Category Archives: Broadband RGB

The Whirlpool Galaxy (M51) from Nerpio, Spain


A classic spiral galaxy in the constellation Canes Venatici – it is 30 million light years distant and 60 thousand light years across with an estimated mass of 160 billion solar masses.  One arm of the galaxy is interacting with a smaller galaxy (M51b or NGC 5195).  The very pronounced spiral structure of the Whirlpool Galaxy is believed to be the result of the gravitational interaction between it and its companion galaxy.

This image represents something of a departure for me as my emphasis to date has been on narrowband imaging.  The dark clean skies at AstroCamp in Spain now open up the possibility of capturing high quality broadband colour data.  Image reduction and luminance deconvolution was carried out using MaxIm DL.  PixInsight was used for further pre-processing and colour calibration, LRGB composition, noise reduction and sharpening.  Final processing and jpeg creation for publishing on the web was carried out in PhotoShop CS4.

Right ascension: 13h 29m 53.88s | Declination: +47° 12′ 00″ | Distance: 30 Million Light Years
Field of view: 37.4 x 24.9 arcmin

Camera: SBIG STL-6303E
Telescope: PlaneWave Instruments CDK 12.5 F/7.9
Guiding: External 80mm F/4 guidescope with an Atik 314L+ for guiding
Mount: Paramount PME
Filters: Astrodon Series E LRGB
Exposures: Luminance (30 x 5min), Red (21 x 5min), Green (21 x 5min), Blue (21 x 5min)
Binning: All filters 1×1
Total exposure: 7.7 hours
Image composition: LRGB
Scale: 0.73 arcsec/pixel
Image acquired: Over 9 nights during April & May 2013

Image capture with MaxIm DL, FocusMax, ACP; Image processed with MaxIm DL, PixInsight, Photoshop CS4

Leo triplet of galaxies

The Leo Triplet is a small group of galaxies about 35 million light-years away in the constellation of Leo.  This galaxy group consists of the spiral galaxies M65, M66, and NGC 3628 (‘The Hamburger’).  Image acquired and processed with help of Olly Penrice at Les Granges Astronomy Holidays, SE France.

Right ascension: 11h 19m 44s | Declination: +13° 19′ 10″ | Distance: 35m Light Years
Field of view: 53 x 53 arcmin

Camera: Atik 4000 Mono (Kodak KAI 04022)
Telescope: TEC APO140ED F/7
Filters: Baader LRGB
Exposures: Lum 30 x 15 min; Red 11 x 10 min; Green 8 x 10min; Blue 15 x 10min
Total exposure: 13 hours
Image composition: LRGB
Scale: 1.56 arcsec/pixel
Image acquired: March 2012 from Les Granges, SE France.

Image capture with Artemis Capture; Image processed with Registar, AstroArt 5.0 and Photoshop CS3