|
Hi just received new G11G and was trying to balance the RA axis and at my latitude of 45 degrees and there was way to much friction to balance the mount. This mount definitely needs the wavy washer. To get around this I used 2 methods to find balance.
1. Set the altitude adjustment to 0 so that all loads are on the bearings and none on the friction plate. This works perfectly.
2. I have an amp meter on my battery box so I set the RA axis to horizontal and slewed in one direction and then the other waiting for the current to steady . I adjusted the weight so that the current was the same. This I could do with the altitude at 45 degrees.
Both were very close to each other.
Rick
|
On the topic of using current to balance RA, has anyone had much luck with the Gemini 2 balance function?? My old iOptron iEQ45 had a similar function and it worked perfectly (and was extremely accurate, it even told where to move the weights), but in my very limited messing with the Gemini 2 one I didn't see much change.
|
Hi Rick
?
I have a G11GT so it¡¯s the Titan RA. I use electronic luggage scales and at the end of the weight shaft pull up then pull down, adjust until the numbers are the same.
?
The heavier your load and higher the altitude the worse it gets.
?
Lately I build like a gear puller to help with the balancing the RA. Pulls the weight off the clutch plate so balancing much more accurate. See video attached.
?
?
?
toggle quoted message
Show quoted text
From: [email protected] <[email protected]>
On Behalf Of rboudah via groups.io
Sent: Saturday, 16 May 2020 12:07 AM
To: [email protected]
Subject: [Losmandy_users_io] Balancing RA
?
Hi just received new G11G and was trying to balance the RA axis and at my latitude of 45 degrees and there was way to much friction to balance the mount. This mount definitely needs the wavy washer. To get around this I used 2 methods to
find balance.
1. Set the altitude adjustment to 0 so that all loads are on the bearings and none on the friction plate. This works perfectly.
2. I have an amp meter on my battery box so I set the RA axis to horizontal and slewed in one direction and then the other waiting for the current to steady . I adjusted the weight so that the current was the same. This I could do with the altitude at 45 degrees.
Both were very close to each other.
Rick
This e-mail and any files attached are intended solely for the use of the addressee. They may contain privileged or confidential information. If you are not the intended recipient, you are hereby notified that any use, disclosure, copying or distribution of
this e-mail is strictly prohibited. If you receive this message in error, please notify the sender immediately and delete the message and any attachments from your system. Thank you.
|
Hi Richard,
I watched your video...now that you mention your "gear puller" I see your wooden rectangular enclosure briefly appears in the video.
I see that the wooden rack pushes down on the RA body mounting, and the front wooden part is attached to the RA front polar scope cover.? There are what appear to be wires pulling up on the RA cover knob, and the wires lift the RA weight off the RA clutch, so it will rotate more easily.??
How do you adjust the wires to pull up?? I see some bolts in front.? Can you sketch or describe how that mechanism?works?
Anyway, that's quite a clever wood lifter idea.? Thanks for sharing that?with the group.
Michael
Hi Rick
?
I have a G11GT so it¡¯s the Titan RA. I use electronic luggage scales and at the end of the weight shaft pull up then pull down, adjust until the numbers are the same.
?
The heavier your load and higher the altitude the worse it gets.
?
Lately I build like a gear puller to help with the balancing the RA. Pulls the weight off the clutch plate so balancing much more accurate. See video attached.
?
?
?
From: [email protected] <[email protected]>
On Behalf Of rboudah via
Sent: Saturday, 16 May 2020 12:07 AM
To: [email protected]
Subject: [Losmandy_users_io] Balancing RA
?
Hi just received new G11G and was trying to balance the RA axis and at my latitude of 45 degrees and there was way to much friction to balance the mount. This mount definitely needs the wavy washer. To get around this I used 2 methods to
find balance.
1. Set the altitude adjustment to 0 so that all loads are on the bearings and none on the friction plate. This works perfectly.
2. I have an amp meter on my battery box so I set the RA axis to horizontal and slewed in one direction and then the other waiting for the current to steady . I adjusted the weight so that the current was the same. This I could do with the altitude at 45 degrees.
Both were very close to each other.
Rick
This e-mail and any files attached are intended solely for the use of the addressee. They may contain privileged or confidential information. If you are not the intended recipient, you are hereby notified that any use, disclosure, copying or distribution of
this e-mail is strictly prohibited. If you receive this message in error, please notify the sender immediately and delete the message and any attachments from your system. Thank you.
|
Hi Michael
?
I had the idea and then just made it up quickly using some left over wood from a wine rack, 150 ib tracer wire and large swivel from fishing tackle shop, two large screws, a couple of washers and
a pin of some sort (or use an allen key).
?
If designed professionally ¨C threaded tube could screw into the RA cover thread and then have the frame and finally something like the Dec clutch tightening knob that threads onto the same threaded
tube.
?
Hope the pictures make sense.
?
Regards Richard
?
?
toggle quoted message
Show quoted text
From: [email protected] <[email protected]>
On Behalf Of Michael Herman via groups.io
Sent: Saturday, 16 May 2020 10:15 AM
To: [email protected]
Subject: Re: [Losmandy_users_io] Balancing RA
?
Hi Richard,
I watched your video...now that you mention your "gear puller" I see your wooden rectangular enclosure briefly appears in the video.
I see that the wooden rack pushes down on the RA body mounting, and the front wooden part is attached to the RA front polar scope cover.? There are what appear to be wires pulling up on the RA cover knob, and the wires lift the RA weight
off the RA clutch, so it will rotate more easily.??
How do you adjust the wires to pull up?? I see some bolts in front.? Can you sketch or describe how that mechanism?works?
Anyway, that's quite a clever wood lifter idea.? Thanks for sharing that?with the group.
?
Hi Rick
?
I have a G11GT so it¡¯s the Titan RA. I use electronic luggage scales and at the end of the weight shaft pull up then pull down, adjust until the numbers are the same.
?
The heavier your load and higher the altitude the worse it gets.
?
Lately I build like a gear puller to help with the balancing the RA. Pulls the weight off the clutch plate so balancing much more accurate. See video attached.
?
?
?
From:
[email protected] <[email protected]>
On Behalf Of rboudah via
Sent: Saturday, 16 May 2020 12:07 AM
To: [email protected]
Subject: [Losmandy_users_io] Balancing RA
?
Hi just received new G11G and was trying to balance the RA axis and at my latitude of 45 degrees and there was way to much friction to balance the mount. This mount definitely needs
the wavy washer. To get around this I used 2 methods to find balance.
1. Set the altitude adjustment to 0 so that all loads are on the bearings and none on the friction plate. This works perfectly.
2. I have an amp meter on my battery box so I set the RA axis to horizontal and slewed in one direction and then the other waiting for the current to steady . I adjusted the weight so that the current was the same. This I could do with the altitude at 45 degrees.
Both were very close to each other.
Rick
This e-mail and any files attached are intended solely for the use of the addressee. They may contain privileged or confidential information. If you are not the intended recipient, you are hereby notified that any use, disclosure, copying
or distribution of this e-mail is strictly prohibited. If you receive this message in error, please notify the sender immediately and delete the message and any attachments from your system. Thank you.
|
Hi Richard,
The extra photos explain your design...the bolts in front push on metal plates, and lift the upper front wood piece, which is attached to the wire holding the front polar scope cover.? Very clever!
The takeaway for me was that, using this method, you did find the RA axis much easier to rotate for perfect balance.? You got the same benefit as the "wavy washer" new design.? The wavy washer requires a slot machined in the drive clutch plate area which my earlier mount designs don't have.? So...you provided some ideas to try.? ?
As for me, to date, I have used a "push" in both rotation directions on my RA axis to get a sense of the RA counterweight balance.? As long as that is pretty close, my RA drive seems to have no trouble.? I can also use the current meter on my Gemini power supply to measure the sidereal drive current with the scope on the East, vs West, side of the mount.??
For DEC, it is far easier...just put the counterweight rod horizontal, and loosen the DEC clutch knob. Then there is zero weight on the DEC clutch and that axis swings around easily with no friction.? That is simple to rebalance.??
Thanks again Richard for sharing your wood lift design.? Something new to try out...!? ?
Very best, Michael
Hi Michael
?
I had the idea and then just made it up quickly using some left over wood from a wine rack, 150 ib tracer wire and large swivel from fishing tackle shop, two large screws, a couple of washers and
a pin of some sort (or use an allen key).
?
If designed professionally ¨C threaded tube could screw into the RA cover thread and then have the frame and finally something like the Dec clutch tightening knob that threads onto the same threaded
tube.
?
Hope the pictures make sense.
?
Regards Richard
?
?
From: [email protected] <[email protected]>
On Behalf Of Michael Herman via
Sent: Saturday, 16 May 2020 10:15 AM
To: [email protected]
Subject: Re: [Losmandy_users_io] Balancing RA
?
Hi Richard,
I watched your video...now that you mention your "gear puller" I see your wooden rectangular enclosure briefly appears in the video.
I see that the wooden rack pushes down on the RA body mounting, and the front wooden part is attached to the RA front polar scope cover.? There are what appear to be wires pulling up on the RA cover knob, and the wires lift the RA weight
off the RA clutch, so it will rotate more easily.??
How do you adjust the wires to pull up?? I see some bolts in front.? Can you sketch or describe how that mechanism?works?
Anyway, that's quite a clever wood lifter idea.? Thanks for sharing that?with the group.
?
Hi Rick
?
I have a G11GT so it¡¯s the Titan RA. I use electronic luggage scales and at the end of the weight shaft pull up then pull down, adjust until the numbers are the same.
?
The heavier your load and higher the altitude the worse it gets.
?
Lately I build like a gear puller to help with the balancing the RA. Pulls the weight off the clutch plate so balancing much more accurate. See video attached.
?
?
?
From:
[email protected] <[email protected]>
On Behalf Of rboudah via
Sent: Saturday, 16 May 2020 12:07 AM
To: [email protected]
Subject: [Losmandy_users_io] Balancing RA
?
Hi just received new G11G and was trying to balance the RA axis and at my latitude of 45 degrees and there was way to much friction to balance the mount. This mount definitely needs
the wavy washer. To get around this I used 2 methods to find balance.
1. Set the altitude adjustment to 0 so that all loads are on the bearings and none on the friction plate. This works perfectly.
2. I have an amp meter on my battery box so I set the RA axis to horizontal and slewed in one direction and then the other waiting for the current to steady . I adjusted the weight so that the current was the same. This I could do with the altitude at 45 degrees.
Both were very close to each other.
Rick
This e-mail and any files attached are intended solely for the use of the addressee. They may contain privileged or confidential information. If you are not the intended recipient, you are hereby notified that any use, disclosure, copying
or distribution of this e-mail is strictly prohibited. If you receive this message in error, please notify the sender immediately and delete the message and any attachments from your system. Thank you.
|
Not sure what my RA washer configuration is, mount is only 1 ? years old. Dec I pulled apart heaps and don¡¯t have the desire to do anything on the RA.
?
Without the ¡°pull¡± system, due to higher system load (which is why I bought the G11GT), I measure about 1.4 kgs at the end of the weight shaft to pull up and same to pull down.
?
With ¡°pull¡± system in place, I¡¯m down to 0.2 kg. It¡¯s almost neutral. Haven¡¯t tried to get to neutral, will try to see what I can get to next time I setup.
?
Yes, Dec much easier to do, including a little push from the counterweight end to completely free it all.
?
?
?
toggle quoted message
Show quoted text
From: [email protected] <[email protected]>
On Behalf Of Michael Herman via groups.io
Sent: Saturday, 16 May 2020 2:37 PM
To: [email protected]
Subject: Re: [Losmandy_users_io] Balancing RA
?
Hi Richard,
The extra photos explain your design...the bolts in front push on metal plates, and lift the upper front wood piece, which is attached to the wire holding the front polar scope cover.? Very clever!
The takeaway for me was that, using this method, you did find the RA axis much easier to rotate for perfect balance.? You got the same benefit as the "wavy washer" new design.? The wavy washer requires a slot machined in the drive clutch
plate area which my earlier mount designs don't have.? So...you provided some ideas to try.? ?
As for me, to date, I have used a "push" in both rotation directions on my RA axis to get a sense of the RA counterweight balance.? As long as that is pretty close, my RA drive seems to have no trouble.? I can also use the current meter
on my Gemini power supply to measure the sidereal drive current with the scope on the East, vs West, side of the mount.??
For DEC, it is far easier...just put the counterweight rod horizontal, and loosen the DEC clutch knob. Then there is zero weight on the DEC clutch and that axis swings around easily with no friction.? That is simple to rebalance.??
Thanks again Richard for sharing your wood lift design.? Something new to try out...!? ?
?
Hi Michael
?
I had the idea and then just made it up quickly using some left over wood from a wine rack, 150 ib tracer wire and large swivel from fishing tackle shop, two large screws, a couple
of washers and a pin of some sort (or use an allen key).
?
If designed professionally ¨C threaded tube could screw into the RA cover thread and then have the frame and finally something like the Dec clutch tightening knob that threads onto
the same threaded tube.
?
Hope the pictures make sense.
?
Regards Richard
?
?
From:
[email protected] <[email protected]>
On Behalf Of Michael Herman via
Sent: Saturday, 16 May 2020 10:15 AM
To: [email protected]
Subject: Re: [Losmandy_users_io] Balancing RA
?
Hi Richard,
I watched your video...now that you mention your "gear puller" I see your wooden rectangular enclosure briefly appears in the video.
I see that the wooden rack pushes down on the RA body mounting, and the front wooden part is attached to the RA front polar scope cover.? There are what appear to be wires pulling
up on the RA cover knob, and the wires lift the RA weight off the RA clutch, so it will rotate more easily.??
How do you adjust the wires to pull up?? I see some bolts in front.? Can you sketch or describe how that mechanism?works?
Anyway, that's quite a clever wood lifter idea.? Thanks for sharing that?with the group.
?
Hi Rick
?
I have a G11GT so it¡¯s the Titan RA. I use electronic luggage scales and at the end of the weight shaft pull up then pull down, adjust until the numbers are the same.
?
The heavier your load and higher the altitude the worse it gets.
?
Lately I build like a gear puller to help with the balancing the RA. Pulls the weight off the clutch plate so balancing much more accurate. See video attached.
?
?
?
From:
[email protected] <[email protected]>
On Behalf Of rboudah via
Sent: Saturday, 16 May 2020 12:07 AM
To: [email protected]
Subject: [Losmandy_users_io] Balancing RA
?
Hi just received new G11G and was trying to balance the RA axis and at my latitude of 45 degrees and there was way to much friction to balance the mount. This mount definitely needs
the wavy washer. To get around this I used 2 methods to find balance.
1. Set the altitude adjustment to 0 so that all loads are on the bearings and none on the friction plate. This works perfectly.
2. I have an amp meter on my battery box so I set the RA axis to horizontal and slewed in one direction and then the other waiting for the current to steady . I adjusted the weight so that the current was the same. This I could do with the altitude at 45 degrees.
Both were very close to each other.
Rick
This e-mail and any files attached are intended solely for the use of the addressee. They may contain privileged or confidential information. If you are not the intended recipient,
you are hereby notified that any use, disclosure, copying or distribution of this e-mail is strictly prohibited. If you receive this message in error, please notify the sender immediately and delete the message and any attachments from your system. Thank you.
|
Hi Richard,
I'm curious: wh at is the kind of scope loaded on your G11T?
Can you estimate the total scope load weight on your dovetail?
I don't have a GT11 (yet) though I certainly have scopes heavy enough to warrant getting that size of mount.? I have several G11s, and a GM8 and a GM811.??
That your pull to get near zero clutch force is only about 1.4 kg ~ 3 lbs seems way too small.? I think the equation would be like? Force = [Total weight of dovetail load + counterweights] x [cosine(elevation angle)]
Maybe your (very newish) system already has a wavy washer in the RA, and your lifter is just adding a little umph to that?? Brian could tell if the G11T has such a wavy washer in it's RA.? (The Titan RA clutch disk is about 6 inch diameter.)
So if you are at a pole your elevation angle would be 90 degrees, and there will be zero downward force on your RA clutch.? If you were at the equator, you would have 100% of the total weight on your RA clutch disk.? In between it would go like the co sine function of the elevation angle.
I have about 130 lbs total scope + counterweight load on my maxed out G11.? ? That's a near 50 lb C-14HD, top dovetail and 80mm guide refractor, about 50 lbs of counterweights.? At my latitude of? 37¡ã21', the cosine would be? 0.79.? So I calculate needing 103 lbs pull to lift all the weight off the RA clutch disk.? I likely need some oak to lift that!!!??
At that point, I will give the ammeter test a try first.??
If I could make a software gadget... worth a try... I'd have something drive the Gemini to switch the RA drive using (a button for)? CW sidereal drive, or (a different button for) CCW sidereal drive, and a Pause/stop button.? ?Then, you could pause, and shift the counterweights, and run back and forth CW va CCW directions to observe the drive current.? In that way, you would not need to change from Scope East vs Scope west positions.??
-------
Someone recently asked about battery power needs to run a mount.? Some thoughts on that follow:
----
What current draw should you expect to use to run a G11 and Gemini, say?
(Note: Power =Amps x Volts, so the current should be smaller if the supplied volts is higher....if it were all due to motor power...but it isn't all motor power).
My amps used on a balanced G11 mount is around these values:
?Sidereal tracking with PHD2 ~2 sec pulse autoguiding:? ? ?0.17 amp at 17 volt DC power ~ 0.25 amp at 12 Volt DC power
Fast slew to distant target, or Park at CWD from a distant target:? ? ?0.6 amp per axis at 17 V ~ 0.9 amp at 12 Volt DC power.? So my max on my 17 volt system is about 1.4 amp.? On a 12 V system might be bear 2 amps max.? This fast slew time is brief...maybe 10 seconds max.
Dew heaters use up a lot of amps...a lot of a battery capacity will be drained quickly by the heater.? I estimate about 10 ohms per dew heater cable, so estimate about 1.2 Amps continuous per dew heater cable if powered at 12 volts.? If you use a digital control, this is reduced by the duty cycle (on time/total time).? But if you are running off a field battery...watch out for killing your battery!? I did kill a 12 V gell pack battery by overdraining it on feeding a dew heater... can be a costly lesson.??
So I'd run my mount and laptop off one battery, and use a separate battery for the dew heater(s).? If the dew heater battery is exhausted, you won't wipe out your camera and laptop.?
You might damage the dew heater battery if you drain it below some voltage level (like I'd guess 10 volts for a nominal 12 volt battery).? Below that you'd probably kill a wet cell.??
Thinking out loud: if you want a circuit to stop battery drain at some desired voltage, (say 10 volts) contact me and I'll make you up a battery drain protection circuit.??
All the best (a Starbucks Frappuccino at dinner is keeping me up most of the night.? At least it wasn't a COV19 attack... this virus panic is horrible...)
Stay well, all !!!? Michael
_______
I'll mention:? I have a batch of Gemini-2 power booster units that I recently made up.? These have an output current digital luminescent meter (ammeter) for the output current.? The output voltage is boosted to 17.1 volts internally by a polarity-protected circuit, from nominal 12 volts input.? That output voltage is also displayed by a digital luminescent display.? The polarity protection is to assure that anyone connecting to a battery input in the dark has no worry about mistaking + for - pins going in... the box automatically switches it to be correct polarity going out to the Gemini unit.??
Here is a photo of a power booster unit driving the RA on that overloaded G11 mount. (And a daytime photo of the overloaded G11 as well). You see that the RA drive is only using about 0.16 amp...because the RA is well balanced.? Most of that 0.16 amp is just running the Gemini (mine are Gemini-1, but you'd get about the same running a Gemini-2).? I get the same 0.16 amp running even a light scope and load.??
Anyone interested in trying one of these units...please contact me off line. I have a small batch of Gemini-2 units ready to go.? If you need a Gemini-1 unit, I will make them up too.? They all come with the correct output cable to go to the specific Gemini units.? ?
Good night!
?
Not sure what my RA washer configuration is, mount is only 1 ? years old. Dec I pulled apart heaps and don¡¯t have the desire to do anything on the RA.
?
Without the ¡°pull¡± system, due to higher system load (which is why I bought the G11GT), I measure about 1.4 kgs at the end of the weight shaft to pull up and same to pull down.
?
With ¡°pull¡± system in place, I¡¯m down to 0.2 kg. It¡¯s almost neutral. Haven¡¯t tried to get to neutral, will try to see what I can get to next time I setup.
?
Yes, Dec much easier to do, including a little push from the counterweight end to completely free it all.
?
?
?
From: [email protected] <[email protected]>
On Behalf Of Michael Herman via
Sent: Saturday, 16 May 2020 2:37 PM
To: [email protected]
Subject: Re: [Losmandy_users_io] Balancing RA
?
Hi Richard,
The extra photos explain your design...the bolts in front push on metal plates, and lift the upper front wood piece, which is attached to the wire holding the front polar scope cover.? Very clever!
The takeaway for me was that, using this method, you did find the RA axis much easier to rotate for perfect balance.? You got the same benefit as the "wavy washer" new design.? The wavy washer requires a slot machined in the drive clutch
plate area which my earlier mount designs don't have.? So...you provided some ideas to try.? ?
As for me, to date, I have used a "push" in both rotation directions on my RA axis to get a sense of the RA counterweight balance.? As long as that is pretty close, my RA drive seems to have no trouble.? I can also use the current meter
on my Gemini power supply to measure the sidereal drive current with the scope on the East, vs West, side of the mount.??
For DEC, it is far easier...just put the counterweight rod horizontal, and loosen the DEC clutch knob. Then there is zero weight on the DEC clutch and that axis swings around easily with no friction.? That is simple to rebalance.??
Thanks again Richard for sharing your wood lift design.? Something new to try out...!? ?
?
Hi Michael
?
I had the idea and then just made it up quickly using some left over wood from a wine rack, 150 ib tracer wire and large swivel from fishing tackle shop, two large screws, a couple
of washers and a pin of some sort (or use an allen key).
?
If designed professionally ¨C threaded tube could screw into the RA cover thread and then have the frame and finally something like the Dec clutch tightening knob that threads onto
the same threaded tube.
?
Hope the pictures make sense.
?
Regards Richard
?
?
From:
[email protected] <[email protected]>
On Behalf Of Michael Herman via
Sent: Saturday, 16 May 2020 10:15 AM
To: [email protected]
Subject: Re: [Losmandy_users_io] Balancing RA
?
Hi Richard,
I watched your video...now that you mention your "gear puller" I see your wooden rectangular enclosure briefly appears in the video.
I see that the wooden rack pushes down on the RA body mounting, and the front wooden part is attached to the RA front polar scope cover.? There are what appear to be wires pulling
up on the RA cover knob, and the wires lift the RA weight off the RA clutch, so it will rotate more easily.??
How do you adjust the wires to pull up?? I see some bolts in front.? Can you sketch or describe how that mechanism?works?
Anyway, that's quite a clever wood lifter idea.? Thanks for sharing that?with the group.
?
Hi Rick
?
I have a G11GT so it¡¯s the Titan RA. I use electronic luggage scales and at the end of the weight shaft pull up then pull down, adjust until the numbers are the same.
?
The heavier your load and higher the altitude the worse it gets.
?
Lately I build like a gear puller to help with the balancing the RA. Pulls the weight off the clutch plate so balancing much more accurate. See video attached.
?
?
?
From:
[email protected] <[email protected]>
On Behalf Of rboudah via
Sent: Saturday, 16 May 2020 12:07 AM
To: [email protected]
Subject: [Losmandy_users_io] Balancing RA
?
Hi just received new G11G and was trying to balance the RA axis and at my latitude of 45 degrees and there was way to much friction to balance the mount. This mount definitely needs
the wavy washer. To get around this I used 2 methods to find balance.
1. Set the altitude adjustment to 0 so that all loads are on the bearings and none on the friction plate. This works perfectly.
2. I have an amp meter on my battery box so I set the RA axis to horizontal and slewed in one direction and then the other waiting for the current to steady . I adjusted the weight so that the current was the same. This I could do with the altitude at 45 degrees.
Both were very close to each other.
Rick
This e-mail and any files attached are intended solely for the use of the addressee. They may contain privileged or confidential information. If you are not the intended recipient,
you are hereby notified that any use, disclosure, copying or distribution of this e-mail is strictly prohibited. If you receive this message in error, please notify the sender immediately and delete the message and any attachments from your system. Thank you.
|
Hi Michael
?
Bit of confusion, when RA is horizontal and I¡¯m balancing the RA, I use portable electronic luggage scales,
at the end of the weight shaft to pull up and same to pull down, when the number is the same I call it balanced. Number is around 1.4 kgs.
?
With RA clutch ¡°disengagement¡± system is in place, I do the same with luggage scales at the end of the horizontal weight shaft, the reading to move RA now is 0.2 kgs.
?
My dovetail weight is around 24 kgs.
?
Guide scope is SharpStar 61 EDPH with QHY5-III 178.
?
Nice ¨C your G11 does look max¡¯ed out !
?
Cheers Richard
?
toggle quoted message
Show quoted text
From: [email protected] <[email protected]>
On Behalf Of Michael Herman via groups.io
Sent: Saturday, 16 May 2020 7:25 PM
To: [email protected]
Subject: Re: [Losmandy_users_io] Balancing RA
?
Hi Richard,
I'm curious: what is the kind of scope loaded on your G11T?
Can you estimate the total scope load weight on your dovetail?
I don't have a GT11 (yet) though I certainly have scopes heavy enough to warrant getting that size of mount.? I have several G11s, and a GM8 and a GM811.??
That your pull to get near zero clutch force is only about 1.4 kg ~ 3 lbs seems way too small.? I think the equation would be like?
Force = [Total weight of dovetail load + counterweights] x [cosine(elevation angle)]
Maybe your (very newish) system already has a wavy washer in the RA, and your lifter is just adding a little umph to that?? Brian could tell if the G11T has such a wavy washer in it's RA.? (The Titan RA clutch disk is about 6 inch diameter.)
So if you are at a pole your elevation angle would be 90 degrees, and there will be zero downward force on your RA clutch.? If you were at the equator, you would have 100% of the total weight on your RA clutch disk.? In between it would
go like the co sine function of the elevation angle.
I have about 130 lbs total scope + counterweight load on my maxed out G11.? ? That's a near 50 lb C-14HD, top dovetail and 80mm guide refractor, about 50 lbs of counterweights.? At my latitude of? 37¡ã21', the cosine would be? 0.79.? So
I calculate needing 103 lbs pull to lift all the weight off the RA clutch disk.? I likely need some oak to lift that!!!??
At that point, I will give the ammeter test a try first.??
If I could make a software gadget... worth a try... I'd have something drive the Gemini to switch the RA drive using (a button for)? CW sidereal drive, or (a different button for) CCW sidereal drive, and a Pause/stop button.? ?Then, you
could pause, and shift the counterweights, and run back and forth CW va CCW directions to observe the drive current.? In that way, you would not need to change from Scope East vs Scope west positions.??
Someone recently asked about battery power needs to run a mount.? Some thoughts on that follow:
What current draw should you expect to use to run a G11 and Gemini, say?
(Note: Power =Amps x Volts, so the current should be smaller if the supplied volts is higher....if it were all due to motor power...but it isn't all motor power).
My amps used on a balanced G11 mount is around these values:
?Sidereal tracking with PHD2 ~2 sec pulse autoguiding:?
? ?0.17 amp at 17 volt DC power ~ 0.25 amp at 12 Volt DC power
Fast slew to distant target, or Park at CWD from a distant target:?
? ?0.6 amp per axis at 17 V ~ 0.9 amp at 12 Volt DC power.? So my max on my 17 volt system is about 1.4 amp.? On a 12 V system might be bear 2 amps max.? This fast slew time is brief...maybe 10 seconds max.
Dew heaters use up a lot of amps...a lot of a battery capacity will be drained quickly by the heater.? I estimate about 10 ohms per dew heater cable, so estimate about 1.2 Amps continuous per dew heater cable if powered at 12 volts.? If
you use a digital control, this is reduced by the duty cycle (on time/total time).? But if you are running off a field battery...watch out for killing your battery!? I did kill a 12 V gell pack battery by overdraining it on feeding a dew heater... can be a
costly lesson.??
So I'd run my mount and laptop off one battery, and use a separate battery for the dew heater(s).? If the dew heater battery is exhausted, you won't wipe out your camera and laptop.?
You might damage the dew heater battery if you drain it below some voltage level (like I'd guess 10 volts for a nominal 12 volt battery).? Below that you'd probably kill a wet cell.??
Thinking out loud: if you want a circuit to stop battery drain at some desired voltage, (say 10 volts) contact me and I'll make you up a battery drain protection circuit.??
All the best (a Starbucks Frappuccino at dinner is keeping me up most of the night.? At least it wasn't a COV19 attack... this virus panic is horrible...)
I'll mention:? I have a batch of Gemini-2 power booster units that I recently made up.? These have an output current digital luminescent meter (ammeter) for the output current.? The output voltage
is boosted to 17.1 volts internally by a polarity-protected circuit, from nominal 12 volts input.? That output voltage is also displayed by a digital luminescent display.? The polarity protection is to assure that anyone connecting to a battery input in the
dark has no worry about mistaking + for - pins going in... the box automatically switches it to be correct polarity going out to the Gemini unit.??
Here is a photo of a power booster unit driving the RA on that overloaded G11 mount. (And a daytime photo of the overloaded G11 as well). You see that the RA drive is only using about 0.16 amp...because
the RA is well balanced.? Most of that 0.16 amp is just running the Gemini (mine are Gemini-1, but you'd get about the same running a Gemini-2).? I get the same 0.16 amp running even a light scope and load.??
Anyone interested in trying one of these units...please contact me off line. I have a small batch of Gemini-2 units ready to go.? If you need a Gemini-1 unit, I will make them up too.? They all
come with the correct output cable to go to the specific Gemini units.? ?
?
Not sure what my RA washer configuration is, mount is only 1 ? years old. Dec I pulled apart heaps and don¡¯t have the desire to do anything on the RA.
?
Without the ¡°pull¡± system, due to higher system load (which is why I bought the G11GT), I measure about 1.4 kgs at the end of the weight shaft to pull up and same to pull down.
?
With ¡°pull¡± system in place, I¡¯m down to 0.2 kg. It¡¯s almost neutral. Haven¡¯t tried to get to neutral, will try to see what I can get to next time I setup.
?
Yes, Dec much easier to do, including a little push from the counterweight end to completely free it all.
?
?
?
From:
[email protected] <[email protected]>
On Behalf Of Michael Herman via
Sent: Saturday, 16 May 2020 2:37 PM
To: [email protected]
Subject: Re: [Losmandy_users_io] Balancing RA
?
Hi Richard,
The extra photos explain your design...the bolts in front push on metal plates, and lift the upper front wood piece, which is attached to the wire holding the front polar scope
cover.? Very clever!
The takeaway for me was that, using this method, you did find the RA axis much easier to rotate for perfect balance.? You got the same benefit as the "wavy washer" new design.?
The wavy washer requires a slot machined in the drive clutch plate area which my earlier mount designs don't have.? So...you provided some ideas to try.? ?
As for me, to date, I have used a "push" in both rotation directions on my RA axis to get a sense of the RA counterweight balance.? As long as that is pretty close, my RA drive
seems to have no trouble.? I can also use the current meter on my Gemini power supply to measure the sidereal drive current with the scope on the East, vs West, side of the mount.??
For DEC, it is far easier...just put the counterweight rod horizontal, and loosen the DEC clutch knob. Then there is zero weight on the DEC clutch and that axis swings around easily
with no friction.? That is simple to rebalance.??
Thanks again Richard for sharing your wood lift design.? Something new to try out...!? ?
?
Hi Michael
?
I had the idea and then just made it up quickly using some left over wood from a wine rack, 150 ib tracer wire and large swivel from fishing tackle shop, two large screws, a couple
of washers and a pin of some sort (or use an allen key).
?
If designed professionally ¨C threaded tube could screw into the RA cover thread and then have the frame and finally something like the Dec clutch tightening knob that threads onto
the same threaded tube.
?
Hope the pictures make sense.
?
Regards Richard
?
?
From:
[email protected] <[email protected]>
On Behalf Of Michael Herman via
Sent: Saturday, 16 May 2020 10:15 AM
To: [email protected]
Subject: Re: [Losmandy_users_io] Balancing RA
?
Hi Richard,
I watched your video...now that you mention your "gear puller" I see your wooden rectangular enclosure briefly appears in the video.
I see that the wooden rack pushes down on the RA body mounting, and the front wooden part is attached to the RA front polar scope cover.? There are what appear to be wires pulling
up on the RA cover knob, and the wires lift the RA weight off the RA clutch, so it will rotate more easily.??
How do you adjust the wires to pull up?? I see some bolts in front.? Can you sketch or describe how that mechanism?works?
Anyway, that's quite a clever wood lifter idea.? Thanks for sharing that?with the group.
?
Hi Rick
?
I have a G11GT so it¡¯s the Titan RA. I use electronic luggage scales and at the end of the weight shaft pull up then pull down, adjust until the numbers are the same.
?
The heavier your load and higher the altitude the worse it gets.
?
Lately I build like a gear puller to help with the balancing the RA. Pulls the weight off the clutch plate so balancing much more accurate. See video attached.
?
?
?
From:
[email protected] <[email protected]>
On Behalf Of rboudah via
Sent: Saturday, 16 May 2020 12:07 AM
To: [email protected]
Subject: [Losmandy_users_io] Balancing RA
?
Hi just received new G11G and was trying to balance the RA axis and at my latitude of 45 degrees and there was way to much friction to balance the mount. This mount definitely needs
the wavy washer. To get around this I used 2 methods to find balance.
1. Set the altitude adjustment to 0 so that all loads are on the bearings and none on the friction plate. This works perfectly.
2. I have an amp meter on my battery box so I set the RA axis to horizontal and slewed in one direction and then the other waiting for the current to steady . I adjusted the weight so that the current was the same. This I could do with the altitude at 45 degrees.
Both were very close to each other.
Rick
This e-mail and any files attached are intended solely for the use of the addressee. They may contain privileged or confidential information. If you are not the intended recipient,
you are hereby notified that any use, disclosure, copying or distribution of this e-mail is strictly prohibited. If you receive this message in error, please notify the sender immediately and delete the message and any attachments from your system. Thank you.
|
Thanks Richard, for clarifying?that.? I thought that 1.4 kg was too small to pull that RA up off the clutch disk.??
I'm quite happy with the way my mount systems are working.? The moonlight and high humidity have stopped my imaging work for the moment.??
For the past week I've been visiting my family in the LA area.? I feel happy to have human touch for the moment, after 2 months of isolation at home.? But work and home maintenance require me to head home for awhile.? So I plan to drive home from Long Beach on Monday, to the San Jose area where my mounts and telescopes are.? I am dreading the drive back home to isolation again.??
I just ordered a cute little fiber input spectrometer, to hook up to that C14 system.? I should be able to get images, and stellar or nebula spectra from that.??
I also have a bunch of nice 300 and 500 sec RGB subs of M51 and some of M81 to process, debayer, and stack.? ?I'm waiting for planetary season to bring Jupiter, Saturn and Mars around again.? That's really what the C14HD was intended for.??
Meanwhile, trying to stay safe and healthy in this crisis.??
Stay well all!
Michael
Hi Michael
?
Bit of confusion, when RA is horizontal and I¡¯m balancing the RA, I use portable electronic luggage scales,
at the end of the weight shaft to pull up and same to pull down, when the number is the same I call it balanced. Number is around 1.4 kgs.
?
With RA clutch ¡°disengagement¡± system is in place, I do the same with luggage scales at the end of the horizontal weight shaft, the reading to move RA now is 0.2 kgs.
?
My dovetail weight is around 24 kgs.
?
Guide scope is SharpStar 61 EDPH with QHY5-III 178.
?
Nice ¨C your G11 does look max¡¯ed out !
?
Cheers Richard
?
From: [email protected] <[email protected]>
On Behalf Of Michael Herman via
Sent: Saturday, 16 May 2020 7:25 PM
To: [email protected]
Subject: Re: [Losmandy_users_io] Balancing RA
?
Hi Richard,
I'm curious: what is the kind of scope loaded on your G11T?
Can you estimate the total scope load weight on your dovetail?
I don't have a GT11 (yet) though I certainly have scopes heavy enough to warrant getting that size of mount.? I have several G11s, and a GM8 and a GM811.??
That your pull to get near zero clutch force is only about 1.4 kg ~ 3 lbs seems way too small.? I think the equation would be like?
Force = [Total weight of dovetail load + counterweights] x [cosine(elevation angle)]
Maybe your (very newish) system already has a wavy washer in the RA, and your lifter is just adding a little umph to that?? Brian could tell if the G11T has such a wavy washer in it's RA.? (The Titan RA clutch disk is about 6 inch diameter.)
So if you are at a pole your elevation angle would be 90 degrees, and there will be zero downward force on your RA clutch.? If you were at the equator, you would have 100% of the total weight on your RA clutch disk.? In between it would
go like the co sine function of the elevation angle.
I have about 130 lbs total scope + counterweight load on my maxed out G11.? ? That's a near 50 lb C-14HD, top dovetail and 80mm guide refractor, about 50 lbs of counterweights.? At my latitude of? 37¡ã21', the cosine would be? 0.79.? So
I calculate needing 103 lbs pull to lift all the weight off the RA clutch disk.? I likely need some oak to lift that!!!??
At that point, I will give the ammeter test a try first.??
If I could make a software gadget... worth a try... I'd have something drive the Gemini to switch the RA drive using (a button for)? CW sidereal drive, or (a different button for) CCW sidereal drive, and a Pause/stop button.? ?Then, you
could pause, and shift the counterweights, and run back and forth CW va CCW directions to observe the drive current.? In that way, you would not need to change from Scope East vs Scope west positions.??
Someone recently asked about battery power needs to run a mount.? Some thoughts on that follow:
What current draw should you expect to use to run a G11 and Gemini, say?
(Note: Power =Amps x Volts, so the current should be smaller if the supplied volts is higher....if it were all due to motor power...but it isn't all motor power).
My amps used on a balanced G11 mount is around these values:
?Sidereal tracking with PHD2 ~2 sec pulse autoguiding:?
? ?0.17 amp at 17 volt DC power ~ 0.25 amp at 12 Volt DC power
Fast slew to distant target, or Park at CWD from a distant target:?
? ?0.6 amp per axis at 17 V ~ 0.9 amp at 12 Volt DC power.? So my max on my 17 volt system is about 1.4 amp.? On a 12 V system might be bear 2 amps max.? This fast slew time is brief...maybe 10 seconds max.
Dew heaters use up a lot of amps...a lot of a battery capacity will be drained quickly by the heater.? I estimate about 10 ohms per dew heater cable, so estimate about 1.2 Amps continuous per dew heater cable if powered at 12 volts.? If
you use a digital control, this is reduced by the duty cycle (on time/total time).? But if you are running off a field battery...watch out for killing your battery!? I did kill a 12 V gell pack battery by overdraining it on feeding a dew heater... can be a
costly lesson.??
So I'd run my mount and laptop off one battery, and use a separate battery for the dew heater(s).? If the dew heater battery is exhausted, you won't wipe out your camera and laptop.?
You might damage the dew heater battery if you drain it below some voltage level (like I'd guess 10 volts for a nominal 12 volt battery).? Below that you'd probably kill a wet cell.??
Thinking out loud: if you want a circuit to stop battery drain at some desired voltage, (say 10 volts) contact me and I'll make you up a battery drain protection circuit.??
All the best (a Starbucks Frappuccino at dinner is keeping me up most of the night.? At least it wasn't a COV19 attack... this virus panic is horrible...)
I'll mention:? I have a batch of Gemini-2 power booster units that I recently made up.? These have an output current digital luminescent meter (ammeter) for the output current.? The output voltage
is boosted to 17.1 volts internally by a polarity-protected circuit, from nominal 12 volts input.? That output voltage is also displayed by a digital luminescent display.? The polarity protection is to assure that anyone connecting to a battery input in the
dark has no worry about mistaking + for - pins going in... the box automatically switches it to be correct polarity going out to the Gemini unit.??
Here is a photo of a power booster unit driving the RA on that overloaded G11 mount. (And a daytime photo of the overloaded G11 as well). You see that the RA drive is only using about 0.16 amp...because
the RA is well balanced.? Most of that 0.16 amp is just running the Gemini (mine are Gemini-1, but you'd get about the same running a Gemini-2).? I get the same 0.16 amp running even a light scope and load.??
Anyone interested in trying one of these units...please contact me off line. I have a small batch of Gemini-2 units ready to go.? If you need a Gemini-1 unit, I will make them up too.? They all
come with the correct output cable to go to the specific Gemini units.? ?
?
Not sure what my RA washer configuration is, mount is only 1 ? years old. Dec I pulled apart heaps and don¡¯t have the desire to do anything on the RA.
?
Without the ¡°pull¡± system, due to higher system load (which is why I bought the G11GT), I measure about 1.4 kgs at the end of the weight shaft to pull up and same to pull down.
?
With ¡°pull¡± system in place, I¡¯m down to 0.2 kg. It¡¯s almost neutral. Haven¡¯t tried to get to neutral, will try to see what I can get to next time I setup.
?
Yes, Dec much easier to do, including a little push from the counterweight end to completely free it all.
?
?
?
From:
[email protected] <[email protected]>
On Behalf Of Michael Herman via
Sent: Saturday, 16 May 2020 2:37 PM
To: [email protected]
Subject: Re: [Losmandy_users_io] Balancing RA
?
Hi Richard,
The extra photos explain your design...the bolts in front push on metal plates, and lift the upper front wood piece, which is attached to the wire holding the front polar scope
cover.? Very clever!
The takeaway for me was that, using this method, you did find the RA axis much easier to rotate for perfect balance.? You got the same benefit as the "wavy washer" new design.?
The wavy washer requires a slot machined in the drive clutch plate area which my earlier mount designs don't have.? So...you provided some ideas to try.? ?
As for me, to date, I have used a "push" in both rotation directions on my RA axis to get a sense of the RA counterweight balance.? As long as that is pretty close, my RA drive
seems to have no trouble.? I can also use the current meter on my Gemini power supply to measure the sidereal drive current with the scope on the East, vs West, side of the mount.??
For DEC, it is far easier...just put the counterweight rod horizontal, and loosen the DEC clutch knob. Then there is zero weight on the DEC clutch and that axis swings around easily
with no friction.? That is simple to rebalance.??
Thanks again Richard for sharing your wood lift design.? Something new to try out...!? ?
?
Hi Michael
?
I had the idea and then just made it up quickly using some left over wood from a wine rack, 150 ib tracer wire and large swivel from fishing tackle shop, two large screws, a couple
of washers and a pin of some sort (or use an allen key).
?
If designed professionally ¨C threaded tube could screw into the RA cover thread and then have the frame and finally something like the Dec clutch tightening knob that threads onto
the same threaded tube.
?
Hope the pictures make sense.
?
Regards Richard
?
?
From:
[email protected] <[email protected]>
On Behalf Of Michael Herman via
Sent: Saturday, 16 May 2020 10:15 AM
To: [email protected]
Subject: Re: [Losmandy_users_io] Balancing RA
?
Hi Richard,
I watched your video...now that you mention your "gear puller" I see your wooden rectangular enclosure briefly appears in the video.
I see that the wooden rack pushes down on the RA body mounting, and the front wooden part is attached to the RA front polar scope cover.? There are what appear to be wires pulling
up on the RA cover knob, and the wires lift the RA weight off the RA clutch, so it will rotate more easily.??
How do you adjust the wires to pull up?? I see some bolts in front.? Can you sketch or describe how that mechanism?works?
Anyway, that's quite a clever wood lifter idea.? Thanks for sharing that?with the group.
?
Hi Rick
?
I have a G11GT so it¡¯s the Titan RA. I use electronic luggage scales and at the end of the weight shaft pull up then pull down, adjust until the numbers are the same.
?
The heavier your load and higher the altitude the worse it gets.
?
Lately I build like a gear puller to help with the balancing the RA. Pulls the weight off the clutch plate so balancing much more accurate. See video attached.
?
?
?
From:
[email protected] <[email protected]>
On Behalf Of rboudah via
Sent: Saturday, 16 May 2020 12:07 AM
To: [email protected]
Subject: [Losmandy_users_io] Balancing RA
?
Hi just received new G11G and was trying to balance the RA axis and at my latitude of 45 degrees and there was way to much friction to balance the mount. This mount definitely needs
the wavy washer. To get around this I used 2 methods to find balance.
1. Set the altitude adjustment to 0 so that all loads are on the bearings and none on the friction plate. This works perfectly.
2. I have an amp meter on my battery box so I set the RA axis to horizontal and slewed in one direction and then the other waiting for the current to steady . I adjusted the weight so that the current was the same. This I could do with the altitude at 45 degrees.
Both were very close to each other.
Rick
This e-mail and any files attached are intended solely for the use of the addressee. They may contain privileged or confidential information. If you are not the intended recipient,
you are hereby notified that any use, disclosure, copying or distribution of this e-mail is strictly prohibited. If you receive this message in error, please notify the sender immediately and delete the message and any attachments from your system. Thank you.
|
I'm a 44N with an older G11 so wavy washer is not an option.? My method now is to loosen the RA clutch knob quite a bit, and push on the shaft with the base of my hand enough to overcome the friction (still have a bit of clutch knob friction).? Achieves about the same effect as Richard's 'puller', and even lower tech.
Keith
|
Michael Herman