NGC 7822 (Sh2-171) in Cepheus

        © Velimir Popov & Emil Ivanov 2020  
      Size: 1800 px    

NGC 7822 (Sh2-171) is an emission nebula in the constellation of Cepheus. It is situeted in the eastern part of the constellation of Cepheus, about 9 ° north of the bright star Caph, in a stretch of the Milky Way strongly obscured by interstellar dust and unlit nebulae. It is actually the northern part of the large cloud complex of Ced 214, linked to the stellar association Cepheus OB4. It has an elongated shape in the east-west direction and in the detailed images jagged structures called elephant proboscis are well evident, globules in erosion due to the strong stellar wind coming from the massive stars of the open cluster Berkeley 59. This cluster contains nine blue stars with spectral classes between O7 and B3, among which stands out BD + 66 1673, one of the hottest stars located within a radius of 1000 parsecs from the Sun. It is an eclipse binary in which the primary star, class O5V, has a surface temperature of 45000 K and a brightness of 100,000 L⊙. Its variable star abbreviation is V747 Cephei.. Below can be seen a Ha SII OIII combination in so called "Hubble Palette":

    Bigger size: 1800 px    
Techn. details os the narrowband image: Optics: 12" ASA Astrograph @/3.6; Mount: ASA DDM 85; Camera: SBIG STL-11kM; Filters: Astronomik LRGB; Baader Ha, SII and OIII;
Dates/Times: 3, 30 November, 1,2 December 2011 ; Location: Rozhen, Bulgaria;
Exposure Details: L=3x10 min; R=3x10 min; G=3x10 min; B=3x10 min; Ha=17x30 min; SII=18x30 min; OIII=17x30 min; Bin 1, Total exp. time = 1680 min (28 hrs)
Image details:



Center of field RA 00:02:47 (h:m:s)
Center of field DE +67:10:34 (deg:m:s)
Size 82 x 59.9 (arcmin)
Pixel scale: 1.7 (arcsec/pixel)
Orientation: Up is 91.2 degrees E of N
Charts and image details obtained from
Optic(s): ASA 12" Astrograph @ f/6.3 (Newton)
Mount: ASA DDM85 Standard
Camera: SBIG STL 11000 M
Filters: Luminance, Red, Green, Blue, Astronomik filters, Ha Baader filter
Dates/Times: 3,30.Nov.2011
Location: IRIDA Observatory, BG, longitude: E 24 44' 18", latitude: N 41 41' 42"
Exp. Details: L:6x10min;R:6x10 min, G:6x10 min, B:6x10 min; Ha:6x15. Bin 1 Total exp.time: 330min 5:30 hrs
More details: Dark and flat frames reduction
Processing: PixInsight / PS
Copyright: Velimir Popov and Emil Ivanov 2020. All Rights Reserved
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