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|
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.
|6027||15h 59m 10.5s||+20° 45' 39"||0.4×0.2'||14.7|
|6027A||15h 59m 11.5s||+20° 45' 15"||0.7×0.5'||14.9|
|6027B||15h 59m 14.8s||+20° 46' 00"||0.4×0.3'||15.3|
|6027C||15h 59m 12.1s||+20° 44' 47"||0.8×0.2'||16.0|
|6027D||15h 59m 13.2s||+20° 45' 33"||0.1×0.1'||15.3|
|6027E||15h 59m 12.7s||+20° 45' 47"||0.8×0.4'||16.5|
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