Re: 365 covers, condensation, and Wavy Washer standing water..
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)
|
Re: 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.?
Anyway, if you do these: ?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.??
Good luck!!!
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
We
are here to help like everyone helped me..
?
Thanks
for the log viewer link.. I was *just* going to look for it, but decided to
check email first..
?
I
also found the one for diagnosing PE.. Seems mine is ¡°good enough¡± and I should
stop trying to make it better or else I might make it worse, not knowing
anything and all..
?
:-))
?
Derek
?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Brian Valente
Sent: Thursday, January 28, 2021
2:19 PM
To: [email protected]
Subject: Re: [Losmandy_users_io]
Used GM-8 Guiding Help
?
Derek that's very kind of you :)
?
Nick..
?
If you give me your address, you can
borrow my extra brass worm to see if you want to install one / if it helps
solve the problem..
?
Then you can either buy one from
Losmandy and send mine back to me or pay me for mine..
?
Email me directly if you are
interested..
?
Derek
?breit_ideas@...
--
|
Re: 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!
|
Re: Used GM-8 Guiding Help
Derek that's very kind of you :)
Nick..
?
If
you give me your address, you can borrow my extra brass worm to see if you want
to install one / if it helps solve the problem..
?
Then
you can either buy one from Losmandy and send mine back to me or pay me for
mine..
?
Email
me directly if you are interested..
?
Derek
?breit_ideas@...
-- Brian?
Brian Valente portfolio
|
365 covers, condensation, and Wavy Washer standing water..
Previously ¡°we¡±
discussed covers and condensation.. Gun Heating Rods sound like a fantastic
solution..
?
Having given away my power
supply ¨C like an idiot ¨C and knowing big rain was coming ¨C I finally
dismounted my refractor and brought the mount inside.. A few days ago I cleaned
and relubed the mount bearings (not to be confused with the drive bearings
which still need to be done) and found something ¡°weird¡±..
?
The cylindrical bearings,
flat bearings, and thrust washers were essentially pristine.. but the wavy
washers were a different story.. They had standing water on them and the lube
was quite sticky.. They cleaned up fine, but I thought I would mention it..
Anyone who mostly keeps there stuff setup, might want to check their wavy
washers more often than the rest of the mount..
?
Also, the Michael Herman clutch discs were still pristine as
well.. A little shiny in spots because I crank my clutches down a lot.. Once I
put it all back together, I did play with the mount and figured out I need a
whole lot less clutch to make things work, as these clutch discs are either
fully slipping or fully engaged.. There is no partially engaged.. Maybe less
tightening will help or even fix my Declination backlash issue.. (I haven¡¯t
had a chance to try the new PHD2 which is supposed to have improved functions
to help with Declination backlash.. )
?
I am glad I put the wavy
washers in the ¡°outside position¡± as recommended so the moisture
didn¡¯t get anywhere near the flat roller bearings, that¡¯s for
sure.. I am more impressed with the G11 every time I touch it.. A really
impressive machine..
?
Derek
|
Re: Hello from a new user
Thanks all. ?
Brian, send my regards to Tanya. She was great throughout.?
|
Re: Hello from a new user
Welcome
to the Fun, Brian..
?
:-))
?
Derek
?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of brianm
Sent: Wednesday, January 27, 2021
8:07 PM
To: [email protected]
Subject: [Losmandy_users_io] Hello
from a new user
?
Hi all.
My wife and I got into this hobby in the mid-80s with a classic orange C8.
After getting a ton of use out if it, both visually and a bit of film-based AP,
a new?10¡± LX50 followed in the late 90s. But life intrudes, and the past
two decades in Dallas and LA put the kebosh on stargazing, for both time and
sky quality reasons. We¡¯ve finally gotten back into it after a move to Utah and subsequent
retirement.?
Three months ago I suddenly discovered that I¡¯m 24 years older than when we
bought the 65-pound Meade contraption, that the assembly and tear down was,
well, tearing me down, and it was time for something more portable. We
researched the crap out of the mount market. Long story short, we bought a new
G11G with the RA extension and two great carrying cases from Scott and company
in the late fall, de-forked the ¡®ol LX50 OTA and started anew. More or
less.?
Three things - first, dealing with the people in Burbank was a true pleasure, and I can¡¯t say
enough positive things about them. Second, the quality and functionality of the
G11G is far beyond our expectations. Third, we¡¯re thrilled by the advancements
in observing and AP tech over the years and look forward to getting back into
it in a big way. We¡¯re confident that our new mount and old scope will give us
a great start.?
Very
happy to join this group, as well as the Gemini group. Good to ¡°meet¡± you all.
Brian
?
|
Re: Used GM-8 Guiding Help
Nick..
?
If
you give me your address, you can borrow my extra brass worm to see if you want
to install one / if it helps solve the problem..
?
Then
you can either buy one from Losmandy and send mine back to me or pay me for
mine..
?
Email
me directly if you are interested..
?
Derek
?breit_ideas@...
|
Re: Eastside Heavy Rule - How to Practically Apply Query
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¡±..
?
With
the Gemini II, you also have a balance function that you might like more, but
since my configuration never changes, I just find where the weights go once and
just put the weights where they go when they need to go there..
?
Derek
?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Terry Pullen via groups.io
Sent: Thursday, January 28, 2021
5:11 AM
To: [email protected]
Subject: [Losmandy_users_io]
Eastside Heavy Rule - How to Practically Apply Query
?
Hello Group
Many times over the years I have seen and heard it mentioned that it is
beneficial to have a non-perfect mount balance such that the 'east side' of the
mount is biased to be slightly heavier when doing astrophotography. Am I
correct in thinking this is to do with reducing backlash when tracking or
guiding or both.
I was wondering if this 'rule' is true at all times irrespective of wthether
the scope or the counterweight shaft is actually on the east side?
How do those who use this approach manage to keep the east heavy rule applied
when imaging? Is it advisable to move the lower weight on the counterweight
shaft further down the shaft a little or have a separate, tempoary additional
'movable' weight that can be placed on either the shaft or the scope depending
which side of the meridian they are?
Just interested in what other imagers do - grateful for any insight. I saw on
this Group several weeks ago an ingenious solution using an automated method
which fasinated me and sparked my interest but is way beyond my mechanical
abilities. I am interested in a better understanding of the 'eastside heavy
rule' and any suggestions for a simpler method to apply the necessary bias.
With help from this Group I am slowly getting back into imaging with my 14 yr
old G11, Gemini-1 and my DSLR after several years away from the hobby.
Many thanks
Terry [uk]
|
Re: Used GM-8 Guiding Help
Just a few further thoughts on periodic error. See graph below:?
If you start imaging at point B, then in half the worm period, you will get a shift in the image of 2P arc seconds. For your G8 data, P is about 20", and the worm period is 8 minutes. Therefore you will get a star moving by 40" in 4 mins (or 5" in 30 seconds). This is the worst case. If you start at point A, you will only get an image shift of P in half the worm period - for your case this would be 2.5" in 30 seconds. If you're imaging at a scale of 2" per pixel, you should be able to get unguided images OK for 15-30 seconds even with the mount as it is now.?
This is ignoring the use of PEC. If you use PEC, then the data in your first figure suggests that P is reduced to only 4 or 5". So with PEC enabled, you would get an image shift of only 1" per minute.?
I'm ignoring any high frequency features in the periodic error - if you can get rid of these you should be OK to do some unguided imaging.
You can check how long you can go before you get an unacceptable rate of bad frames.?
Then you would only need autoguiding if you want to go longer than this.
With some of the recent CMOS cameras that are available (like the ASI 071) there are many who are choosing to go to high gain/short exposure time (10-20 seconds) and simply collecting hundreds of frames, and if you choose to go this route you could potentially get rid of autoguiding altogether.?
|
Re: Hello from a new user
|
Re: Hello from a new user
To paraphrase an old jingle "You meet the nicest people on a Losmandy."? Welcome back Brian!? -- 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
I¡¯ll also add, that my routine for using the AAP with the Gemini 1 is as follows, which might help?
- Power up AAP
- Power on Gemini
- Focus using AAP (I also have an EAF)
- Cold start Gemini (I set up each night)
- set location from stored location if cold start lat long incorrect (check mount time is correct UTC no DST)
- restart Gemini 1 (if changed location)
- connect to mount is AAP
- Undertake PA process in AAP and mount bolts
- Slew to target with AAP
- take preview picture (5 secs)
- plate solve and Centre in AAP (just to ensure the target is centred)
- start looping and guide process in AAP (I always calibrate every time as I setup each time)
- check mount tracking is on (should be automatic)
- Start imaging using auto run in AAP.
- sit in the warm house and monitor on your phone or tablet!
Hope this helps. Took me a while to get a routine that consistently worked with the ASP and Gemini 1. I suspect Gemini 2 isn¡¯t too different.
Bryn
|
Re: Making the most of cloudy winter nights with a new mount and scope
Join the ASIAIR and ASIAIR Pro user groups on Facebook. Lots of excellent help and assistance. The AAP has really been a game changer for me, getting me imaging whenever the weather allows.
Make sure the epoch on the mount is set to ¡°current¡± not J2000. Took me weeks to figure this out after my AAP would never properly plate solve and Centre targets! The AAP uses know (current) Epoch.
Start with Dec and RA aggressiveness of +45 and calibration figures of 500, 300 and 300 for guiding the HM-8 with the AAP, this should give you a reasonable starting point (again, this took me a while to sort and lots of forum surfing!)
Back up the AAP SD card immediately. If it corrupts without backup, it¡¯s a bit of a pain to sort out with ZWO by all accounts.
I can¡¯t really help with other stuff, but I have been using the AAP with Gemini 1 for 5-6 months now so have experience. There do not seem to be many ASP and Gemini users around?
Bryn
|
Re: Hello from a new user
Hi Brian,
Welcome back to astronomy...we've missed you. But seriously...do have fun!!!
Jamey
Hi all. My wife and I got into this hobby in the mid-80s with a classic orange C8. After getting a ton of use out if it, both visually and a bit of film-based AP, a new?10¡± LX50 followed in the late 90s. But life intrudes, and the past two decades in Dallas and LA put the kebosh on stargazing, for both time and sky quality reasons. We¡¯ve finally gotten back into it after a move to Utah and subsequent retirement.?
Three months ago I suddenly discovered that I¡¯m 24 years older than when we bought the 65-pound Meade contraption, that the assembly and tear down was, well, tearing me down, and it was time for something more portable. We researched the crap out of the mount market. Long story short, we bought a new G11G with the RA extension and two great carrying cases from Scott and company in the late fall, de-forked the ¡®ol LX50 OTA and started anew. More or less.?
Three things - first, dealing with the people in Burbank was a true pleasure, and I can¡¯t say enough positive things about them. Second, the quality and functionality of the G11G is far beyond our expectations. Third, we¡¯re thrilled by the advancements in observing and AP tech over the years and look forward to getting back into it in a big way. We¡¯re confident that our new mount and old scope will give us a great start.?
Very happy to join this group, as well as the Gemini group. Good to ¡°meet¡± you all.
Brian
?
|
Eastside Heavy Rule - How to Practically Apply Query
Hello Group
Many times over the years I have seen and heard it mentioned that it is beneficial to have a non-perfect mount balance such that the 'east side' of the mount is biased to be slightly heavier when doing astrophotography. Am I correct in thinking this is to do with reducing backlash when tracking or guiding or both.
I was wondering if this 'rule' is true at all times irrespective of wthether the scope or the counterweight shaft is actually on the east side?
How do those who use this approach manage to keep the east heavy rule applied when imaging? Is it advisable to move the lower weight on the counterweight shaft further down the shaft a little or have a separate, tempoary additional 'movable' weight that can be placed on either the shaft or the scope depending which side of the meridian they are?
Just interested in what other imagers do - grateful for any insight. I saw on this Group several weeks ago an ingenious solution using an automated method which fasinated me and sparked my interest but is way beyond my mechanical abilities. I am interested in a better understanding of the 'eastside heavy rule' and any suggestions for a simpler method to apply the necessary bias.
With help from this Group I am slowly getting back into imaging with my 14 yr old G11, Gemini-1 and my DSLR after several years away from the hobby.
Many thanks
Terry [uk]
|
Re: Used GM-8 Guiding Help
Hello Nick - it looks like you got a lot of data there!?
The first image shows PE of about +/-20". I have heard before that people say that the PE of a G8 mount is double that of a G11, so that would equate to around +/-10" for a G11, which is quite high, but believable (with the old worm).?
However you also need to take account of the fact that the worm period is twice that of the G11. I think the issue with your curve is that there are some PE components with much shorter wavelengths than the worm period.?
The second image also shows around +/-20" but there is a long wavelength sinusoidal component (the green curve) which PECPrep has not accounted for in the numbers in the second figure.?
I have started taking the output from PECPrep and analysing them in Excel, so I can remove longer wavelength components (using Excel's trendline tool) - think PECPrep only removes a linear trend (not anything that is sinusoidal or other type of variation) -? I have also seen a long wavelength sinusoidal component superimposed on the periodic error - I think this can only come from small variations in radius of the large gear wheel (which would explain why people find "high" spots).?
The figure below shows a comparison of my G11 with the old worm and before I regreased and realigned everything and installed a new high precision worm (I also changed the bearings in the RA worm block and put a Belleville washer in). This was with quite a small telescope (around 6 kg) and I'm going to repeat the PE measurement with a larger telescope (since when I did that with the old worm fitted, the PE seemed much smoother). I would definitely recommend putting a high precision worm in the RA axis (but you probably don't need one for DEC). With the older worm I was getting approx +/-10", and once I had put in the new worm, and regreased and realigned everything it came down to about +/-5".
|
Re: Useful tip for G11 Digital Drive owners: https://nova.astrometry.net/
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.?
|
Hi all. My wife and I got into this hobby in the mid-80s with a classic orange C8. After getting a ton of use out if it, both visually and a bit of film-based AP, a new?10¡± LX50 followed in the late 90s. But life intrudes, and the past two decades in Dallas and LA put the kebosh on stargazing, for both time and sky quality reasons. We¡¯ve finally gotten back into it after a move to Utah and subsequent retirement.?
Three months ago I suddenly discovered that I¡¯m 24 years older than when we bought the 65-pound Meade contraption, that the assembly and tear down was, well, tearing me down, and it was time for something more portable. We researched the crap out of the mount market. Long story short, we bought a new G11G with the RA extension and two great carrying cases from Scott and company in the late fall, de-forked the ¡®ol LX50 OTA and started anew. More or less.?
Three things - first, dealing with the people in Burbank was a true pleasure, and I can¡¯t say enough positive things about them. Second, the quality and functionality of the G11G is far beyond our expectations. Third, we¡¯re thrilled by the advancements in observing and AP tech over the years and look forward to getting back into it in a big way. We¡¯re confident that our new mount and old scope will give us a great start.?
Very happy to join this group, as well as the Gemini group. Good to ¡°meet¡± you all.
Brian
?
|
Michael Herman
Chip Louie