Re: Gemini 2 unit resets to default??
The converters are a nice idea.
I make these input polarity protected units for Gemini-2 (the 5.5mm DC input) and a slightly different one for Gemini-1(the DIN power input socket).? I use them at home for my 3 Gemini units. The input DC voltage can be any polarity so in field use you cannot damage the Gemini by a mistake in the dark.
It pumps ~12V DC input, to the correct polarity 17V output (adjustable internally) to the Gemini unit.? It has also has an output voltage and output current meter on it, so I know if there is a motor or gear jam issue by unusual current above normal.? It acts like a power dashboard for my Gemini units.? It aids in worm adjustment also by showing if the worm is jamming.?
With the voltage booster I also provide a? 115VAC to DC 12V 5amp unit. Also, a simple cigarette lighter cord unit can provide field power ~12V, and this gets pumped to 17V for better DC motor torque. I have the cigarette adaptor cords too.??
Anyway, let me know privately if interested.?
All the best, Michael
On Thu, Oct 3, 2019, 10:03 AM Brian Valente < bvalente@...> wrote: Hi Greg
>>What is the best thing to get to increase voltage to the gemini to improve the torque if you guys dont mind me asking here? The Gemini operates best at between 15-18v.?
I sometimes use the Losmandy AC adapter (15v) or a voltage upconverter (something like??)
Do you feel like you're not getting enough torque??
On Thu, Oct 3, 2019 at 9:49 AM Greg via Groups.Io <gregmorris425= [email protected]> wrote: I just changed the battery in my gemini 2 mini and I used my gps module from losmandy when I powered it back up and it reset time and date pretty quick.? I did this because I'm using a TP-link and my ip address on one startup is 192.168.0.111 and the next time may be 192.168.0.100 which affects connecting. The battery did not solve this. I have 3.2 volts according to a meter and the web interface. ( Which is really really cool). What is the best thing to get to increase voltage to the gemini to improve the torque if you guys dont mind me asking here?
Greg
--
Brian?
Brian Valente portfolio
|
Re: Gemini 2 unit resets to default??
Hi Greg
>>What is the best thing to get to increase voltage to the gemini to improve the torque if you guys dont mind me asking here? The Gemini operates best at between 15-18v.?
I sometimes use the Losmandy AC adapter (15v) or a voltage upconverter (something like??)
Do you feel like you're not getting enough torque??
On Thu, Oct 3, 2019 at 9:49 AM Greg via Groups.Io <gregmorris425= [email protected]> wrote: I just changed the battery in my gemini 2 mini and I used my gps module from losmandy when I powered it back up and it reset time and date pretty quick.? I did this because I'm using a TP-link and my ip address on one startup is 192.168.0.111 and the next time may be 192.168.0.100 which affects connecting. The battery did not solve this. I have 3.2 volts according to a meter and the web interface. ( Which is really really cool). What is the best thing to get to increase voltage to the gemini to improve the torque if you guys dont mind me asking here?
Greg
-- Brian?
Brian Valente portfolio
|
Re: Gemini 2 unit resets to default??
I just purchased a waterproof 12V -> 18V DC-DC converter from eBay with a ?8A rated capacity ¨C works fine.? They¡¯re still selling them for about USD20 or so (see eBay item number 162987841478). ? I couldn¡¯t begin to make one for that price!!! ? David
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Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Greg via Groups.Io
Sent: 03 October 2019 17:49
To: [email protected]
Subject: Re: [Losmandy_users_io] Gemini 2 unit resets to default?? ? I just changed the battery in my gemini 2 mini and I used my gps module from losmandy when I powered it back up and it reset time and date pretty quick.? I did this because I'm using a TP-link and my ip address on one startup is 192.168.0.111 and the next time may be 192.168.0.100 which affects connecting. The battery did not solve this. I have 3.2 volts according to a meter and the web interface. ( Which is really really cool). What is the best thing to get to increase voltage to the gemini to improve the torque if you guys dont mind me asking here?
Greg
|
Re: Gemini 2 unit resets to default??
I just changed the battery in my gemini 2 mini and I used my gps module from losmandy when I powered it back up and it reset time and date pretty quick.? I did this because I'm using a TP-link and my ip address on one startup is 192.168.0.111 and the next time may be 192.168.0.100 which affects connecting. The battery did not solve this. I have 3.2 volts according to a meter and the web interface. ( Which is really really cool). What is the best thing to get to increase voltage to the gemini to improve the torque if you guys dont mind me asking here?
Greg
|
Re: Gemini 2 unit resets to default??
Magnus....
what does the web interface indicate as battery voltage?
Timothy summed it all up. ?I¡¯ve seen bad batteries out of the packaging. ?There are quit a few ¡°fake batteries¡± out there. ?Buy from reputable source, mouser, dogikey, arrow, RS
--
Brendan
|
Re: Gemini 2 unit resets to default??
Hi Magnus,
There¡¯s a known bug in the clock chip (this isn¡¯t something that Losmandy can fix with a firmware update). ?When the battery is changed and it loses the date & time, it starts in a state that causes it to drain power rapidly UNTIL you set the date/time (and then everything is normal again).
There are a few techniques to change the battery to avoid this.
1) ?Replace the battery with the unit powered off. ?Once the new battery is installed, immediately power up the Gemini and set the date/time. ?
BTW, you do not need to have the Gemini connected to the mount when you do this. ?So if the mount is in an observatory but you¡¯d rather do this inside where it¡¯s warm ¡ just disconnected RA/Dec cables, remove the Gemini module from the mount and bring it in to change it. ?It will likely complain that the motors aren¡¯t working but¡ this wont affect your ability to set the date and time (and you know the reason the motors aren¡¯t responding is because they aren¡¯t connected.
2) ?Replace the battery while the unit is powered on (running on 12v power). ?Take care here to not touch any of the exposed electronics, ?But since the unit technically never lost power it will still have the date/time set.
I typically just do method #1 and I always immediately re-order a spare battery (I find local stores tend to not have these sizes so I never want to get caught with a dead battery and no spare).
Scott has a YouTube video where he shows how to swap the battery. ?He uses a simple piece of scotch tape so that when he lifts the battery retaining spring he can just pull on the tape and the battery comes out easily.
As for voltage¡
The mount runs on 12v-18v power. ?The electronics are completely happy with 12v power. ?BUT¡ if you run the mount on higher voltage then you get more torque to the motors (especially useful if you have a heavy load). ?If you are running a light load ¡ go ahead and stick with 12v power. ??
Clear Skies,
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Show quoted text
On Oct 1, 2019, at 4:09 PM, Magnus Larsson < magnus@...> wrote:
Hi! OK, not sure I did that. So I'll do it again. But: I don't see
what difference that does.... setting the time and so on, when
changing battery? I'll measure the batter too,? soon as I can.
Magnus
Den 2019-10-01 kl. 20:31, skrev Brendan
Smith:
Magnus when you changed the battery did you immediately set DTG.?
Cam you now measure the battery thru web interface is it above
3.0v?
Gemini units are very pernickety about backup battery voltage for
sure this is your problem. Have even heard of new old batteries
being used that were below voltage out of the packet, so also
maybe check them with a multimeter.?
--
Brendan
|
Re: Gemini 2 unit resets to default??
magnus there's a setting for how gemini boots, "ask if possible" is one of the options. sounds like it's switched to something else
as brendan points out, if it's losing the values you put in, it's backup power related (i.e., the internal battery)
yes, it's good to have 15v for gemini ;)
Brian
|
Re: Gemini 2 unit resets to default??
Hi!
OK, not sure I did that. So I'll do it again. But: I don't see
what difference that does.... setting the time and so on, when
changing battery?
I'll measure the batter too,? soon as I can.
Magnus
Den 2019-10-01 kl. 20:31, skrev Brendan
Smith:
toggle quoted message
Show quoted text
Magnus when you changed the battery did you immediately set DTG.?
Cam you now measure the battery thru web interface is it above
3.0v?
Gemini units are very pernickety about backup battery voltage for
sure this is your problem. Have even heard of new old batteries
being used that were below voltage out of the packet, so also
maybe check them with a multimeter.?
--
Brendan
|
Re: Gemini 2 unit resets to default??
Magnus when you changed the battery did you immediately set DTG.?
Cam you now measure the battery thru web interface is it above 3.0v?
Gemini units are very pernickety about backup battery voltage for sure this is your problem. Have even heard of new old batteries being used that were below voltage out of the packet, so also maybe check them with a multimeter.?
--
Brendan
|
Gemini 2 unit resets to default??
Hi!
I've said this before in this forum, but then it was summer and no astro activity. Now it is fall and I'm up and running again. And this happens on and off - for me, quite unpredictable: When I turn the mount on, it does NOT give me the menu to choose startup mode (COld, Warm, Restart) but just boots. And when I check, the valuyes I'd set are reset to default: speed to 800 (I set it 500), limits to default (and this is really bad, since then automated meridian flips won't work).?
I'm running the unit on 12V, I know there have been discussion on that and a 15 V step-up converter is more or less on it's way. I change battery in the spring, not much used since then. So what could it be??
Magnus
|
Russell Jancic Passed away.
On the losmandy Facebook page a post that Russell passed away from a long illness. ?My condolences to his family, Scott and all at Losmandy.
Russell was Scott¡¯s right hand man a person of many talents who has helped many in these forums and repairing their units back at Losmandy.?
I didn¡¯t know him well he helped me personally enormously, he has a big legacy. ?Goodbye Russell?
--
Brendan
|
Wow!..
Wish my G11 had one of those RA Washers!
?
Derek
?
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Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of John Kmetz
Sent: Sunday, September 29, 2019
9:57 PM
To: [email protected]
Subject: Re: [Losmandy_users_io]
Quite sticky mount
?
Franco,
To insert the washer, you will need to completely remove the RA lock knob while
being careful of the order of the washers and bearings underneath. Pics
attached.
Then you can slide out the upper RA assembly and shaft, then insert the clutch
washer and reassemble in reverse order.
Best Regards,
John
|
Luis,
Yes the purpose of the EQmod group program PECprep.exe is to analyze the Unguided PE data, by the method called FFT, and this tells the owner the exact frequencies present in the RA drive.? That program has a top menu selection for G11 and GM8 also...and many other mounts.? The program originally was designed for the Synta EQ6, but was nicely expanded by the authors to cover many popular mounts.
If the only large frequency is the worm period (on a G11 this is ~240 sec or 4 minutes.? On a GM8 that is 480 sec or 8 minutes), that is what is desired, and the PE value will be shown (in arcsec peak to peak and RMS).? You desire the PE to be under 2 arcsec RMS for a G11, or under 4 arcsec for a GM8.? The reason is that with the identical worm it should be double that for a GM8, because it's RA ring gear is half the diameter of the G11 ring gear.??
Some people have achieved ~1 arcsec RMS with their G11, or about 2 arcsec with their GM8.? It required a Losmandy precision brass worm, and usually (not always) a Losmandy OPW and a high grade ABEC5 or ABEC7 worm bearings, and a Belleville spring washer.??
The program can also tell you about frequencies unique to different drive gears. That way you can identify a problem mechanical component.? The nice part if the Losmandy system is that RA and DEC components are interchangeable, do you can run experiments to find the best parts for the RA drive.
Astronomy is very demanding on equipment...and people.? ?Early astronomers included Gauss, who invented the normal distribution to try and understand the varied data he was getting from other people.? Another was Albert Michelson, who used spectroscopy to (dis)prove the theory of the luminiferous ether, leading instead to the Lorentz equation and finally the theory of relativity.? It is an amazing miracle that our amateur equipment can be made so well that we can expect near perfect tracking from modestly expensive mounts.? We are all seeking perfection and it usually takes extra effort, or extra money, to get closer to it.
Very best, Michael
On Mon, Sep 30, 2019, 3:16 PM Luis Barneo < lbarneo@...> wrote: I had download your document some months ago. Your advise is unchecked? "Precision Pulse guide" and "Sync performs Additional Align". My telescope is in an horizontal position, the "Western Goto limit (from CWD) should be 0 or 90.00? What is the utility?of EQMOD software? To analize PEC?
El lun., 30 sept. 2019 a las 22:21, Michael Herman (< mherman346@...>) escribi¨®: Luis,
Here is a write-up I did for connecting the Gemini 1 to a PC.? There may be some info in there you can use.
The question of remote operation is coming up in this group nowadays.? However, I can't comment on the best ways to do that. Perhaps other owners can speak about how they are doing this. They may have a Gemini-2 and this newer version may make it easier.? I don't have one yet!
Very best,
Michael
On Mon, Sep 30, 2019, 10:58 AM Luis Barneo < lbarneo@...> wrote: Thanks Michael,
1.????? How does I save the model to my PC?
I usually Warm Restart with the hand controller deluxe and synchronized some
stars and not realized the aligment of these stars because I did it in a previous
session and the mount put the star almost in the center of the camera ST-402 (FOV of 8.9 x
13.4 arcmin). After, I connect TheSkyX Prof to find the stellar objects that
are not in the Gemini catalogs (asteroids, small stars,¡) and works with the
camera, focus, etc.
2.????? My small observatory is in the
mountain wihout internet. For the correct time I tried to connect the PC with a
GPS through Geminitelescope.net and gave the correct position, time and altitude.
I don¡¯t? know if these data collected by Geminitelescope.net is transmitted to the
mount that are a little difference of the data that appears when I warm ?with the hand controller (position, time), and
cause or not a disturbing to the mount . For this reason, I¡¯m afraid to control
the mount with the Geminitelescope.net.
El lun., 30 sept. 2019 a las 17:12, Michael Herman (< mherman346@...>) escribi¨®:
In theory, once you build your model, you should save it to your PC and not need to ever cold boot again.? Only do warm boot to load in the last model saved inside the Gemini1 SRAM chip.
I say save it to your PC because if your backup battery dies, the Gemini 1 will lose the settings. You can then upload the saved file after changing the battery.
Be sure to turn off settings in the Gemini.net applet that can affect the model. That is on the advanced panel, upper right checkbox for "Synch performs additional Align".? You don't want that!
Then, just Synch on a known star every time you do the wam boot. ?
And always park your system to a known position like CWD. ?
That's the theory. ?
In practice:
Some programs like Plate Solver programs do not know about the Gemini model and using both is reported to mess up pointing.? So if you are using plate solving, after the first Synch, ?try leaving the Gemini model at all zeros.? See if that fixes the issue. ?
Sometimes my model parameters are messed up. Perhaps I added a bad alignment point.? Or some other thing has happened.? In that case, I build a new model.
There is a chip in the Gemini1 made by Epson. It is called an RTC real time clock chip.? Some people have said that can lose or gain time and so you must reSynch your time.? There is a simple way to do that in ,... I think it's on the Telescope panel. ?
?
Making a good model:
The manual says: add 3 align points on one side of the meridian, then add 3 on the other side of the meridian.? That is, do 3 align points either East (or West) followed by 3 on the other side West (or East).
Have fun, and hope your system stays Aligned!
Best,? Michael
On Mon, Sep 30, 2019 at 2:25 AM Luis Barneo < lbarneo@...> wrote: I suppose that is not a true new topic about the Losmandy mount: how often is advisable to realize the modeling of the mount? Every time when I open in warm restart, only warm or could start? My mount is a Losmandy G11 Gemini1 level4 in a permanent pier.
Luis
|
I had download your document some months ago. Your advise is unchecked? "Precision Pulse guide" and "Sync performs Additional Align". My telescope is in an horizontal position, the "Western Goto limit (from CWD) should be 0 or 90.00? What is the utility?of EQMOD software? To analize PEC?
El lun., 30 sept. 2019 a las 22:21, Michael Herman (< mherman346@...>) escribi¨®: Luis,
Here is a write-up I did for connecting the Gemini 1 to a PC.? There may be some info in there you can use.
The question of remote operation is coming up in this group nowadays.? However, I can't comment on the best ways to do that. Perhaps other owners can speak about how they are doing this. They may have a Gemini-2 and this newer version may make it easier.? I don't have one yet!
Very best,
Michael
On Mon, Sep 30, 2019, 10:58 AM Luis Barneo < lbarneo@...> wrote: Thanks Michael,
1.????? How does I save the model to my PC?
I usually Warm Restart with the hand controller deluxe and synchronized some
stars and not realized the aligment of these stars because I did it in a previous
session and the mount put the star almost in the center of the camera ST-402 (FOV of 8.9 x
13.4 arcmin). After, I connect TheSkyX Prof to find the stellar objects that
are not in the Gemini catalogs (asteroids, small stars,¡) and works with the
camera, focus, etc.
2.????? My small observatory is in the
mountain wihout internet. For the correct time I tried to connect the PC with a
GPS through Geminitelescope.net and gave the correct position, time and altitude.
I don¡¯t? know if these data collected by Geminitelescope.net is transmitted to the
mount that are a little difference of the data that appears when I warm ?with the hand controller (position, time), and
cause or not a disturbing to the mount . For this reason, I¡¯m afraid to control
the mount with the Geminitelescope.net.
El lun., 30 sept. 2019 a las 17:12, Michael Herman (< mherman346@...>) escribi¨®:
In theory, once you build your model, you should save it to your PC and not need to ever cold boot again.? Only do warm boot to load in the last model saved inside the Gemini1 SRAM chip.
I say save it to your PC because if your backup battery dies, the Gemini 1 will lose the settings. You can then upload the saved file after changing the battery.
Be sure to turn off settings in the Gemini.net applet that can affect the model. That is on the advanced panel, upper right checkbox for "Synch performs additional Align".? You don't want that!
Then, just Synch on a known star every time you do the wam boot. ?
And always park your system to a known position like CWD. ?
That's the theory. ?
In practice:
Some programs like Plate Solver programs do not know about the Gemini model and using both is reported to mess up pointing.? So if you are using plate solving, after the first Synch, ?try leaving the Gemini model at all zeros.? See if that fixes the issue. ?
Sometimes my model parameters are messed up. Perhaps I added a bad alignment point.? Or some other thing has happened.? In that case, I build a new model.
There is a chip in the Gemini1 made by Epson. It is called an RTC real time clock chip.? Some people have said that can lose or gain time and so you must reSynch your time.? There is a simple way to do that in ,... I think it's on the Telescope panel. ?
?
Making a good model:
The manual says: add 3 align points on one side of the meridian, then add 3 on the other side of the meridian.? That is, do 3 align points either East (or West) followed by 3 on the other side West (or East).
Have fun, and hope your system stays Aligned!
Best,? Michael
On Mon, Sep 30, 2019 at 2:25 AM Luis Barneo < lbarneo@...> wrote: I suppose that is not a true new topic about the Losmandy mount: how often is advisable to realize the modeling of the mount? Every time when I open in warm restart, only warm or could start? My mount is a Losmandy G11 Gemini1 level4 in a permanent pier.
Luis
|
Sorry that nutty Google is playing new games with my documents.
I'll try and attach the file here again.
Hope it works. If not, send me an email and I'll send it?to you directly.
Best, Michael
On Mon, Sep 30, 2019, 1:38 PM Brian Valente < bvalente@...> wrote: michael this doc that begins with ""
it says I need to request access for it?
On Mon, Sep 30, 2019 at 1:27 PM Michael Herman < mherman346@...> wrote: Here are two documents.? One is about GM8 PE testing.? The other is about fixing the worm lateral containment.? Perhaps there are clues in that to help you solve your GM8 issue.? ?
All the best,
On Mon, Sep 30, 2019, 7:44 AM Michael Herman via Groups.Io <mherman346= [email protected]> wrote:
4 secs seems very long.
I don't think the gearbox itself is a cause, but there is an Oldham coupler that links the gearbox to the worm. Sometimes the metal ends of that coupler can work loose. Usually it's easy to tighten the tiny setscrews that hold those coupler ends to their metal shafts using an Allen hex key wrench. I think the size is 0.050 inch (and is included in sets of American size hex key wrenches by Bondhus).
The movement of the worm toward the ring gear is easy, by design of the worm blocks. ?
The difficult element is the locking of the worm between the worm blocks, but it can be done. It is easier to add in a Belleville spring washer to the place behind the far bearing (far end of the worm, away from the coupler), that will always keep pressure on the bearing and the worm.
My GM8 has essentially no backlash in either axis with these adjustments.? I leave no gap between the worm and ring gear. ?
I am surprised your RA does not have the problem, but perhaps because RA is always driven at some rate (Sidereal or solar or lunar, perhaps). ?
Let me know if you need parts like the spring washers.? I'll send you a PDF about my GM8 results.
Best, Michael Hi,
I have a GM8 from 2006 (no upgrades) and I was looking into decreasing the DEC backlash.
From my understanding, there are 3 main sources of backlash:?
-Worm to gear not tight enough
-Worm loose between its blocks
-Gearbox.
The first two can be addressed with careful alignment.
What about the gearbox? From my tests it seems I need at least 4 seconds at guide speed to clear the backlash between input and output. Does that seems right?
Could this duration be decreased by doing the backlash compensation at higher speed? I don't see this option in PHD2, and I have read that it is better to leave the Gemini backlash compensation off when guiding.
--
Brian?
Brian Valente portfolio
|
Re: Upgrading from Half Hitch FTQ
Thank you everyone for super advice! I'll wait, work on selling my ftq, and consider the gm8.
|
correction, i think you attached the same pdf twice??
On Mon, Sep 30, 2019 at 1:29 PM Michael Herman < mherman346@...> wrote: The other document did not attach correctly...here it is.
Michael
Here are two documents.? One is about GM8 PE testing.? The other is about fixing the worm lateral containment.? Perhaps there are clues in that to help you solve your GM8 issue.? ?
All the best,
On Mon, Sep 30, 2019, 7:44 AM Michael Herman via Groups.Io <mherman346= [email protected]> wrote:
4 secs seems very long.
I don't think the gearbox itself is a cause, but there is an Oldham coupler that links the gearbox to the worm. Sometimes the metal ends of that coupler can work loose. Usually it's easy to tighten the tiny setscrews that hold those coupler ends to their metal shafts using an Allen hex key wrench. I think the size is 0.050 inch (and is included in sets of American size hex key wrenches by Bondhus).
The movement of the worm toward the ring gear is easy, by design of the worm blocks. ?
The difficult element is the locking of the worm between the worm blocks, but it can be done. It is easier to add in a Belleville spring washer to the place behind the far bearing (far end of the worm, away from the coupler), that will always keep pressure on the bearing and the worm.
My GM8 has essentially no backlash in either axis with these adjustments.? I leave no gap between the worm and ring gear. ?
I am surprised your RA does not have the problem, but perhaps because RA is always driven at some rate (Sidereal or solar or lunar, perhaps). ?
Let me know if you need parts like the spring washers.? I'll send you a PDF about my GM8 results.
Best, Michael Hi,
I have a GM8 from 2006 (no upgrades) and I was looking into decreasing the DEC backlash.
From my understanding, there are 3 main sources of backlash:?
-Worm to gear not tight enough
-Worm loose between its blocks
-Gearbox.
The first two can be addressed with careful alignment.
What about the gearbox? From my tests it seems I need at least 4 seconds at guide speed to clear the backlash between input and output. Does that seems right?
Could this duration be decreased by doing the backlash compensation at higher speed? I don't see this option in PHD2, and I have read that it is better to leave the Gemini backlash compensation off when guiding.
-- Brian?
Brian Valente portfolio
|
michael this doc that begins with ""
it says I need to request access for it?
On Mon, Sep 30, 2019 at 1:27 PM Michael Herman < mherman346@...> wrote: Here are two documents.? One is about GM8 PE testing.? The other is about fixing the worm lateral containment.? Perhaps there are clues in that to help you solve your GM8 issue.? ?
All the best,
On Mon, Sep 30, 2019, 7:44 AM Michael Herman via Groups.Io <mherman346= [email protected]> wrote:
4 secs seems very long.
I don't think the gearbox itself is a cause, but there is an Oldham coupler that links the gearbox to the worm. Sometimes the metal ends of that coupler can work loose. Usually it's easy to tighten the tiny setscrews that hold those coupler ends to their metal shafts using an Allen hex key wrench. I think the size is 0.050 inch (and is included in sets of American size hex key wrenches by Bondhus).
The movement of the worm toward the ring gear is easy, by design of the worm blocks. ?
The difficult element is the locking of the worm between the worm blocks, but it can be done. It is easier to add in a Belleville spring washer to the place behind the far bearing (far end of the worm, away from the coupler), that will always keep pressure on the bearing and the worm.
My GM8 has essentially no backlash in either axis with these adjustments.? I leave no gap between the worm and ring gear. ?
I am surprised your RA does not have the problem, but perhaps because RA is always driven at some rate (Sidereal or solar or lunar, perhaps). ?
Let me know if you need parts like the spring washers.? I'll send you a PDF about my GM8 results.
Best, Michael Hi,
I have a GM8 from 2006 (no upgrades) and I was looking into decreasing the DEC backlash.
From my understanding, there are 3 main sources of backlash:?
-Worm to gear not tight enough
-Worm loose between its blocks
-Gearbox.
The first two can be addressed with careful alignment.
What about the gearbox? From my tests it seems I need at least 4 seconds at guide speed to clear the backlash between input and output. Does that seems right?
Could this duration be decreased by doing the backlash compensation at higher speed? I don't see this option in PHD2, and I have read that it is better to leave the Gemini backlash compensation off when guiding.
-- Brian?
Brian Valente portfolio
|
The other document did not attach correctly...here it is.
Michael
Here are two documents.? One is about GM8 PE testing.? The other is about fixing the worm lateral containment.? Perhaps there are clues in that to help you solve your GM8 issue.? ?
All the best,
On Mon, Sep 30, 2019, 7:44 AM Michael Herman via Groups.Io <mherman346= [email protected]> wrote:
4 secs seems very long.
I don't think the gearbox itself is a cause, but there is an Oldham coupler that links the gearbox to the worm. Sometimes the metal ends of that coupler can work loose. Usually it's easy to tighten the tiny setscrews that hold those coupler ends to their metal shafts using an Allen hex key wrench. I think the size is 0.050 inch (and is included in sets of American size hex key wrenches by Bondhus).
The movement of the worm toward the ring gear is easy, by design of the worm blocks. ?
The difficult element is the locking of the worm between the worm blocks, but it can be done. It is easier to add in a Belleville spring washer to the place behind the far bearing (far end of the worm, away from the coupler), that will always keep pressure on the bearing and the worm.
My GM8 has essentially no backlash in either axis with these adjustments.? I leave no gap between the worm and ring gear. ?
I am surprised your RA does not have the problem, but perhaps because RA is always driven at some rate (Sidereal or solar or lunar, perhaps). ?
Let me know if you need parts like the spring washers.? I'll send you a PDF about my GM8 results.
Best, Michael Hi,
I have a GM8 from 2006 (no upgrades) and I was looking into decreasing the DEC backlash.
From my understanding, there are 3 main sources of backlash:?
-Worm to gear not tight enough
-Worm loose between its blocks
-Gearbox.
The first two can be addressed with careful alignment.
What about the gearbox? From my tests it seems I need at least 4 seconds at guide speed to clear the backlash between input and output. Does that seems right?
Could this duration be decreased by doing the backlash compensation at higher speed? I don't see this option in PHD2, and I have read that it is better to leave the Gemini backlash compensation off when guiding.
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Here are two documents.? One is about GM8 PE testing.? The other is about fixing the worm lateral containment.? Perhaps there are clues in that to help you solve your GM8 issue.? ?
All the best,
On Mon, Sep 30, 2019, 7:44 AM Michael Herman via Groups.Io <mherman346= [email protected]> wrote:
4 secs seems very long.
I don't think the gearbox itself is a cause, but there is an Oldham coupler that links the gearbox to the worm. Sometimes the metal ends of that coupler can work loose. Usually it's easy to tighten the tiny setscrews that hold those coupler ends to their metal shafts using an Allen hex key wrench. I think the size is 0.050 inch (and is included in sets of American size hex key wrenches by Bondhus).
The movement of the worm toward the ring gear is easy, by design of the worm blocks. ?
The difficult element is the locking of the worm between the worm blocks, but it can be done. It is easier to add in a Belleville spring washer to the place behind the far bearing (far end of the worm, away from the coupler), that will always keep pressure on the bearing and the worm.
My GM8 has essentially no backlash in either axis with these adjustments.? I leave no gap between the worm and ring gear. ?
I am surprised your RA does not have the problem, but perhaps because RA is always driven at some rate (Sidereal or solar or lunar, perhaps). ?
Let me know if you need parts like the spring washers.? I'll send you a PDF about my GM8 results.
Best, Michael Hi,
I have a GM8 from 2006 (no upgrades) and I was looking into decreasing the DEC backlash.
From my understanding, there are 3 main sources of backlash:?
-Worm to gear not tight enough
-Worm loose between its blocks
-Gearbox.
The first two can be addressed with careful alignment.
What about the gearbox? From my tests it seems I need at least 4 seconds at guide speed to clear the backlash between input and output. Does that seems right?
Could this duration be decreased by doing the backlash compensation at higher speed? I don't see this option in PHD2, and I have read that it is better to leave the Gemini backlash compensation off when guiding.
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Michael Herman
David C. Partridge
Greg
Timothy Campbell
Luis Barneo