Re: Making the most of cloudy winter nights with a new mount and scope
There's only so much you can do without the sky. But you can admire and practice running your mount.
Just don't mess with it. Don't take it apart to look at the parts. Don't think you can improve it, because you can't.
It is too bad you decided to hobble yourself with stubbornness about your Apple and unwillingness to open your mind to other possibilities. Good luck with that.
Going into my adventure with Astro Imaging, one of my early check points was computer platforms. I was willing to change to Apple if it was a better way. It wasn't. So I stuck with my PC.
Glad I did, because you will find yourself hobbled.
But if you are stubborn, you'll find various work arounds that you might get to work.
Your GM811G will work great in spite of you cutting off your nose to spite your face.
I think Paul gave you the best advice above.
--
SonnyE
(I suggest viewed in full screen)
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Re: Used GM-8 Guiding Help
Huh, you beat me to reply. If anybody read the description of the bearings on the McMaster Carr page for the bearings you would have read that the precision S.S. ABEC 5 and 7 bearings are caged. The number of balls is easy to figure out by looking at the materials and static load, dynamic load and max. RPM. Closer tolerance bearings are rated lower and slower which for this application doesn't matter.?
--
Chip Louie Chief Daydreamer Imagination Hardware?
? ?Astropheric Weather Forecast - South Pasadena, CA?
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Re: 365 covers, condensation, and Wavy Washer standing water..
On Fri, Jan 29, 2021 at 02:05 AM, Paul Homer wrote:
Sonny,
?
You should mention to the CFO that most Astronomy happens at night :)
LOL! Well, her exact words were, "When you are done looking at the stars." But she sez it cost too much to leave outside. So unreasonable! ? -- SonnyE (I suggest viewed in full screen)
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Re: Used GM-8 Guiding Help
Update:
I opened up a bearing this morning (the ones from McMaster Carr). It turns out your suspicions as well as my uncertainty in trusting the CAD drawings is correct. There are 8 balls and a retainer. FYI yes I did remove the piece of dog hair before placing the cover back on! :-D
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Re: Used GM-8 Guiding Help
I've had a quick look online - SKF have CAD drawings of their R4-2Z bearings, which suggests they have 8 balls, whereas NTN has a CAD drawing of their R4-ZZ bearings which suggest they have 7 balls.
Bearing Forge of America specifically states there are 8 balls.
I'd be surprised if you could fit twelve balls in.?
Links are below:?
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Re: Making the most of cloudy winter nights with a new mount and scope
On 1/28/2021 10:28 PM, geoffchapman47@... wrote: PA has been especially challenging; I am a Mac guy, and stubborn about it, and not eager to host a windows via parallels or boot camp. ?So I suspect ASCOM and NINA are off my list, as are the most popular devices for PA. And my camera is a Fuji XT3, and I'm not ready to give up on it. So I step into the batter's box with two strikes, I've been told. ?But I am going to give it a run. How about a compromise...... put a cheap (like $200) Windows mini-PC at the scope and let it host all the Windows specific programs you need. Then use your Mac to connect to it via remote desktop either wired or WiFi. ?? Paul -- Paul Goelz Rochester Hills, MI USA pgoelz@... www.pgoelz.com
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Re: Used GM-8 Guiding Help
I worked in the lubricants business for 30 years and the bearings used in the worm blocks are sealed and ¡°fill for life¡± with grease. I don¡¯t think it will be easy to take these apart and regrease them, and even if you could there is an art to packing roller bearings with grease (it is easy to overfill them). Given the bearings are only about $10 each, it is far easier to replace them if there are problems with them. I also found a source of ¡°premium¡± R4ZZ bearings in the UK (but the ABEC value wasn¡¯t specified):
The ¡°premium¡± bearings from the above company are about ?9 whereas budget versions of the same bearings are only ?2.30, so they are likely similar to bearings from Boca Bearings or other suppliers.
I still have some contacts in roller bearings companies like SKF and FAG so I¡¯ll see if I can find some information on now many balls will be in the bearings
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Re: Making the most of cloudy winter nights with a new mount and scope
Geoff,
I wouldn¡¯t worry about polar alignment if using the AAP as the AAP has a pretty good routine and easy to follow. It uses the primary scope and camera so no additional kit needed.?
I can get a good enough polar alignment for 10 min guided subs (I usually do 5mins though) in 2-3 minutes most nights. It also means no bending down or kneeling on concrete or in puddles to crane your head into a polar scope! Always a bonus!
Enjoy
Bryn
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Re: 365 covers, condensation, and Wavy Washer standing water..
Sonny,
You should mention to the CFO that most Astronomy happens at night :)
toggle quoted message
Show quoted text
No problem here.
My CFO insists I bring my toys in at night. So mine is configured to break down for portability by mule train.
And I'm the jackass carrying the parts. LOL!
So when the Doctor asks if I'm getting excersize, I explain my routine to him. I doubt he could carry the mount back and forth.
But my stuff stays high and dry inside the house.
Glad you love your G11G. I'm lovin my G811GHD in between the Spring storms.
Looks like it's going to be a really cloudy one here.
--
SonnyE
(I suggest viewed in full screen)
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Re: Useful tip for G11 Digital Drive owners: https://nova.astrometry.net/
Robert,
I get you now, I assumed you just used the finder scope by eye not the main scope.
Seems like a good approach if you don¡¯t have go to though.
toggle quoted message
Show quoted text
Hello Paul - yes I check that the main and finder scope are aligned and centred, but I usually do this visually, and the issue is the focus point for the eyepiece for the finder and main scope is different from that of the cameras, so once I have found a bright star whose position I know, you then have to refocus the cameras.?
What I am suggesting is that you can bypass the visual step by just pointing the main telescope, with camera focussed, on a random bit of sky somewhere in the region of the DSO, upload the photo to the??website, and after a couple of minutes that will tell you the exact RA and DEC position of the centre of the photo, which you then set on your setting circles, and then you can move to the coordinates of the DSO for the photo session.
Incidentally, I have recently got a new ASI 071 MC Pro Cooled camera, and am seriously considering ditching autoguiding altogether, for simply taking short exposures of 10-20 seconds, and stacking hundreds of images (with the gain set to 200 and offset to 60). If this works it will mean I don't need to autoguide at all. For the image scale I have and the periodic error of my mount, 10 or 20 seconds should be OK for tracking.?
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Re: Making the most of cloudy winter nights with a new mount and scope
Geoff,
A couple of things:
-Bracken's book is for beginners, ergo, it's a "Primer". It's a nice starting point where all the info is in one place. I'm sure there are many other authors out there too.
-For PA,? the polar scopes are giving way to the PoleMaster cameras which will do the same thing electronically with easy step by step software. There is an adapter that fits it into the polar finder threads. Or you can use your guide scope in conjunction with the SharpCap PA routine, which many like since its cheap software and does not require purchase of a another camera. There is also an iPhone app called PS Align which will show the relationship of Polaris to the true NCP from your location.
-If you are are Mac user (I am not) you can set up a Windows virtual machine that will use ASCOM drivers. Dylan O'Donnell has a YouTube video about this on his Star Stuff YouTube channel. And then there is the ALPACA software that serves in place of, or connects to ASCOM from Macs (sorry never used it). A guy named Bob Denny is one of the architects of that software and I'm sure you'll be able to find him online.
Good luck. Sounds like you are starting with a nice mount which is really the one a the best foundations for any AP setup.
Good luck!
John
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Re: Used GM-8 Guiding Help
This is the link to the bearings *which may* have 12 balls? This is the link to the bearings which DO have 8 balls and a retainer
I hesitate stating 12 balls as a fact is because it is solely based on a 3d CAD file which they provide and then I took a section view, no other 2d drawings or descriptions state "12 balls". The reason this can be problematic is demonstrated with the Boca bearings, for example. In Boca Bearings r4-zz their description explicitly says 8 balls, further confirmed by Michael's photo of one opened up, however, when I download their 3d CAD file of this 8 ball bearing, you can see in pic 006 it falsely shows 10 balls. This is why I'm reluctant to put all my confidence in a section view of a provided 3d CAD drawing. Both of these bearings (McMaster Carr and boca bearings) come pre greased and sealed, if dirt gets in them I'm not sure it's possible to successfully open, clean and regrease, probably better to buy new ones.
I have 4 new bearings, I may have to open one up in the name of science and curiosity tomorrow. I will keep you posted if it's really 12 balls :-)
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Re: Used GM-8 Guiding Help
Some
questions..
?
Is
there a link for the 12 ball bearings that I missed??
?
But
for these, are they meant to be opened and packed with grease?? What about the ¡°stock
versions¡±??
?
I
don¡¯t remember what the stock versions look like, but these look like
they would be fantastic for me and my dusty environment as the appear more ¡°sealed¡±
than normal bearings.. But what do I know.. I do know I hate all the dust my
neighbors kick up on my dirt road..
?
Derek
?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Michael Herman
Sent: Thursday, January 28, 2021
7:40 PM
To: [email protected]
Subject: Re: [Losmandy_users_io]
Used GM-8 Guiding Help
?
I think the 12 balls would be better or smoother.? So we will be
happy to see good results from your testing!? I only found the 8 ball
design, shown here.?
Good for you!!! Thanks for discovering this info (and I hope I never need
to run that experiment!!!)
?
Quick update:
Decided to dive into researching the bearings I purchased from McMaster Carr
compared to the Boca Bearings. I was able to download each one's CAD files and
open them up and get a section view, and was surprised to find a major
difference not listed in the descriptions. It appears the McMaster Carr
bearings are "full complement" bearings which do not include a
retainer and also include 12 bearings instead of 8. Researching the differences
of "full complement" bearings, it seems they are able to handle
heavier loads at the expense of lower RPMs due to additional friction (more
balls, and ball-ball friction). They have lighter axial loads due to risk of
balls being forced out of the filling slot. In terms of loading, I'm not sure
for this hobby it will make a huge difference, but I have to imagine with there
being no retainer, the bearing locations during rotation is also a bit less
periodic, not sure on anyone's thoughts? Honestly, if I were buying bearings
again I would stick with Boca Bearings, however, I will say I still stand by
the significant difference of bearing feel these had compared to my existing
bearings and will continue with testing. Not sure if anyone with Boca Bearings
can attest to also being buttery smooth? I would assume they are and my existing
bearings are just old. Pictures below of CAD sections, pic 005 is McMaster
Carr, pic 006 is Boca Bearings
 
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Re: Used GM-8 Guiding Help
I think the 12 balls would be better or smoother.? So we will be happy to see good results from your testing!? I only found the 8 ball design, shown here.?
Good for you!!! Thanks for discovering this info (and I hope I never need to run that experiment!!!)
Best,
Quick update:
Decided to dive into researching the bearings I purchased from McMaster Carr compared to the Boca Bearings. I was able to download each one's CAD files and open them up and get a section view, and was surprised to find a major difference not listed in the descriptions. It appears the McMaster Carr bearings are "full complement" bearings which do not include a retainer and also include 12 bearings instead of 8. Researching the differences of "full complement" bearings, it seems they are able to handle heavier loads at the expense of lower RPMs due to additional friction (more balls, and ball-ball friction). They have lighter axial loads due to risk of balls being forced out of the filling slot. In terms of loading, I'm not sure for this hobby it will make a huge difference, but I have to imagine with there being no retainer, the bearing locations during rotation is also a bit less periodic, not sure on anyone's thoughts? Honestly, if I were buying bearings again I would stick with Boca Bearings, however, I will say I still stand by the significant difference of bearing feel these had compared to my existing bearings and will continue with testing. Not sure if anyone with Boca Bearings can attest to also being buttery smooth? I would assume they are and my existing bearings are just old. Pictures below of CAD sections, pic 005 is McMaster Carr, pic 006 is Boca Bearings
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Re: Making the most of cloudy winter nights with a new mount and scope
>>>So I suspect ASCOM and NINA are off my list, as are the most popular devices for PA.
polemaster has a mac client
>>>Anything I can do indoors on PA?
not really. you can try to refine your altitude adjustment by using the degrees marker on the RA axis, but that's just roughing it in
John,
Thanks for the reply.? I am onto the first three suggestions, and have been digging in. Bracken's book, though, assume a lot of AP knowledge that I don't yet have. On the rest of your list, they will go into my work later this year, I suspect.? Right now I's still working on learning the mount.?
PA has been especially challenging; I am a Mac guy, and stubborn about it, and not eager to host a windows via parallels or boot camp.? So I suspect ASCOM and NINA are off my list, as are the most popular devices for PA. And my camera is a Fuji XT3, and I'm not ready to give up on it. So I step into the batter's box with two strikes, I've been told.? But I am going to give it a run.
So with PA, I am working to learn the polar scope (but I am still in a window of returns and want to know if I can do without it), the Gemini PA routine, and Asiair Pro w. a guide scope. I am not sure I can get any further on this till I get some clear nights. Anything I can do indoors on PA?
When I get that solved, I plan to learn guiding... and then I hope to go after the Orion Nebula with my Fuji, both wide field and through my scope. I suspect that all that will give me a good idea of how much I don't know and where to go next...? Anything I can do to learn guiding indoors??
Bryn, thanks to you also for the notes on the AAP setup and your workflow list.? Very helpful; most of that is something I have not yet worked through, and some of the setup items you list can clearly be done indoors. And I suspect I can practice a number of the items on your workflow list inside. And then on my next clear nights...? Good to have a list to work from! ?
I think I have noticed a half dozen or dozen AAP/Gemini users (as I surf the Gemini2 and Losmandy user groups, and on CN and Asiair Pro forums). There seem to be enough to benefit from what others are doing. Brian's Woodland Hills video on the Mango mini-router gave me what I needed to make the key connections, and there were an armful of detailed posts linking that to the AAP.? They are out there, I think.?
?
-- Brian?
Brian Valente portfolio
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Re: Making the most of cloudy winter nights with a new mount and scope
John,
Thanks for the reply. ?I am onto the first three suggestions, and have been digging in. Bracken's book, though, assume a lot of AP knowledge that I don't yet have. On the rest of your list, they will go into my work later this year, I suspect. ?Right now I's still working on learning the mount.?
PA has been especially challenging; I am a Mac guy, and stubborn about it, and not eager to host a windows via parallels or boot camp. ?So I suspect ASCOM and NINA are off my list, as are the most popular devices for PA. And my camera is a Fuji XT3, and I'm not ready to give up on it. So I step into the batter's box with two strikes, I've been told. ?But I am going to give it a run.
So with PA, I am working to learn the polar scope (but I am still in a window of returns and want to know if I can do without it), the Gemini PA routine, and Asiair Pro w. a guide scope. I am not sure I can get any further on this till I get some clear nights. Anything I can do indoors on PA?
When I get that solved, I plan to learn guiding... and then I hope to go after the Orion Nebula with my Fuji, both wide field and through my scope. I suspect that all that will give me a good idea of how much I don't know and where to go next... ?Anything I can do to learn guiding indoors??
Bryn, thanks to you also for the notes on the AAP setup and your workflow list. ?Very helpful; most of that is something I have not yet worked through, and some of the setup items you list can clearly be done indoors. And I suspect I can practice a number of the items on your workflow list inside. And then on my next clear nights... ?Good to have a list to work from! ?
I think I have noticed a half dozen or dozen AAP/Gemini users (as I surf the Gemini2 and Losmandy user groups, and on CN and Asiair Pro forums). There seem to be enough to benefit from what others are doing. Brian's Woodland Hills video on the Mango mini-router gave me what I needed to make the key connections, and there were an armful of detailed posts linking that to the AAP. ?They are out there, I think.?
?
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Re: Used GM-8 Guiding Help
Thanks again Derek! I'm looking forward to testing!
Michael,
Here is the link to my guide scope I was using during the first night of testing along with the ASI120mm:?
The second night, however, I was using my 430mm refractor with a 0.8x focal reducer (I was sort of in a rush and didn't remove it from previous imaging sessions) for a new focal length of 344mm. Both of these were put into PECPrep with their respective graphs, I think the data is correct (unfortunately). I was able to get drift align working well for both nights which I used for analyzing, the first night I came to 0.2' polar error and the second night was at 0.8' polar error according to guiding assistant. I noticed for my mount to get a good drift align I have to let it run for a full period on the first adjustment and at least half a period for subsequent adjustments. Overall drift align takes me close to 30min, otherwise all the noise you see in these graphs start telling me the wrong stories and corrections to make :-) (this took me a while to figure out). Everything you listed is on my to-do list, and I will definitely keep this post updated!
Thanks everyone for the input, I know my posts are long but I'm hoping keeping this well documented will help someone in the future as well!
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Re: Used GM-8 Guiding Help
The
Stellarvue 50mm finder / guider is f4 and says 210mm..
?
Similar
models are ubiquitous..
?
Derek
?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Michael Herman
Sent: Thursday, January 28, 2021
4:52 PM
To: [email protected]
Subject: Re: [Losmandy_users_io]
Used GM-8 Guiding Help
?
Nick,
One other thing puzzles me.
You said your guide scope is 50mm f/4.
I looked but could not find one.
I have several 50mm 8X magnification guide scopes.? I'm not sure
what their FL is.
I did find a 50mm f3.8 from unknown brand shown online.?
??
But could you please double check and get the FL of that guide
scope?? It's important because the PE Y axis scale depends on that FL
factor.? ?
I always recommend when testing the mount to eliminate any other
variables, put a long FL refractor (no mirror flop) in the dovetail and put the
autoguider camera at prime focus (or use a diagonal if necessary) to get the
camera focussed.? Don't use a piggyback guide scope.? If that flops
it will wipe out your data and question the analysis.??
You discovered that the PECprep type FFT program will try and subtract
a linear error in polar drift due to unfavorable polar alignment.? It
won't subtract a curvy drift error.? The solution is to eliminate
excessive drift.? Best to do a drift alignment and correct as necessary
before tracking the unguided star.? It only takes a few minutes to check
by drift (PHD2 has a good Drift Alignment tool ...try it!)
The bearings you ordered must be the R4ZZ ABEC-7 with kyodo grease
shown here...or maybe the McMaster-Carr equivalent.?
?Change RA to the precision brass worm.
?Put in the better bearings.
?Replace your poor performing RA gearbox with a new one ( or the
DEC gear box if it is better).
?Add the Belleville
spring behind the far bearing (on both RA and DEC) (that far bearing OD must be
polished down to allow the bearing to slide in the block).
?Carefully line up that key Oldham coupler ends by shifting the
gearbox location, so the Oldham ends do not
shift during rotation.?
Seems like a lot but it isn't really.? You will get to the low PE
that this mount is capable of delivering.??
After that, autoguiding will take care of any residual movement.?
?You probably won't need PEC if the natural PE gets low
enough.??
?
Wow, I am blown away by all the good info everyone has been helping out
with, thanks so much!?
Michael,
I will definitely get the serial number and reach out to Losmandy just out of
pure curiosity. I agree the plastic gearbox is likely a contributor to the fast
oscillations. I have high hopes for the new bearings as well, they arrived
today and it is night and day difference to the existing bearings. The existing
ones have a very obvious jitter to them, the new ones are as smooth as butter.
Just for reference for anyone else reading, I ordered the R4-2Z abec 7 bearings
?as
well as belleville
washers
Robert,
That may be one of the best explanations of imaging scale as it relates to PE
I've seen, I've read through various explanations of imaging scales and
exposure time, but this one just seemed to "click" so thanks! When
I'm feeling a little more bold I may extract the PE curve data and play with it
in excel as you've described, I definitely see the long wavelength component,
but not sure there would be a way to correct for this in a PEC curve as they
are typically only one period long, correct? Either way more data and info is
always better! I really appreciate you including you're pre/post HP worm data,
I'm a visual person and it seems like it would be a great investment.
Unfortunately for the time being my imaging camera is a Sony mirrorless (a5100
which is a whole other story, but it wasnt purchased as an astro cam so overall
I'm happy its somewhat usable for now) but I do find the idea of higher gain,
lower shutter speed and more subs intriguing. Honestly my camera is a big
reason why I'm reluctant to mount upgrades piling up - I would really like to
get a dedicated cooled astro cam in the nearish future.
Derek,
That sounds like an offer I can't refuse hah, I will message you shortly!?
Brian,
I agree :-D?
Future Plans:
At this point with the significant difference even by hand feel of the
bearings, I plan to change out the bearings, add the belleville washers and at
the same time switch the RA and Dec worms back to how they were on the first
baseline run. I want to see how this can perform, and assuming I am able to
work out borrowing the HP worm from Derek, I will do another run using the HP
worm and compare. I have to admit, I've really enjoyed imaging several times,
but I also really enjoy problem solving and trouble shooting (on a budget of
course) something about collecting data and being able to analyze and make
sense of it is very satisfying. Thank you everyone for your help thus far, and
I look forward to keeping this updated with step by step progress with
supporting data!
|
Re: Used GM-8 Guiding Help
Quick update:
Decided to dive into researching the bearings I purchased from McMaster Carr compared to the Boca Bearings. I was able to download each one's CAD files and open them up and get a section view, and was surprised to find a major difference not listed in the descriptions. It appears the McMaster Carr bearings are "full complement" bearings which do not include a retainer and also include 12 bearings instead of 8. Researching the differences of "full complement" bearings, it seems they are able to handle heavier loads at the expense of lower RPMs due to additional friction (more balls, and ball-ball friction). They have lighter axial loads due to risk of balls being forced out of the filling slot. In terms of loading, I'm not sure for this hobby it will make a huge difference, but I have to imagine with there being no retainer, the bearing locations during rotation is also a bit less periodic, not sure on anyone's thoughts? Honestly, if I were buying bearings again I would stick with Boca Bearings, however, I will say I still stand by the significant difference of bearing feel these had compared to my existing bearings and will continue with testing. Not sure if anyone with Boca Bearings can attest to also being buttery smooth? I would assume they are and my existing bearings are just old. Pictures below of CAD sections, pic 005 is McMaster Carr, pic 006 is Boca Bearings
|
Re: Used GM-8 Guiding Help
The
worm will be mailed tomorrow..
?
Derek
?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Nick
Sent: Thursday, January 28, 2021
4:16 PM
To: [email protected]
Subject: Re: [Losmandy_users_io]
Used GM-8 Guiding Help
?
Wow, I am blown away by all the good info everyone has been helping out
with, thanks so much!?
Michael,
I will definitely get the serial number and reach out to Losmandy just out of
pure curiosity. I agree the plastic gearbox is likely a contributor to the fast
oscillations. I have high hopes for the new bearings as well, they arrived
today and it is night and day difference to the existing bearings. The existing
ones have a very obvious jitter to them, the new ones are as smooth as butter.
Just for reference for anyone else reading, I ordered the R4-2Z abec 7 bearings
?as
well as belleville
washers
Robert,
That may be one of the best explanations of imaging scale as it relates to PE
I've seen, I've read through various explanations of imaging scales and
exposure time, but this one just seemed to "click" so thanks! When
I'm feeling a little more bold I may extract the PE curve data and play with it
in excel as you've described, I definitely see the long wavelength component,
but not sure there would be a way to correct for this in a PEC curve as they
are typically only one period long, correct? Either way more data and info is
always better! I really appreciate you including you're pre/post HP worm data,
I'm a visual person and it seems like it would be a great investment.
Unfortunately for the time being my imaging camera is a Sony mirrorless (a5100
which is a whole other story, but it wasnt purchased as an astro cam so overall
I'm happy its somewhat usable for now) but I do find the idea of higher gain,
lower shutter speed and more subs intriguing. Honestly my camera is a big
reason why I'm reluctant to mount upgrades piling up - I would really like to
get a dedicated cooled astro cam in the nearish future.
Derek,
That sounds like an offer I can't refuse hah, I will message you shortly!?
Brian,
I agree :-D?
Future Plans:
At this point with the significant difference even by hand feel of the
bearings, I plan to change out the bearings, add the belleville washers and at
the same time switch the RA and Dec worms back to how they were on the first
baseline run. I want to see how this can perform, and assuming I am able to
work out borrowing the HP worm from Derek, I will do another run using the HP
worm and compare. I have to admit, I've really enjoyed imaging several times,
but I also really enjoy problem solving and trouble shooting (on a budget of
course) something about collecting data and being able to analyze and make
sense of it is very satisfying. Thank you everyone for your help thus far, and
I look forward to keeping this updated with step by step progress with
supporting data!
|
Chip Louie
Michael Herman