Feb-Mar 2003


Notizen: NGC 3938 in Ursa Major is one of my favourite galaxies since I imaged it under a good sky in 2001 (to be found at http://www.slilge.de/MX512_img/3938-40gut.jpg.html , effective exposure time 2x10 minutes). I now made a higher resolution version from the city which left me a bit puzzled about the colour of some knots a the left fringe of the galaxy that I expected to be HII regions, but they were definately blue in my colour frames. Still the Halpha image of the galaxy I also took showed two of these knots quite prominently. My search for colour pics of this galaxy led me to a picture by Lowell observatory at http://www.astro.princeton.edu/~frei/Gcat_htm/Sub_sel/gal_3938.htm that also has blue colour for these knots. Another colour pic by Adam Block at http://www.noao.edu/outreach/aop/observers/n3938fries.jpg shows them a bit purple, but still more blue than red. Maybe these are HII regions with bright (young) blue stars embedded? Taken from the middle of Berlin with an 8" LX200 at f/6.3, MX716 camera, video autoguider, Astronomik CLS and RGB filters, 36x10 minutes for L, 10 minutes each for RGB.