Re: A question of balance...counterweights
Michael, Your Jupiter image result was so nice.? I was not familiar with the ADC device until you mentioned it. Thanks for all you comments and imaging planetary tips.? Bob R. ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Michael Herman
Sent: Monday, July 20, 2020 4:21 PM
To: [email protected]
Subject: [Losmandy_users_io] A question of balance...counterweights? The question was asked: Is it better for imaging performance to put fewer counterweights at the far end of the bar, or use more weights close to the RA axis of the mount ? I am not doing deep sky at the moment, and if I bump my scope during planetary video imaging, I can see the video image jump briefly before it damps out.?? Therefore, you can also experiment: if you use your autoguider camera, and put it on your main imaging scope prime focus location, and point to a bright star, and give a bump to your counterweight, you can see or record on video how much the star jumps around.? The video could quantify the frequency and amplitude of the vibration. Then try to adjust your weights position and give a similar bump.? Can you see a difference?? If yes...tell us what you discover!? Can you say whether there is an improvement or no real difference? In terms of academic theory, this would need "finite element" modeling.? And you'd need to know something about the "bump" or driving force.? ? If it's a constant wind, it could drive oscillations of the system (think the famous Tacoma Narrows bridge).? But in the absence of any bump or wind, the only movement is the constant tracking rotation.? There are sporadic autoguiding corrections, and these if large might cause an oscillation.? I don't see any oscillations in my planetary imaging and that is getting frequent autocorrections from FireCapture through ASCOM to the Gemini-1 to the G11. The trade-off is on counterweight bar flex, and image vibration. Also comes up on how heavy a scope and counterweight load can you put on a G11 before it breaks down. For the vibration question...it's a good mechanics/physics question.?? The problem looks like this: [Very Heavy Scope] ----(W1)--------(W2)---- ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ^ ? ? ? ? ? ? ? ? ? ? ?^ is the RA axis pivot What are the frequencies of this case above, versus an alternative putting more weights close to the RA pivot: [Very Heavy Scope] --(W1)(W2)(W3)------ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ^ ? ? ? ? ? ? ? ? ? ? ?^ is the RA axis pivot In general, the bottom case will have higher frequencies than the upper case.? The energy of the higher frequencies might be the same as the energy of the lower frequencies, but the higher frequency vibrations might look just like "Seeing" fluctuations.? The lower frequencies might make larger blurs if your stats. This is a different puzzle for each of us, as we all have different weight scopes, cameras, and weights can vary too.? The heavier the scope the less it will move.?? Think of a flute or better a rope with weights on it: the holes in the flute are either open, providing a point where a sound wave can have no pressure.? On a rope with weights, the weight positions act as a null point. The rope can't vibrate there but if can oscillate between the weights.?? I'll say that both cases can oscillate, but if you space out the weights, you may be able to reduce the oscillation amplitude. Here in the top photo is my overloaded system (in the dark), showing the hollow 3 foot long counterweight shaft.? I put 3 counterweights spaced out to act as nodes to kill off some vibration modes.? The idea was to forces oscillations to go to higher frequency, which are harder for bumps or wind to create - at least that's my thinking.?? ( By the way, finite element analysis is used in bridge design to ensure there are no harmonic frequencies like caused the Tacoma Narrows bridge collapse.? ) Here is a photo of FireCapture set up to evaluate the ZWO ADC atmospheric dispersion corrector.? Seeing usually appears here very severely ad the colors jump all over the place.? A bump here would make the star or planet jump all over too.? The 3rd photo is how Jupiter looked the time of the photo this week.? Hope you can try some experiments to see what is optimal for your system! And let us know what you discover! Best regards and stay healthy,
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Re: Plate solving to build a model, Gemini 2
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Can plate solving with an ASIair be used in conjunction with the Gemini2 modeling routine to build a model.
I suspect it's unlikely - if it supports align command it can do that
however, not sure how much value there is in building a model of you are plate solving
On Mon, Jul 20, 2020 at 3:18 PM Allen Ruckle < aruckle@...> wrote: Can plate solving with an ASIair be used in conjunction with the Gemini2 modeling routine to build a model.
aruckle
-- Brian?
Brian Valente portfolio
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Plate solving to build a model, Gemini 2
Can plate solving with an ASIair be used in conjunction with the Gemini2 modeling routine to build a model.
aruckle
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Re: Resurrecting GM8 Part 2
Hi Bill,
The first time you boot up with a new battery you will get the CMOS reset message. After you enter correct UTC time, etc, then shut off the G1, ...next reboot it should be fine.?
If your unit is still acting defective, ... David Partridge in UK, Brendan Smith in Australia, and I in USA do repairs of G1s.? There are a few components that could go bad and cause the constant Reset messsges.? No way to fix it without seeing it...
All the best!
Michael
Thanks to those that answered my last question regarding the mount screws. Have them replaced, even if two trips to Home Depot had to occur because when my wife went for me, the girl helping her had no clue about screw dimensions.?
New question. I have Gemini 1 with the round plugs. It¡¯s old, so no surprise that the 2032 battery would need replacing. Problem, still get the message CMOS reset on every startup with new battery. Measure the voltage with the correct 3v.? Any ideas?
Bill Gardner --
_____________ Pictor Observatory
Twitter: @pictorobs
Minor Planet 21350 - billgardner
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A question of balance...counterweights
The question was asked:
Is it better for imaging performance to put fewer counterweights at the far end of the bar, or use more weights close to the RA axis of the mount ?
I am not doing deep sky at the moment, and if I bump my scope during planetary video imaging, I can see the video image jump briefly before it damps out.??
Therefore, you can also experiment: if you use your autoguider camera, and put it on your main imaging scope prime focus location, and point to a bright star, and give a bump to your counterweight, you can see or record on video how much the star jumps around.? The video could quantify the frequency and amplitude of the vibration.
Then try to adjust your weights position and give a similar bump.? Can you see a difference?? If yes...tell us what you discover!? Can you say whether there is an improvement or no real difference?
In terms of academic theory, this would need "finite element" modeling.? And you'd need to know something about the "bump" or driving force.? ? If it's a constant wind, it could drive oscillations of the system (think the famous Tacoma Narrows bridge).? But in the absence of any bump or wind, the only movement is the constant tracking rotation.? There are sporadic autoguiding corrections, and these if large might cause an oscillation.? I don't see any oscillations in my planetary imaging and that is getting frequent autocorrections from FireCapture through ASCOM to the Gemini-1 to the G11.
The trade-off is on counterweight bar flex, and image vibration. Also comes up on how heavy a scope and counterweight load can you put on a G11 before it breaks down.
For the vibration question...it's a good mechanics/physics question.??
The problem looks like this:
[Very Heavy Scope] ----(W1)--------(W2)----
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ^ ? ? ? ? ? ? ? ? ? ? ?^ is the RA axis pivot
What are the frequencies of this case above, versus an alternative putting more weights close to the RA pivot:
[Very Heavy Scope] --(W1)(W2)(W3)------
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ^ ? ? ? ? ? ? ? ? ? ? ?^ is the RA axis pivot
In general, the bottom case will have higher frequencies than the upper case.? The energy of the higher frequencies might be the same as the energy of the lower frequencies, but the higher frequency vibrations might look just like "Seeing" fluctuations.? The lower frequencies might make larger blurs if your stats.
This is a different puzzle for each of us, as we all have different weight scopes, cameras, and weights can vary too.? The heavier the scope the less it will move.??
Think of a flute or better a rope with weights on it: the holes in the flute are either open, providing a point where a sound wave can have no pressure.? On a rope with weights, the weight positions act as a null point. The rope can't vibrate there but if can oscillate between the weights.??
I'll say that both cases can oscillate, but if you space out the weights, you may be able to reduce the oscillation amplitude.
----- Here in the top photo is my overloaded system (in the dark), showing the hollow 3 foot long counterweight shaft.? I put 3 counterweights spaced out to act as nodes to kill off some vibration modes.? The idea was to forces oscillations to go to higher frequency, which are harder for bumps or wind to create - at least that's my thinking.??
( By the way, finite element analysis is used in bridge design to ensure there are no harmonic frequencies like caused the Tacoma Narrows bridge collapse.? )
Here is a photo of FireCapture set up to evaluate the ZWO ADC atmospheric dispersion corrector.? Seeing usually appears here very severely ad the colors jump all over the place.? A bump here would make the star or planet jump all over too.? The 3rd photo is how Jupiter looked the time of the photo this week.?
Hope you can try some experiments to see what is optimal for your system! And let us know what you discover!
Best regards and stay healthy, Michael
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Thanks to those that answered my last question regarding the mount screws. Have them replaced, even if two trips to Home Depot had to occur because when my wife went for me, the girl helping her had no clue about screw dimensions.?
New question. I have Gemini 1 with the round plugs. It¡¯s old, so no surprise that the 2032 battery would need replacing. Problem, still get the message CMOS reset on every startup with new battery. Measure the voltage with the correct 3v.? Any ideas?
Bill Gardner -- _____________ Pictor Observatory
Twitter: @pictorobs
Minor Planet 21350 - billgardner
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re Monsoon season in Tucson: Oh, yes.?
Although I don't live there now, I lived in Tucson for 20 years.?
The Official monsoon season begins on July 4, and continues through August. The typical pattern is that the morning sky is clear, then clouds begin to form over the Catalina mountains. By 2PM the sky is cloudy.
During that time you may get rainfall lasting about 10 minutes. The water is cold - 35-45 F. The temp cools from 105F or so to about 70F in a few minutes.?
Then the water begins to evaporate and the humidity skyrockets!
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Don Martin
wd.martin.08@...
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Re: Leaving Mount in the sun
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Thanks Brian. Any idea was the lube I saw was from? Should I give Scott a call?
It would help if you can look more closely at the mount and see where it may be originating? and also any pics of the lube to determine color etc.
It would be most helpful if you could do that sleuthing, email it in, and then give Scott a call (or you can email it to me at techsupport@... and I can run it up the flagpole as well)
Thanks Brian. Any idea was the lube I saw was from? Should I give Scott a call?
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-Kevin
-- Brian?
Brian Valente portfolio
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Re: Leaving Mount in the sun
Thanks Brian. Any idea was the lube I saw was from? Should I give Scott a call?
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-Kevin
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Re: Leaving Mount in the sun
factory lube is jet-lube moly paste mp-50 that's rate?-300¡ãF to 750¡ãF
Hey Louie, thanks for the insight. I will definitely get some aftermarket lube.
As for the age of the mount, it just had its first birthday last week, and is still using its factory grease. I have read here that Losmandy uses a synthetic lubricant that shouldn't be even close to separating at the temps my mount is exposed to, but maybe I'm wrong.?
--
-Kevin
-- Brian?
Brian Valente portfolio
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Re: Leaving Mount in the sun
Hey Louie, thanks for the insight. I will definitely get some aftermarket lube.
As for the age of the mount, it just had its first birthday last week, and is still using its factory grease. I have read here that Losmandy uses a synthetic lubricant that shouldn't be even close to separating at the temps my mount is exposed to, but maybe I'm wrong.?
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-Kevin
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Re: Leaving Mount in the sun
Hi Kevin,
How old is your G11T? The grease used is a common problem, when hot it melts and migrates out of the clutches and into places you do not want oil, the clutches. The grease you choose must not melt and run off in the hot and in the cold it must remain soft as peanut butter.?
Order some Synco Super Lube multi-purpose synthetic grease with Syncolon (Teflon) NOT the Silicone based version from amazon.com before you disassemble the mount to clean the clutches which should be run clean and dry or you can get slippage.?
Disassembly is ease and as others have mentioned there are plenty of videos online to guide you. Use solvent to remove old grease and do not use excessive globs of new grease when relubing, all a bearing needs is a film but you also want to use enough to protect the bearings from contamination so use a little more than a film once worked into a bearing and worm. All other surfaces should be dry and clean.?
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Chip Louie - Chief Daydreamer Imagination Hardware
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Re: Leaving Mount in the sun
While not quite in the sun, my equipment stays out 365. I have a SkyshedPOD and a fixed pier. The mount, telescopes and wiring remain setup. When not in use, the whole assembly is covered by a large aluminized cover I bought from ScopeStuff. Don't know what temperatures the equipment under the cover reaches, but in this heatwave the min/max thermometer in the dome gets up to 112F. Doesn't seem to hurt anything, but I wish it would discourage the spiders...
greg latiak
avalon observatory
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Hi,
my picture of comet Neowise taken last week. Losmandy GM8, Canon 1100D, ED50/330?
Seb
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Re: Leaving Mount in the sun
Kevin:
The clutches should be bone dry of any grease else they may slip.? Scott has a YouTube on cleaning the clutch surfaces (including pads). My guess this is grease separating and migrating from the needle bearings.
Keith
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Re: Leaving Mount in the sun
That is for the reply. Have you ever see a little pooling of lubricant under the ra axis after super hot weeks?
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I bring in my "chunks" every day as a rule. (The CFO's rules) 8^0
But I can also assemble it in my home office/man cave so I can run it or play around with it.
If you could do something like that, store it inside and excersize it now and then, there would be no worries at all.
As long as you don't live in an aquarium.... ;^)
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SonnyE
(I suggest viewed in full screen)
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Re: Leaving Mount in the sun
It's OK, Kevin.
I leave my tripod out and covered. But everything else comes in out of the heat of summer.
So nothing electrical is outside in the heat. Beyond the heat stressing the lubricants, people don't realize excessive heat also stresses the capacitors in the electronics.
I do a new Model every night anyway, and I have my mount "modularized" into "chunks" for moving back and forth.
1. 12" EX12 has the Gemini and wiring harness, and the RA on it; 2. The RAEXT carries the DEC and the bar/weight as a chunk; 3. And lastly is the telescope assembly. (Mine is everything from a D Bar up.)
I cover my tripod with a heavy canvas painters tarp and my 32 gallon plastic dome.
But the tripod remains polar oriented, so when I set up the pieces, the bayonet indexes bring the RA into near Polar Alignment.
The mount is as near a perfect mount as any ever made.
--
SonnyE
(I suggest viewed in full screen)
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Re: Leaving Mount in the sun
Sorry to revive a dead topic, but it isn't worth making a brand new one for a comment.?
I have left my G11T out (sans electronics) with a mylar cover on my deck since early June and I went out today to wipe it and notices a nickel-sized puddle of oil that appears to have been running off the RA clutch. It's been very hot here in Kansas City this year (92-95f this week and my deck gets over 110f).
So I brought the elephant inside and spun the RA axis around for a few minutes while it cooled to redistribute the lube. Needless to say it gave me a spook and I'll probably be giving Scott a call to make sure I don't need to tear it down and re-lube it, or check other internal parts for lube runoff.?
MysMy is that the clutches use something like a gun oil, or bicycle wet-lube for chains and cassettes and this isn't the same as the synthetic grease used for the bearings and gears, but I want to be sure before I load it up again with 60lbs of gear and 35lbs of weights. Also rain is forecast all week so I can't really measure PEC until I have another rare good night of seeing.?
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Michael Herman
Don Martin
Chip Louie