Re: Losmandy G11 bearing question
On Fri, Apr 25, 2025 at 10:13 AM, Laurel O. Sillerud wrote:
I added a third bearing simply by lubricating it slightly, inserting it part way, sliding the shaft into the center, and gently tapping the third bearing into place.
All went very smoothly this way and there was no chance of misalignment.
Laurel
On 4/25/25 9:43 AM, Paul Kanevsky via groups.io wrote:
? [EXTERNAL]
On Fri, Apr 25, 2025 at 10:09 AM, Chip Louie wrote:
Binding due to misalignment is one of the problems I found as a potential way to screw up my perfectly good G11 mount as I contemplated this modification.? To get that perfect non-binding installation the additional bearing would need to be supported on a shaft that is in alignment with the other two bearings as the 3rd is pressed into place.??
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So when I looked at the distance between the bearings and the very short length the axle? is unsupported at the end of the body I figured it should make no difference.? My guess was it would not improve performance even if the 3rd bearing was installed perfectly.? But if not installed perfectly or the axle was not perfectly straight the slight misalignment could be the source of a slight, regular binding as the axle rotated.? So I passed on that modification.??
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The possibility of screwing up the mount is very real, as my first-hand experience made painfully obvious... at least to me :)
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There is no mechanical advantage in doing this if the mount and bearings are in spec.? That said this is the method I suggested if for some reason a person feels compelled to do this.??
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Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
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Off Topic: Convert PT Pier into something more permanent.
I have a PT (1 or 2) that I purchased many years ago. It is the the type that can go up and down. Still works but with my permanent observatory, I have not needed to use that feature in many years (still works though).?
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What I do not like about this setup is the minor movement (even when the pier is all the way down) you can put your finger on the scope mount and 'shake' it scope.?
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I am trying to figure out how to 'convert' this into a permanent mount; ie...fill it with concrete, rocks, sand...etc to help stabilize it. I wont ever need to raise it again so I don't care about the guts on the inside of the pier.
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Any thoughts/recommendations??
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Re: Losmandy G11 bearing question
I added a third bearing simply by lubricating it slightly,
inserting it part way, sliding the shaft into the center, and
gently tapping the third bearing into place.
All went very smoothly this way and there was no chance of
misalignment.
Laurel
On 4/25/25 9:43 AM, Paul Kanevsky via
groups.io wrote:
toggle quoted message
Show quoted text
? [EXTERNAL]
On Fri, Apr 25, 2025 at 10:09 AM, Chip Louie wrote:
Binding due to misalignment is one of the problems I
found as a potential way to screw up my perfectly good G11
mount as I contemplated this modification.? To get that
perfect non-binding installation the additional bearing
would need to be supported on a shaft that is in alignment
with the other two bearings as the 3rd is pressed into
place.??
?
So when I looked at the distance between the bearings
and the very short length the axle? is unsupported at the
end of the body I figured it should make no difference.?
My guess was it would not improve performance even if the
3rd bearing was installed perfectly.? But if not installed
perfectly or the axle was not perfectly straight the
slight misalignment could be the source of a slight,
regular binding as the axle rotated.? So I passed on that
modification.??
?
The possibility of screwing up the mount is very real, as
my first-hand experience made painfully obvious... at least
to me :)
|
Re: Losmandy G11 bearing question
On Fri, Apr 25, 2025 at 10:09 AM, Chip Louie wrote:
Binding due to misalignment is one of the problems I found as a potential way to screw up my perfectly good G11 mount as I contemplated this modification.? To get that perfect non-binding installation the additional bearing would need to be supported on a shaft that is in alignment with the other two bearings as the 3rd is pressed into place.??
?
So when I looked at the distance between the bearings and the very short length the axle? is unsupported at the end of the body I figured it should make no difference.? My guess was it would not improve performance even if the 3rd bearing was installed perfectly.? But if not installed perfectly or the axle was not perfectly straight the slight misalignment could be the source of a slight, regular binding as the axle rotated.? So I passed on that modification.??
?
The possibility of screwing up the mount is very real, as my first-hand experience made painfully obvious... at least to me :)
|
Re: Losmandy G11 bearing question
?
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Hi Paul,
?
Binding due to misalignment is one of the problems I found as a potential way to screw up my perfectly good G11 mount as I contemplated this modification.? To get that perfect non-binding installation the additional bearing would need to be supported on a shaft that is in alignment with the other two bearings as the 3rd is pressed into place.??
?
So when I looked at the distance between the bearings and the very short length the axle? is unsupported at the end of the body I figured it should make no difference.? My guess was it would not improve performance even if the 3rd bearing was installed perfectly.? But if not installed perfectly or the axle was not perfectly straight the slight misalignment could be the source of a slight, regular binding as the axle rotated.? So I passed on that modification.??
?
--
Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
?
?
?
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Re: Losmandy G11 bearing question
On Thu, Apr 24, 2025 at 06:31 PM, fetoma wrote:
I'm doing a deep dive into my G11 and replaced all the bearings. One thing I noticed is while replacing the inner needle bearings is that one end of the RA and Dec axis housings have enough room to fit two needle bearings. See photos. Do you think it would help in any way to add another bearing in this space?
Hi Frank,
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Just as Laurel, I added a third bearing to a G11 more than 20 years ago, when I was planning to put a 10" SCT on it side-by-side with a small refractor. The thinking was to stabilize the axis, fix it so there's little chance of a wobble. It took some effort to install the third bearing -- I didn't have any specialized equipment to do so.
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What was worse was that it became nearly impossible to push the axis through the three bearings. With three bearings that are properly sized, you'll need to make sure that all three are aligned very precisely, that none are even slightly tilted relative to the others. Any slight tilt of the new bearing will surely help secure the axis better, but will also make it nearly impossible to get the axis threaded through all three of them! :( It took me nearly a day to rectify a slight tilt I introduced with the new bearing. The one I installed fit very snuggly into the axis tube, so making adjustments to its position was not easy.
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I can't say for sure that it improved anything with the mount, but after all the pain and suffering, the G11 performed well for years, and I still have it and use it on occasion when I need a portable set up :)
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Regards,
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? ?-Paul
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Re: Losmandy G11 bearing question
Yes,
??? Years ago I added a third bearing to the axis and it markedly
stabilized the tracking.? If you search the archives you will find
a lively discussion about this and how to do the addition.
Laurel
On 4/24/25 4:31 PM, fetoma via
groups.io wrote:
? [EXTERNAL]
Folks,
?
I'm doing a deep dive into my G11 and replaced all the
bearings. One thing I noticed is while replacing the inner
needle bearings is that one end of the RA and Dec axis
housings have enough room to fit two needle bearings. See
photos. Do you think it would help in any way to add
another bearing in this space?
?
-Frank
?
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Losmandy G11 bearing question
Folks,
?
I'm doing a deep dive into my G11 and replaced all the bearings. One thing I noticed is while replacing the inner needle bearings is that one end of the RA and Dec axis housings have enough room to fit two needle bearings. See photos. Do you think it would help in any way to add another bearing in this space?
?
-Frank
?
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Re: Problem with Gemini 1
John
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what version G1 is it?
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This matters as some earlier versions had a habit of ?a bad 5V pwr dual diode that steers 5V to Motor Encoders
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F2 if the wrong type can drop encoder 5V but usually the HC also loses pwr
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Are there any x¡¯s or reset data on boot up?
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It¡¯s kinda strange to have both axes have issues. Almost straight away it sounds like bad 5V somewhere or CPU issue.?
At boot the axes pinions should be tight unmovable till boot is completed. If the pinions can easily be moved during this ¡°boot sequence¡±. ?Then it sounds 5V or possibly damage to the motor encoders.?
You can supply 5V and gnd to each motor (removed from the system) and put a multimeter on encoder channels A and or B. ?Then rotating the pinion (very slowly) you can see if you are getting 5V pulses out of ChA or B! ?This will prove if your motor encoders are ok
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You can also supply let¡¯s say 3 to 5 VDC to the motor pins, either way and it should run.?
Get back on all this we can take it further. Or you can send it to repairer in UK/USA/Australia
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Cheers I await your reply on all this. ?This is repairable.?
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Brendan
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Re: Problem with Gemini 1
Where do you live?? Which repairer to use depends on that ¡ ?
toggle quoted message
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From: [email protected] <[email protected]> On Behalf Of John via groups.io
Sent: 23 April 2025 05:47
To: [email protected]
Subject: [Losmandy_users_io] Problem with Gemini 1? Hello group,
It boots normally, then it says RA motor stalled, or DEC motor stalled.
Then the DEC axis slowly rotates by itself, no buttons pressed.
Hand controlls have no effect.
Time & date set correctly.
Anyone know how too fix it?
Thanks
John
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Hello group,
It boots normally, then it says RA motor stalled, or DEC motor stalled.
Then the DEC axis slowly rotates by itself, no buttons pressed.
Hand controlls have no effect.
Time & date set correctly.
Anyone know how too fix it?
Thanks
John
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Re: Best Way To Determine Periodic Error?
On Mon, Apr 21, 2025 at 08:23 AM, <avishekaiyar@...> wrote:
Hi Jonathan,
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Yeah....PhD2 defaults to multi star guiding...or at least in my version.?
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I attempted calibration last night and made progress (I was fumbling with setting up the calibration run the last time...ultimately figured out that with ST4 guiding using PhD2, I need to setup an Aux mount as "ask for coordinates" and then manually punch in my approx Dec coordinate which was ~8 degrees for me last night).?
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Then I had to stop for absolutely ridiculous/hilarious reasons: calibration kept failing or returning "poor calibration" messages because the roof of my townhome kept showing up in my FoV..haha. I had setup at the wrong location! And by then I was just too demoralized to relocate my setup, run PA and start over. The pains of not having my own private backyard to shoot from, let alone a dark sky location!?
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I am hoping tonight is the night!?
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I did go through the GM8 manual (right now I am focusing on the GM8...my G11 is in storage).....it doesn't provide a lot of detail around the post PEC steps, but I think it should be obvious. I believe after performing PEC, the red LED is always ON during subsequent sessions unless the PEC profile is erased for some reason or you deliberately turn it off. Either way, I will go through this exercise and report back just in the rare case that someone is actually doing what I am doing. :)?
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Avi
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Hi Avi,
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So was last night the night?? If so how did it go??
?
--
Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
?
?
?
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Re: Best Way To Determine Periodic Error?
Hi Jonathan,
?
Yeah....PhD2 defaults to multi star guiding...or at least in my version.?
?
I attempted calibration last night and made progress (I was fumbling with setting up the calibration run the last time...ultimately figured out that with ST4 guiding using PhD2, I need to setup an Aux mount as "ask for coordinates" and then manually punch in my approx Dec coordinate which was ~8 degrees for me last night).?
?
Then I had to stop for absolutely ridiculous/hilarious reasons: calibration kept failing or returning "poor calibration" messages because the roof of my townhome kept showing up in my FoV..haha. I had setup at the wrong location! And by then I was just too demoralized to relocate my setup, run PA and start over. The pains of not having my own private backyard to shoot from, let alone a dark sky location!?
?
I am hoping tonight is the night!?
?
I did go through the GM8 manual (right now I am focusing on the GM8...my G11 is in storage).....it doesn't provide a lot of detail around the post PEC steps, but I think it should be obvious. I believe after performing PEC, the red LED is always ON during subsequent sessions unless the PEC profile is erased for some reason or you deliberately turn it off. Either way, I will go through this exercise and report back just in the rare case that someone is actually doing what I am doing. :)?
?
?
Avi
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Re: Best Way To Determine Periodic Error?
I don¡¯t think using multi star guiding would be an issue. The drive is only recording the corrections received from PHD2. How PHD2 calculates those corrections would not impact what the mount receives. However, I never tried this so I¡¯m basically just guessing lol. If PHD can use multiple stars while using an ST4 style guider then you should be good to go.
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As for activating PEC, once the recording phase is done the new PEC corrections will automatically start. The manual is not very clear nor do I remember well but, I suspect the PEC curve is stored in memory until you apply a new one. If the PEC light is on when you turn the mount on, then you know it¡¯s working ;). However, if it¡¯s deactivated after a power cycle, then you know it¡¯s mostly just a 4 minutes investment to build a new one and, by the time you realize this, you will already know how to do this :)
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In case you haven¡¯t seen it yet, here¡¯s the .
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Good luck
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Jonathan
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Re: Best Way To Determine Periodic Error?
Hi Jonathan?
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This is indeed super helpful.?
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If I get time tonight I will attempt it.?
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I was actually going to use multi star guiding ..I am assuming that is perfectly fine but wanted to confirm since the manual mentions keeping the guide star centered. But I guess that was well before multi star guiding was even available as an option.?
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Once the PEC curve is saved on the controller, is it automatically applied for all tracking sessions going forward ? I assume that is the case until the time I regenerate the PEC profile.?
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Many thanks?
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Avi?
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Re: Best Way To Determine Periodic Error?
Hi Avi,
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it¡¯s been a while since I last used my digital drive so procedures are a bit fuzzy in my memory but, here¡¯s what I¡¯d suggest.
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The 492 drive has an internal feature to save and use a PEC curve. What it does is basically save to its internal memory the corrections applied by the user (or guide camera) while in the recording phase, and then applying those corrections automatically.
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I would start the guiding first with your guide scope/camera. Once the guiding has stabilized I¡¯d turn the recording on and let it rip for however long it needs. After the recording it will start to correct on its own.
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You may wish to disable DEC corrections in PHD2 as those are ignored by the 492 box but, if there¡¯s some drift in DEC leave them on so as to not loose the star.
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Hope this helps
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Jonathan
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Re: Best Way To Determine Periodic Error?
Hello All?
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I wanted to refresh this thread instead of starting a new one for a somewhat related question of my own.?
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I am a recent entrant into AP and have a Losmandy GM8 and CG11, both with 492 digital drives...so strictly push to. (I want to keep it that way for a while before upgrading to OnStep).?
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My question is around the procedure for generating a PEC profile using the 492 Digital drive. I went through the manual but that references a visual setup.?
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I want to do the same thing, but with my autoguider setup using the ST4 ports on the camera and the 492 digital drive unit. My autoguider setup is a 120mm scope attached to a Asi 120mm-s camera. I guess I need to find a way for PhD2 to talk to the 492 digital drive when the PEC setting is engaged. Is that something as simple as running an autoguiding session whilst PEC mode is engaged on the controller ??
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Just to be clear, I am specifically talking about applying a PEC profile to my mount and not about how to autoguide with my setup: I know how to do the latter.?
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Many thanks!?
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Avi?
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Re: Exactly how to set the Gemini 2 over to UTC time?
On Sat, Apr 19, 2025 at 04:53 PM, Brendan wrote:
Yes , set time zone = 0
Enter UTC and your local date, you are now sweet. ?Don¡¯t forget to press ¡°set¡±
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cheers
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--
Brendan
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Good reminder, this is something people forget about 80% of the time then post wondering how it somehow has reverted back.?
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--
Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
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Re: Exactly how to set the Gemini 2 over to UTC time?
On Sat, Apr 19, 2025 at 09:34 AM, David Malanick wrote:
Looking to change my setups over to UTC time. Now do I just change over the time zone in the hand controller and the Gemini settings to 00?
This made the current time listed as the UTC time.? Also, Civil time is now displayed as UTC time.
Is this the correct way to set it up?? The GPS updated my site, and will it do the same to the time?
I assume this is how it gets the UTC time to sync with location and let the Gemini unit work correctly?
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Thanks,
David Malanick
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David
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Yes that way should work fine but I usually use the web interface to make that change.??I recommend using UTC but some apps will reset your time.? ASIAIR does something phoney like that and it changes the time to 12 hour time as it updates time and GPS coordinates from the phone or tablet.? It makes you crazy but I just learned to ignore it.?
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Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
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Re: Exactly how to set the Gemini 2 over to UTC time?
Yes , set time zone = 0
Enter UTC and your local date, you are now sweet. ?Don¡¯t forget to press ¡°set¡±
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cheers
?
?
--
Brendan
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Chip Louie
Paul Kanevsky
David C. Partridge
John