Deep Sky Object in Spring
NGC3718, NGC3729 & HCG56 (Galaxies in Ursa Major)

Date & Time: Mar 3 2017, from 23:02 to 23:46 JST(+0900)
Composed 11 shots with 4 minutes exposed
Optical: Meade 25cm(10") Schmidt-Cassegrain with conversion lens (f=1600mm, F6.3)
with BaaderPlanetarium Moon&Skyglow filter
Auto-guided with Meade LX200 Equatorial & Pictor 201XT
Digital Camera: Nikon D810A
Location: Ooizumi, Hokuto city, Yamanashi pref.

Camera Settings: Recording Format...14bit CCD-RAW, converted to 16bit TIFF(4080×4080)
Device Size...20×20mm
Sensitivity...ISO6400, White Balance...Daylight

NGC3718 / Galaxy, type SB(s)a pec
R.A.11h 32m 35.7s (2000.0)
Dec.+53° 04' 00" (2000.0)
Apparent Size8.1×3.9'
Radial Velocity1177km/s
Distance70 million light yrs.
Group of GalaxiesUrsa Major N Group
Other IDsUGC6524, MCG9-19-114
CGCG268-48, PGC35616
NGC3729 / Galaxy, type SB(r)a pec
R.A.11h 33m 49.9s (2000.0)
Dec.+53° 07' 38" (2000.0)
Apparent Size2.8×1.9'
Radial Velocity1214km/s
Distance70 million light yrs.
Group of GalaxiesUrsa Major N Group
Other IDsUGC6547, MCG9-19-117
CGCG268-51, PGC35711
This image shows you two bared galaxies positioned about 3 degrees west from gamma UMa, a part star of the Big Dipper. NGC3718 has a visual brightness of abour 11th magnitude and a long axis of over 8 arc minutes, you can detect a dimmed light through medium-ranged scopes. And this image has captured a central dark lane clearly.
Another one of NGC3729 is lying about 11 arc minutes east of NGC3718. The galaxy has brightness of about 12th magnitude and a size of less than 3 arc minutes, it's fairly difficult to detect the galaxy with your eyes aided by scopes.
And you can detect tiny five galaxies are gathering about 8arc minutes south of NGC3718. These galaxies are forming a compact galaxy group, have been registered in Hickson Compact Group(HCG) 56. You can see aclose-up image of HCG56 in lower image, each galaxy has Ids from A to E.

Magnification image around HCG56
Magnification image around HCG56
56a11h 32m 46.5s+52° 56f29"1.3×0.2'16.2
56b11h 32m 40.0s+52° 57f00"0.7×0.3'16.2
56c11h 32m 36.8s+52° 56f52"0.7×0.4'15.8
56d11h 32m 35.1s+52° 56f52"0.4×0.3'16.8
56e11h 32m 32.4s+52° 56f22"0.5×0.3'16.4

Arp 299


Copyright(c) 2017 by Naoyuki Kurita, All rights reserved.
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