CTB 1 (“Garlic Nebula”, “Medulla Nebula”) was initially identified by George Abell as planetary nebula, Abell 85, but was later identified as a supernova remnant (G116.9+0.1) in 1972. The CTB designation is from the Caltech Observatory list B catalogue. The designation Abell 85 is still used today.
CTB 1 is in the constellation Cassiopeia (Cas) and is approximately 10,000 light-years from Earth, about 100 light-years in diameter, and is estimated to have formed about 10,000 years ago. It is nearby several other emission nebulae: Sh2-170 (the dot in the Cosmic Question Mark), Sh2-168, and Sh2-173 to name a few.
It has an interesting circular structure with many filamentary structures as well as a rupture in its shell (on the upper right of the photo), a slim and faint OIII signal on part of its shell and lots of surrounding nebulosity.
Capture Dates: 9/30, 10/2, 10/3, and 10/4
Average Moon Illumination ~ 84%
Askar 107PHQ (fL = 749mm)
ASI2600MM Pro (Monochrome camera)
Antlia LRGB-V & SHO (SII, Ha & OIII) 2” mounted 3nm Narrowband Pro Imaging Filters
ZWO AM5 mount with guiding via SV106 and ASI178MM
Narrowband S-H-O Light Frames [Total Exposure 19:00]
-- Ha; 300 sec x 67 = 5:35
-- OIII; 300 sec x 94 = 7:50
-- SII; 300 sec x 67 = 5:35
RGB Frames for Stars [ Total Exposure 0:30]
R, G, B – 10 x 60 sec each
All light frames calibrated with dark, flat, and bias frames
Pre- and post-processed in PixInsight
Additional post-processing in Photoshop for exposure adjustments and generation of reduced size jpeg
Great image Greg, I’ll have to add it to my list. Looks like an interesting area too.
terri
@terri Thanks, Terri. This one could definitely use more time. Nineteen hours really doesn't do it justice in terms of capturing all the detail.
Greg
Maybe, but it still looks great! We’ve landed in Texas and slept in Sonora last night. The ranch is 20 miles away. We’ll be heading over in a bit to stake a claim on the observing field. I hope we get some clear nighttime weather.
terri
Great work, Greg, and a remarkable target. Terrific detail, I can't imagine what more you could hope to get with more time, but I look forward to seeing what you get!
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Fantastic, Terri!! Wish you lots of clear skies while you're there. Bring some nice pics back for us 'seventeen-percenters' stuck here in VT. 😆
Have fun!
Greg
@peter-gillette Thanks so much, Peter! I love these 'off the beaten path' targets but it's a bit harder to know how much detail I should see since there isn't a great body of work on them. From all the previous work on this relative new-comer for Earth (10,000 years old @ 10,000 ly away), it needs about 30 hours or so to do it justice.
The problem with me is I get blinded by the new shiny targets and never wind up getting back to the ones that I'd like to add more time on! I feel like a kid in a candy store sometimes.
Greg
Hi Greg!
This is such a terrific image! You've been posting some unusual objects that I haven't seen before which is so refreshing!
Hope you don't mind I posted your Propeller and this on our VAS Facebook among amazing others you've done ~ 👍👍
Maura
@maura-kelley Thanks so much, Maura! Sure, absolutely put whatever you think is appropriate on the VAS Facebook page. Thanks for doing that and for maintaining that page!
Greg
