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Re: California grease
Hi Chip!
I've been reading along about the gear mesh vs temp discussion. Interesting. My gears are barely meshed (I really have to adjust things at some point -- just haven't gotten around to messing with it since I bought it), so I'm thinking this is the grease. The temps were close to 60 then to 30F kinda quickly. Those Hollywood types...their grease probably comes with a free pair of Baggies and flip-flops. :) Grey tube SuperLube to the rescue! I guess I'll tighten up stuff then too. Thanks! Bob |
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Re: California grease
Hi Bob,
I have had two issues with changes in air temps and tracking error, lubricant as you mention and worm gear mesh. Whatever lubricant is used by Losmandy seems to get stiffer as it gets colder making the mount tracking error level increase as temps fall. As the grease get hotter it gets thinner and over time separates making a runny mess and over time drying out the lubricant making the mount stiffer over time even when warm. The lube issue is an easy fix, just go online and buy a tub/tube of Synco's food grade pure synthetic SuperLube Multi Purpose Grease with PTFE, NOT the Silicone stuff. SuperLube is a true pure synthetic - this stuff stays put very well in the heat with minimal migration and minimal separation of the base. But more importantly IMO for telescope mount applications - it stays very soft even when you are frozen solid, the coldest I have stayed out is about 20F and the mount was tracking perfectly. As you no doubt have experienced in SoCal we can easily experience 50F-70F swings in air temp in the high desert areas where it is darkest. This stuff works perfectly and if you buy it in a tub it's even reasonably priced. Here is an Amazon link:.? ? The other worm gear mesh issue is mechanical binding as the mount gets colder the clearances shrink significantly causing drag and eventually binding and stalling mount movement. So if you set your worm mesh up to have minimal backlash at the tightest point with the large worm wheel in your nice warm house then go outside and the air temperature drops it will get tighter. The only way to avoid this is to set your worm gear mesh in the cold and let the backlash be larger when hot and not in use. My own experiences has been that the mount will guide and track much better with the worm set slightly loose when cold rather than set up perfectly. In other words some very small backlash is needed or tracking suffers.? Chip ? |
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California grease
I have a 2 year old GM-8 and was out Saturday night as the temps got close to freezing. I think the grease in the mount got close to freezing too. The mount started getting real quiet -- not silent, but quiet -- and the 15-second exposure stars started looking a little like comets. It's a 492 system. I have the encoders with the Nexus system and it kept dropping out and saying the telescope was not responding. I thought it was a cold Nexus or iPad, but now I think it was its way of saying the telescope wasn't moving or at least keeping up. Is that expected from the factory grease? The axes were for sure stiffer when I was taking everything down than it was when I put it together earlier in the evening. Not hard, but more firm. Thanks! Bob |
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Re: Polar Scope
Now that the trees have dropped their leaves I was able to try the polar alignment tool in Sharpcap. Pretty amazing... got a decent alignment in record time and a lot more fun than my old drift alignment approach. One points the scope in the general direction of Polaris -- the tool platesolves where you are pointing, then asks that the scope be rotated in RA roughly 90 degrees, then platesolved again. An arrow on the screen shows which way the aim needs to be shoved and an error circle is displayed. So you move the scope a tad and rerun the second image. A couple of passes through this loop and you are done. I was using a Mallincam USB astronomical camera so it was close to live video. The camera was on my scope rather than the guide scope as I wanted to correct the mount, then adjust the guidescope to point at the same place. Worked for me...?
greg latiak avalon observatory |
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Re: Just purchased GM811GHD
¿ªÔÆÌåÓýAll of my astro efforts are done at sites several hours drive away. I have used agm and gel cell batts for running computers mount and cameras. A 79 AH agm has worked well except in cold weather for about 2 nights of imaging with guiding. I recently replaced that with a 50 Ah LiFePO4 batt and found I could go 3 nights on the same setup. At about half the weight, my back has thanked me a lot. My wallet on the other hand is still whining?. I plan to swap out 2 gells (32AH) and another 79 AH agm with more LiFePO4s as the existing batts age and the LiFePO4 batt prices drop. Cheers? Loren On Dec 8, 2017, at 11:52, crocco1250 crocco1250@... [Losmandy_users] <Losmandy_users@...> wrote:
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OnStep Goto Conversion
A few GM8/G11s have been converted to stepper operation by members of?/g/onstep. Stepper drivers, basically current amplifiers, have come a long way since the 492 was developed in the early '90s as have microprocessors. Stepper motors are quite quite when operated at high microstepping rates. Current drives can break each step into 128 movements.? These improvements permit a NEMA 11 stepper (?Frame Size (28 x 28mm)?with a 18;1 gear head to drive a G11. The motor and its gear head tuck neatly under the RA worm housing.? ? |
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Re: Just purchased GM811GHD
¿ªÔÆÌåÓýBryan I agree.? Look at the weight of a slave vs li-fe-po4, though.? An sla gives you a good workout lugging it around! Chuck Sent from my Samsung Galaxy Tab?|PRO -------- Original message -------- From: "bryancashion@... [Losmandy_users]" <Losmandy_users@...> Date: 12/08/2017 12:28 PM (GMT-08:00) To: Losmandy_users@... Subject: RE: [Losmandy_users] Re: Just purchased GM811GHD ? At 0.5 A, a 22 Ah battery would be good for 22 hours on the basis that these types of batteries should not be discharged to more than 50% pf their capacity. 22 Ah*50%/0.5A? = 22 hours
I have had good luck with Power-Sonic SLAs (I have 3).? This is a link to their 12V series. ? Bryan Sent from my Samsung Galaxy Tab?|PRO -------- Original message -------- From: "bvalente@... [Losmandy_users]" <Losmandy_users@...> Date: 12/08/2017 11:33 AM (GMT-08:00) To: Losmandy_users@... Subject: [Losmandy_users] Re: Just purchased GM811GHD ? yes, they will definitely work.? Car starter batteries are more designed around offering a maximum amperage to kick over the motor.? for astro that's not important -? instead we want greater battery capacity, hence amp-hours if your losmandy pulls .5a then a 22 amp-hour will last about 11 hours, or pretty much all night long me, I power my losmandy G11T, intel nuc i5 computer, focuser, dew heater, camera, guide camera, and whatever USB junk is connected to my computer. so my amp-hour usage is a lot more. just FYI B ? |
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Re: Just purchased GM811GHD
¿ªÔÆÌåÓýRight ¨C what he said ;) ? Thanks ? Brian ? ? Brian Valente Brianvalentephotography.com ? From: Losmandy_users@... [mailto:Losmandy_users@...]
Sent: Friday, December 8, 2017 12:28 PM To: Losmandy_users@... Subject: RE: [Losmandy_users] Re: Just purchased GM811GHD ? ? At 0.5 A, a 22 Ah battery would be good for 22 hours on the basis that these types of batteries should not be discharged to more than 50% pf their capacity. ? 22 Ah*50%/0.5A? = 22 hours ? I have had good luck with Power-Sonic SLAs (I have 3).? This is a link to their 12V series. ? ? ? Bryan ? ? Sent from my Samsung Galaxy Tab?|PRO
yes, they will definitely work.? ? Car starter batteries are more designed around offering a maximum amperage to kick over the motor.? ? for astro that's not important -? instead we want greater battery capacity, hence amp-hours ? if your losmandy pulls .5a then a 22 amp-hour will last about 11 hours, or pretty much all night long ? ? me, I power my losmandy G11T, intel nuc i5 computer, focuser, dew heater, camera, guide camera, and whatever USB junk is connected to my computer. so my amp-hour usage is a lot more. ? just FYI ? ? B ? |
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Re: Just purchased GM811GHD
At 0.5 A, a 22 Ah battery would be good for 22 hours on the basis that these types of batteries should not be discharged to more than 50% pf their capacity.
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22 Ah*50%/0.5A? = 22 hours I have had good luck with Power-Sonic SLAs (I have 3).? This is a link to their 12V series. ? Bryan Sent from my Samsung Galaxy Tab?|PRO -------- Original message -------- From: "bvalente@... [Losmandy_users]" <Losmandy_users@...> Date: 12/08/2017 11:33 AM (GMT-08:00) To: Losmandy_users@... Subject: [Losmandy_users] Re: Just purchased GM811GHD ? yes, they will definitely work.? Car starter batteries are more designed around offering a maximum amperage to kick over the motor.? for astro that's not important -? instead we want greater battery capacity, hence amp-hours if your losmandy pulls .5a then a 22 amp-hour will last about 11 hours, or pretty much all night long me, I power my losmandy G11T, intel nuc i5 computer, focuser, dew heater, camera, guide camera, and whatever USB junk is connected to my computer. so my amp-hour usage is a lot more. just FYI B ? |
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Re: Just purchased GM811GHD
¿ªÔÆÌåÓýOn power, you might consider using a lithium iron phosphate battery.? It is tolerant of temp unlike lithium batteries but is not cheap.? But it is lighter and, with purchased battery charger, you can use it at home plugged in.? You just add cig lighter jack and fuse and away you go. https://www.powerstream.com/LLLF-12v.htm Chuck Sent from my Samsung Galaxy Tab?|PRO -------- Original message -------- From: "bvalente@... [Losmandy_users]" <Losmandy_users@...> Date: 12/08/2017 11:33 AM (GMT-08:00) To: Losmandy_users@... Subject: [Losmandy_users] Re: Just purchased GM811GHD ? yes, they will definitely work.? Car starter batteries are more designed around offering a maximum amperage to kick over the motor.? for astro that's not important -? instead we want greater battery capacity, hence amp-hours if your losmandy pulls .5a then a 22 amp-hour will last about 11 hours, or pretty much all night long me, I power my losmandy G11T, intel nuc i5 computer, focuser, dew heater, camera, guide camera, and whatever USB junk is connected to my computer. so my amp-hour usage is a lot more. just FYI B
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Re: Just purchased GM811GHD
Ditto B,
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I use two 55 amp-hr batteries to power? all my imaging equipment each session. John Hobbs
hobbs_john@... -----Original Message----- From: bvalente@... [Losmandy_users] To: Losmandy_users Sent: Fri, Dec 8, 2017 2:33 pm Subject: [Losmandy_users] Re: Just purchased GM811GHD
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yes, they will definitely work.?
Car starter batteries are more designed around offering a maximum amperage to kick over the motor.?
for astro that's not important -? instead we want greater battery capacity, hence amp-hours
if your losmandy pulls .5a then a 22 amp-hour will last about 11 hours, or pretty much all night long
me, I power my losmandy G11T, intel nuc i5 computer, focuser, dew heater, camera, guide camera, and whatever USB junk is connected to my computer. so my amp-hour usage is a lot more.
just FYI
B
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Re: Just purchased GM811GHD
yes, they will definitely work.?
Car starter batteries are more designed around offering a maximum amperage to kick over the motor.? for astro that's not important -? instead we want greater battery capacity, hence amp-hours if your losmandy pulls .5a then a 22 amp-hour will last about 11 hours, or pretty much all night long me, I power my losmandy G11T, intel nuc i5 computer, focuser, dew heater, camera, guide camera, and whatever USB junk is connected to my computer. so my amp-hour usage is a lot more. just FYI B |
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Re: Just purchased GM811GHD
Yes for that amount of money you ca buy a 50 Amp/hr battery.
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John Hobbs
hobbs_john@... -----Original Message----- From: Brian Valente bvalente@... [Losmandy_users] To: Losmandy_users Sent: Thu, Dec 7, 2017 11:10 am Subject: Re: [Losmandy_users] Re: Just purchased GM811GHD
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I'm not sure that's a great battery for astro (although that seems like a good price for a general battery safety thing). 1200 amps is the max for starting a car, which is not important for steady power to astro gear. the important one is 22amp hours. A straight 22 amp hour 12v battery is about $45.?
B
On Thu, Dec 7, 2017 at 5:47 AM, steve hammel shammel00@... [Losmandy_users] <Losmandy_users@...> wrote:
Brian?
Brian Valente
portfolio
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Re: Just purchased GM811GHD
¿ªÔÆÌåÓýBut if you buy a bare battery you of course also need a charger, connectors for whatever you want to hook to it, an inverter if you have stuff that needs 110VAC, and probably some kind of case.?Going the other way, there¡¯s this kind of thing??which costs quite a bit more per watt-hour, but it¡¯s a lithium battery so weighs only about 1/3 of the lead-acid equivalent, and has 5V, 12V, and 110V outputs. Although, come to think of it, a lead-acid battery is still light weight compared to a Losmandy mount. :) ??-Les On Dec 7, 2017, at 8:10 AM, Brian Valente bvalente@... [Losmandy_users] <Losmandy_users@...> wrote:
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Re: Just purchased GM811GHD
wes Bolin
I bought the jump-start battery with minimum number of bells and whistles at Harbor Freight for about $50.? It ran all night with my G11GT and still showed a green led saying it was charged.? YMMV. Wes On Thu, Dec 7, 2017 at 10:10 AM, Brian Valente bvalente@... [Losmandy_users] <Losmandy_users@...> wrote:
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Re: Just purchased GM811GHD
I'm not sure that's a great battery for astro (although that seems like a good price for a general battery safety thing). 1200 amps is the max for starting a car, which is not important for steady power to astro gear. the important one is 22amp hours. A straight 22 amp hour 12v battery is about $45.? B On Thu, Dec 7, 2017 at 5:47 AM, steve hammel shammel00@... [Losmandy_users] <Losmandy_users@...> wrote:
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Brian? Brian Valente portfolio |
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Re: Just purchased GM811GHD
For a battery pack? check out Lowe's they have a Shuemacher 1200 hundred amp power pack on sale for $100
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It has 12 volt Outlets plus a 110 inverter.? Just an option?
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