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.
|
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.
|
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
|
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 actually have the Belleville washers and new bearings mod.
The Oldham coupler is tight too.
No issue with RA since the motion does not reverse.
I got the backlash value from phd2. It automatically adjusts the compensation during guiding and ended at 4000ms which was my Max duration.?
I also directly measured it by moving the Dec at guide speed in photo mode with the hand controller. I placed? an Allen key in the Oldham coupler to easily observe when the shaft starts turning. When I reverse direction it takes at least 4 seconds to see a motion of the shaft.
|
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
|
Re: Upgrading from Half Hitch FTQ
I have seen 492 G11 heads offered for as low as $750 recently. MA adapters are $100-125 used, but they don't come along often. If you can find one this Losmandy made adapter for the G9 will work for a Celestron field tripod. OnStep goto offers a inexpensive alternative to to Gemini II. See my blog for information.
I had a couple and let them go for $40. It would be fairly easy to machine. The center six holes can be omitted as they were for bolting it to a CG-5 tripod hub. The outer holes are located to use three of the six wedge fastening holes and two for the mount fastening holes. A 6" by .05" slice of aluminum rod runs about $20 on eBay. On early tripods the six wedge holes were threaded 5/16th". Later hubs have three threaded and three unthreaded. In the photo of the adapter mounted you can see a 5/16th" bolt under the hub used to fasten the adapter.
George
https://www.stmbluepillkits.com/
|
Just curious how you determined your backlash was 4 seconds? if you are using PHD2 and have some example guidelogs to upload that would be great to see
Brian
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
|
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.
|
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.
|
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
|
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
|
Re: Quite sticky mount... and some ideas to balance loads...
Joe that¡¯s just what is needed empirical data?
--
Brendan
|
Re: Quite sticky mount... and some ideas to balance loads...
Just wanted to add some data to the discussion.? I purchased a new G-11 about 3 years ago and experienced the issue with the sticky RA balancing (I¡¯m at 40 degrees North latitude), so I ordered the wavy clutch washer from Losmandy and that made it significantly easier to balance.? I then measured the force needed to slowly move the RA using a cheap spring balance at the end of the counterweight shaft when the counterweight shaft was horizontal -- it required about 350 to 400 gm (measured perpendicular to the RA axis.) ?Subsequently, I passed that G11 on to my son and this past June I bought a new G11 with the tucked-in motors and SLWs.? Again, the balancing was somewhat problematic, now requiring 900 to 1000gms to get the RA to move.? I had assumed that the new model would come with the wavy clutch washer, but apparently that¡¯s not the case, although I have not taken it apart to look. ? I would also note that compared to a Celestron AVX, the G11 is still fairly sticky, even with the wavy washer installed. ? Joe? ? ?
toggle quoted message
Show quoted text
From: [email protected] <[email protected]> On Behalf Of Michael Herman
Sent: Sunday, September 29, 2019 3:40 PM
To: [email protected]
Subject: Re: [Losmandy_users_io] Quite sticky mount... and some ideas to balance loads... ? Very nice set of emails. Everyone has different mount versions, even if nominally the same model ("G11"). The idea to put in a spring, to separate the upper and lower metal faces of the clutch, is a newer version.? Losmandy never included that in earlier decades of the G11, and it needs a special groove cut in one of the metal clutch drive disks...it is absent on earlier G11 mounts like mine.? I am not aware of it being on any other mount models, but Losmandy does innovate.? I don't think you need it... CWD is the position you want to park at, but it has the disadvantage that all weight forces +scope and counterweights) are on the 1.25 inch RA shaft and it's bearings.? So any imbalance is hard to detect at that position. A better approach is to rotate the RA by 90 degrees, then balance the DEC and then the RA. For the DEC axis balance, you simply rotate the RA axis until the DEC axis is parallel to the ground...then fasten down the RA axis. Then loosen the DEC clutch knob, and balance...usually adjusting the DEC dovetail is sufficient. However, the RA axis, set at your polar elevation, is more tricky. On my system, I don't want to mess with my elevation knob, because my mount is usually close to polar aligned already, and I don't want to mess that up. So, once the DEC is balanced as above, I stay at the RA position where the DEC axis is horizontal.? Then the scope and camera load must be balanced by the counterweights.? A slight shove of the counterweights or the scope around the RA axis, in both CW and CCW directions, is sufficient to overcome static friction, and you can see if the load is close to perfect balance.? Both directions should "decay" to a stop at about the same travel angle.?? The mount is quite strong and a slight imbalance is normally no worry.? Many people in the past have intentionally unbalanced their axes to assure one side of the worm drives the ring gear.?? The final issue to watch out for, related to clutch behavior, is oily contamination of the plastic clutch disk, or it's mating metal surfaces.? If that occurs, you will find the axis slipping...it can be a high viscosity oil so the slippage can be very gradual and temperature dependent.? A cleaning of the surfaces with a solvent like isopropyl alcohol usually suffices. Have fun with your system and clear fall skies, ? Thx all
i am clearly familiar with the clutches!
John you nailed the issue
i am wondering why not put the washer by default
i will call losmandy to ask about the washer
Ciao
franco
|
Re: Quite sticky mount... and some ideas to balance loads...
Very nice set of emails. Everyone has different mount versions, even if nominally the same model ("G11").
The idea to put in a spring, to separate the upper and lower metal faces of the clutch, is a newer version.? Losmandy never included that in earlier decades of the G11, and it needs a special groove cut in one of the metal clutch drive disks...it is absent on earlier G11 mounts like mine.? I am not aware of it being on any other mount models, but Losmandy does innovate.? I don't think you need it...
CWD is the position you want to park at, but it has the disadvantage that all weight forces +scope and counterweights) are on the 1.25 inch RA shaft and it's bearings.? So any imbalance is hard to detect at that position.
A better approach is to rotate the RA by 90 degrees, then balance the DEC and then the RA.
For the DEC axis balance, you simply rotate the RA axis until the DEC axis is parallel to the ground...then fasten down the RA axis. Then loosen the DEC clutch knob, and balance...usually adjusting the DEC dovetail is sufficient.
However, the RA axis, set at your polar elevation, is more tricky. On my system, I don't want to mess with my elevation knob, because my mount is usually close to polar aligned already, and I don't want to mess that up.
So, once the DEC is balanced as above, I stay at the RA position where the DEC axis is horizontal.? Then the scope and camera load must be balanced by the counterweights.? A slight shove of the counterweights or the scope around the RA axis, in both CW and CCW directions, is sufficient to overcome static friction, and you can see if the load is close to perfect balance.? Both directions should "decay" to a stop at about the same travel angle.??
The mount is quite strong and a slight imbalance is normally no worry.? Many people in the past have intentionally unbalanced their axes to assure one side of the worm drives the ring gear.??
The final issue to watch out for, related to clutch behavior, is oily contamination of the plastic clutch disk, or it's mating metal surfaces.? If that occurs, you will find the axis slipping...it can be a high viscosity oil so the slippage can be very gradual and temperature dependent.? A cleaning of the surfaces with a solvent like isopropyl alcohol usually suffices.
Have fun with your system and clear fall skies,
Michael
Thx all
i am clearly familiar with the clutches!
John you nailed the issue
i am wondering why not put the washer by default
i will call losmandy to ask about the washer
Ciao
franco
|
Re: Upgrading from Half Hitch FTQ
ScubaLee,
This is not as good a deal as you think it is. This is the old Gemini 2 on a standard straight drive G11 mount. It has no tripod which will cost you at least $250 to get a Losmandy MA and a used Meade Standard Field Tripod and the minimum fastener hardware.?
If you consider the cost to ship, maybe $150 fully insured and back out the selling value of a used Losmandy SBS @$150 you are paying $1,850 for a older unupdated G11 and original Gemini 2.?
For a small scope like your 80mm and most faster modern ED or triplet apo refractors up to a 150mm or anything from a C6 to C11 a GM8 will do very well. The GM8 is lighter and travels more compactly.
For imaging the Losmandy GM8's standard lightweight tripod is fine if you don't extend the legs much and keep the imaging payload under 20 pounds, 25 pounds with a stiffer tripod.
I have both a full house G11 -illuminated polar scope, 7" double clamped saddle, tucked HT servo motors, spring loaded one-piece worm blocks w/HP worms, RA extension with Gemini 2-mini, all topless knobs etc-? I use for imaging and visual with the C11 and C14 SCTs and a GM8 with classic straight drive and HP worms I use for visual work with everything up to the C11.?
My advice is to buy the latest Gemini 2-mini or the rocker switch Gemini 1 which were the latest version Geminis offered. The Gemin-1 has all of the same functions as the G2 just no color touch screen, USB, Ethernet and web interface. The Gemini-1 is MUCH, MUCH more quiet in operation when slewing. For visual use the G1 when used with a Sky-Fi 3 and Sky Safari-6 Pro you have a much better touchscreen (your smart phone) with the power of a planetarium in your hand, much more useful IMO for the visual observer.?
Be patient, the right deal will come along.
--
Chip Louie - Chief Daydreamer Imagination Hardware
|
Thx all
i am clearly familiar with the clutches!
John you nailed the issue
i am wondering why not put the washer by default
i will call losmandy to ask about the washer
Ciao
franco
|
Franco,
I assume you are talking about mount axis stiction which is resistance while trying to balance the mount with the clutches loose.?
For the RA axis there are two things you can do. First is to crank down the elevation close to zero degrees latitude so the shaft is almost horizontal (watch for tipping!). This lessens the downward force on the RA clutch and will allow an easier spin. However, this is a pain to do repeatedly as you need to redo your polar alignment from scratch each time. The second is to install a clutch washer available from Losmandy for a couple of bucks. If you call them they will know the part involved. This separates the clutch plates a little, but it gets crushed down whenever you re-tighten. I did the latter and go plenty East heavy to see a noticeable drop.
The Dec axis should be moved as close to horizontal too, and then I go camera or eyepiece side heavy. The G11 doesn't really free wheel during balancing like some other mounts but this is normal for the design.
Regards,
John
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Michael Herman
Luis Barneo
Chip Louie