Re: 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
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Re: Need Help with Gemini 1 Movements
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
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Re: Need Help with Gemini 1 Movements
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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Re: Need Help with Gemini 1 Movements
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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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
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Re: Dec motor housing loose
I also had a cracked gearbox causing a wiggly motor. Scott fixed the gearbox for free.
Keith
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Re: Dec motor housing loose
I had a cracked gearbox that resulted in a loose motor. Be sure to check for that, too.
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Re: Polar alignment shifts after meridian flip
For an object at the celestial equator, I don¡¯t think cone error will have any first-order impact on guiding. It shouldn¡¯t lead to the drift in declination that Magnus is seeing. This also means that drift alignment should not be affected by cone error. -Les On 20 Nov 2017, at 12:34, David Pickett yahoo@... [Losmandy_users] <Losmandy_users@...> wrote:
At 21:17 20-11-17,
jfev5mnsvqiyzpq756wvokt55jve7sbg2esr5mip@... [Losmandy_us wrote:
Isn't cone error something else? That does not
"affect" polar alignment, but causes field
rotation and similar problems. I mean, polar
alignment and drift alignment depends on the
mount, not on how the scope is mounted on the mount. Or am I wrong? Cone error is when the axis of the OTA is not
parallel to the RA axis. Then, even though the
mount is accurately polar aligned, the OTA
describes a cone around the projection of the
polar axis. Easy to visualise by imagining that a
refractor is at a 45¡ã angle to the RA axis. Then
as the axis turns the OTA will also turn and will
always be pointing somewhere else other than the NCP.
I am not sure that this explains your problem however.
But what on earth could that be? I mean, flex in
the guidescope could not possible cause this, right? If the guidescope is leaning one way before the
flip and its mounting is loose enough to make it
lean the other way afterwards, I should have
thought it quite possible that this is the reason
for your problem. At all events, I think that
_something_ is moving as the flip happens.
David
------------------------------------
Posted by: David Pickett <yahoo@...>
------------------------------------
------------------------------------
Yahoo Groups Links
[Non-text portions of this message have been removed]
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Re: Polar alignment shifts after meridian flip
At 21:17 20-11-17, jfev5mnsvqiyzpq756wvokt55jve7sbg2esr5mip@... [Losmandy_us wrote: Isn't cone error something else? That does not
"affect" polar alignment, but causes field
rotation and similar problems. I mean, polar
alignment and drift alignment depends on the
mount, not on how the scope is mounted on the mount. Or am I wrong? Cone error is when the axis of the OTA is not parallel to the RA axis. Then, even though the mount is accurately polar aligned, the OTA describes a cone around the projection of the polar axis. Easy to visualise by imagining that a refractor is at a 45¡ã angle to the RA axis. Then as the axis turns the OTA will also turn and will always be pointing somewhere else other than the NCP. I am not sure that this explains your problem however. But what on earth could that be? I mean, flex in
the guidescope could not possible cause this, right? If the guidescope is leaning one way before the flip and its mounting is loose enough to make it lean the other way afterwards, I should have thought it quite possible that this is the reason for your problem. At all events, I think that _something_ is moving as the flip happens. David
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Re: Polar alignment shifts after meridian flip
Hi!
Isn't cone error something else? That does not "affect" polar alignment, but causes field rotation and similar problems. I mean, polar alignment and drift alignment depends on the mount, not on how the scope is mounted on the mount. Or am I wrong?
Magnus
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Re: FS: Gemini-1 and deluxe hand controller
Still Have the Gemini 1 for sale?
Mine is way flakey Greg
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Re: Polar alignment shifts after meridian flip
Isn¡¯t this a text book definition of ¡°Cone
Error¡±??
?
Not that I know anything about it..
?
Derek
?
From:
Losmandy_users@... [mailto:Losmandy_users@...]
Sent: Saturday, November 18, 2017
1:41 AM
To: Losmandy_users@...
Subject: [Losmandy_users] Polar
alignment shifts after meridian flip
?
?
Hi!
Here I am again with a new question (I am soo happy that my previous "not
performing Go To Bright Star" was solved!!!):
I'm trying to improve mu guiding (of course). So I'm experimenting a lot with
PHD2, that is what I use for guiding. Now this is some results from an
experiment yesterday:
I point the scope to the meridian, close to the equator, and run the guiding
assistant. After some 3 minutes, it tells me the polar alignment error is 0.3
arc-min (farily ok, I'd say).
Then I do a meridian flip. Point again to the meridian (that is, slewing
slightly to the east to compensate for the drift that now has occurred) . Run
the guiding assistant again. This time it reports a polar alignment error of
16.3 arc min.
So: what might be going on here? If I trust PHD2, something must be shifting.
But what on earth could that be? I mean, flex in the guidescope could not
possible cause this, right? It must be something with the mount in that case -
or am I wrong? Any suggestions on what to look for and further explore is
welcome.
And yes, this is reflected in poorer guiding after meridian flip. Interestingly
enough, guiding improves after recalibration, which again feels like a mystery.
How could calibration be affected by MF, except DEC switching direction (and
then it would go off wildly, which is not what happens - just some 50 % more
RMS).
Best,
Magnus
?
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Re: Dec motor housing loose
hi,
I'm not clear on just what may be loose.? Here are some ideas to check out: (this is for a conventional G11 or GM8, with or without OPW.? One with an Ovision may be different.)
The motor is bolted to the gearbox.? Is that loose?? if so, find and tighten it's mounting bolts or add flat washers to further compress the mounting.?
The gearbox under the motor is bolted to the mount flange.? Is that loose?? To get to that, you must first unbolt the motor from the gearbox, then tighten down the gearbox...then re-attach the motor.?
The gearbox output shaft holds one of the round Oldham coupler metal parts.? make sure that is not loose.? Make sure the other Oldham coupler metal part is tightly attached to the worm shaft.? Make sure the two Oldham metal parts are tight into the plastic center piece.? (You can loosen the worm metal piece and slide it up into the plastic part, or slide the gear end part toward the plastic part.)??
Key, especially for RA, is to ensure all the parts of the Oldham are in line along the worm axis...look in all angles to get that correct.? You my have to fiddle with the gear box mounting to get that perfected.? Offsets in Oldham axis angles to the worm axis can induce PE, which you want to drive toward zero as much as possible.? ? As far as I recall, on my CG11 and GM8, the mounting of the gearbox to its mount flange are 4-40 size.? You can often find split spring washers and flat washers of that size at hardware stores.? Or one or more flat washers could work.??
Some gear boxes are plastic, perhaps with a metal ferrule fitted, and it takes additional thought about making the mounting rigid.? ?
Hope this helps, ... Michael?
On Nov 17, 2017 5:24 PM, " puzzlewuzzle.dr@... [Losmandy_users]" < Losmandy_users@...m> wrote:
?
How may I tighten up my dec motor housing? It has an 1/8 inch or so play when I grasp the housing and wiggle. The G-11 is newly acquired so I am reluctant to try to use the drive with the looseness of the motor. The motor does run, at least it makes noise when I trigger the control button on the 492. Does the flexible plastic cover peal off to reveal the bolts? Thanks again for all the guidance and response from the group members.
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Re: Dec motor housing loose
there is wiggle in the housing, it's normal.?
I am not a mechanical expert, but i believe the iwggle is in the housing, not in the motor itself or the connections. You will always have that wiggle with the losmandy?
B
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Polar alignment shifts after meridian flip
Hi! Here I am again with a new question (I am soo happy that my previous "not performing Go To Bright Star" was solved!!!): I'm trying to improve mu guiding (of course). So I'm experimenting a lot with PHD2, that is what I use for guiding. Now this is some results from an experiment yesterday: I point the scope to the meridian, close to the equator, and run the guiding assistant. After some 3 minutes, it tells me the polar alignment error is 0.3 arc-min (farily ok, I'd say). Then I do a meridian flip. Point again to the meridian (that is, slewing slightly to the east to compensate for the drift that now has occurred) . Run the guiding assistant again. This time it reports a polar alignment error of 16.3 arc min. So: what might be going on here? If I trust PHD2, something must be shifting. But what on earth could that be? I mean, flex in the guidescope could not possible cause this, right? It must be something with the mount in that case - or am I wrong? Any suggestions on what to look for and further explore is welcome. And yes, this is reflected in poorer guiding after meridian flip. Interestingly enough, guiding improves after recalibration, which again feels like a mystery. How could calibration be affected by MF, except DEC switching direction (and then it would go off wildly, which is not what happens - just some 50 % more RMS). Best, Magnus
|
How may I tighten up my dec motor housing? It has an 1/8 inch or so play when I grasp the housing and wiggle. The G-11 is newly acquired so I am reluctant to try to use the drive with the looseness of the motor. The motor does run, at least it makes noise when I trigger the control button on the 492. Does the flexible plastic cover peal off to reveal the bolts? Thanks again for all the guidance and response from the group members.
|
Re: How much counterweight?
Hi Jim,
I had an 8" EdgeHD, round stars with an EdgeHD OTA are standard equipment. That's certainly going to be a nice setup, a bit long for my favorite subjects without the reducer and a full frame camera sensor but if you have the resources for an 11" EdgeHD and G11G ...? ?
Chip
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Re: How much counterweight?
Sold a CPC1100 and CGEM to put toward a G-11 and 11" Edge HD.? Still hope to gather the same amount of photons, just expect to get rounder stars.
Jim
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-----Original Message-----
From: chiplouie@... [Losmandy_users]
To: Losmandy_users
Sent: Fri, Nov 17, 2017 2:29 pm
Subject: [Losmandy_users] Re: How much counterweight?
?
Hi Jim,
Oh, tell us what you bought so I can live vicariously! I'm broke now, between the last kid in college and a tax return surprise I did not anticipate my astro spending has to be curtailed for more than a few months. I suppose I could stop shopping and go out and use the stuff I have to capture a few photons LOL!?
Chip
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Re: G11 noise from gearbox's
Hi John,
The newer Losmandy gearboxes have bronze bushings on the axles so a drop of light machine oil on the visible bushing the best lubricant for this use. As far as a lubricant for the worm wheels and worm gears IMO the food grade (NOT the silicone version) is the best stuff for this application because it doesn't melt, separate, run, dry up and get gummy, stays soft and operational in extreme cold. A little bit goes a long way. Looks like the photo below, I buy the tub from Amazon.com and share it with my astronomy club friends.?
Chip ??
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Re: How much counterweight?
Hi Jim,
Oh, tell us what you bought so I can live vicariously! I'm broke now, between the last kid in college and a tax return surprise I did not anticipate my astro spending has to be curtailed for more than a few months. I suppose I could stop shopping and go out and use the stuff I have to capture a few photons LOL!?
Chip
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Michael Herman
Paul Kanevsky