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Perhaps someone here has an idea or two that would help me.
I have a GM-8 with Gemini 1 that worked flawlessly from
when I purchased it in 2006 until 2015 when I had to pack up the mount for a move
from the west to east coast two years ago. I¡¯m now ready to use it again and I¡¯ve
come across an interesting problem.
?
When I boot up (counterweight down aiming north, etc),
everything starts off normally:
Correct Mount ¨C> GM-8
Correct date?
yymm.dd
Correct time (UT)
Correct Longitude W 80 deg 33 min
Correct Latitude ???+ 27 deg 45 min
Time Zone is correct?
- 4 hours for EDT
?
Then the problem starts when it asks for alignment
1) not all the Bright Stars are available, even those
that are currently high in the sky, Vega, Deneb, etc.
2) the first alignment GoTo is meaningless ¨C nowhere
close to the selected Bright Star
3) any further GoTo is meaningless, often showing visible
targets as being below the horizon
4) The RA movement of the mount is very minimal, as if
any command to that drive motor is turned off almost immediately.
?
However, in Sidereal mode, the slewing, centering and
tracking commands are all normal, with the mount pointing wherever I want it to
go. So the cables and drive motors are working normally.
?
So far I¡¯ve:
1. Changed the CMOS battery. The new one provides over
3V. ~3.2V
2. I¡¯ve update the EPROM to Ver. 1.05 and that boots
normally.
3. I¡¯ve done a DEFAULT RESET to Losmandy defaults.
4. I¡¯ve put in all the necessary entry items and double checked
to be sure of their accuracy.
5. I¡¯ve spoken to Russell at Losmandy and they are not
sure what the problem could be.
4. I¡¯ve checked the voltage from the power source and it is
13.2V.? I¡¯ve checked the power cable and
the same voltage is getting to the Gemini 1.
?
The problem still remains ¨C loss of some Bright Stars and
meaningless movements of the mount for alignment and GoTo¡¯s.
?
Any ideas? This one has me stumped.
?
Thanks,
Bob
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Hi Bob,
You've done quite a bit of troubleshooting, all the basic things I would've checked. Since the problem appears to be related to your mount settings, this where we should concentrate.
1. Do you use just the HC to do all of this, or control your mount from a PC? If PC, try resetting everything to defaults, and use just the physical HC without connecting the PC.
2. Probably not significant, but Eastern time is now -5 hours from UTC, not -4.
3. When you say RA movement is minimal, what actually happens when you do the first goto from CWD? How long is the slew? Are both axis slewing? How far away is the star from where the mount stops?? Can you move the the mount in RA when pressing HC buttons or does that stop immediately as well?
4. Did you have this problem before you upgrade to v1.05, or did it start after the upgrade? If this started recently, it may be worth a test to plug in the older EPROM, if you still have it.
Regards,
? ?-Paul
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I have shared the same unwelcome experiences too.
My advice is try this.
Leave the Gemini1 disconnected from any computer.? Why: There is a Gemini.net checkbox that allows the PC to send "default" configuration to the Gemini as soon as it connects.? If the computee default is off (say left over from the East coast), this has the chance to overwrite your settings in the Gemini unit itself.
Cold boot.? This zeros all internal T-pointing values.
The Gemini soft ware seems to have no notion of CWD...that is it should read the optical encoder at power up and know the scope position.? ?I know that seems impossible to believe,? but it's my experience.??
Therefore, no matter how far out of whack the first Align star is pointed, just use the hand controller to move (or I suppose slip the clutches would work too), and point the scope to that star.? Then press Enter a few times to Synch and Align to that 1st star.??
Usually, Gemini behaves sensibly after that.? ?
Anyway...such is my experience. ..maybe it will also solve your trouble too.
(Also, when you are going to connect to a computer,? make sure the "Send to Gemini on Connect " checkbox is not checked.? After you have the Gemini working correctly, and you Download From Gemini, store that new configuration.? ?That will override the existing named Default file.? ?Also save a copy with a name like "GM8_good_Nov_22_2017".? )
Best,? Michael Herman?
On Nov 22, 2017 11:32 AM, " yh@... [Losmandy_users]" < Losmandy_users@...> wrote:
?
Hi Bob,
You've done quite a bit of troubleshooting, all the basic things I would've checked. Since the problem appears to be related to your mount settings, this where we should concentrate.
1. Do you use just the HC to do all of this, or control your mount from a PC? If PC, try resetting everything to defaults, and use just the physical HC without connecting the PC.
2. Probably not significant, but Eastern time is now -5 hours from UTC, not -4.
3. When you say RA movement is minimal, what actually happens when you do the first goto from CWD? How long is the slew? Are both axis slewing? How far away is the star from where the mount stops?? Can you move the the mount in RA when pressing HC buttons or does that stop immediately as well?
4. Did you have this problem before you upgrade to v1.05, or did it start after the upgrade? If this started recently, it may be worth a test to plug in the older EPROM, if you still have it.
Regards,
? ?-Paul
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Bob,
One thing to check is have the mount park in the CWD position to confirm it stops at the correct position. If not, then after parking turn off the mount and move the DEC shaft to the CWD position. I had a friend who was having trouble about a decade ago and I couldn't figure out what was wrong. All the settings were correct. Then I noticed that in the menu I could park CWD. Tried it and the park position was about 30¡ã off. Once I powered off and moved to the CWD position, all was cured.
Don
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----- Original Message ----- From: "rcwolpert@... [Losmandy_users]" <Losmandy_users@...> To: <Losmandy_users@...> Sent: Wednesday, November 22, 2017 12:47 PM Subject: [Losmandy_users] Need Help with Gemini 1 Movements Perhaps someone here has an idea or two that would help me.
I have a GM-8 with Gemini 1 that worked flawlessly from when I purchased it in 2006 until 2015 when I had to pack up the mount for a move from the west to east coast two years ago. I¡¯m now ready to use it again and I¡¯ve come across an interesting problem.
When I boot up (counterweight down aiming north, etc), everything starts off normally:
Correct Mount ¨C> GM-8
Correct date yymm.dd
Correct time (UT)
Correct Longitude W 80 deg 33 min
Correct Latitude + 27 deg 45 min
Time Zone is correct - 4 hours for EDT
Then the problem starts when it asks for alignment
1) not all the Bright Stars are available, even those that are currently high in the sky, Vega, Deneb, etc.
2) the first alignment GoTo is meaningless ¨C nowhere close to the selected Bright Star
3) any further GoTo is meaningless, often showing visible targets as being below the horizon
4) The RA movement of the mount is very minimal, as if any command to that drive motor is turned off almost immediately.
However, in Sidereal mode, the slewing, centering and tracking commands are all normal, with the mount pointing wherever I want it to go. So the cables and drive motors are working normally.
So far I¡¯ve:
1. Changed the CMOS battery. The new one provides over 3V. ~3.2V
2. I¡¯ve update the EPROM to Ver. 1.05 and that boots normally.
3. I¡¯ve done a DEFAULT RESET to Losmandy defaults.
4. I¡¯ve put in all the necessary entry items and double checked to be sure of their accuracy.
5. I¡¯ve spoken to Russell at Losmandy and they are not sure what the problem could be.
4. I¡¯ve checked the voltage from the power source and it is 13.2V. I¡¯ve checked the power cable and the same voltage is getting to the Gemini 1.
The problem still remains ¨C loss of some Bright Stars and meaningless movements of the mount for alignment and GoTo¡¯s.
Any ideas? This one has me stumped.
Thanks,
Bob
|
Thanks Paul, Michael,and Don for the comments and suggestions. Here are a few responses:
1. I'm using only the HC, no PC. 2. Right! EST - 5 hrs 3. This problem started with my original ver 1.01. ?When I inserted then 1.05 EPROM with great expectations, the problem remained. 4. When doing the original alignment, the movement of the RA axis is only about 5deg from CWD position. When I see it stop so soon, I know it's going to be a disaster. 5. I've tried moving the mount all the way to the alignment Bright Star and the hitting Align, and then doing a GoTo, but no luck. I get either a meaningless GoTo movement, or a message saying that the object is below the horizon. The mount has no idea where it is. 6. I haven't tried the Park suggestion yet. I'll try that ?when I get home on Sunday.
There seems to be 2 problems going on at once. First, it doesn't seem to pay attention to the Home CWD inputs, so it doesn't know where it is or where to go, and second, it shuts down the RA movement after about two seconds. On top of that, I'm not getting all the Bright Stars, but that could be related to problem one.
More suggestions and thought are welcomed!
Thanks, and Happy Thanksgiving! Bob
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The G1 and G2 have no idea whether the mount is at the CWD position or where it is actually pointing at any time, as there are no sensors in the mount to tell them that. The encoders on the motors only provide data on how much the motor has turned, and therefore where the mount is supposed to be pointing based on an initial assumption of where the mount was when the controller was powered on.
Dave
From: Losmandy_users@... [mailto:Losmandy_users@...]
Sent: 23 November 2017 13:28
To: Losmandy_users@...
Subject: Re: [Losmandy_users] Need Help with Gemini 1 Movements
Thanks Paul, Michael,and Don for the comments and suggestions. Here are a few responses:
1. I'm using only the HC, no PC.
2. Right! EST - 5 hrs
3. This problem started with my original ver 1.01. When I inserted then 1.05 EPROM with great expectations, the problem remained.
4. When doing the original alignment, the movement of the RA axis is only about 5deg from CWD position. When I see it stop so soon, I know it's going to be a disaster.
5. I've tried moving the mount all the way to the alignment Bright Star and the hitting Align, and then doing a GoTo, but no luck. I get either a meaningless GoTo movement, or a message saying that the object is below the horizon. The mount has no idea where it is.
6. I haven't tried the Park suggestion yet. I'll try that when I get home on Sunday.
There seems to be 2 problems going on at once. First, it doesn't seem to pay attention to the Home CWD inputs, so it doesn't know where it is or where to go, and second, it shuts down the RA movement after about two seconds. On top of that, I'm not getting all the Bright Stars, but that could be related to problem one.
More suggestions and thought are welcomed!
Thanks, and Happy Thanksgiving!
Bob
[Non-text portions of this message have been removed]
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Happy Thanksgiving, all.
Thanks, David, for explaining that the Gemini system only measures changes in motor position, that it does not know its exact position.? ?
I am wondering if Bob has some contamination or fogging of the optical encoder in his motor assembly.?? Bob....if you switch RA and DEC motors, does the problem move from RA to DEC?? If so points to the motor assembly...not the Gemini.? ?
I have found at least one case in the past where an optical encoder's clear plastic disk (with black opaque lines printed on them) did fog up over time... if so the Gemini will get wrong values transmitted and calculations will be all wrong, and inconsistent.
Hope you resolve the trouble soon.
Michael
?
The G1 and G2 have no idea whether the mount is at the CWD position or where it is actually pointing at any time, as there are no sensors in the mount to tell them that. The encoders on the motors only provide data on how much the motor has turned, and therefore where the mount is supposed to be pointing based on an initial assumption of where the mount was when the controller was powered on.
Dave
From: Losmandy_users@... [mailto:Losmandy_users@yahoogroups.com]
Sent: 23 November 2017 13:28
To: Losmandy_users@...
Subject: Re: [Losmandy_users] Need Help with Gemini 1 Movements
Thanks Paul, Michael,and Don for the comments and suggestions. Here are a few responses:
1. I'm using only the HC, no PC.
2. Right! EST - 5 hrs
3. This problem started with my original ver 1.01. When I inserted then 1.05 EPROM with great expectations, the problem remained.
4. When doing the original alignment, the movement of the RA axis is only about 5deg from CWD position. When I see it stop so soon, I know it's going to be a disaster.
5. I've tried moving the mount all the way to the alignment Bright Star and the hitting Align, and then doing a GoTo, but no luck. I get either a meaningless GoTo movement, or a message saying that the object is below the horizon. The mount has no idea where it is.
6. I haven't tried the Park suggestion yet. I'll try that when I get home on Sunday.
There seems to be 2 problems going on at once. First, it doesn't seem to pay attention to the Home CWD inputs, so it doesn't know where it is or where to go, and second, it shuts down the RA movement after about two seconds. On top of that, I'm not getting all the Bright Stars, but that could be related to problem one.
More suggestions and thought are welcomed!
Thanks, and Happy Thanksgiving!
Bob
[Non-text portions of this message have been removed]
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Thanks, Dave . . . good point!
Michael, you may have hit on the problem. Since the drives work fine in Sidereal mode, and since the Gemini looks fine until the mount needs to actually move, the problem could very well be with the encoders. I'll look into that this coming week.
- Bob
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I have a similar sounding problem to the OP. Did you ever find the solution?
Thanks!
John
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Hi guys,
Some suggestions to try:
If your pointing is wacky, you have to be completely sure your Model parameters are all zero.??
So first, do a Cold Boot from the CWD position.? That zeros all sky model parameters.
Make sure your mount is set to your correct model, as Gemini 1 will usually default to Titan and the tracking and gotos will be way off for other mounts...(the Titan ring gear is much bigger than a G11, and the G11 has twice the ring gear teeth of GM8).?
?If you change your mount model, reboot the Gemini so it loads the correct settings for that corrected mount.
Check also that your Latitude and Longitude are in degrees and minutes ... though the entry format uses a dot (.) it does not mean fractions of a degree.
After cold boot, slew your RA and DEC away from CWD and then do a Park to CWD. Does the mount return to the correct CWD position?? If back to CWD, it indicates your optical encoders are fine.
Are your target bright star list now sensible???
Other cautions: When you do Align stars to build your sky model, the first 3 stars must be only on one side of the meridian.? That ensures the first critial model parameters are accurate. Then choose and align to 3 stars on the other side of the meridian.??
Hope you solve your mystery...and get back to celestial bliss...
Best, Michael?
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I have a similar sounding problem to the OP. Did you ever find the solution?
Thanks!
John
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Paul Kanevsky
Michael Herman
David C. Partridge