David's Astronomy Pages Notes - Session 608 (2017-12-22)

Notes (S607)

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Notes (S609)

	Session Aims & Highlights
	Operational Issues
	- Critical Issues (0),  Major Issues (0),  Minor Issues (6),  Small Defects (2),  Continuous Improvement (0)
	Image Problem - LX200 + ST-10XME (Dew, Condensation or Frost)
	Corrective Reduction Process
	Image Coma - TS 80mm APO + ASI178MC
	Images from 2017-12-22 >>

Session Aims & Highlights (S608)

Main Aims

This was an early morning session with main aims :

1. Targets. Acquire images of selected deep sky objects
2. Guiding. Test updated routines for initiating PHD2 Guiding from my CCDApp2 Observatory Control Software.
3. Dual Camera Ops. Continue testing of dual camera operations using both PHD2 and SharpCap 3.0.
   

 Equipment & Software

•  12" LX200 and ST-10XME
•  TS 80mm APO & ZWO ASI178MC
   
•  CCDApp2, TheSky6, CCDSoft 5, POTH Hub, PHD2 2.6.4, SharpCap 3.0,  SharpCap Server

Highlights

• Targets. Images acquired for a number of deep sky targets.
• CCDApp2. The VS2017 version of CCDApp2 again worked perfectly during the session (or at least didn't hang or crash at any point).
• Guiding. The updated routines for initiating PHD2 Guiding worked well. 
• Data Connections. Data Connections to Optec TCF-S focuser, Aurora Cloud Sensor, Weather Station Repeater, PHD2 and SharpCap generally worked well for the whole session.
  

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Operational Issues (2017-12-22, S608)

• Critical Issues (0)
• Major Issues (0)
• Minor Issues (6)
• Small Defects (2)
• Continuous Improvement (0)

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Critical Issues

• None

Major Issues

• None

Minor Issues

• Guidescope Images were initially too far out of focus to see any stars. Again quite a bit of time was taken up trying to find focus (knowing which way to turn the focus knob would have been a good start).  Reason: Coarse Focuser on TS 80mm APO scope was accidently turned when trying to tighten the knobs of the dovertail adapter plates.  A Dome Observatory in which the guidescope can be left attached to the LX200 between sessions would also help a faster setup. Issue Resolved in 2018 when a computer controlled stepper focuser was fitted to the GuideScope that allows remote and automated operation.
  Resolved  2018  (TS80 Telescope, Focus Motor)
   
• Aurora Cloud Sensor data wasn't recorded to observatory 'monitor.dat' file for first part of the session. Data recorded ok following a CCDApp2 program restart suggesting no fundamental issue. Issue eventually Resolved
  Fixed (Cloud Sensor, CCDApp2/AstroMain)
   
• Images aqcuired from LX200 + SBIG ST-10 camera had highly surpressed light levels and non-flat & vignetted illumination. It is not entirely clear what was responsible for the poor images. Condensation/Dew on front corrector plate of LX200, condensation on A07 tilt glass or  filter wheel filters,  condensation or frost on the front window of SBIG ST-10 camera, or frost on the CCD Chip inside the ST-10 camera. Issue resolved in Nov 2018 with use of Pegasus UPB Powerbox / Dew Heater Control once initial 12V power supply issue was sorted out.
  Resolved (LX200, Pegasus UPB Powerbox / Dew Heater)
   
• Unable to perform image link of ZWO 178MC fits images in CCDSoft / TheSky 6. These were fits images acquired in PHD2 and SharpCap.   Some images might be too dark and have too few stars, or otherwise be difficult to image link (related to taken Bayer image into CCDSoft). However the most likely reason is that the images taken through TS 80mm APO scope + X/Y Guidestar Finder + ASI178MC camera are taken of a starfield that too far is offset from the target object (centred in 12" LX200+ST-10XME) for the employed plate solution method to achieve a successful match.
  Proposed Solution:  Create plate solving method that performs a wider search (say up to 7 x image area (-3/+3 on x, -3/+3 on y)  )
  [ Image scales 12" LX200+ST10  : 0.442"/px,    80m APO+ ASI178MC : 1.03"/px ,  1x1 binning]
  Eventually resolved with chnages to CCDAp2/AstroMain and installation of ASTAP installed which provides alternative Plate Solution capability.
  Resolved (CCDApp2/AstroMain, ASTAP)
   
• Bottom right region of images taken with TS 80mm APO + ASI178MC camera this session shows obvious coma. This is a known potential issue for this scope which doesn't currently have a field flattener as standard.  Whilst the ASI178MC chip is smaller enough not to show coma when precisely on-axis, the image very probably lies off-axis due to the current setting of Orion X/Y guidestar finder  which hasn't been recentered & checked recently. See images with bottom right coma. A Dome Observatory in which the guidescope can be left attached to the LX200 between sessions would also help retain optimised setups,  balancing the coma issue with perfect alignment between LX200 main scope and the piggybaked TS 80mm APO Scope. A field flattener would also help. Eventually resolved by the addition of a field flattener for the TS 80mm APO scope (See 2" Field Flattener (TSFLAT2, 2019-12-11) ).
  Resolved 2019-12-11 (Secondary Scope, Field Flattener)
   
• CCDSoft autoguiding apparently not working. This only became evident post session when it was found that ST-4 cable from the SBIG camera was found to be not actually connected to the autoguider port on the LX200 front panel. Investigation showed that the issue was caused by the ST-4 cable from SBIG ST-10 camera not being connected to the autoguider port on the LX200 panel (the port was occupied instead by an unused cable that the ZWO ASI178MC camera was originally going to used before it was realised that it could instead guide using LX200 commands).  Guiding was subsequently switched over to use Pulse Guiding using PHD2, which no longer required use of the ST-4 cable connection.
  Resolved in-session (SBIG Camera, LX200)

Small Defects

• Thousands of '>>     ' lines being written to logfile, making the Logfile too large to open. The problem appears to have been caused by either a runaway condition in the code that reads events from PHD2 and/or runaway condition in PHD2 itself.  It was probably responsible in part for CCDApp2 grinding to a halt that required a program restart. Bug fixed.
  Fixed (CCDApp2/AstroMain)
   
• Logfile containing 'Null' character meaning that log data cannot be copied / moved etc. Reason for problem is unclear. The issues requires investigating to see if there is anything that can be done to stop Null characters getting written to the Logfile. Fixed.
  Fixed (CCDApp2/AstroMain)

Continuous Improvement

• None

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Image Problem - LX200 + ST-10XME (Dew, Condensation or Frost)

An image problem affected nearly all of the images acquired during session using LX200 + ST-10XME imaging train. Images show vignetting pattern and raw photometry showed significant reduction below normal transparency levels. Reason for the problem isn't entirely clear. There was some dew formation during the session but it wasn't obviously enough to cause the problem. Clearing the dew with hairdryer didn't eliminate the problem, neither did bringing the CCD Temperature back to 5 degC (ie above freezing point). No condensation was seen on A07 tilt glass or C Filter when the imaging train was partially broken apart the following day.

NGC 2301 - Raw Frame with Problem

Raw CCD Image (50% size) 90s exposure (single frame), 3x3 binning, C Filter 2017-12-22 03:42h UT (#608090) 12" LX200R  (at f/10.4) + ST-10XME (Autoguided using TS 80mm APO + ZWO ASI178MC)

NGC 2242 - Stacked Image with Problem (after conventional dark/flat frame reduction and stacking)

CCD Image (50% size) 5 x 60s exposure (average combine), 3x3 binning, C Filter 2017-12-22 04:04h UT (#608097-101) 12" LX200R  (at f/10.4) + ST-10XME (Autoguided using TS 80mm APO + ZWO ASI178MC)

A reduction process to correct the problem and make the images semi-usable is described in a following section

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Corrective Reduction Process

Poor visual transparency (probably either dew and/or other condensation in the LX200 + ST-10XME imaging train, resulted in the recording of images that would normally be considered too poor to use for public viewing.  A reduction process was used to make the images partially useable.

NGC 2242 - Original Image (after conventional dark/flat frame reduction and stacking)

CCD Image (50% size) 5 x 60s exposure (average combine), 3x3 binning, C Filter 2017-12-22 04:04h UT (#608097-101) 12" LX200R  (at f/10.4) + ST-10XME (Autoguided using TS 80mm APO + ZWO ASI178MC)

NGC 2242 - Computed Flat Frame 1 (Flat computed from background values in orginal image)

(Computed using own software - AstroImageTool)

NGC 2242 - Intermediate Image (Original with flat reduction using Computed Flat Frame 1

Image details as above

NGC 2242 - Computed Flat Frame 1 (Flat computed from background values in intermediate image)

(Computed using own software - AstroImageTool)

NGC 2242 - Final Image (Intermediate Image with flat reduction using Computed Flat Frame 2)

Image details as above

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Image Coma - TS 80mm APO + ASI178MC

The right hand region of images taken with TS 80mm APO + ASI178MC camera during this session shows obvious coma. Coma is a known potential issue for my TS 80mm APO scope which doesn't currently have a field flattener.  Whilst the ASI178MC chip is smaller enough not to show coma when precisely on-axis, the image very probably lies off-axis due to the current setting of Orion X/Y guidestar finder which hasn't been recently recentered & checked. 

Image Coma on right hand side of image

CMOS Image (16% size) 69 x 10s exposure (Live Stack), 1x1 binning 2017-12-22 04:37h UT (#04_37_15Z) TS 80mm APO + ZWO ASI178MC [ Larger Image, 32% size ]

Image Detail from different parts of above image

CMOS Image (16% size) with 100% sized inserts Image details as above

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