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.
Posted inDeep Sky, Nebula|Comments Off on IC1805 The Heart Nebula – SHO
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.
This LRGB image is the result of 3 hrs of imaging with many lost subs due to cloud and some RA imbalance issues. Probably only 1.5hrs with most of those softened by clouds. This results in a noisy and more washed-out image than I would have liked. Still, compared to my first attempts, 14 yrs ago, it’s not bad.
Imaged with the ASI1600MM-Pro, ZWO filters, Lacerta Komakorr Coma Corrector. modified Orion Optics 250mm Next on the CEM70G.This was first-light for my refurbished scope. I had the mirrors re-silvered in 2020, I flocked the tube and replaced the focuser for a Skywatcher low-profile Crayford. I’ve just finished making a brace for the rings – to stop ring wobble – which it does very well. The Lacerta Komakorr Coma Corrector is a big improvement over Skywatcher 0.9 CC. Sharpness has improved across the image, its very noticeable.
I should try and revisit this target again and give it the time it deserves now that my equipment can capture more detail.
Some of my earlier attempts:
A guided session using an HEQ5. Manual focusing is a bit dodgy so lots of detail lost.
An early guided session using my HEQ5.
Taken with a Canon 350d, OO 250mm on an EQ5 unguided.
Taken with a modified webcam using my OO 250mm on an EQ5.
I had a few things to crack like the differential flexure and misting up of the camera that trashed a lot of the subs I took in a 3hr session. As a result, at first when I processed the image I lost all the colour but revisiting the data and being more careful I have been able to bring out a lot more detail and colour. All things considered this is not a bad image – noisier than I would have liked but we can’t have everything.
If you pixel-peep the image you can see the smaller stars are elliptical left to right. This is the result of a high frequency oscillation in the RA axis of the CEM70 that I have fixed by a board swap out.