SH2-170 - Little Rosette Nebula

The Little Rosette Nebula designated as SH2-170 is also known as the Small Rosette Nebula is located approximately 7,500 light-years away in the constellation of Cassiopeia. In its center is a young star cluster named Stock 18 whose brightest star ionizes the hydrogen gas, thus producing the glow. It resembles the larger and more popular winter object The Rosette Nebula in the constellation Monoceros.  I estimated the diameter to be ~45 ly by doing a trigonometric calculation assuming the angular distance of 0.36 degrees (2/3 lunar diameter) and a distance of 7,500 ly.  For comparison the Rosette Nebula is 130 ly across and 5,000 ly away.

I would have liked to get more data but the weather has not been cooperating at all. This is a good object to use the dual band IDAS NBZ filter since it has lots of hydrogen and a bit of oxygen. I separated the RGB and made 'synthetic' Ha and OIII channels and then recombined it as an HOO image. I also did a bunch other stuff including synthetic luminosity layers and Starnet++. Overall I am happy with the outcome.

This is my last image for a while with the 0.7 focal reducer as I plan to test the hyperstar next.  In fact this may be last image for a while period as summer recess is over.  I did manage to solve the issue I was having with stacking in PixInsight, it seems it was my flats after all. This image and my previous image with the setup of SH2-136 - The Ghost Nebula stacked perfectly with PixInsight using my new flats.

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SH2-170 - Little Rosette Nebula

Dates: 8-15, 8-16

Camera: ZWO ASI294MC-Pro
Telescope: Celestron EdgeHD 800
Barlow: None
Focal Length: 2032mm (native)
F/10 (native)
Focal Reducer: Celestron .7 Reducer Lens
Mount: Orion Atlas Pro
Filter Adaptor: ZWO Filter Drawer
Filter: Baader IDAS NBZ (2-inch)
Focuser: ZWO EAF
Autoguiding: ASI120 Mini attached to an Orion ST80
Exposure: NBZ 90 x 180
Gain: 120
Offset 0
Temp: 0 C
Processing: Asiair app, PixInsight, Photoshop, Topaz DeNoiseAI.

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SH2-99 & SH2-100 Region

There is a lot of action going on in this less imaged region of Cygnus. The star features are SH2-99, the bright area a bit right of the center, and SH2-100, the bright area at the center of the image. I could not find much information about the objects, only that Stellarium categorizes them as HII regions. SH2-100 is the brighter of the two and is about 30,000 light-years away with other designations such as NGC 6857 and PK 070+01.2. One of my favorites in this image is the translucent blue and gold wedge part in the top central portion. It is designated as SNR G070.5+01.9 and described as a supernova remnant candidate. There are two other supernova remnants found in this image. 1) The small dense bright orange spot to the left is designated as SNR G070.7+01.2 and 2) the blue stream on the right side is designated as SNR G070.0+02.0. Lastly, the blue-gold arching nebula on the top left is LBN 164, the gaseous region on the bottom center with golden vertical streamers is LBN 159, and the deep blue region on the right is known as LBN 158.

I had not intended to image this over a three week period but the moon and the weather made imaging quite difficult. I started with the narrowband data but then took the camera and unit off mount to do some other stuff. As a result I forgot to carefully align the camera at night. Fortunately it was the RGB data which I was only using for the stars.

As expected, hydrogen was by far the most abundant gas followed by sulfur and oxygen. I spent a lot of time trying to tweak the color but was never truly happy with it until I made adjustments in a totally different way and was able to get something satisfactory. 

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SH2-99 & SH2-100 Region

Dates: 7-19, 7-21, 7-23, 7-26, 8-2, 8-6
Camera: ZWO ASI1600MM-Pro
Telescope: Astro-Tech AT115EDT 115mm Refractor Telescope
Barlow: None
Focal Length: 805mm
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, SII, R, G, B
Focuser: ZWO EAF
Autoguiding: ASI120 Mini attached to an Agena 50mm Guide Scope/ZWO 60mm Guidescope
Exposure: Ha 76 x 240, OIII 52 x 240, SII 60 x 240, R 28 x 60, G 26 x 60, B 27 x 60
Gain: 139
Offset 21
Sensor Temp: 0 C
Processing: NINA, PixInsight, Photoshop, Topaz DeNoiseAI.

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SH2-136 - Ghost Nebula

SH2-136, nicknamed The Ghost Nebula (a.k.a. VdB 141), is a faint reflection nebula in the constellation of Cepheus. The Nebula sits in a heavily dusty region known as the Cepheus Flare molecular cloud complex and is approximately 1,400 light-years away and two light-years across. Star formation is occurring in dense areas of the nebula in fact the bright area with a V-shaped projection on the right end of the nebula is a protostar forming. The projection is believed to be caused by outflow of the rotating accretion disk.

This has been on my someday list but I waited until I had a scope capable of getting some finer detail including some the protrusions pointing upwards which resemble fists with fingers pointed outwards - one of my favorite parts of the nebula. I purposely did not crop it because I wanted to show the even fainter dust which lies on the right side of the main nebula and of course the relatively bright portion on the top of the image. Most of the stars appear slightly yellow being obscured by the dust but some of the large bright blue ones still shine through. Also, I spent some extra star reduction on the larger stars which was a bit tedious but worth it.

This nebula is very faint and really was not in my subframe when imaging with 3-minute exposures. Three minutes is about the maximum I feel comfortable with without using any type of light pollution filter in my neck of the woods. I believe I have found the optimal back focus at 108.5mm for my system at last after several tweaks. I started with the recommended 105mm, then 106.5mm, then 109.5mm, and finally 108.5mm. If you have been following my PixInsight/ASI24MC escapades (https://www.youtube.com/watch?v=Ot5x63kya6A&t=3s), I managed to use PI without the artifacts this time. Could be that I have a better system but I'm not sure yet. I have to test it with the NBZ filter to be sure. Lastly, normally I orient objects so north is up but it looks more like a ghost with south being up.

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SH2-136 - Ghost Nebula (VdB 141)

Dates: 8-2, 8-5
Camera: ZWO ASI294MC-Pro
Telescope: Celestron EdgeHD 800
Barlow: None
Focal Length: 2032mm (native)
F/10 (native)
Focal Reducer: Celestron .7 Reducer Lens
Mount: Orion Atlas Pro
Filter Adaptor: ZWO Filter Drawer
Filter: Baader UV/IR Filter (2-inch)
Focuser: ZWO EAF
Autoguiding: ASI120 Mini attached to an Orion ST80
Exposure: UV/IR 124 x 180
Gain: 120
Offset 0
Temp: 0 C
Processing: Asiair app, PixInsight, Photoshop, Gradient Exterminator, Topaz DeNoiseAI.

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NGC 6543 - Cat's Eye Nebula

NGC 6543 or The Cat's Eye Nebula is a small, very bright planetary nebula found in the northern constellation Draco and 3300 light-years from Earth. My image may give the false impression that it is very large, however, The Cat's Eye is actually the bright core of a much larger complex but you really need a much larger telescope than I have to do it justice. It formed about 1000 years ago when a hot bright central star blew its outer layers into a much fainter region of gas believed to have formed from much earlier expulsions between 50,000 and 90,000 years ago. The entire region is three light-years across.

I have been wanting to do The Cat's Eye or at least the outer region for quite some time but I also wanted to wait until I had a big enough scope to make it worthwhile. I still ended up cropping quite a bit but if I did with the refractor I would have had to crop it 4x more just to see a blue blotch.

I tried to bring out some of the central detail of NGC 6543 but it is so much brighter than the faint outer region that it makes it very difficult. I took shorter exposures thinking I would stack them but there were not many stars bright enough for the stacking programs to register. I did some other 'stuff' to bring out some of the central detail and then focused on the rest of the faint regions. I really love the blue structure of the outer region. I also like the multiple red blips that are located within the translucent blue region and just outside on the left. I purposely offset the nebula to the left as I also wanted to show the barred spiral galaxy NGC 6552 on the right. It is pretty small in my image but it was there.

There really was not that many stars in this region so only one round of star reduction was necessary. I however use a different method courtesy of Dark Archon and Adam Block which seemed to work really well!

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NGC 6543 - Cat's Eye Nebula
Dates: 7-21, 7-23, 7-26
Camera: ZWO ASI294MC-Pro
Telescope: Celestron EdgeHD 800
Barlow: None
Focal Length: 2032mm (native)
F/10 (native)
Focal Reducer: Celestron .7 Reducer Lens
Mount: Orion Atlas Pro
Filter Adaptor: ZWO Filter Drawer
Filter: IDAS NBZ Filter (2-inch)
Focuser: ZWO EAF
Autoguiding: ASI120 Mini attached to an Orion ST80
Exposure: Ha/OIII 163 x 180
Gain: 120
Offset 0
Temp: 0 C
Processing: Asiair app, DSS, PixInsight, Photoshop, Topaz DeNoiseAI.

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