Re: RA Divisor on Gemini 2 G811 mount.
Ed,
The comet tracking reference Brian provided above is for Gemini 1. Gemini 2 uses a different clock so the calculations will be different. I do not do comet tracking, but have a look at the attached document for an explanation of the clock divisors for Gemini 2.
Eric
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Hello everyone!
I'm a relatively new owner of a used GM-8 Gemini 1 with the LW tripod, steel worm (not brass), and original worm block (not OPW). Also I have the old motors, not maxxon or tucked etc. My guiding setup is a 50mm f/4 WO scope piggybacked on my WO Z73 refractor using a ZWO ASI120mm for guiding. Both mount and guide camera work using ASCOM gemini drivers and PHD2. My initial issues were with tight spots in the worm where I would get RA motor lags errors in the same spots. I'm very mechanically inclined and pulled apart the mount after countless hours of research on here, everything was extremely caked in grease I believe from a previous owner, it appeared to be a very good moly grease and nothing was seized etc. I decided to fully clean the mount and all the grease out and re-grease everything using superlube with teflon (typically recommended here). I was able to find high spots in the worm gear (using a 3d printed hand knob connected to the oldham coupler) and adjust the worm block so there was no more tight spots and no play in the worm. I also widened the gear box mounting holes to help align the worm and gear box shaft best as possible. I was successful in getting rid of the RA motor lags, however I am having a very hard time getting decent guiding. I've tried tightening RA axis and leaving it loose (but where clutch doesnt slip), I've tried various PHD2 settings, I've pulled apart the mount 2x now for cleaning, greasing and aligning (out of fear not using enough grease the first time), and I feel I've gotten the process down decently, but still have wild jumps in guiding. My testing days thus far haven't been ideal seeing conditions and intermittent clouds, but I have yet to see even a glimpse of "okay this will work its just a bad day". I'm just hoping someone can give me some guidance on what all these spikes may be, if it's possibly a bad bearing, not enough grease, oldham coupler alignment, bad motor, stiction? I still have several things to test for troubleshooting but want some other input as well to know I'm on the right track. These spikes also make using drift align very difficult and not very reliable, would it be better to use the gemini polar align assist for now? I've attached a PHD2 log just for some substance/visual, I really appreciate any input, I'm trying to avoid spending hundreds on upgrades but would be open to new bearings and the belleville spring mod if it would help.
Thanks everyone!
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Re: RA Divisor on Gemini 2 G811 mount.
Thanks for digging a bit on this Brian. The reference you sent refers to the serial line protocol, which I investigated and it definitely suggests the command set for Gemini supports this if you know the correct tracking rate divisors and other physical parameters for the mount. Im guessing the divisors on the handset are effectively this value, but using the handset for this repeatedly or on a regular basis may be a pain.
My new G811 is still on order so I can't noodle around with it myself yet. As you say, my AP could do this, but its not very portable :-)?
I am assuming I can set a non-sidereal rate in the TheSkyX, as there is a provision for that there, although I have not used it, I will give it a try and report back on my findings.
Thanks to all for their help.
Best, Ed
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Re: Orientation of pier/riser relative to legs
Hi Geoff,
I have never extended my HD tripods legs.
And the stability is still awesome.
About the only place the 12EX might not be a good idea is if you were using a Newtonian Telescope for observation.
I'm basically only interested in imaging. And only use a refractor.
So each has to think about what OTA they wish to use.
--
SonnyE
(I suggest viewed in full screen)
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Bit of fun adding RGB color to a duo band mono luminance shot with a QHY9/FSQ106N. Technically the duo band is 34nm Oiii and 12nm Ha emission lines. I don't have any Ha/Oiii channels but had some RGB from previous years with colors that overlap the duo band spectrum.
I have posted both mono and colours along with the filter specs so you know what I did. The Oiii overlaps and clips the transition from blue to green so the brown still makes it through and the Ha is a subset of the red.
Full res fields are Here: -
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Re: RA Divisor on Gemini 2 G811 mount.
Hi Ed,
this page may be interesting to you, particularly the section on?Coordinate Controlled Tracking.?
Looking at the Gemini interface, it's changed a bit so now you enter the delta RA and Delta DEC over a specified Timespan, but may be more what you're looking for
On Mon, Jan 25, 2021 at 7:41 AM Edward Beshore via <ebeshore= [email protected]> wrote: Hi Brian -
Thanks for the link. I am looking at a more ¡±production¡± oriented approach to asteroid followup that would preclude independently determining track rate by watching the object over 4 or 5 minutes.? I will get rates of motion from JPL Horizons and would like to enter the RA/dec rates of the object or some tracking bias to track the asteroid.?
I would greatly appreciate ?some authoritative guidance on how one would do that.
A humble request please. Gemini needs a proper manual. As it is, information is spread out among multiple webpages with no particular organization, YouTube videos from more than one source, and of course, posts on iogroups.
Kind regards,
Ed Beshore
-- Brian?
Brian Valente portfolio
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Re: Orientation of pier/riser relative to legs
Sonny,
Have a Q about those 12" pier extensions... do you - or do some others - ever leave your tripod legs retracted as you use a 12" extension? I have thought of that as I have moved my observing chair (a catsperch kit I built) around through a night. If the tripod legs were not so wide, it would be a lot easier. But then I suspect that a tighter base might reduce the stability of the OTA? Thoughts?
Geoff
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Re: RA Divisor on Gemini 2 G811 mount.
The Gemini ASCOM driver (and the ASCOM standard) supports setting variable tracking rates. It's entirely possible for software using ASCOM to set the Gemini divisor programmatically, so it's really just a question of finding the right software using ASCOM-provided commands to tell Gemini to track at a speed different than Sidereal. What software does it, I couldn't tell you, but it's totally doable :)
Regards,
? ? -Paul
toggle quoted message
Show quoted text
On Mon, Jan 25, 2021 at 02:18 PM, Brian Valente wrote:
Hi Ed
?
I will look into this some more, but for the Losmandy Gemini, afaik training is the only way Gemini supports custom tracking rates.?
?
If you are looking to do something like import Horizons data, mounts like Astro-Physics have that capability via their APCC/Horizons software.?
?
there may be third party software available to do this with an ASCOM connection, though i'm not aware of any for comets
?
?
Brian
?
On Mon, Jan 25, 2021 at 7:41 AM Edward Beshore via <ebeshore= [email protected]> wrote:
Hi Brian -
Thanks for the link. I am looking at a more ¡±production¡± oriented approach to asteroid followup that would preclude independently determining track rate by watching the object over 4 or 5 minutes.? I will get rates of motion from JPL Horizons and would like to enter the RA/dec rates of the object or some tracking bias to track the asteroid.?
I would greatly appreciate ?some authoritative guidance on how one would do that.
A humble request please. Gemini needs a proper manual. As it is, information is spread out among multiple webpages with no particular organization, YouTube videos from more than one source, and of course, posts on iogroups.
Kind regards,
Ed Beshore
?
?
?
--
Brian?
?
?
?
Brian Valente
portfolio
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Re: Orientation of pier/riser relative to legs
I¡¯ve finally settled on the standard one leg to the north and the Gemini unit to the south (under the polar scope). ?
Having the Gemini off to one side just bugged me aesthetically. ?It looked unbalanced. ?In the uncommon case where I need to use the polar scope, I will just unplug the cables so they are not in my face.
Then for reference, the Losmandy logo on the tripod is set due South. There doesn¡¯t appear to be anyway to have the Losmandy log also to the south since there is only one set of mounting holes for the Gemini brackets and that leaves the logo in the northwest. ?Maybe your extensions give you more flexibility.
I¡¯m satisfied and am not going to worry about it further. ?Now with the single leg to the north, it is also easier to find CWD (which is how this whole discussion started).
Bill
Hi again, Bill.
Yes, when assembling and using my GM811GHD, I tried different locations for the Gemini II, and decided I liked having towards the South, between the two legs, and a single Northward leg.
But to a tinkerer like me, the brilliant configurability of the latest tucked motor design gives a wide array of ways to finally assemble your mount.
Removing, turning, and replacing the 3/8" button head screws as I was deciding on a configuration I felt worked best for me. (I say that because everybody seems to have their own selection of equipment, telescope sizes and configurations, wants, needs, and custom problems.
I always thought I wanted a pier type configuration, so I got a 12EXT with my mount when purchased. The EXT's allow for the Gemini II to be mounted onto them, and I eventually found my spot for mine. At first I had it towards the East, with a single tripod leg pointed due North. But I was uncomfortable with my wiring and swing of my telescope in use. So sitting in the house waiting out 2020's torretial spring rains, I had a lot of days to tinker and think through different configurations.
My current one is the best for me.
I have the HD tripod, but it doesn't really matter. A tripod is a tripod, 3 legs. I set mine so one leg is due North. Then for reference, the Losmandy logo on the tripod is set due South. It is of little consequence, just explaining the picture. ;^)
Each piece of extension offers a 3 bayonet type mounting on one end, and a Hex hole pattern on the other. The Bayonet gives 120¡ã positions, and the Hex pattern gives 60¡ã points of rotation. Ample to configure the rotational axis of the mount to suit each. it's a matter of setting up the tripod, then determining the place for your next piece of the puzzle.
The Male to Male fittings to attach the extension to the MA provided with the mount. Or the RA head to the MA with 60¡ã orientations.
I'd suggest you set up your tripod inside where you have room to look at it and walk around it. Orientate your tripod as it works best for you. Mine is single leg North, Gemini II controller South.
If you don't have a/any extensions, locate the RA head so it points North Axis. (But same thing if you do use a/an extension.)
My RA is buttonhead screwed to the three bayonet slots, semi permanent, and my EX12 attaches to the standard MA with TKS hand screws. The hand screws are my separation point.
Anyway, just try turning and looking at your configuration until you get it aimed the way it works best for you.
Our mounts are really brilliantly adaptable to configure to work for us, if we want to set them up to our liking. ;^)
--
SonnyE
(I suggest viewed in full screen)
--? Bill Tschumy Otherwise -- Longmont, CO
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Re: Orientation of pier/riser relative to legs
Hi again, Bill.
Yes, when assembling and using my GM811GHD, I tried different locations for the Gemini II, and decided I liked having towards the South, between the two legs, and a single Northward leg.
But to a tinkerer like me, the brilliant configurability of the latest tucked motor design gives a wide array of ways to finally assemble your mount.
Removing, turning, and replacing the 3/8" button head screws as I was deciding on a configuration I felt worked best for me. (I say that because everybody seems to have their own selection of equipment, telescope sizes and configurations, wants, needs, and custom problems.
I always thought I wanted a pier type configuration, so I got a 12EXT with my mount when purchased. The EXT's allow for the Gemini II to be mounted onto them, and I eventually found my spot for mine. At first I had it towards the East, with a single tripod leg pointed due North. But I was uncomfortable with my wiring and swing of my telescope in use. So sitting in the house waiting out 2020's torretial spring rains, I had a lot of days to tinker and think through different configurations.
My current one is the best for me.
I have the HD tripod, but it doesn't really matter. A tripod is a tripod, 3 legs. I set mine so one leg is due North. Then for reference, the Losmandy logo on the tripod is set due South. It is of little consequence, just explaining the picture. ;^)
Each piece of extension offers a 3 bayonet type mounting on one end, and a Hex hole pattern on the other. The Bayonet gives 120¡ã positions, and the Hex pattern gives 60¡ã points of rotation. Ample to configure the rotational axis of the mount to suit each. it's a matter of setting up the tripod, then determining the place for your next piece of the puzzle.
The Male to Male fittings to attach the extension to the MA provided with the mount. Or the RA head to the MA with 60¡ã orientations.
I'd suggest you set up your tripod inside where you have room to look at it and walk around it. Orientate your tripod as it works best for you. Mine is single leg North, Gemini II controller South.
If you don't have a/any extensions, locate the RA head so it points North Axis. (But same thing if you do use a/an extension.)
My RA is buttonhead screwed to the three bayonet slots, semi permanent, and my EX12 attaches to the standard MA with TKS hand screws. The hand screws are my separation point.
Anyway, just try turning and looking at your configuration until you get it aimed the way it works best for you.
Our mounts are really brilliantly adaptable to configure to work for us, if we want to set them up to our liking. ;^)
--
SonnyE
(I suggest viewed in full screen)
|
Re: RA Divisor on Gemini 2 G811 mount.
Hi Ed
I will look into this some more, but for the Losmandy Gemini, afaik training is the only way Gemini supports custom tracking rates.?
If you are looking to do something like import Horizons data, mounts like Astro-Physics have that capability via their APCC/Horizons software.?
there may be third party software available to do this with an ASCOM connection, though i'm not aware of any for comets
Brian
On Mon, Jan 25, 2021 at 7:41 AM Edward Beshore via <ebeshore= [email protected]> wrote: Hi Brian -
Thanks for the link. I am looking at a more ¡±production¡± oriented approach to asteroid followup that would preclude independently determining track rate by watching the object over 4 or 5 minutes.? I will get rates of motion from JPL Horizons and would like to enter the RA/dec rates of the object or some tracking bias to track the asteroid.?
I would greatly appreciate ?some authoritative guidance on how one would do that.
A humble request please. Gemini needs a proper manual. As it is, information is spread out among multiple webpages with no particular organization, YouTube videos from more than one source, and of course, posts on iogroups.
Kind regards,
Ed Beshore
-- Brian?
Brian Valente portfolio
|
Re: RA Divisor on Gemini 2 G811 mount.
Hi Brian -
Thanks for the link. I am looking at a more ¡±production¡± oriented approach to asteroid followup that would preclude independently determining track rate by watching the object over 4 or 5 minutes. ?I will get rates of motion from JPL Horizons and would like to enter the RA/dec rates of the object or some tracking bias to track the asteroid.?
I would greatly appreciate ?some authoritative guidance on how one would do that.
A humble request please. Gemini needs a proper manual. As it is, information is spread out among multiple webpages with no particular organization, YouTube videos from more than one source, and of course, posts on iogroups.
Kind regards,
Ed Beshore
|
Re: Orientation of pier/riser relative to legs
That is the way my GM8 is and I was a bit surprised when the G811 came differently. ?I *think* it came that way from the factory. ?I don¡¯t recall putting the riser on myself, but possibly I did and did it incorrectly.
The only problem with having the Gemini unit to the south is that it makes it hard to use the polar alignment scope. ?The cables sticking out of the Gemini get in your face while trying to look through the scope.
What is the orientation of the Losmandy logo? ?Where should it be facing?
Bill On Jan 24, 2021, at 4:24 PM, Brian Valente < bvalente@...> wrote:
There is no "right way" as any of those work
but the generally preferred and accepted "normal" way is to have one leg pointing north and the Gemini mounted to the opposite?(south) side.?
it does not make any difference in performance, though you have to look at things like motor cable lengths to ensure things will connect up
the picture you mention is out of date - you can see it's the older gemini in there?
Brian On Sun, Jan 24, 2021 at 2:53 PM Bill Tschumy < bill@...> wrote: A day or two ago I asked how best to achieve CWD position.? Sonny replied
> When beginning with everything plumb from the tripod up, it is natural for the weight shaft to be centered on a North pointing tripod leg.
I just realized that my tripod is set up so the counterweight shaft is between two legs, it can¡¯t be over a leg.? Not that it matters that much but I think my short pier was put on incorrectly.? I can take our the 6 bolts and rotate it 30? (??) so that I can put the head on with the shaft over a leg.
Can someone tell me what is the correct position?? Is the Gemini 2 unit supposed to be on the east or west side?? The way mine came, the unit would be on the south side.
The picture here seems to indicate it should be on the west side (actually north-west).
Bill
--
Bill Tschumy
Otherwise -- Longmont, CO
-- Brian?
Brian Valente portfolio
--? Bill Tschumy Otherwise -- Longmont, CO
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Re: Orientation of pier/riser relative to legs
The main thing you will notice with the CW over the tripod leg, is that if you have the upgraded aluminum RA knobs to attach the RA to the tripod, the knobs will be close to the Az and Alt adjustment knobs on the RA.
This MAY make it a little harder to get a good grip on those knobs, certainly not really difficult to access, but completely different than the other orientation which places all the Az/Alt knobs away from the RA /tripod attachment knobs/screws.
ALSO, when you orient the CW shaft over the tripod leg, (partially limiting some access to the Az/Alt knobs) you gain the benefit of having the Gemini controller mounting ears positioned so you can mount the Gemini controller due south, instead of at an angle on one side, which MAY affect the limit setting you can use on that side.
It would be awesome if Losmandy were to drill the holes for the controller ears, in both orientations, 1: as is currently, and 2: a new set of alternate (extra) holes, so the RA / tripod aluminum knobs can be oriented so they do not intefere with the AZ/Alt adjustment knobs, while still allowing the Gemini controller to be mounted due south...
The motor cables seem long enough for either orientation...?
Since the ear holes are drilled and tapped at an angle, it is a lot harder to add these without a jig. This may be beneficial for both the main 4" tripod adapter, as well as all of the extensions.
Just a 'wow, it would be great if...' observation...
Astronut Tim
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Re: Declination "Motor Stalled" warning on G11/G-1
I think i have that power supply too!
it should be fine
just try to isolate when and where the problem occurs. From what it sounds like, it's only when you are issuing to goto with both motors running slew speed at the same time?
what happens if you press both RA and DEC buttons at slew speed with the hand controller??
On Sun, Jan 24, 2021 at 4:01 PM Russell Milton < russmilt@...> wrote: [Edited Message Follows]
Thanks, Brian. My supply is a Pyramid 5-amp (7-amp surge), 12-volt supply set for 13.8 volts. I'll look into whether there is a voltage set adjustment internally for a higher input to the mount's electronics. I use power pole connectors between power supply and the Gemini power input cable. But all other connections are via push-in multi-pin connectors. As was mentioned, these can be subject to corrosion or detritus interfering with good, low drop connection.
When I bypassed initial star alignment, I chose sidereal to enable the hand controller to control motors directly. Once I got the Dec motor to respond, the motor-stall error went away on go-to star alignment.
Edit:
I checked the supply voltage - 13.8V idle, 13.6V under light load. I used a small inverter to power a <10W LED lamp. So upping the output voltage looks to be worthwhile. I don't use it for anything but the Losmandy G11 mount.
Russ
-- Brian?
Brian Valente portfolio
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Re: Declination "Motor Stalled" warning on G11/G-1
Russ,
Look at the DIN sockets and you will see the round pin hole, and a linear slot too for each pin.? There are metal fingers in the slots.? You can get a thin nail or blade into the slot and push the metal connector fingers inward.? This might help get your cable connector pins better contact.
Now to isolate the problem.
Swap the RA and DEC cables if you are able.? Does the problem move with the cable?? If yes replace the bad cable.
Swap the RA and DEC motor (just connect the cable end to the wrong motor).? Does the problem move with the motor?? If so...consider buying a new motor.??
If the problem stays in the same place (DEC, or RA) regardless of cable or motor, ...seems like the trouble is in the Gemini.? The Gemini-1 has a chip for each axis that reads the optical encoder.? That chip can become damaged.? I have these parts and do these repairs.? So if that ends up being the problem...in the G-1, you can contact me off line to do a repair.
What causes the optical encoder chip or a motor to become damaged? Simple: the 12 to 18V pins running the motor are far higher than the 5V max HEDS optical encoder unit in the motor, and far exceeds the 5V max of the optical signal detector chip in the Gemini. If one were to mistakenly rotate the round DIN cable then the pins go into the wrong position and ...kapow.??
This happens to someone every year.??
So...label your cable ends with some type of marker and where they insert, so the orientation is clear, even in the darkness when you set up.? I use white label maker labels cut into an arrow shape.??
Very best of luck, Michael
On Sun, Jan 24, 2021, 3:39 PM Russell Milton < russmilt@...> wrote: Good suggestion! That sounds safer and more effective than mechanically removing oxidation. I remember having a spray can of Radio Shack contact clean somewhere. If I can find that, I'll give it a try. Otherwise I'll get some DeOxit. It claims to be protective of the contact surfaces. In the moist environment that would be a plus.
Russ
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Re: Declination "Motor Stalled" warning on G11/G-1
Good suggestion! That sounds safer and more effective than mechanically removing oxidation. I remember having a spray can of Radio Shack contact clean somewhere. If I can find that, I'll give it a try. Otherwise I'll get some DeOxit. It claims to be protective of the contact surfaces. In the moist environment that would be a plus.
Russ
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Re: Declination "Motor Stalled" warning on G11/G-1
Thanks, Brian. My supply is a Pyramid 5-amp (7-amp surge), 12-volt supply set for 13.8 volts. I'll look into whether there is a voltage set adjustment internally for a higher input to the mount's electronics. I use power pole connectors between power supply and the Gemini power input cable. But all other connections are via push-in multi-pin connectors. As was mentioned, these can be subject to corrosion or detritus interfering with good, low drop connection.
When I bypassed initial star alignment, I chose sidereal to enable the hand controller to control motors directly. Once I got the Dec motor to respond, the motor-stall error went away on go-to star alignment.
Edit:
I checked the supply voltage - 13.8V idle, 13.6V under light load. I used a small inverter to power a <10W LED lamp. So upping the output voltage looks to be worthwhile. I don't use it for anything but the Losmandy G11 mount.
Russ
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Re: Orientation of pier/riser relative to legs
There is no "right way" as any of those work
but the generally preferred and accepted "normal" way is to have one leg pointing north and the Gemini mounted to the opposite?(south) side.?
it does not make any difference in performance, though you have to look at things like motor cable lengths to ensure things will connect up
the picture you mention is out of date - you can see it's the older gemini in there?
Brian
On Sun, Jan 24, 2021 at 2:53 PM Bill Tschumy < bill@...> wrote: A day or two ago I asked how best to achieve CWD position.? Sonny replied
> When beginning with everything plumb from the tripod up, it is natural for the weight shaft to be centered on a North pointing tripod leg.
I just realized that my tripod is set up so the counterweight shaft is between two legs, it can¡¯t be over a leg.? Not that it matters that much but I think my short pier was put on incorrectly.? I can take our the 6 bolts and rotate it 30? (??) so that I can put the head on with the shaft over a leg.
Can someone tell me what is the correct position?? Is the Gemini 2 unit supposed to be on the east or west side?? The way mine came, the unit would be on the south side.
The picture here seems to indicate it should be on the west side (actually north-west).
Bill
--
Bill Tschumy
Otherwise -- Longmont, CO
-- Brian?
Brian Valente portfolio
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Re: Understanding a GM8 for Possible Purchase
Chip nice writeup
It's getting better at the shop but it's still quite a few weeks lead time right now
when are you coming back to finish your mount? :)
On Sun, Jan 24, 2021 at 2:20 PM Chip Louie < chiplouie@...> wrote: Hi Jeff,
My name is Chip, Louie is my surname.
The main issue is the value proposition of buying a used Losmandy mount for imaging that lacks Gemini 2 and spring loaded worms. If you don't have these two key features on the mount you will not have an easy time imaging. The older mounts can always be updated but that costs time and money. The time issue is the real problem right now as Scott has no time for doing upgrades because the Losmandy shop is running day and night to keep up due to the Covid-19 surge powered interest in our hobby. This is not going to change for maybe another year is my guess. Several years ago now my old G11 was fully updated to the latest and greatest with all the doodads but those were different times without the Covid-19 rush and it still took a few months to get me scheduled for an update slot. The other issue is that it costs money to have the updates done which is an easy calculation, add up all the features the used mount lacks and subtract that cost from the cost of a new bare mount sans tripod. If you do this you will see that unless you acquired the mount for an very low price or have owned it for several years may or may not be cost effective to upgrade. I had a mint condition G11 and I had it for a while and it was purchased at a price that allowed me to update the mount for less than buying a new one would have cost. Plus it was a valued companion so I waited and updated. My GM8 was a similar situation but I had already been waiting when Covid-19 hit so I figured out the update was just not going to ever come up for an upgrade. So I sold my trusted observing companion GM8 and bought a new GM8G to make new adventures with so now both of my mounts are current version mounts.?
Trust me, as an imager you NEED the spring loaded one pieces worm blocks. This means based on my explainatin above you basically will be buying a new Losmandy mount. If you are not an imager and have zero plans to image my advice is to buy a used Losmandy mount in the best possible condition as cheaply as possible. This means if possible no Gemini but a #492 digital drive and then spend the money for an Astro Devices Nexus DSC and use the Losmandy mount as they were designed to be used, well balanced with fairly loose clutch settings and using two fingers PUSHED-TO your destinatin using the Porter Slip Clutches with the DSC to guide you there.? ?
--
Chip Louie Chief Daydreamer Imagination Hardware?
? ?Astropheric Weather Forecast - South Pasadena, CA?
-- Brian?
Brian Valente portfolio
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Paul Kanevsky
Bill Tschumy
Michael Herman
Russell Milton