David's Astronomy Pages
Notes - Session 556 (2013-11-27)

2013-11-27
Bullet Autostar II (LX200) Firmware Update to 4.2G (2013-11-22)
Bullet USB Hub / COM Settings at 2013-11-23
Bullet Systems Test 2013-11-24 (S556a)
Bullet TPoint Mapping Run 2013-11-24 (S556a)
Bullet Polar Alignment Check 2013-11-24 (S556a)
Bullet Tracking Rate Check & Adjustment 2013-11-28 (S556b)
Bullet Tracking Rate Analysis 2013-12-10 (S557)
Bullet Tracking Rate Analysis 2013-12-10 (S557)
 
Bullet Images from 2013-11-27 >>

Autostar II (LX200) Firmware Update to 4.2G (2013-11-22)

Autostar II Firmware was updated from 4.2g to 4.2G v19 on 2013-11-22 in order to access two critical enhancements :

This was performed as part of a Nov 2013 Imaging Improvement Plan.  The workflow used was as follows:

No Improvement Notes
1 Read up on latest firmware status on Autostar Information Page at http://www.weasner.com/etx/autostar_info.html  Determined that as of  2013-11-12 the latest Autostar II patch kit was  
"Patch Kit for v4.2g (v19) (03/31/13)"
2 Read up about the most secure method for installing a new firmware version.  Determined that the recommended method based on information in forums such as  LX200GPS Yahoo Group is still to use Star Patch.
 (free version is sufficient for updating Autostar II).
Determined that I already had StarPatch 1.6 on my laptop. 
I was unable to find any information about whether current settings on Autostar II (eg alignment, PEC, park position etc) are retained through the upgrade process.
(I decided to proceed on the basis that settings would be lost during the upgrade process)
3 Chose a time in daylight hours when I had plenty of time to make the upgrade Chose a day that I was off-work and weather was ok for me to open the observatory roof, allowing the scope to get its GPS fix on start-up.
4 Opened observatory and started up LX200R scope  
5 Wrote down all my existing Autostar II settings This was to make things easier should settings be lost during the upgrade (they were !)
6 Downloaded existing PEC curve from the LX200 Mount This was done using PemPro 2.7. The saved PE curve is shown below.

This was to make things easier should PEC be lost during the upgrade.
Image
7 Opened StarPatch 2.6 Unregistered trial version
7a Clicked on Options and selected Language (English) and Handset Type (Autostar II  (LX200 GPS)      
7b Clicked on the "File" menu and selected "Get Updates..." to download the latest files Files were downloaded ok
7c Selected required Patch File (PatchLX42ggv19.spf) and selected required options Image

I went with all the default items, together with Block Dimming, 10x finer Tracking Rate and Save Tracking Rate. See following list:

Image

7d Selected the Com port on which telescope is connected and selected Baud Rate (9600) At first I couldn't see the COM Port for the telescope in the StarPatch list of COM ports. I knew Telescope was on COM11 so clicked on "Update Autostar", assuming that StarPatch application would find the COM11, however it didn't.  It seems that StarPatch can only see active ports up to COM9 or so.   As a workaround I connected the scope serial-USB adapter lead to one of the laptop's main USB slots rather than a slot in the Observatory's USB Hub.  This then gave a COM4 port that StarPatch could finally see and use.
7e Turned off Internet Connection and checked that laptop was connected to working Power Adapter. This was based on a recommendation I read online.
(It also said something about making sure there were no cats or children around, so checked that too !)

7e Clicked on Update Autostar to update the Autostar II (LX200 GPS) StarPatch connected with Autostar II (LX200 GPS) and proceeded to update it with new firmware.   The autostar II handset gave a message like : Uploading - do not turn off handset.   Since this was going to take around 10 minutes or so, I popped back in the house. When I returned the upload status was showing 100% but there was an error message saying that Autostar had failed to update. Checking the handset indicated that it has moved to 4.2G   (from 4.2g) but none of the old settings were there.

I proceeded with a second update attempt, but this time stuck around to observe the upload.   After completing the upload, StarPatch sent a message to the AutoStar/LX200 to reset.   After resetting was done, StarPatch put the message that Update had failed  when it connect seemingly connect with the Autostar after the reset.  Whilst the message was not good, it was assumed that the Upload had probably proceeded ok.
8 Reentered Telescope and Handbox Settings Reentered various settings based on the list that was written down directly before the upgrade proceeded.  
Setting RA Pec to "On" caused the scope to begin its drive initialisation movement.
9 Connected with TheSky and Synced scope based on the scope's approximate position. Scope will need to be Synced on a actual star at star of next session.
10 Uploaded PE curve to LX200 PemPro was used to load the previous PE Curve back onto the LX200.
11 Made a couple of power cycles to test
Start Up
Start Up confirmed as 'normal'.  Scope starts up at Park Position (without initialisation movement)  and proceeds to obtain a GPS fix and then wait for further instructions.
12 Test/Check functionality at next night time sesssion. Pending

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USB Hub / COM Settings  at 2013-11-23

USB Ports on USB Hub (from Left to Right) :

USB  Equipment Lead COM Port Com Description
1      
2 TCF-S focuser COM8 Keyspan USB Serial Port
3 ST-10XME Camera    
4 LX200 Telescope COM7  Prolific USB-to-Serial Comm Port
5      
6 Aurora Cloud Sensor COM5 Prolific USB-to-Serial Comm Port
7      

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Systems Test  2013-11-24 (S556a)

Following upgrade for Autostar II to 4.2G v19,  reinstallation of drivers for Prolific Serial-USB  adapter, and a number of enhancements and changes to my Observatory Software (including a new Observatory Tool Bar and access to Aurora Cloud Sensor data), a full systems test was carried out.  This was to check this everything was working together ok and that software was generally robust. 

- Observatory Program was started in debug mode
- COM port for LX200 telescope communication was updated to point to COM7 
- Telescope, CCD Camera and Cloud Sensor were started and connected to Observatory Program
- TPoint mapping run of 48 points was performed until cloud developed ending the session

Despite the deteriorating weather conditions the session (S556a) was judged a success.   Debugging mode caught an error (which would have otherwise caused  the program to crash).  A "try, catch end try"  coding was added and the program continued.  Underlying error related to the monitoring of Temp and  Star Elongation.   A further issue was noted with the Scope Monitoring not able to log scope position when TheSky is performing an image link.

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TPoint Mapping Run 2013-11-24 (S556a)

TPoint Mapping was conducted by using automated routine , but with progress monitoring by indoors computer.   
Mapping was curtailed when cloud began to develop and there was insufficient stars to link/map in the last 16 attempted frames and a remaining 12 points were cancelled

Model Description RMS PSD Notes
0a 48 points, with 0 terms  638 638 one point (#12) has value of > 2000 arc secs and can be flagged as erroneous.
With this point excluded the RMS error falls to 515 arc sec.  (8.6 arc min)
0b 78 points, with 0 terms  515 515 8.6 arc min RMS with no TPoint model, Point #12 excluded
1 48 points, with 6 terms 
(6 equatorial terms)
517 553 one point (#12) has value of ~ 2000 arc secs and can be flagged as erroneous.
2 47 points with 6 terms 
(6 equatorial terms)
422 453  
3 47 points with 8 terms
(6 equatorial terms, plus Fork & Tube Flexure)
165 181 one point (#25) has value of ~950 arc sec and can probably be treated as erroneous

Tube Flexure is more significant term. RMS is 334 without it, compared to 169 without Fork Flexure
4 46 points with 8 terms
(6 equatorial terms, plus Fork & Tube Flexure)
92 101 Polar Misalignment
Azimuth (MA -69,  sigma 19). Need to rotate polar axis east (clockwise) by 2.1 mins
Altitude (ME +198  sigma 60). Need to raise polar axis by 3.3 mins
5 46 points with 12 terms
(6 equatorial terms, plus 6 top harmonic terms)
84 97 Polar Misalignment
Azimuth (MA -73,  sigma 17). Need to rotate polar axis east (clockwise) by 2.3 mins
Altitude (ME -289  sigma 30). Need to lower polar axis by 4.8 mins
6 46 points with 12 terms
(6 equatorial terms, plus Fork & Tube Flexure, plus
4 top harmonic terms)
59 69 Polar Misalignment
Azimuth (MA -73,  sigma 12). Need to rotate polar axis east (clockwise) by 2.3 mins
Altitude (ME +114  sigma 80). Need to raise polar axis by 1.9 mins
7 46 points with 12 terms
(6 equatorial terms, plus Tube Flexure, plus
4 top harmonic terms)
57 67 Polar Misalignment
Azimuth (MA -68,  sigma 12). Need to rotate polar axis east (clockwise) by 2.1 mins
Altitude (ME +133  sigma 75). Need to raise polar axis by 2.2 mins
8 46 points with 12 terms
(6 equatorial terms, plus Fork & Tube Flexure, plus
4 top harmonic terms)
55 64 0.9 arc min RMS -
Polar Misalignment
Azimuth (MA -69,  sigma 11). Need to rotate polar axis east (clockwise) by 2.1 mins
Altitude (ME +161  sigma 60). Need to raise polar axis by 2.7 mins
9 46 points with 14 terms
(6 equatorial terms, plus Fork & Tube Flexure, plus
6 top harmonic terms)
59 71 0.98 arc min RMS 
Polar Misalignment
Azimuth (MA -73,  sigma 12). Need to rotate polar axis east (clockwise) by 2.2 mins
Altitude (ME +117  sigma 80). Need to raise polar axis by 2.0 mins
10 46 points with 16 terms
(6 equatorial terms, plus Fork & Tube Flexure, plus
8 top harmonic terms)
59 73 0.98 arc min RMS 
Polar Misalignment
Azimuth (MA -73,  sigma 11). Need to rotate polar axis east (clockwise) by 2.3 mins
Altitude (ME +112  sigma 60). Need to raise polar axis by 1.9 mins
11 46 points with 12 terms
(6 equatorial terms, plus
6 top harmonic terms)
52 61 0.87 arc min RMS 
Polar Misalignment
Azimuth (MA -76,  sigma 10). Need to rotate polar axis east (clockwise) by 2.4 mins
Altitude (ME +42  sigma 35). Need to raise polar axis by 0.7 mins
12 46 points with 13 terms
(6 equatorial terms, plus
6 top harmonic terms, plus Tube Flexure term)
51 60 0.85 arc min RMS with ?best TPoint Model
Polar Misalignment
Azimuth (MA -74,  sigma 11). Need to rotate polar axis east (clockwise) by 2.3 mins
Altitude (ME +110  sigma 60). Need to raise polar axis by 1.8 mins

 

Data Fit, Fit Information and Polar Misalignment Information 
for Model 8 
(46 points with 12 terms:   6 equatorial terms, 
plus Fork & Tube Flexure and 4 top harmonic terms) 

  Data Fit, Fit Information and Polar Misalignment Information 
for Model 11
(46 points with 12 terms:   6 equatorial terms, 
 6 top harmonic terms)

Image

  Image

Image

 

Image

Image

  Image

 

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Polar Alignment Check  2013-11-24 (S556a)

The TPoint mapping run described above was used to analyze the Polar Alignment of the LX200 Mount

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Tracking Rate Check and Adjustment  2013-11-28 (S556b)

A star at Dec 0 in the southern sky was monitored  for 16 mins, during which time the star drifted westwards at an overall rate of around 0.7 arc secs/min.
This means that scope is tracking too slowly.  The star was then monitored  for a 3 further 16 min periods during which the star continued to drift westwards at overall rates of 1.3 arc sec/min, 0.5 arc sec/min, and 1.0 arc sec/min

The mean rate of drift over the 4 intervals is westwards at  0.9 arc sec/min (ie - 0.9 arc sec/min)

During these intervals the precise star position was analyzed at 13 sec intervals. This provided 161 measurements of the tracking drift over approximately 8 minute period intervals (see graph below). Mean drift was 0.97 arc sec/min (range 0.0 to 2.3, SD 0.47). 

Image

Scatter is graph data assumed to be due to a mixture of residual periodic error and imperfections in the RA gear.  An overall tracking drift of -0.9 arc sec/min is generally supportable.  In order to speed up the scope a positive tracking rate adjustment is required.  This would normally be +0.9 (in practice +1), but since the x10 finer tracking rate patch has been included in the Autostar II firmware upgrade to 4.2G, the required tracking rate adjustment is +9.

Tracking Rate in Autostar II was duly updated to a custom value of +9.   
The setting will be checked at start of next session to confirm that the tracking rate has been preserved between power cycles.

Notes collected from Internet : The *unpatched* tracking rate adjustment is very close to being units of "arcseconds of drift per clock minute" So if a star drifts eastward (i.e. scope too fast) two arcminutes in 15 wall-clock minutes, you'd want to use a Custom value of 2*60 (to give arcseconds) divided by 15 (clock minutes): 2*60/15=8 Since the scope is "too fast", you want a negative Custom value to slow it down. So "-8" is the desired setting. If you have the patch installed, that becomes -80.

The (unpatched) Tracking Rate Custom is in units of tenths of a percent compared to (what the Autostar calls) normal sidereal.  Part of the 10x Finer patch is a change of the prompts from: 'Enter Rate Adj.' to '.01%'s sidereal'

If the polar axis is off by (say) 0.5 deg, the tracking rate could be out by a factor of cos(0.5) = 0.99996.

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Tracking Rate Analysis  2013-12-10 (S557)

In the previous session (S556b) it was estimated that Tracking rate was running too slow by 0.09% of sidereal and a Custom RA Tracking Rate adjustment of +9 was entered into Autostar II before parking the scope and powering down.  Normally (with 4.2g firmware) the tracking adjustment would be lost when scope was powered down, but with the upgrade to 4.2G it was expected that the settings would be retained to the next session.

Session S557 began by examining the RA tracking setting in Autostar II - it showed Custom Tracking with a value of +9.  This indicated that the setting had apparently been preserved as expected.   However there remains some uncertainty whether the saved Custom Tracking Rate is actually being correctly applied from start-up.

Initial tracking rate measurements (8 min moving average) showed that a star at Dec 0 in the southern sky was drifting west at 3.5 arc secs/min. Whilst some variation in measurements was expected (S.D. of 0.5 over 8 min period determined in the last session), the difference from expectation (which was no or little drift) was unreasonably large.  The initial thought was that I must have the sign wrong, and made a second run with tracking rate adjustment set to -9.  In this run the star drifted west at -1.8 arc secs/min.    Further runs were then made with tracking rate adjustment set to +29, +20, +14, +13.

Results of these runs and the previous runs from last session are shown in the graph below.   A best fit line shows that correct sidereal tracking tracking requires a tracking rate adjustment of +11.  This compares reasonably well with the estimate of +9 from the previous session.

Image

Although the scope had been powered down at end of last session with a Tracking Rate adjustment of +9 it behaved on power up as if it had a tracking rate adjustment of around -20 (despite showing a value of +9 on the Autostar II screen).     

The scope was powered down at end of session S557 with a Tracking Rate adjustment of +13.   Tracking rate will again be examined at start of next session to test whether the problem was just a first use issue or whether the problem is more persistent.   After this the tracking rate will be set to +11 and the Tracking Rate measured again.  Residual Periodic Error (after PEC corrections) will mean that tracking will never be perfect, however the aim is to use a RA tracking rate adjustment that cancels the mean RA drift.

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Polar Alignment Adjustment 2013-12-10 (S557)

Polar alignment adjustment was made in both azimuth and altitude based on the misalignment estimates made in previous session

Image

Star in southern sky at approximately Dec 0 was centered in the FOV.  The scope was then jogged by required amounts in RA and Dec. Finally azimuth and altitude adjustments to wedge were made to recenter the star.  Process is illustrated by the following pictures (South Up).

Star centered in field of view
Image
  
Scope jogged north by 1.5 arc min and east by 1.9 arc min
Image
  
Mount adjusted south by ~1.5 arc min and west by ~ 1.9 arc min
(Image affected by wind shake to scope)
Image
CCD Images (50% size)
  10s exp, 2x2 binning, C Filter

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