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IC 1871 – Part of the Soul Nebula Description IC 1871 is a very busy region of the Soul Nebula, Sh2-199. The Soul Nebula itself is often referred to as IC 1848 but in fact, this is the designation of a star cluster within the nebulosity. The Soul Nebula is located within the Perseus Arm of the Milky Way in the constellation Cassiopeia at a distance of around 7,500 light years from the Earth with IC 1871 situated on the north-eastern edge of the nebula. IC 1871 is rich is Ha emissions but less so in OIII which makes this region an ‘interesting’ challenge especially for bicolour imaging as displayed here, despite there being other regions within the Soul Nebula where there is a greater density of OIII emissions. If I could afford a 3nm SII filter, I would have used that too but I can’t so I didn’t! The nebula also plays host to some fascinating dust lanes that produce some great additional features to contrast against the bright ridges of glowing gas clouds. Within these gas clouds, large cavities have been sculpted by radiation and winds from the region's most massive stars. The dense star-forming clouds of IC 1871 are an example of ‘triggered star-formation’, a theory that suggests that the compressed edges of the cavities caused by the outwards push of the radiation and wind cause the region to produce successive generations of new stars. Image Stats Mount: Mesu 200 Telescope: Sky-Watcher Esprit 150 Flattener: Sky-Watcher Esprit specific Camera: QSI 683 WSG-8 Filters: Astrodon 3nm Ha, 3nm OIII Subframes: 15 x 1800 sec Ha, 28 x 1800 sec OIII Total Integration: 21.5 hours Control: CCD Commander Capture: MaxIm DL Calibration, Stacking and Deconvolution: PixInsight Post-Processing: PhotoShop PS3 Location Constellation Cassiopeia RA 02° 59' 41.0" DEC +60° 41' 4.0" Distance ~7500ly
Here's my first attempt at bi-colour HOO narrowband, using the OIII filter I got for Christmas Please do click through to Flickr and have a look at it with the magnifying glass, there's loads of detail in there. 23x600s Ha, 20x60s Ha, 10x600s OIII, 8x60s OIII, darks, flats and bias, equipment as per sig, Pixinsight. It was an absolute joy to process this, it was singing to me from the very first trial combination of stacks. I had lots of fun playing with colour balances (actually it's more like HOo, and then I let the red grow a bit, looks like a watermelon to me). Had fun with the HDR too. I've done some HaLRGB before, and I have the skies for it, but I'm finding HaLRGB to be quite frustrating - takes ages to process to get the balance right, and even then it seems to be a compromise between the detail of the Ha and the colours of the RGB, and all too often, it comes out like a big red smudge. I've got a Pacman in processing that might just end up left on the cutting room floor. It seems I've finally tamed my collimation and coma demons, but on this occasion, my guiding was surprisingly shocking. I normally get something like 0.45" rms error, but this time was as much as 2.5". We'd had near-gales the few days before I took this, and while it was calm at ground level on the nights I was capturing, I guess it was still hurtling around in the upper atmosphere - pretty twinkling stars, and a rather less pretty guide star bouncing around all over the place in PHD. I had to throw away nearly half of my OIII because the stars were too fat, as you can tell from the capture details above. Just for a laugh, here is my first attempt, taken 6 years ago with an unmodded DSLR - a shamefully small set of data (ahem, 13x10s !) and processed within an inch of its life (I think this was about the 4th reprocess), but not a bad attempt I suppose. Anyway, hope you enjoy, comments and cc welcome ! Cheers, Stuart
I lost astro dark a couple of weeks back. I thought, therefore, that I would try capturing narrowband during nautical darkness on the basis that I may as well do something with all the gear. I ended up with 6 hours of Ha and 6 Hours of OIII captured at my home observatory using my Esprit 120 and QSI 690 atop a Mesu 200 mount. Filters are Astrodon and exposures were 30 minutes each. Processing in PixInsight and Adobe Photoshop. I cropped the image slightly to eliminate a couple of brighter stars at the edge of the frame. I'd be interested to hear what people think.
This came as a bonus target, I didn't really plan to shoot it, but I took the opportunity to grab some frames before astrodark or with the DSLR or waiting for other targets So this is a mix of everything: 10x2min Ha with the ASI1600 and 130PDS on the AZ-EQ5. 11x3min Ha with the ASI1600 and Esprit80 on the AZ-EQ5. 19x5min Ha with the ASI1600 and Esprit80, 11 on the AZ-EQ5, 8 on the EQ6-R. 15x5min Oiii with the ASI1600 and Esprit80 on the AZ-EQ5. 74x90s with the DSLR and 130PDS on the AZ-EQ5. For a total of 5:34h. Crop of RGB, HOO and HOO-RGB. Which are your thoughts before I call it the final version? Clear skies! Alex Edit, final:
For reasons unknown, we experienced a good night here last night. Indeed, I managed to get 5 hours of data during 'Astro Dark' - all of it with reasonable guiding. I had an hour of Ha from the previous evening. So this made 9 x 20 mins of Ha and 9 x 20 mins of OIII. All captured using the Esprit 120 and the QSI 690. Filters were 3nm Astrodons. I did my pre-processing in PixInsight. The stacks looked reasonable and I just 'kept going' in PixInsight. This is PixInsight with no Photoshop whatsoever, which is a first for me. It is reasonably clean but my original plan was to get at least 6 hours of Ha and OIII, and I may carry on with that. As usual, I'd appreciate comments and criticism.