IC4640, 4641 and 4647 - three obscure galaxies in the far south (James Tickner)

Celestial hemisphere: Southern · Constellation: Apus (Aps) · Contains: IC 4640 · IC 4641 · IC 4647 · PGC 228558 · PGC 228600 · PGC 228639 · PGC 228777 · PGC 228907

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IC4640, 4641 and 4647 - three obscure galaxies in the far south

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IC4640, 4641 and 4647 - three obscure galaxies in the far south

Continuing to work through the IC and NGC objects lying below 80 degrees south, next up is an obscure trio of three galaxies. All have magnitudes between 13 and 14 and average only about 1 arc minute in diameter, making them tough targets. All were discovered in 1900 by DeLisle Stewart using photographic plates taken using a 24" photographic refactor operating from Havard's Arequipa observatory in Peru. Stewart discovered a total of 669 new IC objects during his career.

IC4640 is a mag 13.6 spiral with a diameter of 1'. IC4641 is another spiral, magnitude 13.1 and with a diameter of 1.2'. Finally, IC4647 is a lenticular galaxy with an unusually bright core; it measure 1.4 x 0.6' and has a magnitude of 13.3

Given their faintness and small apparent diameter, I was pleased to resolve hints of the spiral arms of IC4640-1 using just a 4" scope. The bright core of IC4647 is also readily apparent. All 3 objects are firsts on Astrobin.

Original
Final
D

First on Astrobin

80° South

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Status	Advanced success
Started	...
Astrometry.net job	7735000
PixInsight job	FAHNMI36NX4Y0QN8S77O6BPI6AYYR305
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	17h26m03s.458
RA (top/left)	17h19m27s.130
RA (top/right)	17h32m41s.277
RA (bottom/right)	17h32m26s.342
RA (bottom/left)	17h19m39s.504

Dec (center)	-80°07′16″.17
Dec (top/left)	-80°17′56″.20
Dec (top/right)	-80°17′48″.72
Dec (bottom/right)	-79°56′08″.90
Dec (bottom/left)	-79°56′15″.31

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IC4640, 4641 and 4647 - three obscure galaxies in the far south

IC4640, 4641 and 4647 - three obscure galaxies in the far south

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IC4640, 4641 and 4647 - three obscure galaxies in the far south

IC4640, 4641 and 4647 - three obscure galaxies in the far south

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