This is the Wizard Nebula. I’m told it is supposed to look like a wizard in a pointed hat and gown with open arms. This image is the result of a 7hr session (4hrs Ha, 3 hrs O3) on a night of full moon, (many subs rejected due to clouds and wind). Considering the number of rejected subs I’m pretty happy with the result.
I’ve combined the signals as R=Ha, G= 0.3*Ha +0.7*O3, B= O3. The central blue area of the nebula was enhanced using an O3 range mask and just increasing the blue saturation a little. This was quite tricky to process as the O3 is very weak.
The halos around the bright stars come from reflections and scatter in the O3 filter. I am not sure if I can do much about that without investing in a more premium filter or lots of image processing.
After cleaning and correctly(!) fitting my LRGB filters I decided to go a for a bright broadband target. Clouds, moon and poor seeing did not help but I managed about 45 mins each for RGB and Ha – shot with the ASI1600mm. This is tight cropped as I combined Ha from two sessions and the framing wasn’t very well repeated. (I really must work out a way to index my camera rotation.)
This is the first full imaging session since changing the RA and DEC boards of the CEM70G. The resolving power (Dawes-limit) for the scope is about 0.45 arc seconds. At this focal length the ASI1600mm pixel size is 0.65 arc seconds. This camera is basically working at the limits of the scope. If you pixel-peep this image even with the poor seeing you can tell the CEM70G is now getting the most out of the combination. An OAG may give me fewer reject subs but I am very happy using my 60mm guidescope +ASI290 guide camera.
This was trickier for me to process than the Heart nebula. Although it was clear, conditions were not great and I had few gremlins to deal with. Overall, it meant fewer hours of data so far captured (7hrs total, 2hrs each for Ha and O3, three hours for S2). This shows in the noise and processing artifacts visible in the enlarged image as I attempt to get something close to the Heart image in detail and vibrancy.
Details: ASI1600mm pro, Altair Astro 70mm EDT-F on the HEQ5.
Here is another attempt at processing the data, this time I just used the subs from the second night as they were better framed, so this represents about 3.5hrs of S2, Ha, O3, processed as SHO in a pseudo-Hubble palette.
This is my first imaging season using narrow band filters on a mono camera. I’m enjoying the freedom to image and not fight moonlight or light pollution from the city.
The Heart nebula (IC1805) is in the constellation of Cassiopeia. This is the result of 6hrs of 120s subs in S2, Ha and O3. Imaged using the ASI1600mm pro with a gain of 200. Processed in PixInsight with the Hubble palette SHO.
Visible at the top of the heart image is what looks like a small blue galaxy or planetary nebula. At bit of research reveals this is WeBo 1 (PN G135.6+01.0) a planetary nebula. It has a good signal in Ha and Oii. Perhaps imaging with my 250mm Newt will reveal more of its structure.
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This image is the result of 13 hrs of imaging. I still have much to learn about image processing but I am quite happy with this result. The S1, Ha and Oiii subs were 120s @gain 200 to avoid burning out too many stars.
I imaged this nebula over 2 nights, several weeks ago in August but I had a terrible time processing the data. I was convinced I had some issues with my flats and then my subs. Then I was sure I had some light pollution leaking into the camera. I was at a loss for a solution but then I happened to read a post over at Forum | Backyard Astro that suggested to me the problem was how I used the Weighted Batch Processing script. I had recently updated PixInsight and was just using WBPP script with its out of the box default values.
That was a stupid newbie error, correcting the configuration of WBPP for the flats and light processing completely resolved the problem. As a result, I went back through all my recent images and began a methodical reprocessing.
I don’t want to go through that pain again so I have written down the steps and will publish what has worked for me.
One thing you will notice if you pixel peep the image is that the stars are vertical short lines. Guiding was close to perfect for this target so I believe the problem is caused by the RA motor drive board of my CEM70G which is a 2020 vintage, later mounts have improved RA and DEC boards. At least I hope that is the root cause as I’ve ordered replacements from the iOptron factory and I dont really want to use an OAG. [The last I heard the factory airport was in lock down due to covid so I don’t know when to expect them.] Because of the star shape it is a little more difficult to use my star reduction technique that worked so well for my IC1396 image. I shall have to see how others do it.
One thing I have learnt as a result of writing my steps down is slavishly following a process does not work well for all images. Sometimes you have to deviate from the path and experiment too. But still, a written down process is a good place to start from.
This is a narrow band S2, Ha, O3 image taken over 6 hours (2hrs each) in one night.
Imaged with my Altair Astro 70mm ED-Triplet and my ASI1600mm pro camera.
This image is a reprocess of the same data with slightly less green removal and a different crop.
Finally worked out that Automatic Background Extraction was causing my vignetting in processed images and not poor flats or something else in the data. I’ve had another go and produced an almost full-frame image (minus the few pixels for dithering) with better colour control and handling of the stars:
This is the result of 4 hrs each of S2, Ha and O3 subs taken over three nights, I was lucky to have excellent conditions. I have been able to pull out the gas from the background with very little processing. So more (good) data = easier processing. I need to play with the colour balance it takes some getting used to.
Imaged using my Altair Astro 70mm triplet, ASI160mm Pro and filters on my HEQ5. Each sub was 5mins @ gain 200.