bluedandelion
super member
Reged: 08/17/07
Posts: 197
Loc: Auburn, WA, U.S.A
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I have been happy with my stock Atlas. It has performed nicely for astrophotography. I am considering upgrades such as (i) a hypertune (ii) ceramic bearings and (iii) teflon bearings
Hypertuning will reduce periodic error significantly - that I understand. How do bearing replacements help? Is it again in periodic error? Is it for longevity? Does it help push the mount load limit?
Thanks.
- Ajay
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Ajay Narayanan
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Joseph Gillman
Carpal Tunnel
Reged: 12/06/05
Posts: 2784
Loc: Aston, PA
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Inam in the middle of a months long rebuild myself… don't let me scare you I jus started and then had too much else to do for a few months in between. It isnt too hard to do.
Better grease and/or better bearings will make the periodic error smoother in addition to probably lessening it as a while. Think of an oscilloscope showing a clean sine wave and then showing one with a lot of interference. The latter will be jagged. If your star moves a Ross your guide chip in a jagged motion it will be hard to guide out.
If you have time on your hands and like to tinker and see how the mout works inside then go for it. If you are less mechanically inclined than I am or you are strictly visual and Gotos and tracking are good enough for you then I would recommend leaving well enough alone.
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Nils_Lars
Post Laureate
Reged: 01/04/08
Posts: 3459
Loc: Santa Cruz Mountains , CA
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I just did mine and I think since it was a newer Atlas it wasnt that bad off , the bearings I replaced were solid but had just a little bit more friction in them.
The bearings I think it is totally worth replacing is the worm gear bearings , they were easy to change and are far superior.
In between buying the mount and the recent hypertune I had done a minor teardown where I relubed and reset the gear mesh which helped a little , this in combination with replacing the worm gears would be a big improvement.
I dont think replacing the main bearings will increase the load limit but im sure it will help with longevity and it definitely helped with the PE.
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Erik
Orion Atlas Self Hypertuned (EQMOD)
Orion ED 80
Williams Optics VII reducer
Celestron 8" SCT
Orion Starshoot Autoguider
PHD guide
Canon 400D Hap Griffin Mod w/Baader filter
Astronomik clip-in LP filter and 12nm Ha
Stilleto CVF and Bahtinov mask
Tamron 75-300mm&28-80mm lenses
NexImage webcam
http://www.flickr.com/photos/31986095@N05/
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Joseph Gillman
Carpal Tunnel
Reged: 12/06/05
Posts: 2784
Loc: Aston, PA
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The worm gear bearings can be bought at any skateboard shop. I got a set of ABEC 5 bearings. No need to get those from the expensive-Astro-markup people.
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bluedandelion
super member
Reged: 08/17/07
Posts: 197
Loc: Auburn, WA, U.S.A
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Joseph and Erik,
Thanks for your responses. So it seems that all three mods are for improved PE. I don't plan on an OTA or astrophoto gear upgrade for a little while so increased load is not of immediate concern, but I was still curious to know the reasons.
- Ajay
Edit: added bold text!
Edited by bluedandelion (10/11/09 11:48 AM)
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Joseph Gillman
Carpal Tunnel
Reged: 12/06/05
Posts: 2784
Loc: Aston, PA
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Well mine had poor mesh in RA before an now I know how to fix that. I tried a Meade 10" ota on it and it felt shaky even though rates payload in 10 lb more than that weighs. So hypertuning it may increase payload, sort of … at least in my case.
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cvedeler
Carpal Tunnel
Reged: 12/20/05
Posts: 2164
Loc: Scottsdale, AZ
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I did my own hypertune with my old Atlas. If you have a newer Atlas (less than 3 years or so) the grease is fine and the bearings are fine. The best thing you can do to modify the mount is #1) a better worm gear and #2) better motor trains. My Atlas had about +/- 20 arc seconds of PE. A better worm is the only way to bring this down. It also had issues with smooth tracking (only an issue for very high magnification work) which can only be improved with a better motor train.
The very best modification I ever did was using EQMOD. It is amazing what software can do! And it's free.
When I upgraded to my current AP900 the difference was striking. +/- 3 arc seconds PE and smooth as butter tracking. Of course it costs 6x what the Atlas does.
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Chris Vedeler
Astro-Physics 160EDF
Astro-Physics 900GTO
Q453HR / QHY8 CCD camera
Canon 450XSi
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www.aznightsky.com
Scottsdale, AZ
Edited by cvedeler (10/11/09 09:38 AM)
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morten
member
Reged: 07/22/08
Posts: 30
Loc: Denmark
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One simple thing to try out first is to adjust the tension of the worm gear by the two small Allen set-srews. It can have a major impact on the PE and, more importantly, on the s.e.m. In fact, I think the major improvement people report after hypertuning is the inevitable adjustment of this tension. There are not too many before- and after PE measurements surrounding a hypertune effort.
Here is what I got after just adjusting the tension of the worm gears. Blue is before, and red is after the adjustment. s.e.m. went down from 6.02 to 2.09, and peak PE from 18.62 to 7.80.
Edited by morten (10/11/09 09:55 AM)
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bluedandelion
super member
Reged: 08/17/07
Posts: 197
Loc: Auburn, WA, U.S.A
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Chris and Morten,
Your posts shed a little more light on the matter. Thank you.
My mount is older. I bought it used three years ago. The previous owner probably had it at least a couple of years before that. I have not done a PE analysis, but photographic results look quite good. Here's an example of what it can do with (eqmod): Picture of M92
So I left it alone. It probably has the old Synta glue, I don't know. Because of its age I think these upgrades will keep it going a little while longer.
- Ajay
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Ajay Narayanan
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morten
member
Reged: 07/22/08
Posts: 30
Loc: Denmark
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Really nice pic with round stars. Someone once taught me:
IF IT AIN'T BROKEN DON'T FIX IT.
The few times I have broken that rule, I've generally been punished...
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Charlie Hein
Postmaster
Reged: 11/02/03
Posts: 7971
Loc: 26.06.08N, +80.23.08W
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Quote:
Really nice pic with round stars. Someone once taught me:
IF IT AIN'T BROKEN DON'T FIX IT.
The few times I have broken that rule, I've generally been punished...
I completely agree. Leave it be - that's darn good tracking with the 9.25.
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"He's dead, Jim - I'll get his wallet, you get his tricorder." - Leonard "Bones" McCoy
Weston CSC:
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bluedandelion
super member
Reged: 08/17/07
Posts: 197
Loc: Auburn, WA, U.S.A
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Morten, Charlie,
Well, O.K I think I will leave well alone. That's easy on the pocketbook as well 
- Ajay
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Ajay Narayanan
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