Collecting Photons
NGC 7129 Cepheus
Objects: NGC 7142 (open cluster); NGC 7129 / VdB 146 (reflection nebula); SH2 137 (emission nebula)
Constellation: Cepheus
Coordinates of field center: 21h 44m - +66° 00'
Notes:
This wide field image contains several different objects: besides the obvious
emission and reflection nebulae, are present several dust clouds and some tiny
galaxies visible through the intervening dust. The reflection nebula itself is
fairly rich in Herbig-Haro objects, and 11 of these objects have been
catalogued. The faint emission nebula are the outskirt of SH2 137.
Interestingly, the open cluster itself appears reddened by the dust complex,
clearly suggesting the it lies behind the nebula.
I was very interested in depicting the subtle interplay of the dust with the
very faint emission nebula, that shows well in a wide field HLRG composition.
Telescope and camera: ASA 10'; SBIG STL 11000.
Exposure: H 12x16'; Luminance 27x8'; R, B 12x10'; G 12x8'. Over 12 hrs total.
Date: 30-07-09, 18, 19, 20-08-09
Software used: acquisition, CCDsoft. Calibration; registration and stacking: CCDstack, Registar; processing: PixInsight, Photoshop CS.
Processing notes: control of star was especially difficult: they are simply too many and too bright. I developed a specific procedure to deal with the haloes that is described here.
This full resolution image shows in greater details the reflection nebula itself. At its center there is a small cluster of relatively hot stars: their radiation sweeps through the cloud pushing the gas and dust centrifugally, forming a cavity. At its edges the material moved away meets the surrounding, producing a rim of higher density: here conditions are ripe for the formation of new stars, and the telltale sign of this process is the presence of several Herbig-Haro objects, that show well in the image in the form of the tiny pinkish-red filaments. Eleven HH objects have been catalogued here.
Copyright © 2009 by Gimmi Ratto. (September 1, 2009)
