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Hoag's Object (PGC 54559)

Technical card

Resolution: 4225x2860

Dates:March 24, 2019April 1, 2019April 7, 2019April 10, 2019April 29, 2019May 15, 2019May 21, 2019May 22, 2019June 4, 2019

Optolong Blue 1.25": 123x120" (gain: 10.00)
Optolong Green 1.25": 120x120" (gain: 10.00)
Chroma Lo-Glow LP filter: 240x120" (gain: 10.00)
Optolong Red 1.25": 116x120" (gain: 10.00)

Integration: 20.0 hours

Avg. Moon age: 13.78 days

Avg. Moon phase: 46.77%

Bortle Dark-Sky Scale: 7.50 job: 2728431

RA center: 229.309 degrees

DEC center: 21.586 degrees

Pixel scale: 0.284 arcsec/pixel

Orientation: 271.091 degrees

Field radius: 0.201 degrees

Locations: Home Roof (Bortle 7-8 / Est. Sky Quality: 18.53), Springfield, PA, United States

Data source: Backyard


Just seeing what an 8 inch scope can do on an extremely tiny mag 16 galaxy under Bortle 7-8 skies. It's a super interesting target but detail is basically non-existent. EDIT: I forgot to mention that this is the farthest 'main object' I've imaged - it's over 600 million ly away.

While ring galaxies aren’t unknown, Hoag’s Object (PGC54559) is particularly interesting as the older core is perfectly spherical and the ring lacks an arm-like structure. Ring galaxies generally arise through collisions – a smaller galaxy will crash into a spiral galaxy at high velocity pushing stars outwards and leaving an outer ring separated from the remainder of the core. But with the perfectly spherical shape of Hoag’s Object, the complete lack of any trace of a galaxy collision and with the stars in the ring being much younger than the stars in the core, it doesn’t look like it formed that way. It’s on just about every list of the ‘strangest objects in the universe’ and it’s still unknown how a galaxy like this could have formed.



Chris Sullivan





Crop with Hubble image

Sky plot

Sky plot


Hoag's Object (PGC 54559), 


            Chris Sullivan