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Notes - Session 648 (2019-01-20)
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Main aims
Equipment & Software
Highlights
Images. Images from a number of targets were successfully acquired.
LX200 powered up remotely at start of session using Pegasus UPB
(and later powered down by remote operation)
Improvements in creation of HFD lines from inner and outer focus.Summary Plots & Logs
| Observing Plan (2019-01-20, S648) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Observing Result (2019-01-20, S648) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Night Sky Summary Plot -
2019-01-20, S648 Top axis: Sky Brightness at Zenith (in ADU/s) Lefthand axis: Local Time (hh LT). Righthand axis: Sun Altitude (degs) |
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| Session Event Log (2019-01-20, S649) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Back to Top
Resolved 2019-01-21 (Observatory)
Resolved 2019-04-22 by the introduction of a new 16 AWG Extension Cable to
reduce the voltage drop going to the UPB powerbox, allowing dew heaters to
be run at full power whilst still providing 11.9V input voltage to the UPB
(see Pegasus
UPB - 16 AWG Extension Cable, 2019-04-22)
Fixed 2021-03-31 (Pulsar Shutter Software 1.25)
Fixed 2019-01-21 (AstroMain code (3.8.1) fixed so that Form follow the
correct behaviour)
Fixed 2019-01-21 (AstroMain code (3.8.1) modified to save correct
FlagState)
>> Possibly Fixed 2019-01-25 (Happens when session event is
within 1.5 second of the last saved event. This cause an insert row error in
SessionEvents table which has Event Time as one of its keys and so the event
is not saved to database)
Fixed 2019-01-25 (AstroPlan modified to pass EventDescriptions strings
through a new 'GetDegSymbolCorrectedStr' Function)
Fixed 2019-01-21 (AstroMain code (3.8.1), InsertToO modified to call
'UpdateTpnNextTargets()' routine directly after inserting a ToO target into
the observing queue)
Done 2019-01-21 (AstroPlan code (1.6.2) modified to automaticallu set the
'Lock Data' checkbox after creating any new plan)
Done 2019-01-21 (AstroMain code (3.8.1) modified to perform FullDataSave after refocus changes are made
to Foc2)
Done 2019-08-17 (AstroMove 1.2.7) Back to Top
Three focus profiles created during the session (including HFD measurements).
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Focus Profiles, including new HFD measurements |
| Initial focusing run at start of Session |
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Initial focusing run at start of Session (profile re-run to get HFD data on both sides of best focus) |
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Refocusing run part way through session (focus has drifted with temperature changes) |
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Issues
>> Extend code to limit inner and outer lines to graph area
(difficult but potentially feasible)
>> Extend code to for drawing of inner and outer limit linesBack to Top
After slewing to Comet 46P/Wirtanen at 21:45, attempts to take images to centre target and to make planned observations (45 x 15s exposure) failed and required the Job Queue to be aborted and the observatory then visited to try to resolve the problem. This was done by power cycling the SBIG St-10XME Camera using the A/C Mains Scoket and then restarting the session & job queue. This worked, but shortly after the AstroMain program frooze, which then had to be resolved by killing and restarting AstroMain and other obsrevatory software (CCDSoft & TheSky).
It seem likely that cable to TCF-S focuer and SBIG Camera had most-likely snagged on the front rightand arm of the wedge, and momentarily pulled a USB cable or Power cable from the SBIG Camera. It is unlikely that the earlier accidental Job Abort was responsible in any way. The drop out of the CCD Camera and its reconnection may have contributed to the AstroMain destabilising and freezing up.
Altogether around 15 mins of observing time was lost.
| Time | Event | |
| 21:27 | Started Target 26/40, UGC 118 as a Target of Opportunity | |
| 21:41 | Image quality poor due to cloud and altitude (26 deg). | |
| 21:43 | - User decision to Abort Target | |
| 21:44 | - User accidently hit the Abort Job button instead and accidently Ok'ed the warning | |
| 21:44 | - Queue execution aborted and Control Mode passed back to Manual | |
| 21:45 | User re-enaged Fully-Automated Mode | |
| 21:45 | Obs. Executor reloaded and resumed the original Observing Plan (V1 BEST PLAN) | |
| 21:45 | M77 & GCVS EV Lac Targets skipped due to Missed Start Times | |
| 21:45 | Started Target 25/36, Comet 46P/Wirtanen | |
| 21:45 | - Slewed to Target (alt 62.3, Azim 66.4 deg) | |
| 21:46 | - Locate Images all failed (Error during TakeImage ) | |
| 21:46 | - Image frames all failed as well (Error during TakeImage) | |
| 21:47 | - User decision to Abort Job Queue | |
| 21:47 | - Queue execution aborted and Control Mode passed back to Manual | |
| 21:51 | Observatory visited | |
| 21:48 | - Cables to TCF-S focuser and SBIG Camera noticed to be pulled
somewhat tightly across the arm of the Wedge ( cable was moved from its position to a less critical / less tight position ) |
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| 21:48 | - SBIG USB Camera noticed to have dropped off the computer Device List (Device Manager) | |
| 21:51 | - SBIG Camera power-cycled using A/C mains switch. | |
| 21:52 | User re-enaged Fully-Automated Mode | |
| 21:52 | SBIG Camera connected to as part of 'Session Starting' code (Connection OK) | |
| 21:53 | Obs. Executor reloaded and resumed the original Observing Plan (V1 BEST PLAN) | |
| 21:53 | Started Target 26/36, LAMOST-HVS1 (planned start 22:02) | |
| 21:54 | - Target began wait loop. User began looking at AllSky Image Picture (window overlying AstroMain program) | |
| 21:55 | - AstroMain program was found to be non-responsive | |
| 21:56 | - Killed AstroMain Program, Closed TheSky & CCDSoft, killed secondary instances of TheSky & CCDSoft | |
| 21:56 | User Restarted TheSky, CCDSoft & AstroMain | |
| 21:57 | User Resumed S648 Session | |
| 21:59 | User re-enaged Fully-Automated Mode | |
| 21:59 | Obs. Executor reloaded and resumed the original Observing Plan (V1 BEST PLAN) | |
| 21:59 | Started Target 26/36, LAMOST-HVS1 (planned start 22:02) | |
| 22:06 | Completed Target 26/36 (execution moved to next targer OK) | |
| 22:06 | Began Targets 27 to 36 (execution ok) |
Back to Top
After operating Dew Heater at around 50% level, the Dew Heaters were turned up at around 23:10 due to possible signs of condensation (seen as diminishing transparency from comparison of apparent star brightness against expected brightness from catalogue magnitudes). It was noticed that the UPB Software showed a red warning icon and a pop-up message "A short circuit (SC) detected or input voltage is out of limits". The input voltage was noticed to have dopped to 10.7v (compared to normal supply voltage of 12.1V, and working voltages of 11.6V and 11.3V with Dew Heaters at 0% and 50% respectively.
Having only recently moved to a Pegasus 12V 10A power supply from an older legacy 12v 3A supply I was surprised to start seeing a power issue given the relatively minor amount of connected equipment (a LX200 scope, 2 dew heater bands (12" & 5") and a stepper motor for focusing a guidescope)
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Pegasus UPB - Power Issue (2019-01-20, S648) UPB Powered from 12V, 10A Adapter with a 3m DC extension cable (using LX200, 1 x 12" Heater Band, 1 x 5" Heater Band ) |
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UPB Panel with Dew Heaters are full power. Input Voltage 10.7V, Current 2.1A, Power 22W. Total Output Current 1.9A |
 |
| (The yellow exclamation symbol simply warns that a Temperature/Humidity Sensor is not connected) |
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UPB Panel with Dew Heaters are half power. Input Voltage 11.3V, Current 1.3A, Power 14W. Total Output Current 1.3A |
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UPB Panel with Dew Heaters Off. Input Voltage 11.6V, Current 0.9A, Power 10W, Total Output Current 0.2A |
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UPB Panel with everything off (No Dew Heaters , No
Scope) Input Voltage 12.1V, Current 0.1A, Power 1W, Total Output Current 0.0A |
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The UPB is powered by a Pegasus Astro 12V 10A Supply which sits in the
Observatory Bay. The 1.5m long 12v cable from the Supply Adapter is
too short to reach to firstly reach the bottom of the pier (1.2m away) and then up to the
UPB mounted on the LX200 fork arm at a height 1.6m above the floor level. The
cable length also needs to
allow the fork to swing through +180/-180 degrees when scope is operating. An extension
cable (2.5mm female barrel to 2.5mm male plug) of 2m minimal length is
therefore required. (If the UPB was positioned in a 'conventional' position
on top of the guidescope dovetails, it would be positioned at a height of 2.15m
above the floor level and an even longer cable would be needed)
There was no indication of any short circuit ( the warning icon/message
disappeared which ever device/output was turned off or wasn't present when powering the
UPB directly from the 12V supply rather than using an extension cable)
The issue was investigated further the following day but using 2x12" heater
bands (instead of the items connected during the session the previous night).
This showed input voltage dropping as low as 10.5V (with a current draw of
2.4A) when the dew heaters were fully on. Repeating the test with the Power Adapter connected directly to the UPB
i.e. without
the extension cable (not feasible for normal observatory use involving telescope
slewing) showed the input voltage staying at 12.1V (with a current draw of 2.7A).
A test using an alternate DC extension cable (1.8m long) didn't produce the red warning icon or
message, but delivered much lower output current to the dew heaters
(only 0.59A each versus an expected value of 1.22A each).
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Pegasus PowerBox - Daytime Power Investigations (2019-01-21) (using 2 x 12" Heater Bands, - LX200 not connected ) |
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UPB Powered from 12V, 10A Adapter with 3m DC extension cable UPB Panel with Dew Heaters (2 x 12") at full power Input Voltage 10.5V. Current 2.4A, Total Power 25W, Total Output Current 2.2A |
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UPB Powered directly from 12V, 10A Adapter UPB Panel with Dew Heaters (2 x 12") at full power Input Voltage 12.1V. Current 2.7A, Total Power 32W, Total Output Current 2.4A |
 |
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UPB Powered from 12V, 10A Adapter with an
alternate 1.8m DC extension cable UPB Panel with Dew Heaters (2 x 12") at full power Input Voltage 11.2V. Current 2.5A, Total Power 27W. Total Output Current 1.2A |
 |
The extension cable is a regular extension cable (relatively thin wired) and it is evident that a heavier duty cable is required. Attempts to find a heavy duty cable online with the necessary male and female plug adapters (2.5mm/5.5mm) have so far failed .
| Power Cable from 12V 10A supply (left), Extension Cable to UPB (right) |
 |
Calculations suggest that to loose no more than 3% voltage over a 3m
extension with 12V supply and 10A current draw I would need cable with 3.0mm^2
wires (ie 12 AWG) (or 2.00 mm^2 , 14 AWG for a 2m extension)
https://www.12voltplanet.co.uk/cable-sizing-selection.html
To not
loose more than 3% voltage over 3m with 12V supply and 4A current draw I would
need cable with 1.5mm^2 wire (ie 15 AWG)
(or 1.00 mm^2 wire, ~17 AWG for a 2m
extension)
I note the UPB manual mentions needing at least 18 AWG wire
for custom power cables and to not exceed 3m. 18 AWG (0.82 mm^2) wire would
produce over 4% drop in voltage for 4A current draw and a lot more drop for 10A
current draw.
Follow-Up
Power supply issues were eventually resolved in
April 2019, after the purchase and fitting of a 16 AWG Extension Cable bought
from BixPower in USA
(see
Pegasus UPB - 16
AWG Extension Cable, 2019-04-22)
Back to Top
A selection of 1x1 and 2x2 and 3x3 Dark Sets were acquired at -25 degC to infill the set of Master Frames for this temperature group.
Bin|Num|Exp |
1 15 0.12
2 15
0.12
2 15 0.2
2 15 0.3
2 15 1
2 15 2
3 15 3
3 15 4
3 17 300
3 15 0.3
3 15 0.4
3 15 1.5
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| This Web Page: | Notes - Session 648 (2019-01-20) |
| Last Updated : | 2023-11-26 |
| Site Owner : | David Richards |
| Home Page : | David's Astronomy Web Site |
