Deep Sky Object in Summer
Seyfert's Sextet (Galaxy Group in Serpens)

Date & Time: Apr 16 2004, from 23:38 to 23:59 JST(+0900)
Composed 3 shots with 9 minutes exposed
Optical: Meade 25cm(10") Schmidt-Cassegrain with conversion lens (f=1600mm, F6.3)
Auto-guided with Meade LX200 Equatorial & Pictor 201XT
Digital Camera: Fujifilm FinePix S2 Pro
Location: Ooizumi vil., Yamanashi pref.

Camera Settings: Recording Format...12bit CCD-RAW, converted to 16bit TIFF(3024×2016)
CCD Sensitivity...ISO1600, White Balance...Auto

602715h 59m 10.5s+20° 45' 39"0.4×0.2'14.7
6027A15h 59m 11.5s+20° 45' 15"0.7×0.5'14.9
6027B15h 59m 14.8s+20° 46' 00"0.4×0.3'15.3
6027C15h 59m 12.1s+20° 44' 47"0.8×0.2'16.0
6027D15h 59m 13.2s+20° 45' 33"0.1×0.1'15.3
6027E15h 59m 12.7s+20° 45' 47"0.8×0.4'16.5
Around the tip of Serpent's head, this picture has captured a Hickson's compact galaxy group of HCG79. The group has six small galaxies mainly NGC6027. All members have 15th or 16th magnitude in brightness and smaller than an arc minutes.
Generally we can calculate the distance to such a distant object by using of Hubble's law from its red shift that indicates regression velocity. But in case of this HCG79, actually only a members of D has 5 times large regression velocity than that of other members. It can be considered that the galaxy D is not a member of HCG79, but this fact is an example that we have doubts about universality of Hubble's law.

Members of Seyfert's Sextet



Copyright(c) 2004 by Naoyuki Kurita, All rights reserved.
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