David's Astronomy Pages
Notes - Session 600 (2017-01-18)

2017-01-17 to 2017-01-18
Bullet TS Photoline 80mm APO
Bullet TS Photoline 80mm APO - Arrival  (2017-01-17)
Bullet Orion XY Guidestar Finder (2017-01-17)
Bullet TS Photoline 80mm APO - Day Time Tests (2017-01-17 & 2017-01-18)
Bullet TS Photoline 80mm APO - Mounting (2017-01-18)
   
 
2017-01-18
Bullet TS Photoline 80mm APO - First Light
Bullet Autouiding using 12" LX200 + ST10
Bullet Processing Images using AutoStakkert 2
Bullet Venus - Atmospheric Dispersion, Compensation using Autostakkert 2's RGB Align
Bullet TS Photoline 80mm APO - Field Curvature (f/6 Uncorrected)
Bullet ASI 178MC - Master Dark Frames
Bullet Unexplained Light Artefact - ASI 178MD / Orion X/Y Finder/TS 80mm APO
Bullet Image Display Issue in AIP4WIN
   
 
Bullet Software Notes (2017-01-17 to 2017-01-18)
 
Bullet Images from 2017-01-18 >>

TS Photoline 80mm APO

The notes in the sections below describe the arrival, testing and first light use on my new Guiding/Imaging Scope - a TS Photoline 80mm f/6 APO refractor. The scope is part of a new equipment plan for new/improved astro-imaging in 2017.

There are also notes on new Orion XY Guidestar Finder which arrived at same time as the new scope.


TS Photoline 80mm APO - Arrival (2017-01-17)

New Guiding/Imaging Scope (TS Photoline 80mm f/6 APO refractor) arrived today (2017-01-17). Pictures below:

Views of the new TS Photoline 80mm APO scope
TS Photoline 80mm f/6 APO scope   Back End of TS 80mm APO Scope
2.1/2" Rack & Pinion Focuser, 2" and 1.1/4" adpaters
Image     Image
     
View looking into Front Lens of
new TS 80mm APO scope
   
Image    
     
CNC Rings, 3 holes on top / base of each
tube ring 15mm (metric) spacings
  Vixen-style dovetail bar
(single screw connection to each CNC ring)
Image   Image
     
New TS 80mm APO scope mounted temporarily on Losmandy-Style Dovetail Plate
using an ADM Camera Mount
Scope is shown here connected to Orion XY-GuideStar Finder and ASI 178MC Camera
Image   Image

Back to Top


Orion XY Guidestar Finder (2017-01-17)

Orion XY Guidestar Finder also arrived today (along with new 80mm APO refractor)
This is part of a new equipment plan for the new astro-imaging in 2017.

Views of the new Orion XY Guidestar Finder
The device provides +/- 13.8mm (0.54") adjustment in X and Y
Orion X-Y Guidestar Finder
(Sales Picture)
  Orion X-Y Guidestar Finder
(shown connected to camera and
80mm APO Refractor)
Image     Image
     
Guidestar Finder - Centre Position   Centre Position (close-up)
Image   Image
     
Guidestar Finder - Top Position
Y - 13.8mm
  Guidestar Finder - Bottom Position
Y + 13.8mm
Image   Image
     
Guidestar Finder - Left Position
X - 13.8mm
  Guidestar Finder - Right Position
X + 13.8mm
Image   Image
     
Guidestar Finder - Bottom-Left Position
X - 13.8mm, Y + 13.8mm
   
Image   The photos above show that the camera sensor
(ASI 178MC) recieves good illumination when
the Guidestar Finder is adjusted to top, bottom,
left & right positions.

However the camera sensor becomes partially
covered when the Guidestar Finder is moved to either
of the 4 corner positions. This may not
 be significant for autoguiding but is
a clear limitation for astrophotography.
However one would normally use a
central (on-axis), position for best imaging.

Back to Top


TS Photoline 80mm APO - Daytime Tests (2017-01-17 & 2017-01-18)

Daytime Tests
- Initial attempt with 26mm and 13mm eyepieces sitting in the scope's 1.1/4" adapter failed completely.
  A distant object couldn't be brought into focus with the rack & pinion focuser, even when
  positioned at it's maximum tube extent. This was surprising, was there something wrong ?
- Removing the eyepiece and adapter revealed a clear large inverted focussed image when
  looking from a position some distance behind the scope, showing that nothing was fundamentally wrong.
- Tried again with eyepieces using a 1.1/4" and 2" diagonals that increased the optical path, and this time
  I got good focussed visual views.  (using an extension tube in place of a diagonal should permit
  straight-through viewing if required - this wasn't actually actually tried but it should work)
- Canon EOS 400D camera  connected to scope using EOS-T2 adapter and T2 extension tubes
  Took series of images using EOS Utility software.
- ZWO ASI178MC camera  connected to scope using T2 extension tubes
  Took series of images using SharpCap.

Visual view through 80mm f/6 scope (no eyepieces) showing large inverted image
Image   Image
Imaging Tests with Canon EOS 400D camera
Euronete Building - 2180m distance   Hill - 5100m distance
Image   Image
Canon EOS 400D, 1/250s, ISO 100
(reduced in size from original image)
  Canon EOS 400D, 1/400s, ISO 100
(reduced in size from original image)
 
Wind Turbines - 5900m distance (check!)   Wind Turbine - detail
Image   Image
Canon EOS 400D, 1/320s, ISO 100
(reduced in size from original full frame)
  Canon EOS 400D, image details as left
(cropped from original image)
     
Imaging Tests with ZWO ASI178MC camera
Wind Turbine - 5900m distance (check!)   Wind Turbine - detail
Image   Image
ZWO ASI 178MC, 1/320s, ISO 100
(reduced in size from original full frame)
  ZWO ASI 178MC, image details as left
(cropped from original image)
     
Euronete Building - 2180m distance   Wind Turbines - detail
Image   Image
ZWO ASI 178MC, 4ms, gain 84
(reduced in size from original full frame)
  ZWO ASI 178MC, image details as left
(cropped from original image)
     
Trees - 720m distance   Trees - 720m distance
 Image   Image 
ZWO ASI 178MC, 8ms, gain 0
(reduced in size from original full frame)
  ZWO ASI 178MC, 8ms, gain 0
(reduced in size from original full frame)
     
Birds in Tree - 720m distance   Birds in Tree - detail
Image    Image 
ZWO ASI 178MC, 8ms, gain 0
(cropped & reduced in size from
original full frame)
  ZWO ASI 178MC, Image details as left
(cropped from original full frame,
unsharp masked)
     
Telesgraph Pole - 190m distance   Rabbit on Dune  - 1650m
Image    Image 
ZWO ASI 178MC, 8ms, gain 0
(reduced in size from original full frame)
  ZWO ASI 178MC, Image details as left
(cropped from original subarea frame)

Back to Top


TS Photoline 80mm APO - Mounting (2017-01-18)

- The new scope is to be mounted to a 3" wide Losmandy dovetail rail attached to my 12" LX200R main scope.

- The precise fixing to be used was one of the uncertainties at time new scope was purchased, which wouldn't
   be resolved until the new scope arrived and it could be properly examined

- The TS Photoline 80mm APO comes fitted with a pair of CNC Tube Rings attached to a Vixen Style Dovetail bar.
- The CNC Tube Rings have 3 holes at Top and Base. The holes have 15mm spacing (ie Metric Scale)
- This prevent double bolt fitting to traditional ADM/Losmandy D-Series Dovetail Clamps which have 1/2" spacing.

- The Tube Rings appear to be securely fitted to the Vixen Style dovetail, even though there is only one bolt on each ring. 
- Given the difficulty of finding a better solution it is proposed to purchase an 'ADM Losmandy to Vixen Female Adapter' for
  mounting the scope to the Losmandy dovetail rail.  In meantime the scope can be mounted, though in a less firm manner,
  by attaching the scope to a Camera Mount on the LX200R with 1/4" screw.

- The nature of my shed observatory means that I don't have the head-space below the roof to permanently connect
  the TS 80mm APO scope to the LX200R main scope, and will need to attach / deattach the 80mm APO refractor at
  start and end of each session.

- The final method for mounting the TS 80mm APO was eventually decided on 2017-01-26 after successful testing an ADM Universal Adapter Block

Views of the new TS Photoline 80mm APO scope
CNC Rings, 3 holes on top / base of each
tube ring 15mm (metric) spacings
   TS Vixen Level dovetail bar (PS14 / 138mm long)
(single screw connection to each CNC ring)
Image   Image
     
New TS 80mm APO scope mounted temporarily on Losmandy Dovetail Plate
and connected to Orion XY-GuideStar Finder and ASI 178MC Camera
Image   Image
     
Views showing Losmandy dovetail rail attached to top of LX200R main scope
(Note lack of room for permanently mounting the TS 80mm APO refractor)
Image   Image 
     
First Light Mounting for TS 80mm APO refractor.
Views showing new scope piggy-backed onto top of LX200 using a Camera Mount
(This is a temporary arrangement - see notes on final mounting plan here)
Image   Image 
     

Back to Top


 TS Photoline 80mm APO - First Light  (2017-01-18)

 ZWO ASI178MC colour camera and Orion XY Guidestar Finder
connected to new TS Photoline 80mm f/6 APO refractor
(mounted on top of 12" LX200R)
Image 
 
First Light Image - M42
Image
CMOS Colour Image (Full Area, 16% size)
5s exposure, 300 gain, 1x1 binning, RAW16
2017-01-18 18:57h UT (#18_57_41Z / 0001)
ZWO ASI178MC camera taken through TS 80mm f/6 APO

Back to Top


 Autoguiding using 12" LX200 + ST10

During the second half of the session, the images taken with ASI178MC camera through TS 80mm f/6 APO refractor benefited from  autoguiding. This was performed by CCDSoft using 2s exposures taken with ST10 camera through the 12" LX200 main scope.   Sky conditions where relatively stable and autoguiding proceeded well for each of the targets.   

To be completed ....

Target Time Exp
(s)
No.
Subs
Autoguided FWHM
Median
FWHM
Range
Aspect %
Median
Aspect %
Range
  Curvature
%
Curvature
Range
Collination
"
M42 18:57 5 15 No 2.2 2.13-2.28 80 77-84        
M42 19:14 30 15 No 3.3 2.6-10.2 72 9-96 Longer exposure      
M1 21:54 10 146 No 2.4 2.21-2.55 71 63-82        
                         
M1 23:59 10 146 Yes 2.49 2.35-2.58 70 67-85   19.6 10.5-24.7 4.6"
M51 01:02 10 50 Yes 2.23 2.18-2.29 81 78-83   14.9 8.8-19.9 1.4"
M3 01:40 10 71 Yes 2.32 2.26-2.37 79 76-83   30.3 21.6-33.9 3.0"

Back to Top


Processing Images using AutoStakkert

 Screen Shots showing Processing of a set of Lunar Images (02_31_50Z.ser)
Image
 
Image
 
Final Image
Image

Back to Top


 Venus - Atmospheric Dispersion, Compensation using Autostakkert 2's RGB Align

Initially stacking of images of planet Venus (lying at 16 deg altitude) showed the effects of
atmospheric dispersion (i.e. a red tinge on limb closest to horizon and a blue tinge on limb furthest from horizon)

Image were then restacked using Autostakkert's RGB Align feature
This is performed on a subpixel level after stacking (resampling!)

[ At a future session I will try using a ZWO Atmospheric Dispersion Corrector (ADC),
this is part of new equipment plan for 2017. Experimentation may begin using 80mm f/6 APO,
before using it with 12" LX200 f/10 SCT where it is anticpated to provide the most benefit ]
        
Stacked image without RGB align      
Image    Image:



Total Exposure:
Subs/Exposure
Details:
Date/Time:
Image Set:

Equipment:

Software:

CMOS Colour Image (200% size)
P20 Stacking, Best 62 frames from 311
Without RGB Align

124 ms (0.12 sec)
62 x 2ms, 1x1 binning
Gain 0, Raw16, ROI 320 x 240  
2017-01-18 18:32h UT
(#18_32_24Z)

TS 80mm f/6 APO + ASI178MC (OSC)
mounted on 12" LX200R
Frames acquired using SharpCap (SER)
Stacked using Autostakkert 2
       
Stacked image with RGB align      
Image    Image:




CMOS Colour Image (200% size)
P20 Stacking, Best 62 frames from 311
With RGB Align

Image details a/a
       
       

Back to Top


 TS Photoline 80mm APO - Field Curvature (f/6 uncorrected)

It was expected that the image of the TS 80mm f/6 APO would not be flat. The products web page states:-

"The Photoline f/6 apo is suitable for astrophotography without restrictions, but, as with any fast refractor, the field has to be corrected for keeping the stars nicely round even at the edge. For this, we offer the following options which are linked in the accessories section ..." 

These options being
- 2" field corrector without change of the focal length (TSFlat2), inserted into the 2" adapter
- 2.5" field corrector without change of focal length (TSFlat2,5), screwed to the M63 thread.
- 2" Photoline x0.79 reducer and corrector (TSRed279), inserted into the 2" adapter
- 3" Photoline x0.79 reducer and corrector (TSRed379), screwed to the M63 thread.

So with several options costing different amounts and with various pros/cons it was decided to hold from buying any corrector (with/without reducer) until the native f/6 APO scope had been characterised and requirements/tradeoffs could be better understood through actual use of the scope for various tasks.  

The impact of curvature would likely be non-round stars towards the field edge, uneven focus across the field of view and uneven focus /star shape moving the XY finder between its +/-13.8mm limits.

Whilst the image might be reasonably flat for a relatively small sensor in ASI178MC camera (7.4 x 5.0mm), compared to a larger sensor in say a Canon EOS 400D camera (22.1 x14.8mm) for some tasks the sensor would be placed off-axis using Orion X-Y Guidestar Finder where field curvature effects would be potentially much larger.  Working the XY finder at its +/-13.8mm limits means the area of possible placement of the ASI178MC sensor becomes effectively 35.0 x 32.6mm !. This is not dissimilar to the area of 35mm film (36 x 24mm).

 To be completed ...

 
 
 
 
 
 

Back to Top


ZWO ASI178MC - Master Dark Frame

A master dark frame (RAW16, 3096x2080, gain 400, exp 10s) was acquired using SharpCap as an average of 25 individual frames The Master Dark was then used for the realtime (live) reduction of 10s light frames acquired during the session (S00600).

Master Dark Frame (log scale, 16% size)
Raw16, 3096x2080, gain 400, av. 25 x 10s
(dark_25_frames_2017-01-18T21_08_59.fits)
Levels adjusted to show the brighter areas in bottom-left, bottom-right and top-right corners
Image
[ Larger Size, 32% ]
 
Master Dark Frame (linear scale, 16% size)
Master Frame details a/a
ADU range 0 to 10000
The dark noise is very low apart from a few hot pixels
Image
 
  The histogram for above Master Dark Frame indicate that
90% of pixels have ADU value of between 4 and 8.
but there is collection of 'hot' pixels with a peak values around 3900 ADU
and a set of defective pixels with value from 8000 to 58985 ADU.
Image

Back to Top


Unexplained Light Artefact - ASI178MC / Orion XY Finder / TS 80mm APO

A light artefact was noted whilst imaging a region of M45 (Pleiades). The artefact is unexplained.

The artefact was present on multiple subframes on one particular image sets. The artefact would seem to relate to light coming from a particularly bright star located at a particular part of the field of view.   It it unclear if the artefact is due to some imperfection in the APO lenses of the TS 80mm scope, some imperfection in the sensor (or glass cut) or a light reflection inside the optical train.

 

Light Artefact
Reddish Patch to left of bright star
     
Image   Image:


Exposure:
Details:
Image ID:

Date/Time:

Equipment:



Software:
CMOS Colour Image (16% size)
Live Stacking of 60 frames

10 min (60 x 10s)
Binning 1x1, Gain 400, Raw16, ROI 3096x2080 
#00_19_25Z

2017-01-19 00:19h UT

ASI178MC (OSC) + TS 80mm f/6 APO
Mounted on 12" LX200R
Autoguiding using ST-10XME + 12" LX200R f/10

Frames acquired using SharpCap (Stack FIT)
Processed using DeepSkyStacker
Autoguiding using CCDSoft
  Same star but re-positioned onto right hand side of sensor
(the 'light artefact' in previous image is clearly not a deepsky object)
     
Image   Image:

Exposure:
Details:
Image ID:


Date/Time:

Equipment:



Software:

CMOS Colour Image (16% size)
Live Stacking of 66 frames

11 min (66 x 10s)
Binning 1x1, Gain 400, Raw16, ROI 3096x2080 
#00_32_52Z

2017-01-19 00:32h UT

ASI178MC (OSC) + TS 80mm f/6 APO
Mounted on 12" LX200R
Autoguiding using ST-10XME + 12" LX200R f/10

Frames acquired using SharpCap (Stack FIT)
Processed using DeepSkyStacker
Autoguiding using CCDSoft5
       
Light Artefact - Detail
Reddish patches to the left of bright star
also a small yellow-white patch to the immediate right of star
(are they related ?)
     
Image   Image:


Exposure:
Details:
Image ID:

Date/Time:

Equipment:



CMOS Colour Image (50% size, cropped)
Live Stacking of 60 frames

10 min (60 x 10s)
Binning 1x1, Gain 400, Raw16, ROI 3096x2080 
#00_19_25Z

2017-01-19 00:19h UT

ASI178MC (OSC) + TS 80mm f/6 APO
Mounted on 12" LX200R
Autoguiding using ST-10XME + 12" LX200R f/10
        
Light Artefact - Detail
artefact to the immediate right of star
artefact is present on each of the 60 subframes
     
Image   Image:






CMOS Colour Image (100% size, cropped)
Live Stacking of 60 frames
Alternative Contrast Setting

Image details as above

Back to Top


 Image Display Issue in AIP4WIN

Whilst trying to find a suitable workflow for displaying stacked colour images the program called AIP4WIN was initially used to display Live Stacked images from SharpCap or post-session stacked images from DeepSkyStacker.  It was quicker noticed however that  brightest stars looked very unnatural in the 'finished' display image, involving what seemed a supersaturated white peak with a blue spilling in an upwards direction (see first image below)

It was assumed that the problem with the stars was due to the image being saturated in all three colour channels due to the 10s exposure being simply too long for correct handling of these brighter stars.   However it is now suspected the problem might be due to AI4WIN's handling of non-signed 16bit and non-signed 32bit FIT images.

After eventually working out how to display/manipulate images in DeepSkyStacker, it was discovered that the DeepSkyStacker display didn't produce these ugly looking stars but instead produced normal looking stars from the very same stacked FITS image file (see second image below)

Stacked Image created using DeepSkyStacker

a) displayed in AIP4WIN
     
Image   IImage:


Exposure:
Details:


Date/Time:

Equipment:


Software:


CMOS Colour Image (40% cropped)
P50 Stacking, Best 8 frames from 15

4 mins (8 x 30s)
Binning 1x1, Gain 300, Raw16, ROI 3096x2080
ID #19_34_54Z. Non-Guided.
  
2017-01-18 19:34h UT

ASI178MC (OSC) + TS 80mm f/6 APO
Mounted on 12" LX200R

Frames acquired using SharpCap (FITS)
Stacked using DeepSkyStacker
Displayed using AIP4WIN
       
  b) displayed in DeepSkyStacker      
Image   Image:


Details:

Software:
CMOS Colour Image (40% size,cropped)
P50 Stacking, Best 8 frames from 15

Image details a/a

Frames acquired using SharpCap (FITS)
Stacked using DeepSkyStacker
Displayed using DeepSkyStacker

Back to Top


Software Notes (2017-01-18 to 2017-01-19)

Further notes taken during continued testing and operation of ZWO ASI178MC camera with different software.

CCD Inspector 2.5.3
32 bit images are unable to opened by CCDInspector (error message is given to alert the user)
This means the CCDInspector is unable to open such files as :-  
     32-bit .fts files produced by Live Stacking Process in SharpCap

 

Back to Top