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Re: [Losmandy_users] Re: PE in old G11


Sep 11, 2003

 


----------------------------

#17089 Sep 11, 2003

Hi all,



I have an older G11 (purchased 1993) which seems to track remarkably

well, at least what I can tell visually. I used the Celestron guiding

eyepiece and 2.5x powermate on my C11 (each tick mark 4.2 arcseconds)

and stars appear to have only 3-4 arc seconds periodic error. I'm

getting a STV to verify quantitatively. My question is this: given

such performance, should I upgrade to the new worms for (possibly)

even better performance? I also purchased new worm bearings and third

bearings for both axis, but I'm afraid that my mods will ruin the

already excellent tracking ability of my mount. Any

comments/suggestions welcomed. Thanks,



Sandy



----------------------------

#17090 Sep 11, 2003

Sandy,



I'm a firm believer in the saying, "if it aint broke, don't fix it".

Your mount sounds like a fine performer. I have a 1996 vintage G-11

that I lapped the gears on. I'm not an expert at this, but after the

lapping, the mount had less than +/- 4 arcseconds of P.E. I got one

of Scott's new gears, and it is just a little bit better than the

lapped worm. If your mount meets your needs as it is, I wouldn't

worry about getting the new worm.



Allen



--- In Losmandy_users@yahoogroups.com, "sandmanchang"

sandmanchang@h...> wrote: > Hi all,

>

> I have an older G11 (purchased 1993) which seems to track

remarkably > well, at least what I can tell visually. I used the Celestron

guiding > eyepiece and 2.5x powermate on my C11 (each tick mark 4.2

arcseconds) > and stars appear to have only 3-4 arc seconds periodic error. I'm

> getting a STV to verify quantitatively. My question is this: given

> such performance, should I upgrade to the new worms for (possibly)

> even better performance? I also purchased new worm bearings and

third > bearings for both axis, but I'm afraid that my mods will ruin the

> already excellent tracking ability of my mount. Any

> comments/suggestions welcomed. Thanks,

>

> Sandy



----------------------------

#17091 Sep 11, 2003

Sandy,



If the PE is reasonably smooth with no sudden jumps, you don't need

the new worm.



G11s are sensitive to adjusments. If it's working well now, there's

no reason to take it appart and then spend a long time adjusting

everything just to get it back to the the same level of functionality.



If your PE is 3-4 arcsec peak-to-peak, that's exceptional and I

wouldn't touch it. If it's 6-8 arcsec peak-to-peak, that's still

excellent, and I'd recommend you leave it alone and enjoy.



Just my opinion, :-)



-Paul



--- In Losmandy_users@yahoogroups.com, "sandmanchang"

sandmanchang@h...> wrote: > Hi all,

>

> I have an older G11 (purchased 1993) which seems to track

remarkably > well, at least what I can tell visually. I used the Celestron

guiding > eyepiece and 2.5x powermate on my C11 (each tick mark 4.2

arcseconds) > and stars appear to have only 3-4 arc seconds periodic error. I'm

> getting a STV to verify quantitatively. My question is this: given

> such performance, should I upgrade to the new worms for (possibly)

> even better performance? I also purchased new worm bearings and

third > bearings for both axis, but I'm afraid that my mods will ruin the

> already excellent tracking ability of my mount. Any

> comments/suggestions welcomed. Thanks,

>

> Sandy



----------------------------

#17094 Sep 11, 2003

Sandy,



If it ain't broke, don't fix it.



Take Care,



--- In Losmandy_users@yahoogroups.com, "sandmanchang"

sandmanchang@h...> wrote: > Hi all,

>

> I have an older G11 (purchased 1993) which seems to track

remarkably > well, at least what I can tell visually. I used the Celestron

guiding > eyepiece and 2.5x powermate on my C11 (each tick mark 4.2

arcseconds) > and stars appear to have only 3-4 arc seconds periodic error. I'm

> getting a STV to verify quantitatively. My question is this: given

> such performance, should I upgrade to the new worms for (possibly)

> even better performance? I also purchased new worm bearings and

third > bearings for both axis, but I'm afraid that my mods will ruin the

> already excellent tracking ability of my mount. Any

> comments/suggestions welcomed. Thanks,

>

> Sandy



----------------------------

#17112 Sep 12, 2003

Hello :



I'm a newcomer in this forum , and surely, the problems I have with my old G11 are the result of a low maintenance, as bad as my English. Reading Paul K who said :

G11s are sensitive to adjusments. If it's working well now, there's

no reason to take it appart and then spend a long time adjusting

everything just to get it back to the the same level of functionality.



I had many questions about adjustments and "strange" behaviours in my mount .I was searching in the WWW and I found some information about , but having in mind that my experience or hability with thumbscrews and precision engineering is very small , I would ask somebody how to solve the problems with the simplest solution available.( Probably this questions will have been answered formerly , sorry for repeating topics)



1.- I live in a 39. N latitude ,( exactly 39. 04').Having my mount well leveled and aligned with the polar finder, the altitude adjustment circle marks exactly 38..What could be wrong?. With this orientation , I couldn't see any appreciable derivation observing a star at 400X.

2.- I've tightened the Allen head screws on both sides of the Elevation axis firmly to increase friction, but I still have backlash. Any suggestion?( No drilling, please)

3.-If the stepper motors (the original Hurst ones),run better and more continuously at 8 or 16X speed than slower ones, and their caracteristic clicking sound appears and dissapears, roughly in a periodic manner, could it be misalignement or a lack of torque?.

4.-Finally, having the telescope fixed in a position , I have noticed a little movement when touching the tube (a 0.28 m SCT)in order to change its position, with no movement in RA or Dec. but very apparent at great magnifications. .:--((



Thanks in advance



Vicent















[Non-text portions of this message have been removed]







----------------------------

#17115 Sep 12, 2003

1.- I live in a 39. N latitude ,( exactly 39. 04').Having my mount well

leveled and aligned with the polar finder, the altitude adjustment circle

marks exactly 38..What could be wrong?. With this orientation , I

couldn't see any appreciable derivation observing a star at 400X.



I live at 29:24 but the drift aligned mount indicates 32:xx Scott Losmandy

said these marks are only for reference, they are NOT accurate.



2.- I've tightened the Allen head screws on both sides of the Elevation axis

firmly to increase friction, but I still have backlash. Any suggestion?( No

drilling, please)



Backlash where? RA? If in RA you should check the RA "Worm" to Gear

adjustment. This is different than the large allen screws on ether side of

the Elevation axis shaft.



3.-If the stepper motors (the original Hurst ones),run better and more

continuously at 8 or 16X speed than slower ones, and their caracteristic

clicking sound appears and dissapears, roughly in a periodic manner, could

it be misalignement or a lack of torque?.



Check that you have biased your RA balance to the East. Clicking/ticking

could indicated you don't have enough weight on the worm to keep the gear

faces in contact. On my old GM-100, which is similar to the GM-11, the

ticking went away when I properly balanced the mount. Do that first, but if

you still receive the periodic, on-off of the ticking then I'd look into

replacing the old motors.



4.-Finally, having the telescope fixed in a position , I have noticed a

little movement when touching the tube (a 0.28 m SCT)in order to change its

position, with no movement in RA or Dec. but very apparent at great

magnifications. .:--((



Again, RA or DEC? Check by grabing the diagonal and moving it in Ra, then

DEC to determin whic axis has the slop. If you see shifts that jump a fair

amount then you need to take it our with Worm to Gear adjustments. Careful,

too tight is worse than too loose...joe :)



Thanks in advance



Vicent















[Non-text portions of this message have been removed]







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