Re: GM8 Belt drive stepper mount
Very nice project John, and very good description of your improved torque from the gear reductions.
On the EQ6 mount (Synta in China makes them, and marketed in the US by Orion as the EQG), some owners replaced the 2 transfer gears with a belt to reduce gear noise while slewing (calling it a "coffee grinder").? Now Synta makes that mount with the belt drive stock from the factory.? So belt drives are popular and proven workable.? The belt also eliminates gear gap and hysteresis time lag too.??
Anyway, very nice clean design job.? Thanks for that!
Michael
On Fri, Jan 17, 2020, 11:25 PM John Scherer < jrsphoto@...> wrote: Forgot to mention, I'm not driving anything to crazy on the GM8.? a C8 is about the biggest this will see, and the longer focal lengths are the main reasons for wanting better tracking.? These stepper mounts are really for someone NOT using the OEM motors and controller.? I've converted this mount to .
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Re: GM8 Belt drive stepper mount
Forgot to mention, I'm not driving anything to crazy on the GM8.? a C8 is about the biggest this will see, and the longer focal lengths are the main reasons for wanting better tracking.? These stepper mounts are really for someone NOT using the OEM motors and controller.? I've converted this mount to .
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Re: GM8 Belt drive stepper mount
Hey Sonny;
Torque is indeed one of the benefit of using additional gear reduction between the motor and the worm gear though not my primary goal.? For me its tracking resolution.? I'm driving the mount with 400 steps/rev, NEMA 17 stepper motors.? The stepper driver is further dividing these steps by 32.? Add to this the additional 4:1 belt drive reduction I'm adding at the motor, driving the 180-tooth worm gear and this gives me 256000 steps/deg for RA/DEC, and a tracking resolution of 0.14 arc-seconds.
Not sure what Gilmore belts are but the belts I'm using are 6mm GT2 timing belt with a 60-tooth and a 15-tooth GT2 pully.
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Re: Strange digital 492 drive behaviour
I use these cables on my Celestron CG11 492 DDS (3x all the same RA/Dec/HC)
Coil Cords - Hand Controller to 492 electronics and 492 to stepper motors
? This is the coil cord that came?from Losmandy included with the new HC that I purchased from them:
??? OEM Assmann WSW Components AT-C-26-6/6/B-7/R?
?? ?Cross ref?to:??
? Digi-Key P/N: A2662R-07C-ND, $3.98/ea.
? Qty: 3 (3x$3.98=$11.94)
? Style: Reverse
? Black, Flat, Coiled Cable Assembly
I purchased spares, all work fine.
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Re: OPW Adjustment Steps with Belleville Washer
Hi Taylor,
Some comments...I hope help.
Once you assembled the OPW, and in doing that you squeezed the Belleville washer flat, and so the worm will stay compressed.??
If your OPW has a cover that you can leave off, so you can see the Oldham coupler, do that.? You ideally want to see how the Oldham coupler parts look when the drive is slewing.? ?
There were 2 forms of OPW for the G11 (RA in the GM811): a)? Older long style (about $350?) has provision for the gearbox to bolt on.? This type requires a longer Oldham coupler (because the gearbox is further from the worm).? Prefer this type of you can get one, because the gearbox can be kept lined up with the worm ahead of time. b) Newer shorter style (~$150?). The gearbox does not attach to this one. Like the original design, the gearbox bolts to the mount.? This one takes the (original) short Oldham coupler.? Like the original drive design, the gearbox is fixed in position, so it's necessary to line up the? gearbox with the worm after the worm is positioned.??
If you have the older style OPW that has the Oldham coupler and gearbox attached, install those while the OPW is off the mount.? If you have the newer type, leave the gearbox off for now.
Now attach the OPW and just lightly force the worm into the teeth of the ring gear.? The Losmandy instruction is to rotate the axis so you use the ring gear teeth to force the worm toward the gearbox.? If you have the Belleville washer in place, the worm isn't going to move at all.? Just a very light force of the worm toward the ring gear is all you need.? Too much pressure could cause "stall" messages on the Gemini, which senses motor current.
Now allow the Oldham coupler ends to be loose.? You will want to slide the Oldham coupler in and out between the gearbox and the worm shaft, to center the gap between these.??
Now attach the gearbox and try to line up the shafts.? Gently lock down the gearbox...you may have to shift it's mounting once the Oldham is installed.
Now attach the two metal ends of the Oldham coupler, so that the white center is tight between the metal ends, and tighten down the setscrews in the metal ends.
Now attach the motor and run the drive and inspect the Oldham coupler as it rotates.? If the metal parts are not shifting in the plastic part, that's what you want...pure rotation.? If not, you might have to enlarge the gearbox mounting holes to shift it's position to try and line up these parts.? (The drive will work if the coupler shifts,? but you want lowest PE and absolutely no glitches in the drive.)
Shifting the gearbox is a pain because the motor is attached to it.? This can be work taking it apart and putting it back. Once it's done, you don't mess with it.? It should stay in the right position, and work properly for (forever?)...
(Or email me privately and call me if you need to...!)
On Fri, Jan 17, 2020, 2:06 PM taylor waber < taylorwab@...> wrote: My mount is a GM811 with a OPW, no springs. I added the Belleville washers as recommended by Michael H. but have a question about the steps for adjusting the worm.?
My steps as I understand how to do this:
I squeeze the worm blocks, in order to load the Belleville washer, then tighten down the bolts underneath.?
Then I bolted down the OPW cover that bolts into the side of the OPW blocks.?
Next I loosened the bolts underneath the blocks and followed Losmandy's YouTube video on OPW adjustment (setting the backlash).?
And finally just tighten everything back up.?
Is this correct? When I loosen the underneath bolts for the OPW blocks, does this take the load out of the Belliville washer? Or does the worm cover keep the load??
Thanks,
Taylor
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OPW Adjustment Steps with Belleville Washer
My mount is a GM811 with a OPW, no springs. I added the Belleville washers as recommended by Michael H. but have a question about the steps for adjusting the worm.?
My steps as I understand how to do this:
I squeeze the worm blocks, in order to load the Belleville washer, then tighten down the bolts underneath.?
Then I bolted down the OPW cover that bolts into the side of the OPW blocks.?
Next I loosened the bolts underneath the blocks and followed Losmandy's YouTube video on OPW adjustment (setting the backlash).?
And finally just tighten everything back up.?
Is this correct? When I loosen the underneath bolts for the OPW blocks, does this take the load out of the Belliville washer? Or does the worm cover keep the load??
Thanks,
Taylor
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Re: GM8 Belt drive stepper mount
OK John,
I'm not to proud to ask why?
I was the guy in class who usually asked the questions that made the Instructor sweat.
I didn't care if it removed all doubt, it clarified the discussion for me.
Besides bigger, torque-ier, motors, and Gilmore belts, are you driving an exceptionally large payload?
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GM8 Belt drive stepper mount
I've made what I'm hoping will be the final design changes to my Losmandy GM8 belt drive stepper mount.? You can find all the info on the page.? I've redesigned the plate to make it rectangular rather than that bent-rectangle design I had before.? The benefit of this is that the same cover design fits both the RA and DEC stepper mount.? I've also added a bearing mount in the cover so if you wish, you could extend the shaft on the 60T pulley so that it would recess into the bearing for added stability.? A very quick video is .? I'm waiting on couplers from R+W, they take a while but I think they are made to order.? The plan after that is to have them machined from aluminum.
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I'm a one wire guy.
I have a (12V). (A 4 port can work, but I have delusions of grandeur and filter wheels and expansion... but in reality, I use 4 ports on my hub.)
My cameras plug into it (I got short USB2 Male A to Male B cables), and a single 12 foot USB cable comes off my mount to my computer.
I also have a single 12V wire to power my Atik Infinity, the hub, the mount, and my focuser.
So, everything the computer runs, runs through that single USB cable.
When I first began, I ran a loom of wires off the mount. But I got smarter as I went along and instead of a hub near the computer, I moved the hub near the work. And a single USB cable to my computer.
I also tried one of those NUC type computers. But dang near wore a path without a display at the mount. So I got a Dell 2 in 1 so I'd have a display at the mount, as well as the WiFi to my inside computer.
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Re: Initial Setup of the Mount
Amen Sonny, The better you get with your set up the better your experience will be. Ajusting the front leg of the tripod to Polais when you can see it finally. As Sonny, mentioned the compass heading is just the start of your alignment process.
Sent from my Galaxy Tab A
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-------- Original message --------
From: sonnyedmonds@...
Date: 1/15/20 9:36 PM (GMT-06:00)
Subject: Re: [Losmandy_users_io] Initial Setup of the Mount
I use a small magnetic compass,or the GPS on my cell phone.
I set y tripod up so a single leg points North. (It came with the sing leg pointing South. Just moved the pin 180¡ã.)
But remember, Polar North for your tripod is a very rough and general setting.
When you can locate Polaris, there's your aim point.
Just practice. Eventually, you'll be able to aim yourself North, look up and there it is.
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Re: Initial Setup of the Mount
I use a small magnetic compass,or the GPS on my cell phone.
I set my tripod up so a single leg points North. (It came with the single leg pointing South. Just moved the pin 180¡ã.)
But remember, Polar North for your tripod is a very rough and general setting.
When you can locate Polaris, there's your aim point.
Just practice. Eventually, you'll be able to aim yourself North, look up and there it is.
Edit In: Something else I've done is to use a long "yardstick" from the shop (aluminum, 48") and set it on the ground. Then compare it to my GPS on my smarter-than-me-phone.
Then adjusted it so it is in line with North/South, then set my tripod using that as a reference, and the opposing legs evenly spaced from the edge of the Yardstick.
Gets close enough to Azimuth into place for me.
Please correct me if I'm wrong, but aren't Losmandy tripods machined so any leg can be your North leg? (120¡ã slots for assembly)
One of my biggest concerns is finding Polaris. At some sites there are just too many darned stars.
For that I use the Big Dipper's Bucket.? 8^)
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Meridian Flip G11 with Gemini 2 and SGP
So I've gotten meridian flips to work, now I just want to understand how, why, and more importantly how to control when it happens. Here's my rudimentary understanding of my settings and how to go forward. Tracking an object on the east side of the pier, my Western limit is 97* 12" and I've set my Western GoTo Limit to 7* 12". This lets Gemini know that a goto for the object past the actual meridian or 90* (Western limit - Western GoTo Limit) requires a flip. Now Gemini will keep tracking until it hits the Western Goto Limit if I let it, but in SGP I have it set to do a flip at 0 minutes past the meridian. This triggers the flip since my object is now past 90*. Now if I want to keep imaging say up to 95* or 5* past the meridian all I need to do is adjust SGP to do a flip 20 minutes (4min x 5*) past the meridian. The object will be on the west side of 90* so Gemini will know to flip. No need to mess with Gemini since it won't flip without being issued a goto command. Does this sound correct? All of my source info and pics are coming from?
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Re: Initial Setup of the Mount
Bill, I place the compass down in the middle of the tripod extention and it points North. It points the same on the ground below the tripod.? so their is not enough ferrous material to affect the compass. But with a cell phone app the effects would be
moot.
Sent from my Boost Mobile Phone.
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-------- Original message --------
From: Bill Gardner <pictorobservatory@...>
Date: 1/15/20 7:55 PM (GMT-06:00)
Subject: Re: [Losmandy_users_io] Initial Setup of the Mount
But I see it is already obvious that everyone *does* use a compass in proximity to the mount.. That¡¯s what I wanted to know, as I thought that wouldn¡¯t work
because of all the metal..
Compasses and magnets are not attracted to all metal.? Aluminum for instance is not a magnetic material
Bill
_____________
Pictor Observatory
Twitter: @pictorobs
Minor Planet 21350 - billgardner
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Re: Initial Setup of the Mount
But
I see it is already obvious that everyone *does* use a compass in proximity to
the mount.. That¡¯s what I wanted to know, as I thought that wouldn¡¯t work
because of all the metal..
Compasses and magnets are not attracted to all metal.? Aluminum for instance is not a magnetic material
Bill
_____________ Pictor Observatory
Twitter: @pictorobs
Minor Planet 21350 - billgardner
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#1 best thing i did was get a small nuc-style computer and mounted it on top of my telescope. life has never been easier
#2 best thing was to switch to anderson powerpoles, so i can run one power cable up and have power distro on top of the camera
There are some excellent DIY-type solutions that complete can less than $300 for the computer, powerpole distro, and a wifi router as well
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Also: add a good USB3.0 powered hub with a long USB cable to that too.
For reliable use, you must get one with the big USB3.0 connector like the ASI cameras use. The mini USB 3.0 thin flat connector starts to fail under cold damp conditions...it was intended for indoor use where there is no mechanical stress on the connection.?
Best regards,
Easy ($$$). I bought longer USB cables...these are the fast 3.0 type USB for later model ASI cameras.? Still...you do have to watch where your PC is positioned!
Have fun, Michael
So.. New subject..
How do *you* connect up
cameras so the scope can access everything it normally can access (in the sky)..
?? My CMOS cameras both have short USB cables, which I plug into the computer
that sits on a table right next to the scope to the East of the mount.. For
Planetary imaging, for instance, this means I can only image from slightly
before the Meridian
to the Western Horizon.. I can¡¯t image, say, 45 degrees up in the East.. When
I move and get back into Astronomy, I hope to be able to operate ¨C i.e.
place the table ¨C to the north of the mount, and I assume that will give
me some access to both sides of the mount, such as from 45 degrees up in the
East to 45 degrees up in the West..
??? BUT! What
does it take to get farther from the mount, say ten feet?? I have a multi port
USB hub, so do I just plug both cameras into that and then run a new USB cable
from the hub to the laptop?? And do I mount the hub to the tripod??
?
??? I ask,
because I have previously tried to run the camera with a 6¡¯ cable instead
of the 3¡¯ cable it came with and it dropped almost all the frames, so I
am *ASSUMING* USB has severe cable length issues???
Some
Notes.. The 6¡¯ cable was ¡°good¡±, as at the time I had two ASI
cameras and both camera cables came with them.. the ASI178 came with the 3¡¯
and the ASI120 came with the 6¡¯.. Since I wasn¡¯t guiding at the
time, I could use either cable.. Also, these *ARE* USB3 cameras and my laptop
only has USB2 ports.. This hasn¡¯t been a problem yet.. I have imaged at
200 fps, albeit not full frame, and I don¡¯t see that transmission rates
over the USB cable would be an issue when only sending an image downline no
faster than every 60 seconds..
??? So how
would I ¡°move away from the mount¡±?? What are my options?? Please
speak slowly, as ¡°USB Hub¡± is the only phrase I know in this ¡°foreign
language.. :-))
?
Derek
?
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Easy ($$$). I bought longer USB cables...these are the fast 3.0 type USB for later model ASI cameras.? Still...you do have to watch where your PC is positioned!
Have fun, Michael
So.. New subject..
How do *you* connect up
cameras so the scope can access everything it normally can access (in the sky)..
?? My CMOS cameras both have short USB cables, which I plug into the computer
that sits on a table right next to the scope to the East of the mount.. For
Planetary imaging, for instance, this means I can only image from slightly
before the Meridian
to the Western Horizon.. I can¡¯t image, say, 45 degrees up in the East.. When
I move and get back into Astronomy, I hope to be able to operate ¨C i.e.
place the table ¨C to the north of the mount, and I assume that will give
me some access to both sides of the mount, such as from 45 degrees up in the
East to 45 degrees up in the West..
??? BUT! What
does it take to get farther from the mount, say ten feet?? I have a multi port
USB hub, so do I just plug both cameras into that and then run a new USB cable
from the hub to the laptop?? And do I mount the hub to the tripod??
?
??? I ask,
because I have previously tried to run the camera with a 6¡¯ cable instead
of the 3¡¯ cable it came with and it dropped almost all the frames, so I
am *ASSUMING* USB has severe cable length issues???
Some
Notes.. The 6¡¯ cable was ¡°good¡±, as at the time I had two ASI
cameras and both camera cables came with them.. the ASI178 came with the 3¡¯
and the ASI120 came with the 6¡¯.. Since I wasn¡¯t guiding at the
time, I could use either cable.. Also, these *ARE* USB3 cameras and my laptop
only has USB2 ports.. This hasn¡¯t been a problem yet.. I have imaged at
200 fps, albeit not full frame, and I don¡¯t see that transmission rates
over the USB cable would be an issue when only sending an image downline no
faster than every 60 seconds..
??? So how
would I ¡°move away from the mount¡±?? What are my options?? Please
speak slowly, as ¡°USB Hub¡± is the only phrase I know in this ¡°foreign
language.. :-))
?
Derek
?
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You would think that, but right now I¡¯m dealing with a camera where that doesn¡¯t seem to be the case ? B
?
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From: [email protected] [mailto:[email protected]] On Behalf Of Gregory Latiak
Sent: Wednesday, January 15, 2020 4:37 PM
To: [email protected]
Subject: Re: [Losmandy_users_io] Camera Wiring ? One has to assume that the vendor has considered isolation between the camera circuitry and the TEC. On my two QHY183s there is a separate power connection for the TEC -- which potentially can take a lot. I use a small laptop power supply to feed mine. Works great.
greg latiak
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One has to assume that the vendor has considered isolation between the camera circuitry and the TEC. On my two QHY183s there is a separate power connection for the TEC -- which potentially can take a lot. I use a small laptop power supply to feed mine. Works great.
greg latiak
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Thanks
Peoples.. For answering both questions, actually..
?
?is
the one I have.. (2 actually.. One for a backup..)
?
7
Port / USB3 / 5V / 5 AMP.. Sounds like I am on the right track, as it is ¡°only¡±
for 2 cameras..
?
A
Secondary Question.. I forgot about this being a powered device.. My new
camera, the QHY178 Cool, obviously, has a cooler that runs on 12v.. Since I
also neglected to remember that ¡°normal¡± USB carries power, should
I be wary of both 5v from USB and 12v for the cooler coming from separate sources
to one device causing ground loops (or similar issues) or can I ASSUME QHY
knows how to separate the two?? Maybe I need to employ my favorite Electrical
Engineer to check my method of power??
??? ¡°Stop
being so thick Derek! Plug them in, wire them up, and enjoy! SHEESH!¡±
Yes,
but I would much rather let the world know I am not in sharp focus than let out
the magic blue smoke and have to buy another camera.. or computer, for that
matter.. :-))
?
Derek
?
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From: [email protected] [mailto:[email protected]] On Behalf Of Les Niles
Sent: Wednesday, January 15, 2020
3:07 PM
To: [email protected]
Subject: Re: [Losmandy_users_io]
Camera Wiring
?
All other things being equal, a hub with a 12V power input is more
likely to robustly supply 5V to the USB ports than is a hub with a 5V power
input. ?Also, if one has multiple devices that draw significant USB power
then it¡¯s important to pay attention to the total power capability of the
USB hub. ?Lots of them have one or more ports that can supply 1-2 amps but
may only be rated at 2 or 3 amps total from all the ports. ?USB 2.0
devices are supposed to draw no more than 500mA, while USB 3.0 allows up to 900mA,
but with the advent of USB-based battery chargers the power specs are sometimes
not strictly observed. ? ?
?
Derek,
Some cameras draw their power from the USB cables.
Having a powered hub helps. I use the hub with 6' and 9' USB3 cables going to
my cameras. But, I run an active USB3 cable to the hub from my computer. The
hub is attached to the mount with velcro, and excess cable is coiled and
attached to the tripod as well. This way, there is ample power, ports, and you
don't have the mount dragging around a lot of cable (which can affect goto and
tracking).
?
On Wed, Jan 15, 2020, 4:26 PM Stu Beaber <wd4sel@...> wrote:
I use a hub at the mount and 4 usb cables plug into
it...from the hub I run a 32 foot usb cable to the computer (inside the
trailer) the key is it's a powered hub. It has it's own 5vdc power source and
that makes it possible. Also some guide cameras (like I use a DSI guide camera)
draw a lot of usb power and you probably need the extra power for that anyways.
You can also (I think) buy powered usb cables. I've got 12vdc at the mount
anyways so I just knock it do to 5vdc for the hub...
?
So.. New subject..
How do *you* connect up cameras so the scope can access
everything it normally can access (in the sky).. ?? My CMOS cameras both have
short USB cables, which I plug into the computer that sits on a table right
next to the scope to the East of the mount.. For Planetary imaging, for
instance, this means I can only image from slightly before the?Meridian?to the Western Horizon.. I can¡¯t
image, say, 45 degrees up in the East.. When I move and get back into
Astronomy, I hope to be able to operate ¨C i.e. place the table ¨C to
the north of the mount, and I assume that will give me some access to both
sides of the mount, such as from 45 degrees up in the East to 45 degrees up in
the West..?
????BUT!
What does it take to get farther from the mount, say ten feet?? I have a multi
port USB hub, so do I just plug both cameras into that and then run a new USB
cable from the hub to the laptop?? And do I mount the hub to the tripod??
?
????I
ask, because I have previously tried to run the camera with a 6¡¯ cable
instead of the 3¡¯ cable it came with and it dropped almost all the
frames, so I am *ASSUMING* USB has severe cable length issues???
Some Notes.. The 6¡¯
cable was ¡°good¡±, as at the time I had two ASI cameras and both
camera cables came with them.. the ASI178 came with the 3¡¯ and the ASI120
came with the 6¡¯.. Since I wasn¡¯t guiding at the time, I could use
either cable.. Also, these *ARE* USB3 cameras and my laptop only has USB2
ports.. This hasn¡¯t been a problem yet.. I have imaged at 200 fps, albeit
not full frame, and I don¡¯t see that transmission rates over the USB
cable would be an issue when only sending an image downline no faster than
every 60 seconds..
????So
how would I ¡°move away from the mount¡±?? What are my options??
Please speak slowly, as ¡°USB Hub¡± is the only phrase I know in this
¡°foreign language.. :-))
?
Derek
?
?
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Michael Herman
John Scherer