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LX80 RA tracking

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#1 Wigleydh

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Posted 03 July 2012 - 08:31 PM

Asking for some help. Sorry this is long.

There are three of us that have a combined equipment setup for astrophotography. One of us has ordered and received a LX80 (we have been using his LXD55 ). During first light Friday night, we found an issue with it not tracking properly in RA, which I’ll explain. The issue has only been not tracking properly in RA. The DEC has been good. The gotos have been good. The LX80 seems fine except for the RA tracking. Also it is much more solid/stable than the LXD55.

The guy that bought the mount called Meade Monday. He told them what it was doing. He also asked what the RA ratio value should be as default, in attempt to verify that. Meade told him that they would have to call him back. Didn’t hear back on Monday, he called again this morning, got no call again so called back very late today. He was now told to e-mail the issue to them. He had to go to work and will have to e-mail them after he gets off work.

We discussed it and he wanted me to ask here - Can someone that has a LX80 please check their hand controller to see what value the RA ratio is? I hope it isn't wrong to post what ours is showing. Ours had +2.75075 as the RA ratio and +2.75077 for the DEC ratio. After having absolutely no luck, as a debug step we did temporarily change the RA to see if it affected the situation. We set it about +8 and the drift then went the other way. When we set it to about +6.75 that caused the star to be just about steady then. The RA ratio has now been re-entered to +2.75075 as it originally showed. We did see a value close to that on another site. The value they showed listed it as being LX90 & LX80. Is that correct for both? The reset of the audiostar hand controller still showed +2.75075 but it has huge drift at that.

Also, I don’t believe we’re overlooking something but please say so if anyone notices something we might be overlooking.

Friday night, the mount was physically setup in EQ/polar mode, verified the hand controller also showed polar/EQ mode. The mount was balanced in both axis - picture is attached (80mm F7.0, 66mm F6.0, flip mirror & DSI pro, diagonal & eyepiece).

We did the same alignment routine we’ve been doing with the LXD55. Polar align roughly eyeballed. Then one star alignment (which goes to Polaris first), physically adjust the mount to center Polaris. It then picked Arcturus. It went near Arcturus (goto was better than the LXD55 usually does). Arcturus was then centered using the hand controller = successfully alignment. We then did gotos back and forth between Polaris and Arcturus. Each time when at Polaris - physically adjust the mount to remove out about half the error. Then on Arcturus center with hand controller and sync. Once we get the alignment error out enough that both stars are in the field of view with a 12.5mm eyepiece in the 80mm F7.0, we would then focus cameras and do a drift align using PHD guiding and really nail the alignment, then guide and image (that has been working well on with the LXD55 – see the FLI8300C gallery of starsabove.net).

After getting alignment close going between Polaris and Arcturus, when we went to near the meridian to do the 1st part of the drift alignment, the LX80 was not tracking worth a hoot in RA. The DSI pro through the 66mm F6.0, showed the stars drifting left to right across the screen about 3/16 to 1/4 of an inch every two seconds exposure with the DSI. We’ve never seen drift like that on the LXD55 at that same step in our routine – the star has always been mainly steady while just looking at it on screen. PHD would not calibrate due to the star kept drifting out of the star search box.

We have reset the hand controller, verified the hand controller also showed polar/EQ mode,motor calibration routine has been run a couple of times, trained the drive a couple of times, Started all over on polar aligning several times. Verified the hand controller set for sidereal tracking rate. Turned targets to terrestrial to see if the LX80 was tracking at all in RA – it was – the star drift got worse as it should have when set to terrestrial targets , then turned targets back to astronomical – back to same bad amount of drift. We did set it up in alt/az and did an alignment. That showed the star drifting the other direction – right to left (but some less drift and the star would move slightly up a couple of frames then down a couple of frames then repeat while drifting left – we don’t normally do alt/az but wanting to try it to see how stable that tracking was)

Sunday morning, Venus was put in the field of view on the eyepiece with the mount set up as EQ and Venus did drift out. When it did the DEC was still good – only off in RA. I wasn’t there helping Sunday morning, so this time the other guy did all the setup/balancing/alignments, so more than one person has set it all up with the exact same results.

As mentioned earlier, the gotos have been good. The mount I didn’t think was very noisy on normal slew and goto was very quiet with the quiet slew mode turned on. The LX80 fit and finish is good. Much easier to balance as both axis are much smoother than the LXD55.

I would think that if there was some big mechanical issue, gotos would be off but they are good.

We would appreciate someone letting us know the default RA ratio value their LX80 shows. Let us know if we’re being brain dead and overlooking something obvious or other ideas on the issue that might help isolate what's happening. Maybe there are something more that could be tried before he gets feedback from Meade.

Once it is acting properly, we plan to pulse guide it through the hand controller with PHD like we've done with the LXD55 and I'll let everyone know how that goes.

Attached Files



#2 OzAndrewJ

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Posted 03 July 2012 - 11:05 PM

Gday Dennis

First things first, what firmware version does the Hbx have?

The LX90, LX80 and LT scopes all use the same "ratio" in the code,
but change sign as required for direction.

The signs for Az/Alt ratios are
LX90 -/+
LT and LX80(AltAz) +/-
LX80(GEM) +/+

The correct absolute value based on the LX90 is 2.75074479,
and that has been independently confirmed by doing a mechanical cross check.

I havent seen/heard any details of whats in the LX80s to allow a similar check to be done.
If gotos were good, then the ratio sounds like it is probably OK.

There is a bug in the handbox where the ratio values can automatically increase if you use the edit screen,
but that wont show as much error as you are seeing in tracking.
( If you open the ratio edit screen and then hit enter,
then repeat several times, you will see the data changes
even tho you never changed it :p )

Also Pls confirm if you have used PEC or turned it ON??

Andrew

#3 Dwight J

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Posted 03 July 2012 - 11:45 PM

Had the same problem with a LXD 55 mt when I got it. It was the first run of mounts and RA tracking was not right until about the fifth update of the firmware. Prior to that I adjusted the RA rate by watching a guide star and adjusting the RA tracking rate until there was no drift. The difference was variable but generally 3 - 5 percent. This, of course, was using Autostar. The rate can be varied from 0 to 100 percent and to -100 as each step was a 1 percent change in tracking speed. This may be what you will have to do until a later firmware update fixes the rate.

#4 OzAndrewJ

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Posted 03 July 2012 - 11:53 PM

Gday Dennis

And after a quick squizz at the code, there is a new bit in the motor speed setting section, that only applies to an LX80 when set up as a GEM.
In this case, the base tracking rate is multiplied by 1.01155, ie your drive would be running fast.
I have an idea why its there, but its only a guess at present.
Firstly, can you do a test to confirm the encoder ratio.
Set the scope up AltAz and point at a terrestrial target.
Press and hold mode to bring up the display screens and scroll down to the AltAz one.
Now slew slowly in one direction till you can mark a target.
Log the current Az reading.
Now slew 360deg until almost back at target then slow down the rate and recentre the target ( without reversing the drives )
Relog the AZ. Is it the same????
If so ( within an arcmin or so ), the ratios are correct.

Andrew

#5 Wigleydh

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Posted 04 July 2012 - 10:06 AM

I'm not sure about the PE is showing as on or not. We did not even look at that Friday night. He had setup the mount in his living room Thursday but only did a quick two star alignment (accepting were it pointed) to see if things worked for that and slewing. I doubt he even looked at PE then.

I forgot what firmware version it is. I did look at the version Friday but I don't think I wrote it down, as I can't find it.

The mount is at his house, so I'll have to have him check to see if the PE is showing on or off and firmware version. Same for the suggested test. I'm not sure what he and his family are doing today for the holiday but he'll likely be able to check it.

We both thought the LX80 was nicer in making adjustments to the mount than the LXD55 during polar alignment. The DEC adjustment on the LX80 is a good improvement in my opinion. It was much easier and smoother than the way the LXD55/LXD75 mounts adjust the DEC axis, which was effected more by how much weight that mount was carrying. That should help make drift aligning the LX80 easier, once we get the tracking issue corrected.

#6 rmollise

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Posted 04 July 2012 - 03:24 PM

Since none of the owners are reporting similar, I'm not sure it can be a code problem. What was the _direction_ of the drift? The magnitude in minutes or arc? _How far off was your POLAR ALIGNMENT_?

#7 OzAndrewJ

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Posted 04 July 2012 - 05:23 PM

Gday Rod

Not many users have reported doing "proper" polar tracking tests with an LX80 yet either??
All i'm pointing out is the user reported seeing a large "drift" when tracking in Polar.
I had a quick look at that part of the code and i can see a new bit of code that specifically applies to an LX80 when set up as a GEM ( and nothing else ).
It appears to speed up the drive by 1.155%.

If that matches the symptoms, then its a smoking gun to be pursued.

Andrew

#8 rmollise

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Posted 04 July 2012 - 05:30 PM

And you may be entirely correct. But the first thing for the OP to do is confirm they had a good polar alignment. I, for example, have been known to align on Kochab instead of Polaris on occasion. :lol:

#9 OzAndrewJ

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Posted 04 July 2012 - 05:46 PM

Gday Rod

Nahhh...
The first test is to confirm the encoder ratio matches
the gearing in the units ( as that's a daylight test ;)).
We need to get as much info as possible to pin it down,
ie piccies and toothcounts for gearing/encoders etc would be nice.
Also,
a) i think you would need a pretty severe polar error
to get "RA" drifting "at the rate" reported,
B) the report that "gotos were good",
indicates a reasonably good "mechanical" polar alignment

All good fun

Andrew

#10 Alph

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Posted 04 July 2012 - 06:21 PM

the report that "gotos were good",
indicates a reasonably good "mechanical" polar alignment


Nahhh... :)
Two star alignment does not require accurate polar alignment.

#11 OzAndrewJ

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Posted 04 July 2012 - 09:57 PM

Gday Alph

Nahhh...
Two star alignment does not require accurate polar alignment.



Agreed, but I can only go on what i read, ie

Polar align roughly eyeballed. Then one star alignment



If they were polar one star aligning, there is no correction matrix used in gotos, ie all other things being OK, accuracy of gotos is a function of how well mechanically polar aligned the scope is.
If the gotos were OK, i suspect the polar align was close enough to
remove that as a reason for the "RA drift" they see,
esp when you reread the magnitude of drift they report.

Andrew

#12 TALK2KEV

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Posted 05 July 2012 - 11:03 AM

I'm one of the three guys that share equipment.

first and foremost Thanks for all the good information and thing to double check.

firmware version A3S1

I know we are on the Pole I took a green laser and taped it to the top of RA box and rotated the scope in RA and it arced around Polaris.

As far as PEC it is turned off.As stated the mount was aligned using One star and then sync and back to Polaris and take half of the error out using mount screw adjustments this was done until both stars would be in 12.5mm close to center without adjustment. Which I know is not dead on but very close and at that point using DSI pro and PHD to drift align.

A New problem happen last night
on first start up doing alignment the mount was totally lost
it was about 4:00am and Vega was west of the meridian but still very high in the sky doing alignment it wanted to point near the ground, Power down return to Home polar double checked site, date and time it was right, power up and it did the same. power down again return to home polar power on and it was in the right area of sky moved the scope with hand controller wanted to change the slew speed the display was showing 8x or 16x when I changed it but the slew was still in guide speed even though the display showed other wise, very strange after it was all done the scope acted right. Goto was dead on with objects being in 20mm EP centered and then Sync with 12.5mm EP I tracked Venus for a while it would drift out in RA only each time after asking the scope to move to Venus it would put it in 12.5mm EP. The scope is only moving west in RA no noticeable change in the DEC.

The direction of drift is to the east, Its slow in RA tracking and moves west each time when asked to Goto object

I will do a two star setup tonight to see how close we are to the pole and get some numbers for you guys.

#13 TALK2KEV

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Posted 05 July 2012 - 11:06 AM

Does anyone know if the hand controller has a diagnostic test maybe a button combo that runs a test on the unit?

#14 tejasdragon

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Posted 05 July 2012 - 12:34 PM

I know we are on the Pole I took a green laser and taped it to the top of RA box and rotated the scope in RA and it arced around Polaris


It may not be your main issue but, If Polaris was in
the center of the arc you are not polar aligned.
At least not enough to do AP. The first thing
I would do is get it polar aligned. I don't
know what Meade has for stuff in there firm
ware these days if they have a something to do
a good polar align with use it, or learn to drift
align, personally I prefer a visual drift alignment.

A laser pointer is nice but it will not align your
scope good enough for AP in my opinion.

And remember Polaris is not on the NCP.

Henry

#15 Wigleydh

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Posted 05 July 2012 - 01:21 PM

As decribed in my originaly post, we've been doing an iterative alignment method. We've used that method for several years now on a LXD55 mount. Always have gotten very close using that. We've usually then tweeked that using PHD to drift align. Using PHD to drift align is much faster than just visually drift aligning - the PHD graph show the error quickly. We're doing the exact same iterative method on the LX80. The thing is once done, there has been a huge drift in RA - unlike when we've setup the LXD55 using the same method.

Once Kev ordered the LX80, I even started setting up the LXD55 not even using it's polar alignment scope only using the iterative method & had no issue - I wanted to get ready for the LX80, since it doesn't have a polar scope - have not had any issue.

The 497 autostar and the LX80's audiostar have the same routines in them. We are using the same one star alignment then the same iterative method, that we've been using successfully with the other mount.

I believe that Kev did the laser thing just to ensure that it wasn't point way the heck off - after having so much trouble, start 2nd guessing oneself. We've never seen drift before in such a large amount after aligning. I was there on Friday night but Kev has setup the mount several times since and keeps getting the same results. I don't believe it is an alignment issue - don't think the same amount of misalignment would be done over and over, when we've had very good luck using iterative alignment on the LXD55.

#16 rmollise

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Posted 05 July 2012 - 01:36 PM

The direction of drift is to the east, Its slow in RA tracking and moves west each time when asked to Goto object


If the drift is east, your tracking can't be slow. It would have to be too _fast_.

#17 dmdouglass

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Posted 05 July 2012 - 03:23 PM

Hello Kevin D.....

I am following this thread very closely. I too have a new LX80 mount. I operate my mount in the Alt/Az dual scope configuration. Initially, for the first series of tests, everything was working smoothly. That was with the single scope (Meade 6" SC).

Then i modified the configuration for dual scopes. I was testing indoors to see about balance and overall operation. I started experiencing strange slewing movement during the alignment procedure. Sort of what you described. I will try and put it my words...

The mount starts out normal. Then, it will stop. It might think about things for a sec or two, but then start up again, in VERY SLOW motion. It might also start up again, in regular speed, but then stop again, and resume in VERY SLOW motion. Both descriptions occurred with me. It will ultimately make it to the target, and resume normal operations.

I also noted that after calibration, if i set the speed up to "9" (max), and just used the slewing buttons to move the scope (in az direction) around for awhile, it would suddenly stop. It would not resume motion until i released the button, and repressed it. This went on for a day or so (of testing indoors....). I was looking for the problem.

All of a sudden, the control box (Audiostar) went dark. As in not working any more. Dead.

I also have a Meade ETX-90. I found out that the Audiostore controller is compatible with the ETX-90.. Thus the reverse should also be true. I tried that controller with LX80, and everything was working fine.

Meade is sending me a new Audiostar controller, which i should have tomorrow evening. I will verify it works correctly, and then look to see what the settings are, and post back -- probably Saturday sometime.

#18 OzAndrewJ

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Posted 05 July 2012 - 06:40 PM

Gday Kev

Good info, but like Rod, I am a little confused by the drift direction.
If the star is drifting to the East, then the scopes tracking is too fast, which is what my initial code analysis predicts. Can you reconfirm the direction of drift?
Just for a second simple test, can you do your std iterative/drift align.
Now, set the scope model to LX90 and Polar, then change the RA ratio to have a -ve sign.
Reboot the scope, and after the date/time is set, the scope will start tracking in RA. :cool:
Now, "manually" slew to a star near the equator/meridien and let it settle.
Do you still see the same rate of drift?
( By selecting LX90 Polar, you still invoke the standard polar base tracking rate, but it excludes the LX80GEM multipication factor, and any GEM specific code )

Andrew

#19 Starhawk

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Posted 06 July 2012 - 12:35 AM

I'm floored.

-Rich

#20 OzAndrewJ

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Posted 06 July 2012 - 03:27 AM

I'm floored


Why???
It may just be a bad encoder ( similar to what one early poster had )
or it may be that no-one has tested in polar properly until now.
Until we get more details, we dont really know whats happening.
( I suspect some bench testing code has been left active,
in which case its an easy fix, but if so, it shouldnt have happened )

Irrespective of that, the new Audiostar firmware is basically the same
as that issued with the LX90s, LTs, ETXs etc, so we know the basics work,
notwithstanding there are several other bugs continued through.
I suspect its just one of the new "one line changes" associated
with the LX80s that may be biting.

Andrew

#21 TALK2KEV

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Posted 06 July 2012 - 04:46 AM

Not sure if I'm explaining this the right way.
Once you have target I was using Venus I would sync on that target with 12.5mm EP and let the scope do it thing "track" after 30min to hour. Now not looking through the eyepiece just looking at the mount, The mount would move to the west only to re-center Venus.I would thing that if the mount was running fast it would over take Venus and have to back up to the east to recenter . But its moving to slow in RA letting Venus get ahead of the mount.So each time I select Venus and tell the mount to GOto Venus the mount moves to the west only.

#22 TALK2KEV

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Posted 06 July 2012 - 05:31 AM

David and Andrew

It good to know that Meade ETX-90 Hand controller will work on The LX80. I talked to Meade Thursday evening with some luck I will be getting a new Hand controller. So I hope this will solve the problem I do like this mount and with the tapered roller bearings it makes life so much easier to balance. And easy to polar align. I also like the fact one Set up tool does everything that was well thought out. Two things I don't like about the mount One all the cables plug into the box that is in motion in RA so cable management will need to be address. The other is the sectional Counter weight rod.I know why Meade did that for all of the different configuration Alt/Az , Duel Ota and Eq this might not be a big issue but while doing Astro Photography you always fighting flexure. In the dark if you grab the counter weight to loosen the RA clutch it could loosen the counter weight sections as well, this happen once already. While I don,t see loosing the weight each section has lots of threads. I might look into having one machined.

#23 Jack Huerkamp

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Posted 06 July 2012 - 10:45 AM

My LX80 is en route and hopefully by the time it arrives next week, the RA tracking issue will have been resolved. I initially wanted a replacement for my iOptron MT (lots of problems) and then MT PRO (o problems) that I owned. And the thought of being able to use one mount for both Alt-Az and EQ modes was the primary motivation to purchase the LX80. Throw in the increased weight carrying capacity and it was a no brainer.

Jack

#24 dmdouglass

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Posted 06 July 2012 - 01:05 PM

Kevin.. (and everyone else following this)

I am working with Meade this morning. The new Audiostar controller arrived, and the problem now is determining which "Mount" to select, as the LX80 is not included in the list. Apparently, Meade's training to the support personnel is saying to use the ETX-90.

My main operation is in Alt/AZ. Although the mount is slewing to the correct direction (AZ), it is now pointing DOWN instead of UP. We are trying to figure that out now.

As to the DEC lock, and the counterweight issue you mentioned, try using the "tool" into the holes in the dec lock. You can gently tighten and loosen the lock with that.

More later when Meade calls back.

#25 jmiele

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Posted 06 July 2012 - 01:18 PM

So, is this to be the next saga in the Meade release debacle? More bad firmware and faulty tracking rates. It's really unfortunate they would allow another miscue following the LX800 tragedy. More important, is the money and time of our astro friends being tied up to fight through summer heat and technical problems. I enjoy learning about new gear as much as the next person. I also don't mind working through "some" issues. However, there is a continued pattern of neglect here. No LX80 to select from the LX80 drop down menu? Really Meade..? Really?

David I hope this works out for you. Sorry for your trouble.

Best, Joe






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