Object

M51 (NGC 5194) The Whirlpool Galaxy

Object Information

Image information

Object Type

Galaxy (Spiral) Type Sc

Instrument

LX200GPS 14” OTA @ F5 effective FL≈1778mm

Constellation

Canes Venatici

Guiding

SXV / SkyWatcher 80mm achro @ F/6

Magnitude

+8.4

Focal Reducer

Optec NextGen 0.5x

Coordinates

RA 13:29.9 Dec +47:12

Mount

Paramount ME

Size

11 x 7 arc min

Location

Stoney Hills, S.E England

Distance

37 Million Light Years

Acquisition Date

21st March 2007

Notes

M51 The Whirlpool Galaxy is one of the showpiece objects in the Northern night sky. At mag +8.4 it is bright and relatively easy to observe and image and contains a wealth of detail and colour.

Whilst commonly referred to as the Whirlpool Galaxy this is really two objects. M51 (NGC 5194) is the main galaxy in the image and the object to the left of it is the irregular galaxy NGC 5195. Whilst it appears that the two galaxies are connected it is likely that NGC 5195 now lies beyond M51. However the two galaxies recently did pass close to each other and the gravitational interaction probably caused the distorted shape of NGC 5195 and the pronounced spiral structures in M51.

The image also contains a number of more distant galaxies in the background.

Charles Messier discovered M51 on October 13 1773, Pierre Méchain discovered NGC 5195 on 21st March 1781.

Capture Device

Starlight-Xpress SXV-H9 Sony ICX285AL Exview HAD Cooled CCD Array 1392 x 1040 @ 6.45uM / Pixel 

Filter Type

Astronomik Type IIc RGB

Colour Technique

LRGB

FOV

≈17 x 13 arc mins (0.747 arcsec/pixel)

Exposure

120 m Total

Integration

L (13 x 250 sec bin 1x1)

R (4 x 300 sec bin 2x2)

G (4 x 330 sec bin 2x2)

B (4 x 360 sec bin 2x2)

Notes

Finally - good conditions for imaging. Low wind and humidity, dark clear night. Electronics, mechanics and optics all now working and I’m happy with the result.

RGB Combining and Luminance Digital Development filter applied in Maxim, Layering and luminance channel combining and further processing in Photoshop.