professor emeritus
Reged: 01/25/07
Posts: 605
Loc: Homebase - Albuquerque, NM; c...
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Quote:
I found this link very helpful for figuring out why my finderscope wouldn't focus. Apparently the lock-ring on many of the RAFS are too wide to properly focus. Removing it solved my problem.
We tried this on my neighbor's Z10 last night and it did the trick. Now he can actually use the finder scope whereas before now, it was a hunk of junk decorating the scope. We had been talking about buying him a different one. Thanks for the post on this! 
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Tom
The Secret To Life:
Focus on what you have, not on what you don't;
Focus on what you can do, not on what you can't.
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Lucky13
sage
Reged: 10/21/07
Posts: 281
Loc: Ashtabula, Ohio
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Quote:
We tried this on my neighbor's Z10 last night and it did the trick. Now he can actually use the finder scope whereas before now, it was a hunk of junk decorating the scope. We had been talking about buying him a different one. Thanks for the post on this!
Yeah, once I figured out how to focus the Z10's finder, I really like it. You can actually see some DSO's right in the finder! How cool, compared to my old Tasco!!
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Sean
A Z10 and some other stuff
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RS67Man
Tinker King
Reged: 11/10/07
Posts: 740
Loc: Spanaway, WA USA!
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My list of mods so far:
(1) Locktight on the altitude bearing screws.
(2) Telrad.
(3) Degree circle in base.
(4) Aiming knob at end of OTA.
(5) Altitude spring elimination kit.
(6) Remounted cooling fan to a aluminum plate.
(7) Replaced AA battery pack with a 12v 4.4ah battery.
See Pics!
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Celestron 15X70 binos
Zhumell 10" "Photon Cannon"
Baader Hyperions 5mm, 8mm, 13mm, and 17mm, + FTR's
70mm Meade refractor on "broken" 494 Autostar tripod
6" F/8 "Ellis" 50 Year Old Newtonian Project!
AEACC The Automatic Electric Aluminum Can Crusher thread
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pike_fly
sage
Reged: 10/10/07
Posts: 365
Loc: Roxborough Park, Colorado
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Here's the thread for additional ways to remove and mount the fan. Click here.
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Lee
8" Celestron f6 Dobsonian
10" Zhumell Dobsonian
Class 4 Bortle Scale Backyard Site
View Lee's Gallery
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BradC
sage
Reged: 01/31/07
Posts: 420
Loc: St. Louis, MO
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A while back I posted a method for giving your laser collimator a pinpoint dot. It even gives the beam a faint refraction pattern that can be used like a barlowed laser! (Don't forget to collimate the laser, too!)
Another important requirement: Check the center spot of your primary mirror to see if it is actually in the center! My Z10 center spot was about 1mm off, which makes a surprising amount of difference when trying to get perfect collimation.
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My God! It's full of stars!
Zhumell 10" dob - First Light Report
Celestron OptiView 10x50 LPR Binoculars
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Laurel
super member
Reged: 02/11/07
Posts: 130
Loc: Iowa,USA
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Got a Zhumell 8" DOB coming soon and was wondering if anyone knows if the Orion 2x shorty barlow will work in it without a problem?I've been reading through the forums and seen where some have to move the eyepiece in the focuser,or move the primary mirror to achieve focus.
This is the first time I've posted outside the Begginer Forum,Hope it's in the right place.
Laurel
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Jaxdialation
Carpal Tunnel
Reged: 04/01/07
Posts: 1791
Loc: St. Augustine, FL
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Laurel,
Sorry, I don't have any experience with the Orion Borlow.
If you don't get an answer here you might want to try posting this as a new thread in the relector forum.
Congrats on your new purchase, I see you have a Telrad on the way too. If you have the barlow already, I'd wager that it will work...Orion and Zuhmell scopes are very similar.
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John
SST/Tak/RCOS/SBIG/CCDWare
I started CCD AP December '07 Why didn't someone stop me?
New Zhumell Owner? Read this: New Zhumell Owner Upgrade Mega Thread
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