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CounterWeight
Pooh-Bah
Reged: 10/05/08
Posts: 1305
Loc: PDX chronoplast
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Hello all,
Well I'll know a little more maybe later today if time permits. I've been noticing on my images that some have a 'spike' in the dec direction (and only) looking like a light stripe across the middle of the stars. I hasn't happened a lot, and I haven't had to toss out many images. I've on ocassion heard a loud 'click' sound while slewing but thought it was something else.
Last night I was shocked terribly as the clicking became prominent and consistent during a slew! Yikes.. almost like someone was tapping loudly on the housing with the handle of a screwdriver. On slowing down onto the target there was a visible image shift along with a click or two. Then it started happening pretty regularly - each time the image would shift in the dec direction. After about 30 minutes it stopped and none of the images show the spiking.
What could be the cause? And more importantly what can be done to remedy the problem?
I just processed this to show what the result is in an image...
As always, thanks for any help 
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CGE (Frankenmount mod.)
Onyx 80ED, Tak FS-128 #02058, TEC APO160ED #030
CCD: Orion SSPDSCIv2, SSI3, SSAG
diags, ep's, tubes, filters, Binocs
My CN Image Gallery
Experience is a difficult teacher, it gives the test first, and gives the lesson later
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David Pavlich
Postmaster
Reged: 05/18/05
Posts: 8683
Loc: Mandeville, LA USA 30.22 X 90....
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That almost sounds like a tooth missing on a gear. You need to take the Dec. cover off and watch the inner workings while slewing.
David
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Proud Member; PAS NOLA,
"If we knew what we were doing, it wouldn't be called research..."
A. Einstein
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Eddgie
Carpal Tunnel
Reged: 02/01/06
Posts: 2703
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I is possible that there is a tooth damage, however, I think that if the worm mesh has gotten to big, this can cause the problem too.
What will happen is that the worm gear can start nipping at the side of the crown of the worm wheel teeth. Bad. Bad. Very bad. While it may not break the tooth, it can cut into it causing a metal burr.
The other possibility is that something has gotten into the gear mesh. Bad only if it was to hard to crush (there is tremendous pressure on this gear interface and it can grind bone). If it passed though, it could have bent the worm wheel though. and that would give your symptom.
Open the the hosing SOON. As I recall, it is four screws.
Use the controller to move the mount in dec (you don't have to latch the cluth, just watch the dec worm turn). If the worm is bent, that is your problem. Now you just have to find out what bent it.
If the worm is not bent, check the mesh. (you can do this even with the cover on.. Lock the clutch and attempt to move the saddle in DEC. If it moves more than a tiny amount, either the worm is bent or the backlash needs adjusting).
My guess is that something got in there and possible bent the worm.
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Celestron C14, CGE (Big Al)
Astro-Physics 6" f/8 (Buffy)
Televue 101 (No name, but I call it my Widescreen HD Space TV)
The night sky is my mistress. She seduces me away from all other lovers.
Edited by Eddgie (09/21/09 02:34 PM)
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CounterWeight
Pooh-Bah
Reged: 10/05/08
Posts: 1305
Loc: PDX chronoplast
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Thanks David,
I'll be doing that early evening. Out of a stream of 36 - 8 minute images only the first six had this, a missing tooth might explain it all.
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CGE (Frankenmount mod.)
Onyx 80ED, Tak FS-128 #02058, TEC APO160ED #030
CCD: Orion SSPDSCIv2, SSI3, SSAG
diags, ep's, tubes, filters, Binocs
My CN Image Gallery
Experience is a difficult teacher, it gives the test first, and gives the lesson later
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CounterWeight
Pooh-Bah
Reged: 10/05/08
Posts: 1305
Loc: PDX chronoplast
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Thanks Ed,
The symptom first showed up about 2 weeks ago - in an occasional image I'd get this, thought it was maybe a guidescope shift or something not correctly secured. I'll be opening it up as soon as I can this eve to take a look.
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CGE (Frankenmount mod.)
Onyx 80ED, Tak FS-128 #02058, TEC APO160ED #030
CCD: Orion SSPDSCIv2, SSI3, SSAG
diags, ep's, tubes, filters, Binocs
My CN Image Gallery
Experience is a difficult teacher, it gives the test first, and gives the lesson later
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Eddgie
Carpal Tunnel
Reged: 02/01/06
Posts: 2703
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I said worm WHEEL, but of course that was a mistake. I may have bent the worm itself.
Let us know what you find out.
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Celestron C14, CGE (Big Al)
Astro-Physics 6" f/8 (Buffy)
Televue 101 (No name, but I call it my Widescreen HD Space TV)
The night sky is my mistress. She seduces me away from all other lovers.
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CounterWeight
Pooh-Bah
Reged: 10/05/08
Posts: 1305
Loc: PDX chronoplast
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Well, this is weird. Both RA and DEC appear tight with no play in RA or DEC if movement attempted (with slight pressure) with mount powered up and at home position.
The sound is coming from both the RA and DEC housings. I removed the scopes and mount D plate mounting platform. Removed the covers for both motor/gear housings. Slewed and looked at the gear / worm gear operation. The worms and gears 'appear' good, no maring or bend on worm, or missing/bad teeth on the gear. The operation of the two gear connecting the motor to the worm gear assy look fine also. I had to look from top, but on each side of the actual friction point - it's extremely difficult to look at the contact point directly as the assy are in the way and the worm gear housing obscures from above.
The noise is random and inconsistent - sometimes it happens and sometimes not and almost never in the exact same place from time to time, and seems to happen anywhere druing movement from stop to stop or not at all. Apparently 'load' isn't a factor as it does it without scope(s) or counterweight(s). Whatever is doing it I cant see.
Slapped the covers back on, reattached cw mount bar and cw's, re-mounted scopes. Balanced scopes / cw's. "Kochab clock" PA'd and did a 2*4 align (occasional click heard), put imager on the big scope, slewed to NGC7023 and it was near center on imaging chip. !?! Atm was terrible! couldn't get FWHM or HFD under 6's most of time, this while guiding. So I gave up on imaging and tried to look at Jup, Nep, Ura and seeing was just terrible to horrible. So I hung it up for the night.
Will try to call "C" today and see what they have to say. Could it be a lube problem? I'd at this point characterize it as 'random skipping'.
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CGE (Frankenmount mod.)
Onyx 80ED, Tak FS-128 #02058, TEC APO160ED #030
CCD: Orion SSPDSCIv2, SSI3, SSAG
diags, ep's, tubes, filters, Binocs
My CN Image Gallery
Experience is a difficult teacher, it gives the test first, and gives the lesson later
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gnowellsct
professor emeritus
Reged: 06/24/09
Posts: 733
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Hard to imagine what could bend a worm gear, unless they're using something real skinny and fragile!
Servos dying maybe? I thought servos were prone to rapid suicide in failure mode.
Greg N
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"Aperture will get you through times of no money better than money will get you through times of no aperture."
featuring selected astrojunk:
bunch o' widefield eyepieces
bunch o' narrowfield eyepieces
couple o' Barlows
couple o' scopes
couple o' mounts
couple o' tripods
and a pier 'n' stuff
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gnowellsct
professor emeritus
Reged: 06/24/09
Posts: 733
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Just a thought if the problem is erratic it could be in the wires somewhere, i.e. intermittent power cutoffs causing abrupt starting and stopping of the motors for a click or tapping sound. I recall reading that CGE has bad wires and that a lot of people get better wires right away (on the Yahoo CGE group, I lurk from time to time).
good luck,
Gre gN
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"Aperture will get you through times of no money better than money will get you through times of no aperture."
featuring selected astrojunk:
bunch o' widefield eyepieces
bunch o' narrowfield eyepieces
couple o' Barlows
couple o' scopes
couple o' mounts
couple o' tripods
and a pier 'n' stuff
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CounterWeight
Pooh-Bah
Reged: 10/05/08
Posts: 1305
Loc: PDX chronoplast
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It's an odd one to be sure. The wiring has been redone and tested, no symptoms like that missing 'sheath' signal path - thankfully But with this mount certainly shouldn't be overlooked - so I'll test again. It hadn't crossed my mind to do so.
I need to finish prep for a talk tomorrow night, so my mental resources are limited until that is completed (an active field / galaxy shapes, structure, distribution)... please keep any ideas coming ? thanks again.
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CGE (Frankenmount mod.)
Onyx 80ED, Tak FS-128 #02058, TEC APO160ED #030
CCD: Orion SSPDSCIv2, SSI3, SSAG
diags, ep's, tubes, filters, Binocs
My CN Image Gallery
Experience is a difficult teacher, it gives the test first, and gives the lesson later
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lineman_16735
Tak-o-holic
Reged: 12/04/04
Posts: 2604
Loc: Central PA
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Could it simply be dec backlash that is finally overcome by autoguider corrections then....jump?
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Chris
A mount from Illinois
A scope from Japan
A camera from Cal-I-Fornia
A dog from Kentucky
A wife and kids from the "Twilight Zone"
The Geek Shed
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CounterWeight
Pooh-Bah
Reged: 10/05/08
Posts: 1305
Loc: PDX chronoplast
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Well, it just stopped? At least for now. Two nights ago fine for visual but unable to image at all - star trails all over the place, thing sounded like a popcorn popper!. Just let it sit, and went to bed. Tonight I started visual and no clicking sound, and not a click or a clack!, so now I'm taking 9 minute exposures of the soul... I don't know if I should be happy or not?
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CGE (Frankenmount mod.)
Onyx 80ED, Tak FS-128 #02058, TEC APO160ED #030
CCD: Orion SSPDSCIv2, SSI3, SSAG
diags, ep's, tubes, filters, Binocs
My CN Image Gallery
Experience is a difficult teacher, it gives the test first, and gives the lesson later
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Alph
sage
Reged: 11/23/06
Posts: 261
Loc: Melmac
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Quote:
The noise is random and inconsistent - sometimes it happens and sometimes not and almost never in the exact same place from time to time, and seems to happen anywhere druing movement from stop to stop or not at all.
If it sounds like in this video http://www.youtube.com/watch?v=2Uqld79zW60 then you have bad worm shaft bearings. You can get a pair for $30 from Celestron.
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gnowellsct
professor emeritus
Reged: 06/24/09
Posts: 733
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Quote:
Quote:
The noise is random and inconsistent - sometimes it happens and sometimes not and almost never in the exact same place from time to time, and seems to happen anywhere druing movement from stop to stop or not at all.
If it sounds like in this video http://www.youtube.com/watch?v=2Uqld79zW60 then you have bad worm shaft bearings. You can get a pair for $30 from Celestron.
Wow bad bearings. And celestron charges to replace them!!!
That's a new one on me. GN
--------------------
"Aperture will get you through times of no money better than money will get you through times of no aperture."
featuring selected astrojunk:
bunch o' widefield eyepieces
bunch o' narrowfield eyepieces
couple o' Barlows
couple o' scopes
couple o' mounts
couple o' tripods
and a pier 'n' stuff
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CounterWeight
Pooh-Bah
Reged: 10/05/08
Posts: 1305
Loc: PDX chronoplast
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Thank you Alph for the utube link - that is it!!
Yep... when it happens it sounds like a popcorn popper, mine I guess is doing it on both axis so multiply that sound by 2! - I did phone Celestron abt it - mount is still under warranty 'on paper' - actually got to talk to someone again WOW that is great - and a welcome change. I guess they replace for free if i sent in the mount head, but I dont want to be without it for so long.
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CGE (Frankenmount mod.)
Onyx 80ED, Tak FS-128 #02058, TEC APO160ED #030
CCD: Orion SSPDSCIv2, SSI3, SSAG
diags, ep's, tubes, filters, Binocs
My CN Image Gallery
Experience is a difficult teacher, it gives the test first, and gives the lesson later
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CounterWeight
Pooh-Bah
Reged: 10/05/08
Posts: 1305
Loc: PDX chronoplast
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OK...
When the new one's get here(bearings), any pointers about replacement, lube/grease?
Thanks everyone - hope this does it.
Jim
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CGE (Frankenmount mod.)
Onyx 80ED, Tak FS-128 #02058, TEC APO160ED #030
CCD: Orion SSPDSCIv2, SSI3, SSAG
diags, ep's, tubes, filters, Binocs
My CN Image Gallery
Experience is a difficult teacher, it gives the test first, and gives the lesson later
|
Alph
sage
Reged: 11/23/06
Posts: 261
Loc: Melmac
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Quote:
When the new one's get here(bearings), any pointers about replacement,
There is some info on how to disassemble the worm shaft on the CGE yahoo group in the files section. You could also search the message archive there for ‘worm bearings’ to get additional tips/hints.
If I were you I would send the mount to Celestron. Their standard procedure is to replace whole motor assembly. Don't let them get away with it so easily. Alternatively, if they agreed to ship the bearings free of charge (Is that right?), they should also agree to shipping whole motor assembly.
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