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Equipment Discussions >> Mounts

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OzAndrewJ
scholastic sledgehammer
*****

Reged: 11/30/10

Re: LX80 RA tracking new [Re: rmollise]
      #5322549 - 07/17/12 07:43 PM

Mornin All

Gday Rod

Quote:

I WONDER if the alt-az drive rate system is somehow being carried over to polar mode. In alt-az, the drive rate WILL change depeneding on where you are in the sky...





I suspected that,( as there IS a way for a Polar aligned scope to revert to AltAz tracking for short bursts ), but i dont think it could give the drift being seen,
and more importantly, it doesnt explain TOM.
Also,we should see low level DEC creep and we dont

However, to test the motor speed theory anyway,
i had sent David a "special" rom with a quicky "peek" patch loaded,
and a little app to script a known peek sequence over time.
His data showed the correct motor speeds were being calculated and sent to the scope. Ie the rate was always peeked as being the "polar rate".

I am working on a new "higher frequency peeking" version for him to test with that will do more diagnostics, but it only works if the firmware has been patched.
Again, none of this explains Toms results.

Andrew


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dmdouglass
professor emeritus


Reged: 12/23/07

Loc: Tempe, AZ
Re: LX80 RA tracking new [Re: neilson]
      #5322550 - 07/17/12 07:43 PM

Quote:
--------------------------------------------------------------------------------
As for Meade being "silent on the fix....", well, we need to consider a very important question. Has anyone reported it to them yet ?? I have not.
--------------------------------------------------------------------------------
This amazed me, so I just did.
.......

Not sure why it amazed you. If you have been following the thread, then you would know that i have not been able to do a visual confirmation. All of my readings, and tests, have been from a "dummy" alignment, indoors, with controlled time and target. This in and of itself is valid from my point of view, however, visual confirmation is still needed before i report to Meade. AND.... that will happen tonight.

My world is in Alt/AZ. And that is working beautifully. I have lots of test numbers from both "dummy" alignments, as well as long term real sky visual observation. This situation is NOT a serious problem for me...... However, there was a user (Kevin and Dennis) who reported visual problems (drifting), but did not have the numbers.

Since there were no other owners checking in, i entered the discussion, mostly from a technical curiousity point of view. Additionaly, i may want to do something with polar, and i wanted to check it out.

Had i called this one into Meade without a visual confirmation, i am sure i could generate their response. Andrew, also is not the right one to report it... especially since he did not have a mount in hand.

We were getting there... it needed to be reported (and apparently now has been), and in the interim, we have several more users checking things out. This is good. Of course, the results are BAD ! But we needed to confirm it.

I will continue my personal tests tonight, and report back tomorrow. I am confident there will be no surprises. And it will be interesting to monitor Meade's responses, and finally learn the outcome for resolution. I just hope it is not a RECALL, like the LX800.


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OzAndrewJ
scholastic sledgehammer
*****

Reged: 11/30/10

Re: LX80 RA tracking new [Re: neilson]
      #5322579 - 07/17/12 08:01 PM

Gday Neilson

Quote:

Hi, Here are my results from the 1 hour indoor test.
I entered date and time to last night at 9:30pm because Arcturus was straight up.
One star alignment then
..Arcturus starting RA 14:15.9 one hour 5 min RA 14:41.9 came to +26.0
..Deneb starting RA 11:03.6 after 30 min. RA 11:04.8 but one hour was RA 11:03.3
This didn't make sense to me




Me either, but its a good clue.
The Arcturus result shows the current 50% slowdown problem.
The Deneb result shows the 1.01155 speed up i see in the code.
I cant see how the sign of the targets DEC can affect tracking
( as it simply uses a hardcoded RA rate for motor )
but it gives me some thoughts.
Just for fun, if would be nice the other testers could do a dummy align using the same time etc and select similar targets with +ve then -veDEC
to see if they replicate your data???

Andrew


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OzAndrewJ
scholastic sledgehammer
*****

Reged: 11/30/10

Re: LX80 RA tracking new [Re: OzAndrewJ]
      #5322633 - 07/17/12 08:45 PM

OOhhh, had another thought
Kev and Dennis mentioned having a real LXD75 as well
Can you connect the A3S1 handbox to your LXD75.
Now reselect the mount as an LX80-GEM.
It should allow it.
If so, just do the dummy one star align test
as before and see what happens.
If it works OK, then its another pointer towards the problem
being in the LX80 motorcards.
If it fails, it points to something subtle in the A3S1 firmware.

Andrew


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neilson
professor emeritus


Reged: 08/22/10

Re: LX80 RA tracking new [Re: OzAndrewJ]
      #5322728 - 07/17/12 09:47 PM

I have an LXD75 as well and I put the LX80 handbox on it. Mine only has LX80 Alt/Az and LX80 polar. No GEM choice. So I used polar. It initialized I put in yesterday at 9:30pm then tried one star alignment, pressed enter and the mount turned in RA to the right until it was upside down trying to tear off my handbox connector. I turned power off. I tried again but with easy alignment and it turned to the left this time upside down until I turned power off. It didnt work on mine.
Neilson


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OzAndrewJ
scholastic sledgehammer
*****

Reged: 11/30/10

Re: LX80 RA tracking new [Re: neilson]
      #5322852 - 07/17/12 11:24 PM

Gday Neilson

My apologies, i wasnt expecting you to do it

The firmware shows LX80-Polar, but that really just defaults to GEM mode,
and the LXD75s are the only other GEMs in the Hbx list.
Thus they make good cross test baselines, as GEM processing is different to Polar.
The problem you saw was probably due to ratios ( which Kev/Dennis are up to speed on )
The LX80-Polar has its ratios set to +2.7507 for both the Az/RA and Alt/DEC motors.
The sign controls which direction it goes.
The LXD75s default is Az = -2.5371 and Alt = +2.5371
Sooo, after connecting to a "real" LXD75, but with the Hbx selected to LX80-Polar
your Hbx will report both Alt and Az ratios as +2.7507
You need to manually edit the sign of the Az/RA ratio from +ve to -ve.
It should then work OK for dummy testing.
To do real sky testing ( with a "real" LXD75 but selected as an LX80-Polar) ,
you would need to set the Alt and Az ratios to -2.5371 and +2.5371 respectively.
Soo if yr happy to try again with a -ve Az ratio ( it should work )

I have tried my LX90 cards now with A3S1 using a Nth and Sth Hemi location
with gotos to targets with +ve and -ve DECs and in all cases, i see the
expected 1.0115 fast factor.

Andrew

Edited as i had my directions mixed up

Edited by OzAndrewJ (07/17/12 11:39 PM)


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OzAndrewJ
scholastic sledgehammer
*****

Reged: 11/30/10

Re: LX80 RA tracking new [Re: OzAndrewJ]
      #5322996 - 07/18/12 01:57 AM

Gday All

Found a new clue that may explain part of it.
Every 2 seconds ( under stable tracking )
the firmware is supposed to recalc the required motor speed
and send it to the motor cards.
The data returned by Davids peeking indicated the correct values were sent,
( but were they ?? )
I have just been looking at reality,
ie what "really" happens on the actual data lines
between the Hbx and the motorcards.
The initial data is confusing.
In AltAz, i clearly see the speed data being resent every 2seconds.
In Polar, i see NO speed calcs being sent within 30sec timeframes.
Thus something appears to be blocking the resending of speeds when polar.
If in polar, a wrong speed some how got sent ( or got corrupted),
on the very first speed setting command
this may explain why polar fails and AltAz doesnt
ie AltAz is self repairing within 2 secs.

So now for some more fun.
We know PEC recording is stuffed and some of the playback also may not work correctly
but if PEC is ON, it forces a resend of speed data.
Soooooo, just to see what happens,
can users who have done the dummy drift tests
do another dummy align etc and get it driting as before.
Then, using the Hbx, set PEC to ON
See what happens.

Andrew


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dmdouglass
professor emeritus


Reged: 12/23/07

Loc: Tempe, AZ
Re: LX80 RA tracking new [Re: OzAndrewJ]
      #5323036 - 07/18/12 03:01 AM

I promised the results of tonights observations. I also said i did not expect any surprises. On that point, i was wrong....

In polar:
Arcturus was the selected star for the one-star alignment.
Decided to stay with it.....
All centered, and started test.
Original RA 14 15.5
Dec 19:10
At 20 min, Arcturus was leaving my field of view (recall - about 1 degree overall, thus about one-half degree center to exit.)

Final RA 14 17.4 (+1.9 in 20 min)
Dec 19 10
Selected a GOTO to Arcturus, and it recentered.... The mount knows where it is.... confirmed !!!

Did a GOTO to Deneb (since it was mentioned in the thread..).
Good slew.
Centered, and started test.
Original RA 20 41.3
DEC 45 15
After 15 min, star was still at center of FOV (Interesting !!)
Final RA 20 41.2
DEC 45 15

Did a GOTO to Altair...
Good slew.
Centered and started test.
Original RA 19:50.6
DEC 08 51
After 15 min, star was still at center of FOV (Still Interesting !!)
Final RA 19 50.6
Dec 08 51

Deneb and Altair were to my East and SouthEast and high.
Arcturus (and in the past tests...Spica, which I used for all indoor tests) is to my SW and high)

I had planned on using Spica and Denebola, and thus a + and - DEC.... but local vegetation sort of prevented that.
Arcturus was the same general azimuth, (slightly more westerly) and higher.

So.... I did NOT get a + and - dec. All three targets are + Dec.

But for sure, Altair and Deneb stayed more or less centered, and the RA stayed good in the reading.
And both of these targets are in the opposite (more or less) part of the sky....


End of testing for the evening...


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TALK2KEV
sage


Reged: 03/08/06

Loc: Oklahoma
Re: LX80 RA tracking new [Re: dmdouglass]
      #5323130 - 07/18/12 06:41 AM

Andrew

I did two star without touching the mount from last setup it picked Vega within 12.5mm I centered Vega then it picked fomalhaut just outside on 12.5mm centered that star. Alignment Successful 1^ 11< goto Altair. Slewed in FOV,20mm centered with 12.5 then Sync watched it drift with 2min.45sec in 12.5mm on 80mm f/7 on edge of FOV turned on PEC centered Altair (with PEC On) and still drift out it was slower took about 4min Ok now to Deneb see if it had drift. And 5:10am centered went in to write this went back out to the scope at 5:30am it was out of FOV in 20mm this also had PEC on .

so No luck


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neilson
professor emeritus


Reged: 08/22/10

Re: LX80 RA tracking [Re: TALK2KEV]
      #5323303 - 07/18/12 09:40 AM

Andrew
Hi, I changed the Az/Ra to neg. on my LX80 handbox and put the date/time to the 16th at 9:30 pm again and selected day lights saving time yes and immediately the LXD75 mount started slowly chattering turning to the left in a slow pulsating movement so I tried again same thing happened but I selected easy alignment right away and it selected Arcturus and was turning to the right. the dec turned to the correct place pointing straight up but the RA just kept going up side down until I turned it off. I'm going to start my indoor dummy tests on the LX80 turning PEC on now.
Neilson

Edited by neilson (07/18/12 10:30 AM)


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exparrot
member
*****

Reged: 02/13/12

Loc: Dallas/Fort Worth, TX
Re: LX80 RA tracking [Re: OzAndrewJ]
      #5323547 - 07/18/12 12:39 PM

Hey Andrew

Results of a dummy test w/PEC enabled

Polar 1-star alignment
Alignment star - Sirius

START 10:29
Coordinates: RA 06:45.2 / DEC -16*41'
PEC ON 10:31
Coordinates: RA 06:45.6 / DEC -16*41'
END 11:30
Coordinates: RA 07:39.2 / DEC -16*41'


Jerry


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jmiele
Patron Saint?
*****

Reged: 12/04/10

Re: LX80 RA tracking [Re: exparrot]
      #5323586 - 07/18/12 01:08 PM

So PEC is making tracking adjustments/mis alignment corrections? If so, is it even possible for it to perform the desired PEC function?

Curious... Joe


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neilson
professor emeritus


Reged: 08/22/10

Re: LX80 RA tracking [Re: jmiele]
      #5323704 - 07/18/12 02:29 PM

Andrew
Hi, I set the 16th at 9:30pm lx80 indoor dummy test.Aligned selected Arcturus then turned PEC on and after 1 hour 5 min. +8.6 yesterday without pec it was +26.0 Then tried Anteres and got +22.6 with pec on. yesterday without pec it was +11.4 Then I tried Dabih(I said deneb yesterday by mistake) I started without pec RA 11:03.6 for 20 minutes RA 11:04.0 then turned pec on and checked it 20 minutes later and it was back at RA 11:03.6 and stayed there for the remainder of the hour. (yesterday it started at 11:03.6 then 30 minutes it was 11:04.8 then at one hour 5 min. 11:03.3 with no pec.)
I noticed Anteres and Dabih the scope was on the west side of the mount. I thought the night of the 16th when Anteres kept drifting out of my eyepiece the scope was on the east side of the mount. So right now I am testing Spica which places the scope on the east side of my mount. I am testing without pec then with pec. I will post the results when I am done.
Neilson


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scott4comp
super member
*****

Reged: 01/23/08

Loc: Boston, MA
Re: LX80 RA tracking [Re: neilson]
      #5323734 - 07/18/12 02:56 PM

I think its awesome how you guys are tracking this down !

Kudos !



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Lee Jay
Pooh-Bah
*****

Reged: 02/27/08

Loc: Westminster, CO
Re: LX80 RA tracking [Re: scott4comp]
      #5323743 - 07/18/12 03:02 PM

Could this be a side-of-the-meridian thing?

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Tmohr36
member


Reged: 09/27/10

Loc: Nevada
Re: LX80 RA tracking [Re: Lee Jay]
      #5323821 - 07/18/12 04:18 PM

I'm not going to bore you with too many details, but I (TOM) did several RA Tracking tests this morning. Recall that my mount arrived in hand on 2 May 2012 (I think that's the earliest in the group). All my tests were done with PEC off but I did turn it on and back off for the last two tests. During earlier testing PEC was erased as some tests were done with Andrew back in May. AZ/RA Alt/Dec percent set to 55% (I think this is backlash and hasn't been changed since receiving the mount). I've done Train Drives in Alt/Az mode but not Germ Mt Adj (equivalent of train drive in GEM mode). I've done a couple Calibrate Motor (should do this when attached equipment changes (ie. different camera, heavy diagonals/eyepieces). Andrew asked me to note the change in a couple registers, but as you'll see below, that hasn't effected my normal 1.0115 drift.

I set the time at 21:30 on 17 July 2012, DST Yes, 1 star align (first to Polaris {no adjustments made}, then to the single star) PEC was off and tracking is Sidereal. Additional stars were selected via the handbox and goto. Mount was allowed to track 30 minutes on each star. I did not document final values because what I saw was the normal drift documented previously not the Super Drift experienced by others.

Arcturus:
RA 14:15.5 Normal drift (as documented by Andrew's tests)
DEC 19*10'
Deneb:

RA 20:41.3 Normal drift
DEC 45*16'

Altair
RA 19:50.6 Normal drift
DEC 8*52'

Antares
RA 16:29.3 Normal drift
DEC -26*24

Spica
RA 13:25.0 Normal drift
DEC -11*09'

Spica: PEC On just for S & Gs @1230 local PDT
RA 13.24.5
DEC -11*09'

after 5 minutes with PEC on, I noticed more drift than before and I'm almost certain this is due to my ERASE PEC operation done months ago.
Spica
RA 13.23.7
DEC -11*09'

After 10 minutes PEC on, even more drift
Spica
RA 13.21.7
DEC -11*09'

Turned PEC off again, goto commanded to Spica, slew to target 35 min track watch
Spica
RA 13:25.1
DEC -11*09'

Spica Final Values
RA 13.24.6 Normal drift
DEC -11*09'

I can only imagine how much alcohol it takes for Andrew to process this information. My head is spinning just thinking about it.

Keep at it Andrew, I'm sure you're going to find the culprit code somewhere...

Edited by Tmohr36 (07/18/12 04:22 PM)


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dmdouglass
professor emeritus


Reged: 12/23/07

Loc: Tempe, AZ
Re: LX80 RA tracking [Re: Tmohr36]
      #5323835 - 07/18/12 04:27 PM

My confidence has grown that the readings we take at the Audiostar Handbox during off hour “fake” alignment tests are accurate, and are providing accurate data. This has been proven now via various visual observations, including my own. When the target appears to be “drifting”, the Audiostar is actually reporting that drift acccurrately. This is confirmed in two ways. First, a simple “GOTO” at the end of a timed observation, back to the target star, re-centers the target. Secondly, in either the case just described, or without the return GOTO, the mount slews correctly to the next target. Bottom line here is that the mount “knows” where it is.

The oddity that has developed, is that the “drift” does not always appear. It does, it the same part of the sky, but in some parts of the sky, it seems to stay locked on. This has now been reported by multiple users, including myself, based upon visual observations over 15 min or more, as well as Audiostar RA/Dec reading.

This evening, we are once again clouded. However, with strong confidence in the Audiostar readings, I will conduct a series of timed “observations” of 15 min on 9 targets spaced apart by about 40 degrees azimuth, keeping the elevation between 30 degrees to 47 degrees, with one exception at 17 degrees. The sampling will include both +/- Dec values.

Once the test (Polar alignment) is complete (about 2.5 hours), I will re-run the test in Alt/AZ, with the same time settings, and same targets. This should be interesting. I will post results when available.


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neilson
professor emeritus


Reged: 08/22/10

Re: LX80 RA tracking [Re: Lee Jay]
      #5323837 - 07/18/12 04:29 PM

Andrew
Hi, I just finished testing Spica. started RA 13:25.4 after 57 minutes RA 13:34.4 thats +9.0 but it was dropping and 3 minutes later RA 13:33.6 At that point I turned PEC on. After 10 minutes it was the same. After 20 minutes more it was RA 13:31.5 At that time I did another goto to Spica and it slewed back to Spica's original location Pec still on RA 13:25.2 After 20 minutes it was still at RA 13:25.2 After 25 more minutes RA 13:24.8
Neilson


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ur7x
professor emeritus


Reged: 01/08/12

Re: LX80 RA tracking [Re: neilson]
      #5323853 - 07/18/12 04:43 PM

Meade should be handing out some kind of medal/reward for the effort that you all are putting into this.

Kudos's to you all!


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OzAndrewJ
scholastic sledgehammer
*****

Reged: 11/30/10

Re: LX80 RA tracking [Re: jmiele]
      #5323995 - 07/18/12 06:46 PM

Gday Joe
Quote:

So PEC is making tracking adjustments/mis alignment corrections? If so, is it even possible for it to perform the desired PEC function?




As i mentioned earlier, PEC is severely broken, and has been since the 497EP/Audiostar handboxes came out.
There are 150 PEC bins per rev of the worm, and the first 127 of them should work correctly during "playback". I was hoping that in this period, speeds would get resent every bin change and users would see tracking stabilise.

Andrew


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