Re: Portable Power for your AP setup
One of the reasons I switched to ZWO wax to get into the ASIAIR-PRO computer system for imaging. The ZWO uses so much less power it is not even funny.
The ASIAIR app and firmware has come so far in the last year it has basically replaced my very fast but also power hungry Intel Skull Canyon i7 w/32GB RAM and 1TB NVMe SSD NUC mini-PC. The ASIAIR-PRO also takes up a lot less space on the top dovetail than the i7 NUC mini-PC does.?
The best thing is that I can now image all night even where there is no utility power available.?
--
Chip Louie Chief Daydreamer Imagination Hardware?
? ?Astropheric Weather Forecast - South Pasadena, CA?
|
Re: Making the most of cloudy winter nights with a new mount and scope
*Thanks again* to all you guys for your input and suggestions.??A few notes:
¡¤??????I did look at the Mac client for PoleMaster, last updated in 2018 as far as I could tell, and saw multiple complaints on its performance¡ and it would mean another device¡ Wouldn¡¯t want to spend another $300 to find out it just adds a new layer of problems.
¡¤??????I got out two nights ago under unexpectedly(!!) clear skies for several hours. I was finally able to work on two PA routines ¨C using the Losmandy polar scope with the PS Align app, and working the AAP PA with my guide scope (including a bug workaround - ¡®have to rotate my OTA *with the HC* 60¡ã since AAP will only rotate it 8¡ã¡¯). Both worked very well, and using the PS Align reticle orientation off my Apple watch made that method *very fast*. I have a third PA method w/in reach on the G2 HC, which I haven¡¯t yet tried.
¡¤??????I¡¯m aware that I could gain access to ASCOM drivers off a Mac virtual machine, and glad to know I could put a Windows mini-PC on my OTA if I am forced to repent of my stubbornness (wouldn¡¯t be the first time!). But it seems like the?KStars/EKOS/INDI suite is worth exploring for a while, and I would love to be free of a laptop and drive my viewing and capture sessions off an iPad, and several on and off this thread are doing the same thing and have helpfully offered assistance along the way (many thanks!!)
¡¤??????Practicing my setup and workflow inside has been very helpful for me with the new mount and its G2 HC, the AAP devices, and my Fuji XT3. And then having a clear night to do it outside was good. Even got some first photos of the Orion Nebula, and made a list of things to work on while I wait for the next clear night. Those first photos were so sweet! ;-)
?
I have a further thought and a question¡
¡¤??????Thought: On Windows/Mac. In my own career I went to Mac about 25 years ago, often as the only one on the team, and made it work. I¡¯ve appreciated the Apple ecosystem and happily live in it, recently upgrading to a new M1 MacBook. B/c I have always found ways to make it work, and b/c I have so much already invested in that ecosystem, I am willing to try and make it work again. Along the way am glad to give a little more incentive to the astronomy developers to make things work across platforms.??I don¡¯t mind workarounds, am glad for helpful hints and don't mind supportive cautions...?
?
¡¤??????Question: If you go down the AP rabbit hole, do you have to go all the way to the bottom???I was talking to a vendor this past week, and we got into this discussion. He described his own observatory to me, well supplied with devices and very good OTA¡¯s, all set up and ready to go.??Then he told me that these days when he goes out and rolls back the roof, he doesn¡¯t turn anything on. He just pulls up a lawn chair and grabs a set of binoculars and sits back and looks up. No scopes, no capture, no post- processing¡ His comment was that years ago he didn¡¯t get into this in order to spend hours and hours on setup, capture and post-processing. He got into it to look heavenward. Yep, I thought, me too. There is something about the immediacy of being out under the stars that I treasure, and do not want to lose to hours working with setups and a computer...?
?
So a question: Can I get into AP a ¡®little bit¡¯, still spending most of my time looking up? I realize that the end product (AP photos) would suffer, but my enjoyment (speaking of my own interests here and realizing that others have very different interests) will likely be linked to the time I spend outdoors. Any suggestions for stopping places on the journey down the rabbit hole?
|
Re: Portable Power for your AP setup
There are some new risk-v systems coming out that are even more efficient -- but you may have to compile the whole astro stack by hand, and it will be buggy. They may be better to try in a year or two.?
|
Re: Portable Power for your AP setup
Switching to a raspberry pi over x86 makes a huge difference. I tried to switch from a pi3 to an atom x86 and the lithium power tank I use, only lasted 2 hours. Switch back to the pi and it runs for two nights.?
|
Re: Portable Power for your AP setup
Hi Scout, I run my GM-8/Gemini 2 Mini, ASI294MC camera, ASIAIR Pro, guide camera, and a single lightly used dew heater with a Goal Zero Yeti 500X? power box. It is Lithium and has lasted 8 hours (as long as I could stay awake!!) ?Tom?--- bvalente@... wrote: From: "Brian Valente" <bvalente@...> To: [email protected]Subject: Re: [Losmandy_users_io] Portable Power for your AP setup Date: Sat, 30 Jan 2021 19:49:46 -0800 Hi Scott
i've done various versions of all the above, from rolling my own w/ deep cycle marine batteries to my latest jackery. of course they all have pros and cons
the most important thing I did was figure out my nightly amperage. for a solid winter night of imaging (about 8pm-6am) for Gemini II, an Intel-NUC, Trius Pro694MM cooled to -20C, no dew heaters, it ran about 15ah.?
at that time i opted for at 25AH lead acid battery hooked to everything via anderson powerpole distribution plates. worked great and gave me plenty of headroom for adding dew heaters
Lately i bought a Jackery which must be lithium, because it's super light but a bit pricey. It did a great job, but i am not putting as much load on there as i did previously (i think i test ran an allsky with a nuc and allsky camera:? it was about 10ah total for the full night into morning).?
DIY with deep cycle/lead acid is definitely much less expensive and more $/ah. but it is heavier and you have to rig up your own. Jackery seems to be the hot thing right now, and I can see why, but it's pricey. your laptop is going to eat more battery with the screen.
hth
Brian
On Sat, Jan 30, 2021 at 6:56 PM Scott Popjes via <imagemover= [email protected]> wrote: What is everyone using to power their mount, laptop and other gear when at a remote location?? I'd love to get something that can handle imaging sessions as well as GoTo observing sessions where I may be touring around the night sky.
I have a G11 w/Gemini 2, Laptop, ZWO ASI294MC PRO (cooled).? ?Weighing the options of building my own power station using a deep cycle battery, or going with something like a Jackery or similar unit (pricey).
Relatively new to all this so I'd love to get insights from all of you experienced folks.
Thanks,
Scott Popjes
Los Angeles, CA
-- Brian?
Brian Valente portfolio
|
Re: Semi OT - Small DSO Targets
What I'm seeing in my captures of Thor's Helmet looks to be.
***
HAHA!!
I have nowhere NEAR the computing power to do an image like that.. If I zoom in
on Thor¡¯s Helmet, it probably wouldn¡¯t fit in my FOV.. MY FOV is
just about the right size to have M51 fill the FOV with a bit of ¡°framing¡±
around it..
?
says
my FOV is 0.47 x 0.31 degrees, so roughly 30 x 20 arcmins.. Someday I will
trying imaging thru the guidescope, but that¡¯s still only 45 x 30 arcmins
and isn¡¯t in the same league as my good scope.. So not anytime soon..
?
Fortunately
Stu helped me out by giving me an excellent starting point..
?
Derek
?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Sonny Edmonds
Sent: Saturday, January 30, 2021
8:22 PM
To: [email protected]
Subject: Re: [Losmandy_users_io]
Semi OT - Small DSO Targets
?
GM811GHD, ED80T CF telescope, Atik Infinity OSC camera. Not sure what
that comes out to in Arc Minutes, sorry.
All I target are DSO Nebula. Usually small, because my telescope and camera
combination works best with them.
For example, tonight I'm chasing Thor's Helmet. Last week was the Rosette
Nebula, which filled my FOV.
What I'm seeing in my captures of Thor's Helmet looks to be.
And my Rosette Nebula
I'm more laid back and just go out there, pick a victim, and suck
the light out of it.
I'm not real scientific about it. After all, it's a hobby, not an obsession for
me.
I use Stellarium as a Planetarium program, and it runs my 811 to the chosen
object.
Usually once I'm on something, I come in the house and run remotely.
I might be one of the laziest astro imagers on here. ;^)
--
SonnyE
(I suggest viewed in full screen)
|
Re: Portable Power for your AP setup
I, too, used an AGM battery for many years.
But I don't go afield much anymore.
When I did I used the AGM Group 24 battery to run the mount and cameras.
And I used my truck to run the inverter and my laptop. "noisy" power from the truck idling doesn't affect the laptop.
If we go off in the RV, it has 2 big deep cycle batteries I can tap, and it's own generator if we don't have shore power.
--
SonnyE
(I suggest viewed in full screen)
|
Re: Portable Power for your AP setup
Hi Scott,
I use an AGM cell in a large heavy duty Craftsman plastic tool box. The box was chosen for its generously sized bottom section and deep lid with flip open storage. There is plenty space for cigarette jacks and volt meters and the DC-DC converters to regulate voltage in two banks, 13.5V and 18.0V. My portable power pack?also has a couple of high current 5V USB charging ports and volt meters for the 13.5V & 18V outputs. Also in the box is the smart charger and 175 Watt inverter just in case I need AC for anything. I have run both mounts from the pack for a couple nights observing but our club site has AC power and I usually leave the pack plugged in while using it if possible.?
--
Chip Louie Chief Daydreamer Imagination Hardware?
? ?Astropheric Weather Forecast - South Pasadena, CA?
|
Re: Semi OT - Small DSO Targets
GM811GHD, ED80T CF telescope, Atik Infinity OSC camera. Not sure what that comes out to in Arc Minutes, sorry.
All I target are DSO Nebula. Usually small, because my telescope and camera combination works best with them.
For example, tonight I'm chasing Thor's Helmet. Last week was the Rosette Nebula, which filled my FOV.
What I'm seeing in my captures of Thor's Helmet looks to be.
And my Rosette Nebula
I'm more laid back and just go out there, pick a victim, and suck the light out of it.
I'm not real scientific about it. After all, it's a hobby, not an obsession for me.
I use Stellarium as a Planetarium program, and it runs my 811 to the chosen object.
Usually once I'm on something, I come in the house and run remotely.
I might be one of the laziest astro imagers on here. ;^)
--
SonnyE
(I suggest viewed in full screen)
|
Re: Portable Power for your AP setup
Hi Scott
i've done various versions of all the above, from rolling my own w/ deep cycle marine batteries to my latest jackery. of course they all have pros and cons
the most important thing I did was figure out my nightly amperage. for a solid winter night of imaging (about 8pm-6am) for Gemini II, an Intel-NUC, Trius Pro694MM cooled to -20C, no dew heaters, it ran about 15ah.?
at that time i opted for at 25AH lead acid battery hooked to everything via anderson powerpole distribution plates. worked great and gave me plenty of headroom for adding dew heaters
Lately i bought a Jackery which must be lithium, because it's super light but a bit pricey. It did a great job, but i am not putting as much load on there as i did previously (i think i test ran an allsky with a nuc and allsky camera:? it was about 10ah total for the full night into morning).?
DIY with deep cycle/lead acid is definitely much less expensive and more $/ah. but it is heavier and you have to rig up your own. Jackery seems to be the hot thing right now, and I can see why, but it's pricey. your laptop is going to eat more battery with the screen.
hth
Brian
On Sat, Jan 30, 2021 at 6:56 PM Scott Popjes via <imagemover= [email protected]> wrote: What is everyone using to power their mount, laptop and other gear when at a remote location?? I'd love to get something that can handle imaging sessions as well as GoTo observing sessions where I may be touring around the night sky.
I have a G11 w/Gemini 2, Laptop, ZWO ASI294MC PRO (cooled).? ?Weighing the options of building my own power station using a deep cycle battery, or going with something like a Jackery or similar unit (pricey).
Relatively new to all this so I'd love to get insights from all of you experienced folks.
Thanks,
Scott Popjes
Los Angeles, CA
-- Brian?
Brian Valente portfolio
|
Re: Portable Power for your AP setup
Scott...I use 2 options...I have a Honda 2KW generator (very quiet) (pricy too) and a bank of deep cycle (group 27) batteries. It's best not to mix things on the same battery...like cameras and dew heaters and the computer will require 1 all by it's self...actually I have 7 in my trailer (also pricy)...
Good luck, Stu
On Sat, Jan 30, 2021 at 9:56 PM Scott Popjes via <imagemover= [email protected]> wrote: What is everyone using to power their mount, laptop and other gear when at a remote location?? I'd love to get something that can handle imaging sessions as well as GoTo observing sessions where I may be touring around the night sky.
I have a G11 w/Gemini 2, Laptop, ZWO ASI294MC PRO (cooled).? ?Weighing the options of building my own power station using a deep cycle battery, or going with something like a Jackery or similar unit (pricey).
Relatively new to all this so I'd love to get insights from all of you experienced folks.
Thanks,
Scott Popjes
Los Angeles, CA
|
Portable Power for your AP setup
What is everyone using to power their mount, laptop and other gear when at a remote location?? I'd love to get something that can handle imaging sessions as well as GoTo observing sessions where I may be touring around the night sky.
I have a G11 w/Gemini 2, Laptop, ZWO ASI294MC PRO (cooled).? ?Weighing the options of building my own power station using a deep cycle battery, or going with something like a Jackery or similar unit (pricey).
Relatively new to all this so I'd love to get insights from all of you experienced folks.
Thanks,
Scott Popjes
Los Angeles, CA
|
Semi OT - Small DSO Targets
Stu
wrote ¨C
?
The FOV for my combo is 14x20 arcmin
***
I
would *LOVE* to hear about this size DSO target, relatively bright.. Say in the
180 - 300 minute total integration time range.. small bright beginner (single
night) targets..
This
is probably completely OT ¨C Losmandy G11 !! ¨C so if you have such
targets ¨C Gemini II !! ¨C maybe emailing me directly is a plan.. :-))
?
breit_ideas@...
?
Derek
|
Re: Eastside Heavy Rule - How to Practically Apply Query
The
primary reason (like 98%) is because I can do it MUCH sooner than I could with
a camera.. I have a closeby ridge that blocks the Sun from hitting the scope
early in the afternoon.. (17 deg in the SW, 0 deg at 290 deg azimuth).. In the
Winter especially (Northern Hemisphere / California)
I am doing this with the Sun at least 10 degrees above the horizon (or more)
and the sky is quite bright..
The
secondary reason is my crap Laptop, which takes awhile after opening to be
useful for imaging. It has a hard time running my small camera (ASI178MC or MM)
at full resolution at the speed needed in broad daylight.. (I have often that
of trading my 12¡± SCT for a decent laptop for this very reason ¨C SF
Bay Area only!! ).. It works just fine for the slow frame rate of DSO¡¯s
and beautifully for ROI planetary imaging at high speed..
?
But
yes, I *could* just use the camera if I was starting in a darksky and it would
work all the time for me too..
?
Derek
?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Stu Beaber
Sent: Saturday, January 30, 2021
10:42 AM
To: [email protected]
Subject: Re: [Losmandy_users_io]
Eastside Heavy Rule - How to Practically Apply Query
?
Why mess with an eyepiece at all. Just use your camera to begin with. I
use a G11 (Gemini1) with a 10" SCT and 999 times out of a 1000 the object
is in the FOV when I do a "goto". The FOV for my combo is 14x20
arcmin and it works great for the past 18 years. I did do what you do the first
year I did AP but quickly decided it as a waste of time.
?
Yes..
Yes, sort of.. Being a (former)
Carpenter, I use a tape measure and measure between the Toe Saver Washer on the
end of the counterweight shaft and the bottom edge of the lower weight.. *but*
I only do this before initial startup when I am finding the ¡°It balances
here¡± and ¡°I need to move the weight a half an inch here¡±..
Then I put it back balanced, power up, and ¡°do my thing¡±.. For me,
that involves an eyepiece, a GOTO a bright star or planet, switch to a high
power eyepiece, center.. Then I switch to the camera, adjust the weight
slightly, center the target, and synch.. All this occurs before Sunset and
before you can see any stars (by looking up at the sky).. (To do this, you need
to know exactly where the focus point of your eyepieces are, as the contrast of
a target in a bright sky is quite low..).. Then I wait or do other setup things
until it is actually dark..
?
Once it¡¯s dark, if I switch
sides of the pier, I just move the weight ¡°by feel¡±.. i.e. one hand
feels the counterweight shaft and edge of the weight while the other loosens
the bolt holding the weight and I ¡°feel¡± how much the weight moves,
tighten the bolt, and carry on..
?
It¡¯s not an exact science and
it depends on the payload.. My G11 is only carrying about 30 pounds so *for me*
it doesn¡¯t matter if it is ¡°barely¡± or ¡°a lot¡±
East Heavy.. My Goal is ¡°just enough¡± so the drive wont be able to
¡°flop¡± to the other side of the gear tooth.. With a heavy payload
¨C like when I get around to mounting my 12¡± SCT ¨C I will be
*much* more exact.. When I do this, I will make two sticks or rods that can go
between the weight and the toe saver so I can accurately adjust with no light..
?
YMMV, but it works for me and my
tracking is pretty good..
?
Derek
?
?
On Thu, Jan 28,
2021 at 10:54 AM, Derek C Breit wrote:
I move the lower
counterweight up or down the shaft depending on which side of the mount things
are.. *AND* I find where these points are ¨C before ever turning on the
mount ¨C during initial balancing..
?
Doesn¡¯t
take much offset from balanced, just ¡°some¡±..
Derek
Thanks very much for replying and explaining your approach to this topic. Just
checking I understand correctly - So when the counterweight shaft is on the
eastside you slide the lower weight a little down the shaft from it's
'correctly balanced' position and when the scope is on the eastside you slide
the lower weight up the shaft a little way beyond it's 'correctly balanced'
position. Presumably you use tape or something to mark the shaft for each
position?
Is this method which most use?
Many thanks
Terry [uk]
|
Re: Used GM-8 Guiding Help
Awesome..
Thanks for explaining that, as I like to learn..
?
Now
if can just answer the question I have (on a different topic) I¡¯ll be golden
for awhile.. I¡¯ll tyr and find the answer online, but I might (OK Probably) ask
it anyway.. :-))
?
Derek
?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Chip Louie
Sent: Saturday, January 30, 2021
10:09 AM
To: [email protected]
Subject: Re: [Losmandy_users_io]
Used GM-8 Guiding Help
?
Derek,
The worms use a miniature ball bearing because this type of bearing can be used
to carry both radial and axial loads. Needle roller bearings are only really
used to carry a radial load. Losmandy uses two kinds of cylindrical roller
bearings each designed and located to carry loads in the direction for the
bearing design used.?
--
Chip Louie Chief Daydreamer Imagination Hardware?
? ?Astropheric Weather Forecast - South Pasadena, CA?
|
Re: Eastside Heavy Rule - How to Practically Apply Query
Why mess with an eyepiece at all. Just use your camera to begin with. I use a G11 (Gemini1) with a 10" SCT and 999 times out of a 1000 the object is in the FOV when I do a "goto". The FOV for my combo is 14x20 arcmin and it works great for the past 18 years. I did do what you do the first year I did AP but quickly decided it as a waste of time.
Stu
Yes..
Yes,
sort of.. Being a (former) Carpenter, I use a tape measure and measure between
the Toe Saver Washer on the end of the counterweight shaft and the bottom edge
of the lower weight.. *but* I only do this before initial startup when I am
finding the ¡°It balances here¡± and ¡°I need to move the weight
a half an inch here¡±.. Then I put it back balanced, power up, and ¡°do
my thing¡±.. For me, that involves an eyepiece, a GOTO a bright star or
planet, switch to a high power eyepiece, center.. Then I switch to the camera, adjust
the weight slightly, center the target, and synch.. All this occurs before
Sunset and before you can see any stars (by looking up at the sky).. (To do
this, you need to know exactly where the focus point of your eyepieces are, as
the contrast of a target in a bright sky is quite low..).. Then I wait or do
other setup things until it is actually dark..
?
Once
it¡¯s dark, if I switch sides of the pier, I just move the weight ¡°by
feel¡±.. i.e. one hand feels the counterweight shaft and edge of the
weight while the other loosens the bolt holding the weight and I ¡°feel¡±
how much the weight moves, tighten the bolt, and carry on..
?
It¡¯s
not an exact science and it depends on the payload.. My G11 is only carrying
about 30 pounds so *for me* it doesn¡¯t matter if it is ¡°barely¡±
or ¡°a lot¡± East Heavy.. My Goal is ¡°just enough¡± so the
drive wont be able to ¡°flop¡± to the other side of the gear tooth.. With
a heavy payload ¨C like when I get around to mounting my 12¡± SCT ¨C
I will be *much* more exact.. When I do this, I will make two sticks or rods
that can go between the weight and the toe saver so I can accurately adjust
with no light..
?
YMMV,
but it works for me and my tracking is pretty good..
?
Derek
?
?
On Thu, Jan 28, 2021 at 10:54 AM, Derek C Breit wrote:
I move the lower counterweight up or down the shaft
depending on which side of the mount things are.. *AND* I find where these
points are ¨C before ever turning on the mount ¨C during initial balancing..
?
Doesn¡¯t take much offset from balanced, just
¡°some¡±..
Derek
Thanks very much for replying and explaining your approach to this topic. Just
checking I understand correctly - So when the counterweight shaft is on the
eastside you slide the lower weight a little down the shaft from it's
'correctly balanced' position and when the scope is on the eastside you slide
the lower weight up the shaft a little way beyond it's 'correctly balanced'
position. Presumably you use tape or something to mark the shaft for each
position?
Is this method which most use?
Many thanks
Terry [uk]
|
Re: Used GM-8 Guiding Help
Derek,
The worms use a miniature ball bearing because this type of bearing can be used to carry both radial and axial loads. Needle roller bearings are only really used to carry a radial load. Losmandy uses two kinds of cylindrical roller bearings each designed and located to carry loads in the direction for the bearing design used.?
--
Chip Louie Chief Daydreamer Imagination Hardware?
? ?Astropheric Weather Forecast - South Pasadena, CA?
|
Re: Eastside Heavy Rule - How to Practically Apply Query
Yes..
Yes,
sort of.. Being a (former) Carpenter, I use a tape measure and measure between
the Toe Saver Washer on the end of the counterweight shaft and the bottom edge
of the lower weight.. *but* I only do this before initial startup when I am
finding the ¡°It balances here¡± and ¡°I need to move the weight
a half an inch here¡±.. Then I put it back balanced, power up, and ¡°do
my thing¡±.. For me, that involves an eyepiece, a GOTO a bright star or
planet, switch to a high power eyepiece, center.. Then I switch to the camera, adjust
the weight slightly, center the target, and synch.. All this occurs before
Sunset and before you can see any stars (by looking up at the sky).. (To do
this, you need to know exactly where the focus point of your eyepieces are, as
the contrast of a target in a bright sky is quite low..).. Then I wait or do
other setup things until it is actually dark..
?
Once
it¡¯s dark, if I switch sides of the pier, I just move the weight ¡°by
feel¡±.. i.e. one hand feels the counterweight shaft and edge of the
weight while the other loosens the bolt holding the weight and I ¡°feel¡±
how much the weight moves, tighten the bolt, and carry on..
?
It¡¯s
not an exact science and it depends on the payload.. My G11 is only carrying
about 30 pounds so *for me* it doesn¡¯t matter if it is ¡°barely¡±
or ¡°a lot¡± East Heavy.. My Goal is ¡°just enough¡± so the
drive wont be able to ¡°flop¡± to the other side of the gear tooth.. With
a heavy payload ¨C like when I get around to mounting my 12¡± SCT ¨C
I will be *much* more exact.. When I do this, I will make two sticks or rods
that can go between the weight and the toe saver so I can accurately adjust
with no light..
?
YMMV,
but it works for me and my tracking is pretty good..
?
Derek
?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Terry Pullen via groups.io
Sent: Saturday, January 30, 2021
6:04 AM
To: [email protected]
Subject: Re: [Losmandy_users_io]
Eastside Heavy Rule - How to Practically Apply Query
?
On Thu, Jan 28, 2021 at 10:54 AM, Derek C Breit wrote:
I move the lower counterweight up or down the shaft
depending on which side of the mount things are.. *AND* I find where these
points are ¨C before ever turning on the mount ¨C during initial balancing..
?
Doesn¡¯t take much offset from balanced, just
¡°some¡±..
Derek
Thanks very much for replying and explaining your approach to this topic. Just
checking I understand correctly - So when the counterweight shaft is on the
eastside you slide the lower weight a little down the shaft from it's
'correctly balanced' position and when the scope is on the eastside you slide
the lower weight up the shaft a little way beyond it's 'correctly balanced'
position. Presumably you use tape or something to mark the shaft for each
position?
Is this method which most use?
Many thanks
Terry [uk]
|
East side weighting cord vs preloading both worm bearings...is there a difference?
Hi gang,
Several really nice contributions have raised the question: ? How can one get better performance of the RA (that is, reduce periodic error and improve "unguided tracking" duration)?
Many people use a weighted cord wrapped around the RA axis, so the torque on the RA axis tugs the ring gear (aka worm wheel) counterclockwise (viewing the RA from the front as if looking down the polar scope shaft ).? ?The weight?must hang off to the East? if you are operating in the Northern (but West if you are in the Southern) hemisphere.? The weight must always push the worm toward the Oldham coupler.??
That torque on the ring gear pushes it's left thread sides against the worm right thread sides, pushing the worm to the left.? On a G11 or GM8 that compresses the worm bearing closest to the gearbox, compresses the Oldham coupler, and (on a plastic stock gearbox) can push the gearbox drive shaft slightly outward.??
This is pretty easy to do, and requires no effort other than buying some flexible cord or maybe wire, and hanging a weight off the East side of the RA axis.? It must hang off the East if you are operating in the Northern (but West if you are in the Southern) hemisphere, otherwise all those compression effects I note above reverse and become loosened.??
The only thing that weighted cord will not do is compress the right "far" worm bearing.? That bearing will be loosened (axially).? (If you have a Belleville spring pushing that far bearing toward the worm, then that bearing is also compressed by the spring. )?
Does it matter if one bearing is compressed and the other one is not compressed???
Please read this nice write-up by a bearing industry expert about getting the most performance from a ball bearing system:
So the question is: do you?consider an?Astronomical mount to be a case where "Preload is critical in most high-precision and high-speed applications, particularly where rotational and positional accuracy is required."
You already know my answer.? It is probably the most critical application if you are doing high focal length astro-photography.??
That article goes on to say:
?Spring preloading is simple, inexpensive, and should be a designer¡¯s first consideration. Coil springs or wave spring washers are most commonly used, but a variety of spring types are available. The spring is used to press the races together, or apart. Spring preloading provides a relatively constant preload because it is less sensitive to differential thermal expansion and can accommodate misalignment. Spring preload is what a Belleville spring washer will do for both worm bearings at the same time...and all the worm drive components (Oldham coupler parts too) pushing them toward the gearbox end.?
But installing a Belleville spring is a bit of work (getting out the old bearing by heating the aluminum block works), and slight cost (new $12 each bearings and a $1 spring) , and polishing down the far bearing OD so it will slide, lubed, with the spring behind it.??
And the Belleville spring approach will not keep the ring gear teeth always on the East side (West side if in the S hemisphere) of the worm threads.? Maybe the SLW spring keeps the teeth centered into both sides of the ring gear teeth and the worm teeth.? Maybe (if the SLW spring is backed off by it's smaller bolt to reduce it's friction) then you still need a weighted cord?? The SLW does nothing to address the worm bearing axial pre-compression question.??
Maybe you need both things?? I've not tried that trick on the RA.?? Have fun thinking about these topics and trying your own experiments.? If you are happily imaging and happy with your tracking and autoguiding...keep enjoying yourself!? If driven toward further goals then think about some improvement options.
There is a great story in the (1000 and 1) Arabian Nights stories...the story of Prince Agib.? Maybe read that tale first!!! Here is a good link to the story.
Now...are these palaces the beautiful heavens we seek to photograph? Who are the 10 men?? That's another good riddle for you!
Very best of luck and health, clear skies (and easy available vaccines...) Michael
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Re: Making the most of cloudy winter nights with a new mount and scope
Have you looked at the KStars/EKOS/INDI suite on the Mac?? EKOS has a polar alignment routine that I use (on Linux).? It is also the only astro capture software that I use.
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Chip Louie
Jamie Amendolagine
Michael Herman
Richard Beck