Sunday, September 25, 2022

Sh2-91 - Part of a Large Supernova Remnant

Sharpless 91 (Sh2-91) is a portion of the large supernova remnant (SNR), SNR 065.2+05.7. Along with Sh2-94 and Sh2-96 they are all filaments of the SNR with a diameter of about 230 light-years (70 parsecs) and an age approximately 30,000 years. It is located in Cygnus very close to the Veil Nebula but further away at 2500 light-years (Ly) as opposed to 1500 Ly for the Veil and it is four times older. Also located in this image is the small Planetary Nebula Min 1-92 (Minkowski's Footprint). In my image it looks like a tiny blue elongated star roughly in the center left of the large blue star and just below the nebula (there is a white star next to it so they almost look like they could be a double star system). I really like the blue and red intertwining filamentary structure. I also like the colorful starfield that this nebula resides in, however, it is a double edge sword as those same stars really had to be reduced in order to bring out the nebula.

So this image represents my first attempt at doing a mosaic and it was by accident (?). What happened is I thought I had my camera oriented 90 degrees from and I did not realize it until after I started - this object is much dimmer than the Veil. After I got started I decided to go with the mosaic as even if I had the camera oriented differently I still would not have captured the whole thing. The mosaic is 3-planes oriented vertically and it was really easy to set up a plan for the other two planes in N.I.N.A. as all I had to do was adjust the right ascension. I did the mosaic processing in PixInsight following YouTube instructions from Windy City Astrophotgraphy (Nick). It worked well or so I thought when I first looked, however, when I removed the stars the merging was quite apparent. The good news is it was not so bad and I was able to do a little processing gymnastics to fix it. There is another program, Microsoft Image Composite Editor, that has been getting good reports so the next time I do a mosaic I might try it instead.

Dates: 8-1-22, 8-2, 8-3, 8-5, 8-6, 8-8, 8-12, 8-14, 8-18, 8-20, 8-23, 8-26, 8-27, 8-29, 8-31, 9-1, 9-2, 9-9

Exposure: 
Plane1 - Ha 51 x 300, OIII 61 x 300, R 55 x 60, G 51 x 60, B 50 x 60
Plane2 - Ha 53 x 300, OIII 46 x 300, R 39 x 60, G 41 x 60, B 40 x 60
Plane3 - Ha 49 x 300, OIII 68 x 300, R 32 x 60, G 37 x 60, B 37 x 60


Sh2-91 - Part of a Large Supernova Remnant (2022)
Dates: 8-1-22, 8-2, 8-3, 8-5, 8-6, 8-8, 8-12, 8-14, 8-18, 8-20, 8-23, 8-26, 8-27, 8-29, 8-31, 9-1, 9-2, 9-9
Camera: ZWO ASI1600MM-Pro
Telescope: Astro-Tech AT115EDT 115mm Refractor Telescope
Barlow: None
Focal Length: 805mm (644mm w/ FR)
f/7
Focal Reducer: 0.8x AstroTech Field Flatterner/Focal Reducer
Mount: Orion Sirius
Filter Wheel: ZWO EFW 8 x 1.25"
Filter: ZWO Ha, OIII, R, G, B
Focuser: ZWO EAF
Autoguiding: ASI120 Mini attached to an Agena 50mm Guide Scope/ZWO 60mm Guidescope
Exposure: 
Plane1 - Ha 51 x 300, OIII 61 x 300, R 55 x 60, G 51 x 60, B 50 x 60
Plane2 - Ha 53 x 300, OIII 46 x 300, R 39 x 60, G 41 x 60, B 40 x 60
Plane3 - Ha 49 x 300, OIII 68 x 300, R 32 x 60, G 37 x 60, B 37 x 60
Gain: 139
Offset 20
Sensor Temp: 0 C
Processing: NINA, PixInsight, Photoshop, Topaz DeNoiseAI, StarXTerminator.

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Thursday, September 8, 2022

HB3 - Supernova Remnant Next to the Heart Nebula!

The framing is not a mistake, it is centered on HB3 (a.k.a. G132.7+1.3). HB3 is a Supernova Remnant (SNR) first cataloged by a radio astronomer and imaged optically in February of 2022 by a research group (article from the Royal Astronomical Society, https://arxiv.org/abs/2202.07749v1). I first found out about this object from Göran Nilsson who produces incredible images using his dual RASA rig from Värmland, Sweden (https://www.astrobin.com/96arhu/B/). According to the authors of the article, the SNR formed in a wind bubble cavity created by the progenitor star. The estimated mass of this Wolf-Rayet star is 34 solar masses.

As can be seen on the image the blue OIII structures from SNR are visible, however, they were quite difficult to bring out even with the over 20 hours of data. A starless version is most certainly needed in order to bring it out and fortunately many good star removal programs are available these days. Even so, it was still very difficult to process, in fact after one day of processing, I did not like what was produced and started over. In addition to the Heart Nebula, several other dark nebulae are scattered throughout the image including some on the right side. I cropped it only a small amount as I wanted to show the rest of the field including Segin, the bright blue star in Cassiopeia. I was hoping it would be more strongly visible but then again none of the SNR was visible in any of the 5-minute exposures.

If you do go after this object be prepared to get a lot of data and even then it is a bit iffy. On the positive side even if you don't get HB3, you will still get a decent image of the Heart Nebula. I have several images of the Heart Nebula that I have taken over the years so I did not mind not having it be the center of attention.


HB3 - Supernova Remnant Next to the Heart Nebula!
Dates: 8-23-22, 8-26-22, 8-29-22, 8-31-22, 9-1-22, 9-2-22 
Camera: ZWO ASI2600MC-Pro
Telescope: Canon EF 200mm f/2.8L II USM Lens
Barlow: None
Focal Length: 200mm
f/4 with stepdown rings
Focal Reducer: None
Mount: Orion Atlas Pro
Filter Wheel/Drawer: ZWO EOS Filter Drawer
Filter: IDAS Nebula Booster NBZ Filter
Focuser: None
Autoguiding: ASI120 Mini attached to a ZWO Mini 30/120mm Guidescope
Exposure: 250 x 300
Gain: 100
Sensor Temp: 0 C
Processing: ASIAIR Pro, PixInsight, Photoshop, StarXTerminator.
Power: BINZET AC to DC 12V 10A 120W Power Supply

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