Two targets imaged with Nina at the helm.
Took decision to run Darks first – I think a good idea, the temperature held pretty steady all night and saved time this morning when I had to start Work. Flats were all I had to do this morning.
Both targets with the Optolong l-Enhance and running at 1600 gain 120s exposures
Barnard33 – Horsehead Nebulae
Rosette Nebula (NGC2237)
The only issue I had was when I came to review the rig this morning I found that the Safety Horizon limit had kicked in, i.e. Nina did not appear to take account of my local horizon and stop – it kept shooting even when the object was no longer visible. Not sure if this is related to multiple object run.
I think I found the answer when I examined the logs and the images from tonight. What I saw was nothing unusual in the logs, actually the imaging session ran until around 3am and then it stopped – completely correctly, this is around the time when I would expect to lose the image behind obstruction on my local horizon. This is backed up by the last few exposures taken that evening. What I believe was the fault was that I had failed to ensure that the scope was parked on imaging end. Hence, the scope would continue to sidereal track the sky and eventually hit my safety horizon – good job I put that in the EQMod as otherwise I think I would have been ripping up the gears and crushing the camera into the tripod for a few hours before I got up!
Not sure why this would not have happened on previous runs – I’m sure the scope has peaked previously- need to look into that.
LESSON – MAKE SURE SAEFTY HORIZONS ARE IN PLACE.
Results
Still on the steep learning path with PixInsights so decided to process with DSS and post process with Photoshop. I did add one complication which was to try removing the stars from the image by running the Level and Curve Stretched TIF image through Starnet++. This provided me with the ability to reduce the brightness of some of the stars and the effect of the star bloat by creating a Star Mask and applying brightness and contrast reduction. The following shows the Starless and Final version (cropped). I processed both images using the same workflow.
Barnard33 – Horsehead Nebula
Combination of 73 + 122 Lights taken over two sessions. 122 Lights where better quality taken on 4th January 2022. All taken at ISO 1600 with 2m 0s subs. Flats / Darks and Bias where also taken separately on each night so where processed using Deep Sky Stackers File Groups Each Night in one group. Total Integration time of 6h 30m
Barnard33, Horsehead Nebula Starless
Final Cropped Image with Stars
I’m happy with the image, irrespective of the large amount of star bloat that Starnet++ couldn’t quite get to grips with I really like the starless image. focusses attention on the delicate clouds.
NGC2237 – Rosette Nebula
75 Subs of 2m gave me 2h30m of integration time. On Rosette I used the same processing workflow as with the Horsehead nebula, i.e. After stacking (with 2* drizzle) I went into photoshop to stretch the image before then using Starnet++ to remove the stars. I then created a mask with just the stars from the original image and used that as a mask to allow me to desaturate and lower the brightness of use the stars alone.
Both the starless image and my final image are shown below:-
Rosette Starless
Rosette Final
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