“Small Toby Jug” and “The Jaws” by Zaytsev and Hanson
Revisiting the scene near the NGC 6188 “Fighting Dragons of Ara” [1], containing two remarkable DSOs with much larger integral exposure and in modified SHO colors:
WRAY 15-1508 (PK 335-01.1, Hen 2-169) planetary nebula [2] that looks like a smaller version of IC 2220 Toby Jug nebula [3] - hence calling it a “Small Toby Jug” nebula.
PCG 11 (PHR 1633-4928) Wolf-Rayet star and associated ring nebula [4-6] that has been named “The Jaws” by Logan Carpenter [7] who first introduced it to Astrobin back in 2023 [8, 9].
The earlier image obtained for this scene in H-alpha only with the same Chilescope T1 system back to 2024 is available under [10]. Many other diffuse structures and dark nebulae are visible across the frame, emphasized even better in the color compared to the H-alpha only view.
Fig. 1 shows a cropped version of the image centered on WRAY 15-1508 at 200% of original resolution. According to [11] it is identified as a flat bipolar outflow planetary nebula, yet many additional structural features are revealed in this image, including a disruption in the “arms” of the nebula in the middle likely hinting the presence of a neutral gas disk in the middle. The distance estimate to WRAY 15-1508 given in [12, 13] based on Gaia EDR3 [14, 15] data is 2177 ± 233 pc, so the linear size of the “arms” of the nebula is about 0.33 px x 0.39 pc, and the gap in the middle is only 0.027 pc = 5.6 kAU wide.
Fig. 1. Annotated copped version of the image shown at 200% of original resolution showing the area around WRAY 15-1508 planetary nebula [2].
Fig. 2 shows a cropped version of the image centered on PCG 11 at 150% of original resolution. Based on the distance estimate to PCG 11 of 4100 ± 400 pc given in [5, 6] the linear size of the shell of the nebula is about 1.50 pc x 1.97 pc and the characteristic size of non-uniformities in the rim is just about 0.22 pc. According to [5, 6] the explanation for thee unusual disruptions of the ring structure on the inner side of the rim of PCG 11 is as follows:
Fig. 2. Annotated cropped version of the image shown at 150% of original resolution showing the area around PCG 11 nebula [4-6].
"Material at the inner boundary of that enveloping material suffers Rayleigh-Taylor instability. This appears as a highly regular scalloping of the inner margin of the nebulous Ha ring, defined by fingers of infalling ionized matter. There is a very well-defined wavelength for this phenomenon in PCG 11 and it is observed around the entire nebula rim."
These are likely the most detailed views obtained for WRAY 15-1508 and PCG 11 thus far, but both can be excellent targets for the larger aperture systems.
Data and initial calibration/integration: Alexandr Zaytsev https://www.astrobin.com/users/m57ring/
ASA Ritchey-Chretien RC-1000: D=1m, f/6.8 on alt-azimuthal direct drive fork mount, FLI ProLine 16803 with secondary mirror based motorized focusing and automatic de-rotation (Telescope #1 system of ChileScope observatory, Río Hurtado Valley, Chile).
12x Ha + 10x OIII + 10x SII guided 1200 sec exposures (10h 40min of combined integral) collected over 7 imaging sessions spanning 21 months long period and carried out on Jun 11, 2023, Jun 29, 2024, Feb 28, 2025, Mar 1, 2, 3, 4, 2025 using Chilescope Telescope #1 system.
Image Processing: Mark Hanson https://www.hansonastronomy.com
Enjoy, Mark and Alex
[5] https://ui.adsabs.harvard.edu/abs/2005MNRAS.360.1439C/abstract
[6] https://articles.adsabs.harvard.edu/pdf/2005MNRAS.360.1439C
[7] https://www.astrobin.com/users/DrKrud/
[8] https://www.astrobin.com/0ixeqy/
[9] https://www.astrobin.com/0mn0q5/
[10] https://www.astrobin.com/v827pf/
[11] https://academic.oup.com/mnras/article/383/3/1029/1035938
[12] https://arxiv.org/abs/2206.04458
[13] https://arxiv.org/pdf/2206.04458
[14] https://www.cosmos.esa.int/web/gaia/data-release-3
[15] https://www.aanda.org/articles/aa/pdf/2023/06/aa43680-22.pdf