Sharpless-308, the Dolphin Nebula (Aleix Roig)

Sharpless-308, the Dolphin Nebula

Sharpless-308, also known as the Dolphin Nebula, it's a faint nebula created by a massive Wolf-Rayet star; the bright star near the center of the nebula, known as EZ Cannis Majoris, EZ CMa or WR 6. These massive stars can have 20 times the mass of the Sun, and are thought to be a pre-supernova phase.

This bubble-shaped nebula lies some 5,200 light-years away from Earth and it covers a diameter of 60 light-years. That corresponds to a similar angular diameter as the Full Moon. It can be seen towards the constellation of Canis Majoris.

This deep sky object it's quite difficult to be captured from the northern hemisphere locations due to its low altitude. It only rises some 24º when it passes through the meridian. That implies being affected by the southern horizon light pollution. Even Though I live in the south of Europe (Prades) in a quite dark location (Bortle 3/4), it's at the limit of my technical capabilities.

I struggled to get as much data as I could with my dual Takahashi FSQ setup during several full moon January 2022 nights. For the nebula structure I used a 3nm Ha filter in front of my ASI2600M and FSQ106 EDX4 and also a 6,5nm [OIII] filter on the FSQ85 with the smaller ASI294MM sensor. RGB images were captured by the FSQ106 to create the starfield image in natural color.

Thanks for taking your time on this site.

Image details:FSQ106:

Ha 167x600" (27h50')
RGB: (18,18,15) x 300" (4h15')

FSQ85:

[OIII]: 320x300" (26h40')

Calibrated with darks, flats and dark-flats.

Total exposure: 58h45' Moon at 85% (on average)

Image resolution: 1.46”/pixelFOV (full image): 2º18' x 1º33'

Equipment:

FSQ106 EDX4 + ASI2600MM + LRGB Astrodon filters + Ha3nm Antlia - with ZWO EFW 7 pos
FSQ85 + ASI294MM + SHO LRGB Baader filters - with ZWO EFW 8 pos
Mesu200 mount
Guiding with ASI120MM and ZWO Mini Guide Scope

Software: SGP, PHD2, APP, PIX, LR, TPZ, PS.

Aleix Roig, February 2022
Prades (Tarragona, Catalonia - Spain).

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Status	Advanced success
Started	...
Astrometry.net job	5466538
PixInsight job	U59920ZAK5M2QLTGY5T3ZCZRIM05ANHG
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	06h54m19s.58
RA (top/left)	06h50m59s.99
RA (top/right)	06h50m51s.57
RA (bottom/right)	06h57m42s.93
RA (bottom/left)	06h57m44s.30

Dec (center)	-23°30′00″.0
Dec (top/left)	-22°20′09″.1
Dec (top/right)	-24°38′58″.5
Dec (bottom/right)	-24°39′38″.2
Dec (bottom/left)	-22°20′51″.7

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