Apparently so!
here's the pic again
|
Water Logged GI Controller
I have an MI-250 set up in my side yard with the Gem I system.? It's been happy there for the past several years, under my Telegizmos 365 cover, needing a new internal battery about once a year.? The installation requires me to lay the controller flat on top of the pier, behind the mount.? Been there three full years, no complaints.
The other day using my MI-250, despite my bum hearing, I noticed my GI controller giving off a warning tone, like the pier proximity signal.? The tracking then stopped, display froze and the controller just stopped working, becoming unresponsive to any command.??
Swearing more than a bit, I unplugged everything and removed the controller.? When I stood it "upright", water came pouring out of the bottom of it, a good shot glass worth.? ?Oh, boy, I bet this thing is toast and started thinking about a replacement or going to GEM II.? I took the cover off? and let it sit around for a few days to dry out.? ?Just for grins, I hooked it up to my G11 and booted it up.? And it seems to be working just fine now.??Surprise, surprise!??
We did have a rather wet summer & fall but I'm going to now take the controller inside with me when I pack everything up for the night.
Lesson learned and let's hear it for the the robust build quality!
Jeff
|
Gemini 1 Internal Battery holder Sensitivity
Boy, I was going crazy as all three of my Gem I controllers were going crazy with the same gibberish at start up within a couple of weeks of each other.? One was left outside undercover and had water pouring out of it from condensation (which is a different story).? All were connected to my MI-250.? I swapped EVERYTHING out and set up all controllers inside on my G11.? After hours of fussing around and changing out paddles, cables, internal batteries and checking their voltages, I noticed that the batteries seemed rather loose in their holders.? I typically have to man-handle the clips to get the old batteries out but there have been no problems at all over the years, even with dead batteries.? Then BAM, trouble.??
So, I mashed the clips down before inserting new batteries (again!), bending them as much as I could.? I then inserted the new batteries, noting that the fits were tight to the point that I had difficulty even rotating the batteries in the holders.
And now everything seems to be working just fine.??
Jeff
|
brian, ? ? Did you attach a photo that did not come through?
aruckle
|
Hi aruckle,
There is some discussion over at PemPro forums on this.
My G11GT PE looks like this
Thanks
Brian
Brian Valente
Brianvalentephotography.com
From: Losmandy_users@... [mailto:Losmandy_users@...]
Sent: Tuesday, November 28, 2017 12:19 AM
To: Losmandy_users@...
Subject: [Losmandy_users] Re: How to train PEC
Brian,
I noticed your comment about having a 42 second recurring error on your G11GT.
A couple of weeks ago I bought the Losmandy RA-AXIS Titan module as an update to my G11. I have been having problems being able to record a PEC file using the Gemini2 built in PEC training. Today I looked at a PHD2 guide log and it appears from that one guiding session my mount has a Spike on the 28% point of my chart (using PEM Pro viewer). It doesn't match up with any of the harmonics of the single worm revolution.
Tonight I ran a 3 cycle run and a 5 cycle run which I will be able to confirm if that is the case.
The spike I saw on that guide log today was by far the highest peak of the log. Since it does not coincide with the 319 second worm period or the harmonics to the 5th or 6th order. I am wondering were to look for the problem.
If you would like to have more of a discussion of this issue and how to resolve it, we could set up a separate thread on this or the Titan Mount group. Since all the new Titans have the tucked motors they may all have the same issue.
aruckle
[Non-text portions of this message have been removed]
|
Brian, ? ? ?I noticed your comment about having a 42 second recurring error on your G11GT. ?? A couple of weeks ago I bought the Losmandy RA-AXIS Titan module as an update to my G11. ? I have been having problems being able to record a PEC file using the Gemini2 built in PEC training. ?Today I looked at a PHD2 guide log and it appears from that one guiding session my mount has a Spike on the 28% ?point of my chart (using?PEM Pro viewer). ? It doesn't match up with any of the harmonics of the single worm revolution.
? ? Tonight I ran a 3 cycle run and a 5 cycle run which I will be able to confirm if that is the case.
? ?The spike I saw on that guide log today was by far the highest peak of the log. ?Since it does not coincide with the 319 second worm period or the harmonics to the 5th or 6th order. ?I am wondering were to look for the problem. ?
? ?If you would like to have more of a discussion of this issue and how to resolve it, we could set up a separate thread on this or the Titan Mount group. ? Since all the new Titans have the tucked motors they may all have the same issue.
? ?aruckle
|
Re: Help with DEC backlash/jumpy guiding
well i only mentioned it in pretty much all of my posts ;)
I believe the source is in the tucked in gearing.
As Ray mentioned he's working (finishing?) on a two worm cycle PE correction, which would address this.
I'm just waiting on that to be released, I know Ray has been working on it and had to get through a lot of bugs. hopefully soon
B
|
Re: Repackaged RA motor assembly
Hi John
yes they have the tucked in motor upgrade. I don't know if they only do RA or both, but it's a nice upgrade. give them a ring about this
B
|
Repackaged RA motor assembly
Sorry in advance for a question that I'm sure has been asked and answered: Until now I've more or less ignored all the talk about the G-11 upgrades since mine has been functioning very well.? But I was wondering if Losmandy has a simple way to tuck the RA motor under the worm like they show for the upgraded models on their website.? It would be nice to get the motor out of the way once and for all but I don't need or want any of the other upgrades. John
|
Re: Help with DEC backlash/jumpy guiding
ok. you win.? I never saw that written...til now.? Thanks for explaining this new design. I'll stay out of this, and will look forward to hearing the cause and cure of the "42 sec" PE issue.?
Best, Michael?
On Nov 26, 2017 1:26 PM, " yh@... [Losmandy_users]" < Losmandy_users@...> wrote:
?
Michael,?
Brian has a G11GT mount, which has a Titan-based RA and a G11-based DEC assembly. RA has a 270 tooth wheel, which translates into just under 320 seconds worm cycle.
Regards,
? ? -Paul
|
Re: Help with DEC backlash/jumpy guiding
Magnus,
A little backlash is actually preferred and is often better than no backlash at all. If your RA axis does not have any movement at all, the worm might be too close to the gear causing just a bit too much friction under some conditions and mount position. It's best to leave just a little wiggle room between the worm and the gear, and to then weigh the mount slightly heavier to the East side. This allows the worm to turn freely, with the gear fully engaged,?while the Eastern over-weight helps stop it from wobbling in between worm teeth.
Regards,
? ?-Paul?
|
Re: Help with DEC backlash/jumpy guiding
toggle quoted message
Show quoted text
?
Hi!
Lately, I'm experiencing bad guiding in DEC on mu G11. It's OK in RA and at times also in DEC, but unpredictable (so far). Good means a RMA of about 0.7 arc secs. Bad means RMS over 1.5. I use PHD2, and when measuring backlash there, I get values ranging from 16.6 to over 70. So there is a lot of questions here - how can it vary so much, and where does it stem from?
I've got the blocks into which the worm gear goes pressed together, to there is no identifiable slack there that, no wiggle back and forth. I've adjusted the worm gear in relation to the gear wheel, so it is close as I dare have it. What else can cause these variations and backlash?
The DEC gearbox sounds a lot - far louder than the RA. Could that be a source of backlash and instability?
All suggestions very welcome.
Magnus
|
Re: Help with DEC backlash/jumpy guiding
Rob,
I'm hoping to have the initial V3 release available tomorrow. That said, there will be a quick set
of follow-up releases as I have not finished updating the documentation and a couple new features.
-Ray Gralak
Author of APCC (Astro-Physics Command Center):
Author of PEMPro:
Author of Astro-Physics V2 ASCOM Driver:
Author of PulseGuide:
Author of Sigma:
toggle quoted message
Show quoted text
-----Original Message-----
From: Losmandy_users@... [mailto:Losmandy_users@...]
Sent: Sunday, November 26, 2017 1:52 PM
To: losmandy_users@...; losmandy_users@...
Subject: Re: [Losmandy_users] Re: Help with DEC backlash/jumpy guiding
Ray,
A quick question for you. Is there set yet for Pempro 3?
Rob
Get Outlook for iOS <>
________________________________
From: Losmandy_users@... <Losmandy_users@...> on behalf of 'Ray Gralak
(Groups)' groups3@... [Losmandy_users] <Losmandy_users@...>
Sent: Sunday, November 26, 2017 1:37:59 PM
To: Losmandy_users@...
Subject: RE: [Losmandy_users] Re: Help with DEC backlash/jumpy guiding
Michael,
This is a quote directly from the Losmandy G11 mount manual, which says the G11 period is 4 minutes = 4¡Á60sec =240 sec, right? I know you are just trying to help, but Brian's mount is not a G11. It is a G11GT, as both Brian
and Paul have already confirmed in their recent posts.
Best regards,
-Ray Gralak
Author of APCC (Astro-Physics Command Center):
physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro:
Author of Astro-Physics V2 ASCOM Driver:
Author of PulseGuide:
Author of Sigma:
-----Original Message-----
From: Losmandy_users@... [mailto:Losmandy_users@...]
Sent: Sunday, November 26, 2017 1:18 PM
To: Losmandy_users@...
Subject: RE: [Losmandy_users] Re: Help with DEC backlash/jumpy guiding
Ray,
This is a quote directly from the Losmandy G11 mount manual, which says the G11 period is 4 minutes = 4¡Á60sec =240 sec, right?
Here is the text, from the Losmandy website:
Periodic Error Correction (PEC)
Periodic Error Correction, or PEC, is a system that improves the tracking accuracy of the drive.
PEC is designed to improve photographic quality by reducing the amplitude of the worm gear errors.
Periodic error is a
slight oscillation in right ascension caused by imperfections in all drive gears. The cycle of the periodic error is equal to one rotation of the worm gear, which is four minutes for the G-11. No matter how
precise, all telescope
drives will have some periodic error, though it is already extremely low on the Losmandy G-11. Using the PEC function is a two-step process. First, you must guide for at least four minutes, keeping the
guide star centered on the cross hairs of your guiding eyepiece, during which time the system records the correction
you make. It takes the worm gear four minutes to make one complete revolution, hence the need to guide for
four minutes. The second step is to play back the corrections you made during the recording phase. The
microcomputer inside the electronic console does this automatically after one revolution of the worm gear.
Keep in mind that this feature is for advanced astro-photographers and requires careful guiding. Here?¡¯s how to
use the PEC function most effectively.
On Nov 26, 2017 12:35 PM, "'Ray Gralak (Groups)' groups3@... [Losmandy_users]"
<Losmandy_users@...> wrote:
That 239.4/42 = 5.7. That's a non-integer ratio and no way for PEC to treat that... it will
have to be eliminated
mechanically if possible, or different gears used to get it to be an integer fraction of 239.4
sec, but that sounds
Sorry Michael Herman, but I'm afraid you are using the wrong worm period. The worm period is
about 319.1 seconds, over which a 42.55-second frequency repeats 7.5 times. This is not correctable
using PEC over
a single worm cycle, but it is correctable over two worm cycles as the frequency repeats 15.0 times. The worm
gear contributes about 3.7 arc-seconds peak-peak, and the 15x fundamental contributes about 2.8 arc- seconds
peak-peak.
Best regards,
-Ray Gralak
Author of APCC (Astro-Physics Command Center):
physics.com/index.htm?products/accessories/software/apcc/apcc <
physics.com/index.htm?products/accessories/software/apcc/apcc>
Author of PEMPro:
Author of Astro-Physics V2 ASCOM Driver:
Author of PulseGuide:
Author of Sigma:
-----Original Message-----
From: Losmandy_users@... [mailto:Losmandy_users@... <mailto:Losmandy_users@...> ]
Sent: Sunday, November 26, 2017 10:43 AM
To: Losmandy_users@...
Subject: Re: [Losmandy_users] Re: Help with DEC backlash/jumpy guiding
I am certain you are right... if you can identify which gear is the culprit, that should be also sent to the EQMOD
group who made up PECprep to add to their G11 list.
How does that 42 sec peak compare in size to the Worm peak at 239.4 sec. Is it anywhere near
as high as
that one?
(Or better for me: send me [mherman346@...] your raw PHD2 log file and I can run it in
my PECprep.exe program to see its FFT.)
That 239.4/42 = 5.7. That's a non-integer ratio and no way for PEC to treat that... it will
have to be eliminated
mechanically if possible, or different gears used to get it to be an integer fraction of 239.4
sec, but that sounds
to me like a design problem...
Best,
Michael
On Sun, Nov 26, 2017 at 10:24 AM, bvalente@... [Losmandy_users]
<Losmandy_users@... <mailto:Losmandy_users@...> > wrote:
Michael
I would be happy to show you the 42 sec interval. i have a G11GT, and I think the tucked in
motors introduce new gearing ratios (probably true for G11G as well).
This has also been confirmed by Ray with PemPro
B
--
Michael Herman
mobile: 408 421-1239 <tel:(408)%20421-1239>
email: mherman346@...
|
Re: Help with DEC backlash/jumpy guiding
Ray,
A quick question for you. Is there set yet for Pempro 3?
Rob
Get
toggle quoted message
Show quoted text
From: Losmandy_users@... on behalf of 'Ray Gralak (Groups)' groups3@... [Losmandy_users]
Sent: Sunday, November 26, 2017 1:37:59 PM
To: Losmandy_users@...
Subject: RE: [Losmandy_users] Re: Help with DEC backlash/jumpy guiding
?
?
Michael,
> This is a quote directly from the Losmandy G11 mount manual, which says the G11 period is 4 minutes =
> 4¡Á60sec =240 sec, right?
I know you are just trying to help, but Brian's mount is not a G11. It is a G11GT, as both Brian and Paul have already confirmed in their recent posts.
Best regards,
-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma
> -----Original Message-----
> From: Losmandy_users@... [mailto:Losmandy_users@...]
> Sent: Sunday, November 26, 2017 1:18 PM
> To: Losmandy_users@...
> Subject: RE: [Losmandy_users] Re: Help with DEC backlash/jumpy guiding
>
>
>
> Ray,
>
> This is a quote directly from the Losmandy G11 mount manual, which says the G11 period is 4 minutes =
> 4¡Á60sec =240 sec, right?
>
> Here is the text, from the Losmandy website:
>
> http://www.losmandy.com/g-11-manual.html
>
>
> Periodic Error Correction (PEC)
>
> Periodic Error Correction, or PEC, is a system that improves the tracking accuracy of the drive. PEC is
> designed to improve photographic quality by reducing the amplitude of the worm gear errors. Periodic error is a
> slight oscillation in right ascension caused by imperfections in all drive gears. The cycle of the periodic error is
> equal to one rotation of the worm gear, which is four minutes for the G-11. No matter how precise, all telescope
> drives will have some periodic error, though it is already extremely low on the Losmandy G-11. Using the PEC
> function is a two-step process. First, you must guide for at least four minutes, keeping the guide star centered
> on the cross hairs of your guiding eyepiece, during which time the system records the correction you make. It
> takes the worm gear four minutes to make one complete revolution, hence the need to guide for four minutes.
> The second step is to play back the corrections you made during the recording phase. The microcomputer
> inside the electronic console does this automatically after one revolution of the worm gear. Keep in mind that
> this feature is for advanced astro-photographers and requires careful guiding. Here?¡¯s how to use the PEC
> function most effectively.
>
>
>
> On Nov 26, 2017 12:35 PM, "'Ray Gralak (Groups)' groups3@... [Losmandy_users]"
> wrote:
>
>
>
>
>
>
> > That 239.4/42 = 5.7. That's a non-integer ratio and no way for PEC to treat that... it will have to be
> eliminated
> > mechanically if possible, or different gears used to get it to be an integer fraction of 239.4 sec, but that
> sounds
>
>
> Sorry Michael Herman, but I'm afraid you are using the wrong worm period. The worm period is about
> 319.1 seconds, over which a 42.55-second frequency repeats 7.5 times. This is not correctable using PEC over
> a single worm cycle, but it is correctable over two worm cycles as the frequency repeats 15.0 times. The worm
> gear contributes about 3.7 arc-seconds peak-peak, and the 15x fundamental contributes about 2.8 arc-seconds
> peak-peak.
>
> Best regards,
>
> -Ray Gralak
> Author of APCC (Astro-Physics Command Center): http://www.astro-
> physics.com/index.htm?products/accessories/software/apcc/apcc
> physics.com/index.htm?products/accessories/software/apcc/apcc>
> Author of PEMPro: http://www.ccdware.com
> Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
> Author of PulseGuide: http://www.pulseguide.com
> Author of Sigma: http://www.gralak.com/sigma
>
>
> > -----Original Message-----
> > From: Losmandy_users@... [mailto:Losmandy_users@...
> ]
> > Sent: Sunday, November 26, 2017 10:43 AM
> > To: Losmandy_users@...
> > Subject: Re: [Losmandy_users] Re: Help with DEC backlash/jumpy guiding
> >
> >
> >
> > I am certain you are right... if you can identify which gear is the culprit, that should be also sent to the
> EQMOD
> > group who made up PECprep to add to their G11 list.
> >
> > How does that 42 sec peak compare in size to the Worm peak at 239.4 sec. Is it anywhere near as
> high as
> > that one?
> > (Or better for me: send me [mherman346@...] your raw PHD2 log file and I can run it in my
> > PECprep.exe program to see its FFT.)
> >
> >
> > That 239.4/42 = 5.7. That's a non-integer ratio and no way for PEC to treat that... it will have to be
> eliminated
> > mechanically if possible, or different gears used to get it to be an integer fraction of 239.4 sec, but that
> sounds
> > to me like a design problem...
> >
> > Best,
> > Michael
> >
> >
> >
> > On Sun, Nov 26, 2017 at 10:24 AM, bvalente@... [Losmandy_users]
> > > wrote:
> >
> >
> >
> >
> >
> > Michael
> >
> >
> > I would be happy to show you the 42 sec interval. i have a G11GT, and I think the tucked in motors
> > introduce new gearing ratios (probably true for G11G as well).
> >
> > This has also been confirmed by Ray with PemPro
> >
> >
> > B
> >
> >
> >
> >
> >
> >
> >
>
> > --
> >
> > Michael Herman
> > mobile: 408 421-1239
> > email: mherman346@...
> >
> >
> >
>
>
>
>
>
|
Re: Help with DEC backlash/jumpy guiding
Michael, This is a quote directly from the Losmandy G11 mount manual, which says the G11 period is 4 minutes =
4¡Á60sec =240 sec, right? I know you are just trying to help, but Brian's mount is not a G11. It is a G11GT, as both Brian and Paul have already confirmed in their recent posts. Best regards, -Ray Gralak Author of APCC (Astro-Physics Command Center): Author of PEMPro: Author of Astro-Physics V2 ASCOM Driver: Author of PulseGuide: Author of Sigma: -----Original Message-----
From: Losmandy_users@... [mailto:Losmandy_users@...]
Sent: Sunday, November 26, 2017 1:18 PM
To: Losmandy_users@...
Subject: RE: [Losmandy_users] Re: Help with DEC backlash/jumpy guiding
Ray,
This is a quote directly from the Losmandy G11 mount manual, which says the G11 period is 4 minutes =
4¡Á60sec =240 sec, right?
Here is the text, from the Losmandy website:
Periodic Error Correction (PEC)
Periodic Error Correction, or PEC, is a system that improves the tracking accuracy of the drive. PEC is
designed to improve photographic quality by reducing the amplitude of the worm gear errors. Periodic error is a
slight oscillation in right ascension caused by imperfections in all drive gears. The cycle of the periodic error is
equal to one rotation of the worm gear, which is four minutes for the G-11. No matter how precise, all telescope
drives will have some periodic error, though it is already extremely low on the Losmandy G-11. Using the PEC
function is a two-step process. First, you must guide for at least four minutes, keeping the guide star centered
on the cross hairs of your guiding eyepiece, during which time the system records the correction you make. It
takes the worm gear four minutes to make one complete revolution, hence the need to guide for four minutes.
The second step is to play back the corrections you made during the recording phase. The microcomputer
inside the electronic console does this automatically after one revolution of the worm gear. Keep in mind that
this feature is for advanced astro-photographers and requires careful guiding. Here?¡¯s how to use the PEC
function most effectively.
On Nov 26, 2017 12:35 PM, "'Ray Gralak (Groups)' groups3@... [Losmandy_users]"
<Losmandy_users@...> wrote:
> That 239.4/42 = 5.7. That's a non-integer ratio and no way for PEC to treat that... it will have to be
eliminated
> mechanically if possible, or different gears used to get it to be an integer fraction of 239.4 sec, but that
sounds
Sorry Michael Herman, but I'm afraid you are using the wrong worm period. The worm period is about
319.1 seconds, over which a 42.55-second frequency repeats 7.5 times. This is not correctable using PEC over
a single worm cycle, but it is correctable over two worm cycles as the frequency repeats 15.0 times. The worm
gear contributes about 3.7 arc-seconds peak-peak, and the 15x fundamental contributes about 2.8 arc-seconds
peak-peak.
Best regards,
-Ray Gralak
Author of APCC (Astro-Physics Command Center):
physics.com/index.htm?products/accessories/software/apcc/apcc <
physics.com/index.htm?products/accessories/software/apcc/apcc>
Author of PEMPro:
Author of Astro-Physics V2 ASCOM Driver:
Author of PulseGuide:
Author of Sigma:
> -----Original Message-----
> From: Losmandy_users@... [mailto:Losmandy_users@...
<mailto:Losmandy_users@...> ]
> Sent: Sunday, November 26, 2017 10:43 AM
> To: Losmandy_users@...
> Subject: Re: [Losmandy_users] Re: Help with DEC backlash/jumpy guiding
>
>
>
> I am certain you are right... if you can identify which gear is the culprit, that should be also sent to the
EQMOD
> group who made up PECprep to add to their G11 list.
>
> How does that 42 sec peak compare in size to the Worm peak at 239.4 sec. Is it anywhere near as
high as
> that one?
> (Or better for me: send me [mherman346@...] your raw PHD2 log file and I can run it in my
> PECprep.exe program to see its FFT.)
>
>
> That 239.4/42 = 5.7. That's a non-integer ratio and no way for PEC to treat that... it will have to be
eliminated
> mechanically if possible, or different gears used to get it to be an integer fraction of 239.4 sec, but that
sounds
> to me like a design problem...
>
> Best,
> Michael
>
>
>
> On Sun, Nov 26, 2017 at 10:24 AM, bvalente@... [Losmandy_users]
> <Losmandy_users@... <mailto:Losmandy_users@...> > wrote:
>
>
>
>
>
> Michael
>
>
> I would be happy to show you the 42 sec interval. i have a G11GT, and I think the tucked in motors
> introduce new gearing ratios (probably true for G11G as well).
>
> This has also been confirmed by Ray with PemPro
>
>
> B
>
>
>
>
>
>
>
> --
>
> Michael Herman
> mobile: 408 421-1239 <tel:(408)%20421-1239>
> email: mherman346@...
>
>
>
|
Re: Help with DEC backlash/jumpy guiding
Michael we're talking a G11GT - the 'T' is for the titan RA portion which is the 319 worm
also I don't know about the regular G11 with tucked in gears, but i wouldn't be surprised if those added some periodic error somewhere as well
B
On Sun, Nov 26, 2017 at 1:18 PM, Michael Herman mherman346@... [Losmandy_users] <Losmandy_users@...> wrote:
?
Ray,
This is a quote directly from the Losmandy G11 mount manual, which says the G11 period is 4 minutes = 4¡Á60sec =240 sec, right?
Here is the text, from the Losmandy website:
Periodic Error Correction (PEC)Periodic Error Correction, or PEC, is a system that improves the tracking accuracy of the drive. PEC is designed to improve photographic quality by reducing the amplitude of the worm gear errors. Periodic error is a slight oscillation in right ascension caused by imperfections in all drive gears. The cycle of the periodic error is equal to one rotation of the worm gear, which is four minutes for the G-11. No matter how precise, all telescope drives will have?some?periodic error, though it is already extremely low on the Losmandy G-11. Using the PEC function is a two-step process. First, you must guide for at least four minutes, keeping the guide star centered on the cross hairs of your guiding eyepiece, during which time the system records the correction you make. It takes the worm gear four minutes to make one complete revolution, hence the need to guide for four minutes. The second step is to play back the corrections you made during the recording phase. The microcomputer inside the electronic console does this automatically after one revolution of the worm gear. Keep in mind that this feature is for advanced astro-photographers and requires careful guiding. Here?¡¯s how to use the PEC function most effectively.
-- Brian?
Brian Valente portfolio
|
Re: Help with DEC backlash/jumpy guiding
Michael,?
Brian has a G11GT mount, which has a Titan-based RA and a G11-based DEC assembly. RA has a 270 tooth wheel, which translates into just under 320 seconds worm cycle.
Regards,
? ? -Paul
|
Re: Help with DEC backlash/jumpy guiding
Ray,
This is a quote directly from the Losmandy G11 mount manual, which says the G11 period is 4 minutes = 4¡Á60sec =240 sec, right?
Here is the text, from the Losmandy website:
Periodic Error Correction (PEC)Periodic Error Correction, or PEC, is a system that improves the tracking accuracy of the drive. PEC is designed to improve photographic quality by reducing the amplitude of the worm gear errors. Periodic error is a slight oscillation in right ascension caused by imperfections in all drive gears. The cycle of the periodic error is equal to one rotation of the worm gear, which is four minutes for the G-11. No matter how precise, all telescope drives will have?some?periodic error, though it is already extremely low on the Losmandy G-11. Using the PEC function is a two-step process. First, you must guide for at least four minutes, keeping the guide star centered on the cross hairs of your guiding eyepiece, during which time the system records the correction you make. It takes the worm gear four minutes to make one complete revolution, hence the need to guide for four minutes. The second step is to play back the corrections you made during the recording phase. The microcomputer inside the electronic console does this automatically after one revolution of the worm gear. Keep in mind that this feature is for advanced astro-photographers and requires careful guiding. Here?¡¯s how to use the PEC function most effectively.
On Nov 26, 2017 12:35 PM, "'Ray Gralak (Groups)' groups3@... [Losmandy_users]" < Losmandy_users@...> wrote:
?
> That 239.4/42 = 5.7. That's a non-integer ratio and no way for PEC to treat that... it will have to be eliminated
> mechanically if possible, or different gears used to get it to be an integer fraction of 239.4 sec, but that sounds
Sorry Michael Herman, but I'm afraid you are using the wrong worm period. The worm period is about 319.1 seconds, over which a 42.55-second frequency repeats 7.5 times. This is not correctable using PEC over a single worm cycle, but it is correctable over two worm cycles as the frequency repeats 15.0 times. The worm gear contributes about 3.7 arc-seconds peak-peak, and the 15x fundamental contributes about 2.8 arc-seconds peak-peak.
Best regards,
-Ray Gralak
Author of APCC (Astro-Physics Command Center):
Author of PEMPro:
Author of Astro-Physics V2 ASCOM Driver:
Author of PulseGuide:
Author of Sigma:
> -----Original Message-----
> From: Losmandy_users@... [mailto: Losmandy_users@yahoogroups.com]
> Sent: Sunday, November 26, 2017 10:43 AM
> To: Losmandy_users@...
> Subject: Re: [Losmandy_users] Re: Help with DEC backlash/jumpy guiding
>
>
>
> I am certain you are right... if you can identify which gear is the culprit, that should be also sent to the EQMOD
> group who made up PECprep to add to their G11 list.
>
> How does that 42 sec peak compare in size to the Worm peak at 239.4 sec. Is it anywhere near as high as
> that one?
> (Or better for me: send me [ mherman346@...] your raw PHD2 log file and I can run it in my
> PECprep.exe program to see its FFT.)
>
>
> That 239.4/42 = 5.7. That's a non-integer ratio and no way for PEC to treat that... it will have to be eliminated
> mechanically if possible, or different gears used to get it to be an integer fraction of 239.4 sec, but that sounds
> to me like a design problem...
>
> Best,
> Michael
>
>
>
> On Sun, Nov 26, 2017 at 10:24 AM, bvalente@... [Losmandy_users]
> < Losmandy_users@yahoogroups.com> wrote:
>
>
>
>
>
> Michael
>
>
> I would be happy to show you the 42 sec interval. i have a G11GT, and I think the tucked in motors
> introduce new gearing ratios (probably true for G11G as well).
>
> This has also been confirmed by Ray with PemPro
>
>
> B
>
>
>
>
>
>
>
> --
>
> Michael Herman
> mobile: 408 421-1239
> email: mherman346@...
>
>
>
|
Re: Help with DEC backlash/jumpy guiding
That 239.4/42 = 5.7. That's a non-integer ratio and no way for PEC to treat that... it will have to be eliminated
mechanically if possible, or different gears used to get it to be an integer fraction of 239.4 sec, but that sounds Sorry Michael Herman, but I'm afraid you are using the wrong worm period. The worm period is about 319.1 seconds, over which a 42.55-second frequency repeats 7.5 times. This is not correctable using PEC over a single worm cycle, but it is correctable over two worm cycles as the frequency repeats 15.0 times. The worm gear contributes about 3.7 arc-seconds peak-peak, and the 15x fundamental contributes about 2.8 arc-seconds peak-peak. Best regards, -Ray Gralak Author of APCC (Astro-Physics Command Center): Author of PEMPro: Author of Astro-Physics V2 ASCOM Driver: Author of PulseGuide: Author of Sigma: -----Original Message-----
From: Losmandy_users@... [mailto:Losmandy_users@...]
Sent: Sunday, November 26, 2017 10:43 AM
To: Losmandy_users@...
Subject: Re: [Losmandy_users] Re: Help with DEC backlash/jumpy guiding
I am certain you are right... if you can identify which gear is the culprit, that should be also sent to the EQMOD
group who made up PECprep to add to their G11 list.
How does that 42 sec peak compare in size to the Worm peak at 239.4 sec. Is it anywhere near as high as
that one?
(Or better for me: send me [mherman346@...] your raw PHD2 log file and I can run it in my
PECprep.exe program to see its FFT.)
That 239.4/42 = 5.7. That's a non-integer ratio and no way for PEC to treat that... it will have to be eliminated
mechanically if possible, or different gears used to get it to be an integer fraction of 239.4 sec, but that sounds
to me like a design problem...
Best,
Michael
On Sun, Nov 26, 2017 at 10:24 AM, bvalente@... [Losmandy_users]
<Losmandy_users@...> wrote:
Michael
I would be happy to show you the 42 sec interval. i have a G11GT, and I think the tucked in motors
introduce new gearing ratios (probably true for G11G as well).
This has also been confirmed by Ray with PemPro
B
--
Michael Herman
mobile: 408 421-1239
email: mherman346@...
|
Hi!
Great, thanks!! Will play with this next clear night.... next year or so, I guess... :)
Best,
Magnus
|
Michael Herman
Paul Kanevsky