ccasal
member
Reged: 05/11/09
Posts: 18
Loc: San Juan, PR
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Hi guys,
I have a friend who has a CI-700 he bought back in 99. Recently he purchased an Orion Autoguider and we are having a lot of problems guiding the mount. This mount has the original stepper motors. For some reason usually starts guiding correctly until it just goes haywire usually in Dec.
We have played with the aggressiveness in PHD and other parameters but no luck. We also tried Maxim with same results.
Anyone has any insight into what could be the problem.
Thanks
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Carlos
Orion 8" Newtonian
Sirius EQ-G
Canon Rebel XT (Unmodded)
Orion 4.5" Starblast
Orion SSAG
http://picasaweb.google.com/carlos.casaldeiro/BudgetAstrophotography?feat=directlink
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Synergy
sage
Reged: 11/18/03
Posts: 254
Loc: Reading, UK
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Hi Carlos, i used to own a CI700 for AP and never got auto guiding to work properly, Especially in DEC. I think this was due to various problems such as the DEC worm being slightly bent and binding or slipping with the main gear.
Another issue i had was with the clutches slipping. If the scope was even slightly off balance, PHD couldn't do a proper calibration and if it did, when it tried to make a correction sometimes it just didn’t move until PHD and sent loads of corrections. Then there was back lash and worm play issues making everything worse.
The steps I took to try and address this were..
Add grippy clutch pads to the clutches
Balance the scope precisely for the area of sky you’re imaging
Set PHD to only make DEC corrections in North or South direction not Auto. This will make PHD only make corrections in one direction, the other direction will be handled by the natural drift caused by the mount not being perfectly polar aligned.
Set the CI700 to 0.7x guide rate (I think) or at least don’t use a really slow setting.
I also noticed there was a regular bump in the worm on the RA axis which caused PHD issues.
Strip down the whole mount and re-grease everything
I hope this helps, I sold mine in the end and got an EQ6 Pro :-)
George
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Celestron C9.25
WO ZS80II ED
EQ6 Pro
Canon 350D
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ccasal
member
Reged: 05/11/09
Posts: 18
Loc: San Juan, PR
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Thanks George,
He has already dealt with the clutches and stripped and regreased the mount... We are able to do calibration... and it guides for a couple of minutes but then it always starts bouncing back and forth... like its overcompensating...
Were you able to guide for a while?
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Carlos
Orion 8" Newtonian
Sirius EQ-G
Canon Rebel XT (Unmodded)
Orion 4.5" Starblast
Orion SSAG
http://picasaweb.google.com/carlos.casaldeiro/BudgetAstrophotography?feat=directlink
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MDearingJaxFL
Astronomicus
Reged: 08/28/04
Posts: 2092
Loc: Florida
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my CI-700 tracks well with a DSI- pro used as an autoguider with PhD; but, when I use a side by side ota arrangement, I have to be extremely careful to balance the DEC first and then the RA. BTW, I use the .5X speed position. The size and shape of your payload can track well at higher angles and poorer at lower unless the balance is modified.
:>) mark
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Synergy
sage
Reged: 11/18/03
Posts: 254
Loc: Reading, UK
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Hi Carlos,
Yes I did get it to track ok, but never completely reliably, sometimes something like every 4th image would be ruined and it was usually caused by the load on the motors not being consistent, which was caused by slippage and stickiness in the clutches and load bearings.
An issue I recall was that if the mount wasn’t adequately polar aligned, making a correction in one axis would affect the other axis and in turn the other axis and so on until phd seemed to be constantly making corrections to each axis in turn causing an oscillation.
Setting phd to only make dec corrections in one direction (usually north for me), doing a good polar alignment and setting the guide camera so the guide star would move perfectly vertically and horizontally on the screen, really helped
You might want to check the gear mesh isn’t too tight between the cogs on the motors and the clutch and that your power source can give enough juice as well
I completely agree with Mark’s comment’s, balance was critical to good guiding, you might want to just try guiding with your guide scope on the mount only.
My CI-700 only had issues in dec, unguided, the mount was amazing with 8 minute exposures only showing tiny errors which could have been handled by PEC.
Hope this helps
George
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Celestron C9.25
WO ZS80II ED
EQ6 Pro
Canon 350D
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JoshH
member
Reged: 11/07/08
Posts: 47
Loc: Jefferson City, MO
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What works well for upgrading the clutches? I just picked up one of these mount and any upgrade suggestions would be appreciated. Thanks!
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16" F4.5 Astrosystems Telekit, Galaxy Optics Primary
Meade LX-50 8" F10 SCT Magellen II DSC (For Sale)
Intes Micro MN-56 Maksutov Newtonian
Orion 100mm F6 Achromat
Orion ST-80 F5 Acrhomat
Unistar Alt-Az Mount
Celestron CI-700 Mount
UO 40mm MK-70, 26mm Nagler, 20mm Pentax XW, 13mm Ethos, 8mm Ethos, 4.7mm 5k UWA, TMB Planetary Set, Paracorr.
Modified Canon 400D
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Synergy
sage
Reged: 11/18/03
Posts: 254
Loc: Reading, UK
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Using jar grippers is a good choice, obviously cut them to size. Some people also use washers (from a tap) for the slow motion clutches.I found using the jar gripper material great for both.
I was trying to google some information to share, but don’t seem to be able to find it anymore, however I did download a lot of pictures at the time and some guides which I still have and have zipped them up.
you can download it here..
http://www.webserver.matinee.co.uk/george/ci700.zip
The content of this zip file (12Mb) was created by other people; I hope you find it useful.
George
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Celestron C9.25
WO ZS80II ED
EQ6 Pro
Canon 350D
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JoshH
member
Reged: 11/07/08
Posts: 47
Loc: Jefferson City, MO
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Thanks for the info!
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16" F4.5 Astrosystems Telekit, Galaxy Optics Primary
Meade LX-50 8" F10 SCT Magellen II DSC (For Sale)
Intes Micro MN-56 Maksutov Newtonian
Orion 100mm F6 Achromat
Orion ST-80 F5 Acrhomat
Unistar Alt-Az Mount
Celestron CI-700 Mount
UO 40mm MK-70, 26mm Nagler, 20mm Pentax XW, 13mm Ethos, 8mm Ethos, 4.7mm 5k UWA, TMB Planetary Set, Paracorr.
Modified Canon 400D
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scope dog
Pooh-Bah
Reged: 07/26/04
Posts: 1323
Loc: USA
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I had the neoprene disk and worked. However using no material at all works too. Just a metal to metal contact.
This what I have now. You will still need the nylon bearing under the gear. But consider having a machine shop make a conical spacer that would rest on the c-clip on the shaft.
This would support the worm and friction from the nylon bearing would be removed. This would allow less pressure applied to the clutch removing distortion to the worm.
The other approach Mike came up with years ago was installing a large needle thrust bearing where the nylon bearing is. Later celestron used that design on the cge.
Keep in mind during backlash adjustment there is slight play on the shaft, very. But enough enough to bind the worm 180 degrees out, so don't set too tight.
I have some pictures here of some of the mods I did.
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Jim
Santel MK91
Astreya-SAPO
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JoshH
member
Reged: 11/07/08
Posts: 47
Loc: Jefferson City, MO
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Thanks a lot Jim, where are the pictures at so I can see them?
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16" F4.5 Astrosystems Telekit, Galaxy Optics Primary
Meade LX-50 8" F10 SCT Magellen II DSC (For Sale)
Intes Micro MN-56 Maksutov Newtonian
Orion 100mm F6 Achromat
Orion ST-80 F5 Acrhomat
Unistar Alt-Az Mount
Celestron CI-700 Mount
UO 40mm MK-70, 26mm Nagler, 20mm Pentax XW, 13mm Ethos, 8mm Ethos, 4.7mm 5k UWA, TMB Planetary Set, Paracorr.
Modified Canon 400D
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scope dog
Pooh-Bah
Reged: 07/26/04
Posts: 1323
Loc: USA
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some are here web page I had a web page but yahoo deleted it.
O well
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Jim
Santel MK91
Astreya-SAPO
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Phil Cowell
sage
Reged: 05/24/07
Posts: 378
Loc: Southern Tier NY
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I had a CI-700 sent it off to get the bearings and clutches updated and the owner of the company doing the work stole it. Fortunately TSS are no longer in business.
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If it'll fit on a sig you don't have enough
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scope dog
Pooh-Bah
Reged: 07/26/04
Posts: 1323
Loc: USA
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I had the CI700H group too. A few people wanted me to do some work. But it takes too much time right now. The one picture with the bronze disk bearing, the disk really doesn't get used. The upper part of the shaft I have a thrust bearing with a spacer and then a 2" dia neoprene disk. When the clutch is enguage the work gear is sandwich between the main clutch and the spacer. There is no friction since the gear floats above the bronze bearing. If I mod this more I will install a clutch that will pressure at the center of the gear and not the outside. This was a fun project. This mount has more bearings than you can shake a stick. The new shafts are chrome moly drill rod. This mount is insanely
HD. I had tested 125lbs on top and 60lbs counter. steel weights, but my goto SSK worked at the 34:1 ratio, since I changed to 74:1. Anyway the weekest link is the tripod. The cast housing seem it was ready to blow a bolt at that weight.
I think when max load is mention the tripod becomes a factor with all mounts.
A few suggestions to all CI700 owners. trim the knobs. If you can bear it trim them down. I seen and heard about more bent worm-shafts because of this. Celestron does not offer them no more. I had some made and sold most.
The CI700 is basicly a plop and go mount and works well doing this. The soft clutch system I believe was to give, if the mount was off balance this kept you from blowing off the worm-shaft bearings.
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Jim
Santel MK91
Astreya-SAPO
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