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Notes - Session 601 (2017-01-23)
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2017-01-23 Initial LX200 problems (Dropped Connection, Unable to Get GPS Fix) ASCOM - POTH Hub - With setup in TheSky, PemPro, PHD2, Metaguide Autoguiding using TS 80mm APO SharpCap - Live Stacking with FWHM Filter Enabled ST-10XME - Uneven Illumination (Frost/Condensation) Software Notes 2017-01-25 (Follow-Up) POTH Hub & Telescope Parking MetaGuide ASCOM Scope Connection, Pulse Guiding with PHD2 & MetaGuide 2017-01-26 TS Photoline 80mm APO - Mounting, Part 1 2017-02-03 TS Photoline 80mm APO - Mounting, Part 2 
Images from 2017-01-23 >>
In recent sessions I've been powering up the 12" LX200 scope whilst the observatory roof is still on. The mount seems to get a GPS Fix without difficulty this way and it saves 2-3 minutes once the roll-off roof is finally pulled back (previously I used to wait until roof was open before starting up the LX200, this was more from a worry that the scope might spring into movement and hit the observatory roof).
This session things went normally for a while. I powered up the LX200 and got on with setting up my laptop etc and other preparatory tasks. I then opened the roof, added on the TS 80mm APO + ASI178MC to the Losmandy dovetail rail, connected the LX200 to TheSky program and slewed the LX200 scope to a star for position check and sync. Which it did just fine. Shortly after and for some unknown reason (some system glitch or other) the connection to the LX200 was lost and couldn't be recovered. It seemed to happen when I was trying to make a connection to my Aurora Cloud Sensor (coincidence, or not ?). In the end I re-parked the LX200 and powered it down.
Upon restarting the LX200 I found that it just wouldn't get a GPS fix (it just kept looking for satellites, and showing asterisks in the display panel). I couldn't see why it had lost connection and couldn't get a GPS fix. I was beginning to worry that something was badly wrong with there being two problems at the same time (In 2016 I had a failed front/ main board which ended up needing a new board, so still a bit nervous).
Looking at forums and information online, it looked like the
problem was possibly due to some interference with the LX200's GPS system and
such that it
couldn't see the satellites that it was expecting.
(Meade
GPS Tips & Hints:
https://www.optcorp.com/global-positioning-satellite-gps-tips-hints-0/)
I returned outdoors, temporarily removed the TS 80mm APO scope
and then
restarted the LX200. This time the LX200 mount got a GPS fix without problem. After
recentering a bright star and re-syncing, the LX200 then performed normally for the
rest of the session.
The encounter seems to show a requirement for my LX200R
to get its GPS fix before adding the TS 80mm APO scope on top. This would be my
normal observing setup routine anyway, but if the LX200R is restarted for any reason, it suggests
that I should temporarily remove the TS 80mm APO either pre-emptively or as soon
as it appears that the LX200R is having problems getting a GPS fix.
The initial lost connection was probably just a glitch on the laptop side (which a Windows restart may have sorted out).
Subsequent Note: In the course of daytime testing a couple of days later, it was noted LX200 was unable to get a GPS fix when powering up with observatory roof closed. Not sure if this is related to where satellites were in the sky during daytime, as the LX200R mount has been able to get a GPS fix ok during last 5-6 night time sessions.
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Up until now I 've only been able to access my LX200 mount from one program. When I've been using PemPro for example I've had to disconnect the LX200 scope in TheSky before I connect to it from PemPro. And then vice versa at the end. This is a bit annoying, but didn't know of any other option.
Now with the plan for autoguiding the 12" LX200 with the TS 80mm APO + ASI178MC camera I have a critical need for the autoguiding software to access Declination information from the mount, at the same time as my imaging/control software have access to telescope' positional information plus ability to control and move the mount to new targets.
Researching online I came across
POTH (standing for Plain
Old Telescope Handset) which is an ASCOM hub which allow access to a scope or
other equipment by more than one program. This part of ASCOM v6.
To access it from TheSky I needed to download and install "TheSky™
ASCOM Telescope (TeleAPI) Plug-In for TheSky 5/6 (5.0.4)" from
ASCOM PlugIns Page
(Working with TheSky:
http://ascom-standards.org/FAQs/TheSky.htm)
Setup of POTH Hub in TheSky6, PemPro, PHD2 and Metaguide are described in
sub-sections
below
The setup was successful performed in the first 3 of these
programs, however the setup in MetaGuide couldn't actually be achieved as the
program produces 2 error message and then crashes whenever an attempt is made to
choose the ASCOM scope/driver. (Update: As part of post-session
follow-up I downloaded and installed the latest ASCOM platform (Vn 6.2) and this
seems to know allow me to use ASCOM Scope Chooser from the MetaGuide setup
dialog without it crashing.)
During the session S00601 the POTH Hub seemed to work fine and allowed
multiple programs to connect to the LX200R mount.
One particular issue
was noted at the end of the session when a 'Park Scope' was issued from my
command program (using TheSky6 Telescope object via VB.net) , but didn't cause
the Scope to Park. The connection to TheSky6 was terminated but the scope was
found to still be active and pointing high in the Western Sky, when I went out
the observatory to close things down. The scope had to be parked using the Park
Scope command on the Autostar II handbox. It's not clear if this was
a one off issue or a regular problem.
(I might need to close POTH and
reconnect TheSky directly to the scope using 'LX200 GPS by Meade Instruments
Corporation' LX200 in order to Park it ?).
Follow-up
Note: A daytime session a couple of days later confirmed that there is indeed a
problem using here
TheSky6's RASCOMTele.Park method when connected to scope
via POTH Hub (See more details and workaround)
.
(Link
to ASCOM's Meade LX200GPS
Driver Information/Help - This is copy of the htm sitting on C Drive)
- TeleAPI Plugin in TheSky6
-
POTH setup in PemPro
-
POTH setup in PHD2
-
POTH setup in MetaGuide
-
POTH Status Window
Configuration of TeleAPI Plugin is shown in the diagram below
| TeleAPI configuration (picture from http://ascom-standards.org website) |
 |
POTH Setup in TheSky6 (Telescope Control).
One-time setup is described below.
1. In the Telescope menu, select
Setup.
2. In the Telescope Setup window, at the top, select Telescope API
3. Just below that selector, click Settings... the ASCOM Telescope Chooser will
appear. Select "POTH Hub".
4. Now click Properties... Under Scope
click on Choose Scope and select "Meade LX200GPS/R".
5. Click on
Properties to bring up the driver setup window fro LX200GPS/R. Verify that it is
set up (the correct COM port, etc.).
6. Click OK to close the Telescope
Choose dialog (Meade LX200GPS/R).
7. Click OK to close the POTH Hub Setup
dialog (POTH Hub)
8. Click OK to close the Telescope Choose dialog (POTH Hub)
.
9. Click Close to close the Telescope Setup window.
10. Now, Click
'Establish Link' from TheSky's Telescope Toolbar. Check to see the crosshairs
indicating telescope's current position, and that there is telescope control
work.
| Telescope Setup (TheSky6) |
 |
| Settings -> Telescope Chooser - POTH Hub |
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| Properties -> Telescope Chooser - POTH Hub |
 |
| Choose Scope -> Telescope Chooser - MeadeLX200GPS/R |
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| Properties -> ASCOM MeadeLX200GPS/R Setup |
 |
POTH Setup in PemPro
(PE/PEC)
- On the Mount/Scope Configuration dialog, click on ASCOM
Drive and select "POTH Hub"
- Click Ok
- Click Close
| Telescope Setup (PemPro) - Mount/Scope Configuration dialog |
 |
| ASCOM Driver -> Telescope Chooser - POTH Hub |
|
|
POTH Setup in PHD2
(Autoguiding)
- On the "Connect
Equipment" dialog, select "POTH Hub (ASCOM)" from Aux Mount list.
- Then
click Connect / Close
| Telescope Setup in PHD2 - Connect Equipment dialog |
 |
POTH Setup in MetaGuide
(Autoguiding)
- On the "Scope Setup
Tab in Setup dialog, select "ASCOM as Guiding Method
- Now one would expect
to then choose POTH Hub when the ASCOM Scope Chooser button is clicked
-
Unfortunately I get an error messages at this point, and then MetaGuide program
crashes.
- Instead of the ASCOM
option, I instead put ASI as guiding method and then manually enter Declination
in the Setup Window
Update: As part of post-session follow-up I downloaded and installed the latest ASCOM platform (Vn 6.2) and this seems to know allow me to use ASCOM Scope Chooser from the MetaGuide setup dialog without it crashing.
| Telescope Setup in MetaGuide - Setup dialog |
 |
| ASCOM Scope Chooser -> Error Messages (before crashing !) |
 |
 |
POTH Status Window
- Once active the POTH driver display as Status Window.
- From here it's
possible to examine the traffic passing through the POTH ASCOM interface
| POTH Status Window |
 |
| POTH ASCOM Traffic |
 |
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The primary aim of the session was to test out the autoguiding of 12" LX200R main scope (+ ST-10XME camera) using piggy-backed TS 80mm APO scope (+ ASI178MC camera). This was performed using
PHD2
- Initial setup with Mount set to
'On Camera' (ie ST4 connection with ASI 178MC camera)
- Demonstrated that
Manual Guide Jogs were successfully moving the scope in N / S & in E / W
directions
(it hadn't been clear from
previous session whether N/S
movements were actually occuring during Calibration)
- Calibrated on star
close to Meridian and Dec 0.
Calibrated using much
longer calibration steps than previous session (ie 2000ms instead of 50-200ms)
- Calibration later complained that steps were few in number and that
calibration might be inaccurate (but PHD2 decides itself the number of steps to
make !)
- At Guiding Rate of x0.5, sidereal rate of 15.04 arc sec/sec,
pixel scale of 1.03 arc sec/px and Dec 0,
the expected North and West
rates would be 7.30 px/sec
- West Rate (6.39 px/sec) and North Rate (6.60
px/sec) are fairly similar as would be expected at near Dec 0,
but
are around 10% lower than the expected rate (7.30 px/sec)
In the
previous session, using small calibration steps, the North Rates were
exceedingly low/invalid (Either no movement
in the scope was
generated by the small calibration pulses or the backlash had not been cleared
probably due to the calibration pulses being too short?)
| PHD Log View Plot of Calibration |
 |
 |
Update: As part of post-session follow-up I downloaded/installed "PHD2 Log File viewer" a tool written by Andy Galasso for quickly visualizing guiding performance and spotting problems. (http://adgsoftware.com/phd2utils/). The tool was used for creating the above plot and others on this page.
- Proceeded to Autoguide on a star. Appeared to be successful,
then bit erratic due to bad seeing (wind shake).
- Autoguiding task is
probably relatively straightforward under good sky conditions, however under
more challenging conditions, ie some wind, where the task is more difficult.
There seemed to be quite a narrow 'window' in which PHD2 would recognise a
particular star has having the 'right amount of star mass' on not flash the
window red.
- If exposure is slightly too short/gain too small, the star is
all to easy to become too dim to follow if/when it gets smeared by a bit by wind,
however if exposure is to slightly too long/gain is too high on the otherhand, the
star easily saturates the 256 range on the FWHM profile and has a wide/flattened
top to its profile (It would seems that PHD2 uses just 8 bit download (?)
when it would be better off to use 14 bit (stretched to 16 bit), to maintain a
better star profile/centroid. I'm unable to see any setting in PHD2 to control this).
| PHD Log View of guiding data showing the Dec/RA errors and Star
Mass (Occasions where the guide star was 'lost' due to star mass falling below 50% are highlighted. Whilst PHD treated star as lost, SNR was typically still in range 9-17 and usable) RA RMS 2.33", Dec RMS 2.29" |
 |
- There is nowhere to enter Declination when entering Calibration Information manually. PHD2 doesn't seem to have a way of manually entering Declination for applying a calibration rates do a different Declination position.
- Later in session Aux
Mount was setup to point to Ascom POTH Hub (and thus to the LX200GPS/R scope).
Guide
Stats window showed that the program was successfully accessing the scope's
Declination.
- Conditions not suitable for autoguiding whilst actively imaging a Target Object. However a test was briefly carried out where PemPro actively monitored a star through 12" LX200 for 14 minutes whilst PHD2 autoguided on a guide star through TS 80mm APO scope. Conditions where poor (wind, declining sky transparency, frost on ST-10 sensor), but the results seemed to show that the autoguiding was ironing out the 10-15 arc sec bumps in RA with 104s period that have been affecting the scope.
| PemPro plot showing Residual Tracking Errors in RA Drive -
Autoguiding through Guide Scope (2017-01-23) Poor conditions - some of the jitter is due to wind shake on the monitored star Note: The star become to faint to reliably monitor towards the end of the run due to falling sky transparency. |
 |
| PemPros plot showing Residual Tracking Errors in RA Drive - No
Autoguiding (2017-01-17) Graph shows the RA bumps in RA occuring with a period of around 104-105s, that can't be eliminated using PEC. |
 |
MetaGuide
- opened MetaGuide program, setup camera and general properties
and became acquainted with the sofware and how to take continous pictures of
guide star field with ASI178MC camera.
- initial setup with Guiding method
set to ASI (ie guiding to be performed using ST4 connection between camera and
mount)
- demonstrated that Manual Guide Jogs were successfully moving the
scope in N / S & in E / W directions
- proved difficult to get a Full
Calibration, so didn't really complete a proper autoguiding test
-
calibration process generally started off with messages saying "Found No Cam !"
and "Open ASI camera failed", whilst evidently the ASI camera was working and
busy streaming Preview pictures to MetaGuide. Calibration progress bar then
should the calibraton getting so far and then seeming stop and not go any
further. (I think it completed one time early in the session)
- later on
tried to use 'ASCOM Scope Chooser' in setup in order to directly access
Declination data from the LX200 Mount, but each I tried it produced two error
message from DriverHelper before crashing.
Update: As part of
post-session follow-up I downloaded and installed the latest ASCOM platform (Vn
6.2) and this seems to know allow me to use ASCOM Scope Chooser from the
MetaGuide setup dialog without it crashing.
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Screen capture below showing Live Stacking of images from M37 in progress.
- Align Frames and Enable FWHM Filter are both enabled.
- At this point
12 frames have been used for Stacking, whilst 14 frames have been ignored
-
Green Bars in the graph on the Filter tab show the frames that have recently
been stacked (most recent frame to the right)
- Red Frames are
filtered out due to FWHM being above threshold, and are ignored by the Live
Stacking
- Frames marked '???' appear to be frames that can not be aligned,
and are ignored by the Live Stacking
(not clear why they can't be
aligned, visually they look not dissimilar)
| Live Stacking in SharpCap using FWHM Filtering |
 |
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As part of trialling the autoguiding of the 12" LX200R main scope using
piggy-backed TS 80mm APO scope, some framing images taken using the ST-10XME
camera on the main scope showed uneven illumination, involving a darkened centre
surrounded by a relatively lighter outside region.
It is thought that
this was probably due to frost formation or condensation formation in the CCD
Camera (either on the CCD sensor or on the CCD's front window). As a
precaution the CCD's desicator canistor was removed the next day for
drying/regenerating in an oven.
| ST-10XME - Uneven Illumination (frost or condensation in CCD Camera ?) |
 |
| ST-10XME - Dessicator Cannister (+ Seal) |
 |
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Further notes taken during continued testing and operation of ZWO ASI178MC camera with different software.
To be added....
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My normal procedure at the end of a session is to click a button in my VN.Net Control Program (CCDApp2) that calls a routine that uses TheSky6's RASCOMTele.Park method. The method calls the LX200 to park iself at its stored Park Position and wait there until turned off. The software has worked perfectly fine on this task for the last few years .
During the S00601 session on 2017-01-23 it was noted that when a 'Park Scope' command was issued from my VB.Net program (CCDApp2) at the end of the session, it didn't cause the LX200R scope to Park as normal. The connection to scope from TheSky6 appeared to terminate but the scope was found to still be active and pointing unexpectedly at a high point in the Western Sky, when I went out to the observatory to close things down. The scope was still awake and I parked it using the Park Scope command on the Autostar II handbox.
During a daytime test of the scope a couple of day later, it was confirmed that there is indeed a problem. Two further attemps to Park Scope resulted in the same behaviour from the mount with it slewing to/towards a location high up in the Western sky, remaining awake & unparked.
I will look again at the events being transmitted to the scope using POTH's Traffic window (in case they show up something informative). However at this point it looks unlikely that I will be able to fix things so that my routine leads to the LX200 parking where it should, each and every time.
At this point in time I conclude that calling TheSky6's RASCOMTele.Park
method is UNSAFE when connected to "Meade LX200GPS/R" via POTH Hub, and
therefore I must disable the Park Scope facility in my command software when
POTH Hub is operating, and instead use one of the two following options for
parking the scope.
a) Use 'Park Scope' button on the POTH
status window.
(I tested this, and it works - the scope parks at
is correct position)
b) Disconnect from the scope (i.e. TelescopeAPI) in TheSky6, disconnet the scope/POTH Hub from other programs like PHD2 and PemPro, then reset scope/contol system name as 'LX200 GPS by Meade Instruments Corporation', reconnect to scope and then issue the Park Scope command from my software.
It might be helfpul to uncheck the 'Can Park' option in advanced capabilities settings in POTH, but this might have the consquence that is stops option a) from working
I notice that the performance of TheSky6 using POTH.Hub is somewhat degraded. May it has to wait longer for telescope RA/Dec position requests to be returned when going through the POTH and the 'ASCOM Meade LX200 GPS/R' drivers. Will need to monitor and see if this is going to be an issue.
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MetaGuide didn't worked properly during the S00601 session on 2017-01-2 : Messages produced when trying to Calibrate ("Found No Cam !" and "Open ASI camera failed"), calibration wouldn't run to completion. There were also crashes of the program when trying to use 'ASCOM Scope Chooser'.
The problem with the program crashing when clicking ASCOM Scope Chooser was solved by downloading and installing the latest ASCOM platform (Vn 6.2).
However the program then started having problems when connecting to ZWO ASI178MC camera when starting, producing new error messages and no picture from the camera. This was solved by downloading the latest Beta version of MetaGuide (Vn 5.2.15).
With these things fixed, the software produces live pictures from the ASI178MC camera again and allows the POTH Hub (or other ASCOM scope) to be selected from the ASCOM Scope Chooser without crashing.
It's not yet known whether it will be PHD2 or MetaGuide that I
eventually use as my main autoguiding tool.
For the time being I'm trying to
get both software options working and available.
| New MetaGuide error messages after Installing ASCOM Vn 6.2 |
 |
|
Latest Beta Version of MetaGuide Installed (fixes the above errors) |
 |
| Selecting POTH Hub from ASCOM Scope Chooser |
|
|
| ASCOM Scope Connection Set to POTH telescope |
 |
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During the session S00601on 2017-01-23 the guiding connection to the LX200 Mount was made from the ASI178MC camera via a ST-4 cable. However the LX200R (GPS) also has the the ability to be operated by Pulse Guiding, which has certain advantages.
To test this connection method PHD2 was setup to use POTH Hub as the Mount
(rather than Aux Mount as before) Once connected Manual Guide
buttons were used to nudge the scope in N,S, E and W directions whilst watching
POTH's Traffic Window. The traffic confirmed that PHD2 was sending guide
commands and that POTH was passing them onto the LX200 Scope.
(A
new nightime session will be required to test the overall behaviour of the full
system using PHD2)
| PHD2 - Mount Set to POTH Hub (ASCOM) |
 |
| PHD2's Manual Guide dialog |
 |
|
POTH Ascom Traffic window The messages confirms PulseGuide operations are being sent to the scope. The 'Done' responses suggest the commands were heard. |
 |
In a second test using MetaGuide the POTH Hub was selected as the ASCOM Scope
and again Manual Guide buttons were used to nudge the scope in N,S, E and W
directions whilst watching POTH's Traffic Window. The traffic confirmed that
MetaGuide was sending guide commands and that POTH was passing them onto the
LX200 Scope.
(A new nightime session will be required to test
the overall behaviour of the full system using MetaGuide)
|
MetaGuide - ASCOM Scope Connection set to POTH telescope Manual Controls used to nudge scope N, S, E and W directions |
|
|
|
POTH Ascom Traffic window The messages confirms PulseGuide operations are being sent to the scope by MetaGuide. The 'Done' responses suggest the commands were heard and acted upon. |
 |
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The precise final method of mounting my new TS 80mm APO scope to the Losmandy Style dovetail rail attached to 12" LX200R main scope has been uncertain until this point. However after recieving and successfully testing a pair of ADM Universal Adapter Blocks the final method has now been selected:
- TS 80mm APO
- CNC Tube Rings (supplied with Scope)
- ADM Universal Adapter Block
- ADM D Series Dovetail
Plates Adapter
- ADM Losmandy-type Dovetail for 12" Meade
- 12" LX200R
Pictures of the UAB Blocks and the initial temporary fitting of one of the block are shown below.
|
ADM Universal Adapter Blocks (Pair) Top row is for Metric connection to Tube Rings Bottom row is for Imperial connections to Adpater Plate |
 |
|
UAB Block Fitted to TS 80mm APO Lying next to scope is the ADM D-Series Dovetail Plate Adapter (a second block will be fitted to the other ring later) The two M6x10mm screws are too long and required spacer washers to stop them digging into the telescope's aluminium tube. |
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|
ADM D-Series Dovetail Plate Adapter Fitted to TS 80mm APO Bottom View (a second adapter plate will be fitted to other ring later) |
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| Side View |
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The second plate adapter and the shorter M6 bolts arrived today. Pictures below shown them fitted to the TS 80mm APO.
|
ADM Universal Adapter Blocks (Pair) Top row is for Metric connection to Tube Rings Bottom row is for Imperial connections to Adpater Plate |
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UAB Blocks Fitted to TS 80mm APO Fitted using 1 x M6x6mm and 2 x M6x8mm screws per block (two ADM D-Series Dovetail Plate Adapters waiting to be fitted) |
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ADM D-Series Dovetail Plate Adapters Fitted to TS 80mm APO Bottom View |
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| This Web Page: | Notes - Session 601 (2017-01-23) |
| Last Updated : | 2017-12-01 |
| Site Owner : | David Richards |
| Home Page : | David's Astronomy Web Site |