Collecting Photons

Star Clusters

A deepish rendition of the seven sisters

NGC 869 - NGC 884 "Double cluster" (Perseus)

A wide field image shot with the Megrez 80. I have added star spikes with two steel wires crossed in front of the lens. Asinh stetch and lots of attentions to preserve star colours. 34x4 min iso 800.

NGC 2437 - M46 (Puppis)

The cluster and the associated planetary nebula.

NGC 2168 - M35 (Gemini)

The area around M35. The open cluster is near the north end of the frame and the the two emission nebula are IC 443 and NGC 2174 (north and south, respectively). The field is 4° 3' by 5° 14'. 40 mn exposure, 300 mm f4. Kodak 2415 plus deep red filter. .32 MB jpg

M35 (Gemini)

Boy is this an horrible picture! A close up of the open star cluster M35. The smaller cluster on the south edge of the frame is NGC 2158. Notice a few yellowish stars among the vast majority of blu stars. The reddish hue of the dimmest stars is an artefact of the film. 20 mn exposure, C8, f 10. 3M 1000.

M45 Pleiades (Tauri)

The seven sisters and their reflection nebula. This is my first light image for my new Megrez fluo triplet. This is a composite effort: to the short focus stack I have added some the stacks shot with the C8 to add details around Alcyone, Maia and Merope. These images have been scaled, rotated and blended to the wide field image. Processing in Iris (calibration, stacking and hyperbolic sine stretching), Pixel Insight (histograms, gradient removal, masked curves and erosion), Photoshop CS (composition and blending of the long focus images, final touches), Neat Image Pro (noise control). Canon 350D, Megrez 80, f 6.0, 60x4', iso 800 in two separate nights. C8 f6.3, 36x8' in three separate nights. Almost 9 hours of exposure.

M45 Pleiades (Tauri)

The southern sister Merope and the surrounding nebulosity. Canon 300D, C8, f 6.3, 9x8', iso 400.

M45 Pleiades (Tauri)

The northern sister Maia and the surrounding nebulosity. Canon 300D, C8, f 6.3, 16x8', iso 400.

M45 Pleiades (Tauri)

The northern sister Maia and the surrounding nebulosity. Canon 300D, C8, f 6.3, 16x8', iso 400.

NGC 5024 - M53 and NGC 5053(Coma Berenices)

A lovely couple (see the link) of globular cluster at the edge of the Virgo sea of galaxies (13.0', m 7.7). ASA 10", STL11000. 10 hours in total in four nights.

NGC 5272 - M3 (Canes Venatici)

(18.0' m 6.0) C8, f 10, 300D, iso 400.

NGC 6205 - M13 (Herculi)

This image has been processed to enhance the colour index difference between the two main star population that form the Great Cluster. The F-type stars shine in white-blue light, while the cooler giants glow in orange. C8, f 6.3, 300D, 6x5', iso 400. Further details on the processing on a previous take of this subject are here.

NGC 6205 - M13 (Herculi)

A few years passed by: a new telescope, a new mount and a new CCD camera. ASA 10", STL 11000.

M4 - NGC 6121 (Scorpio)

This is one of the largest globular clusters of all: 36' in diameter, and, indeed, it almost fills the field. The colour balance is a bit off, because this cluster is so low on the horizon that is severely reddened by the atmosphere. Differential refraction also causes a tiny amount of distortion of stellar images with a slight misalignment of red and blue planes. This can be corrected by registering the three colour planes at the end of stacking. C8 with focal reducer to f 6.3. Canon 350D. There is a trace of an asteroid at hour 7 in respect of the centre of the cluster. This was 2050 Francis, at the time (about UT 0, on June 15, 206) it was shining at mag 14.0.

Send anything that comes to mind to Gimmi Ratto gimmi@in.pi.cnr.it