Weltevreden SA
08-08-2017, 08:01 AM
The meticulous S African observer Susan Young (http://sandandstars.co.za/2016/08/21/about-me/)lives in the Kalahari Desert (http://sandandstars.co.za/2016/08/21/the-kalahari/) with her two dogs and two dobs (http://sandandstars.co.za/2016/08/21/about-my-telescope/). It's one of the worst places in the world to live—except for meerkats and MEERKATS (http://sandandstars.co.za/category/kalahari/), in which case it turns into one of the best places in the world.
Susan has posted three impressively detailed observing reports of supernova remnants on her blog Sand & Stars (http://sandandstars.co.za/2016/08/21/about-me/):
Sh 2-91 (http://sandandstars.co.za/2017/07/26/cygnus-other-snr/)
Cygnus Loop & Veil (http://sandandstars.co.za/2017/07/23/the-veil-nebula/) (http://sandandstars.co.za/2017/07/23/the-veil-nebula/)
Vela SNR (http://sandandstars.co.za/2017/04/22/velas-snr-neighbourhood/)
Of these, Sh 2-91 is the most interesting because the object is so seldom observed . It's the oldest SNR visible in amateur instrument; estimates range from 240,000 to 470,000 years. By compare, the Cygnus Loop is a tyke at 5,000–8,000 years old; the Vela SNR is 11,000–12,300 yro; and Simeis 147 in Taurus is ~40,000 yro.
In the professional literature Sh 2-91 is the least studied of all SNR: SIMBAD links only 6 papers, dating from 1976 discovery paper (http://simbad.u-strasbg.fr/simbad/sim-ref?bibcode=1976A%26AS...25...25D) up to a spectral study of all the Sharpless H II emission nebs in 1995. (http://simbad.u-strasbg.fr/simbad/sim-ref?bibcode=1995ApJS..100..389C) The most informative study is Reich et al 1979 (http://simbad.u-strasbg.fr/simbad/sim-ref?bibcode=1979A%26A....72..270R). While it is a radio continuum study and depicts emission unseen by us, Section 7 starting on p.27 provides quite a bit of interesting facts on Sh 2-91 and SNRs in general. Frankly, I learned more from Susan's blog than all the SIMBAD papers combined.
The Finnish artist/sim producer named J-P Metsavianio (https://astroanarchy.blogspot.co.za/) (https://astroanarchy.blogspot.co.za/)has done a superb 3D full-rotation sim of the Cygnus Loop, as though we were at standoff radius watching it all happen. The eggshell-like surface configuration of SNRs (https://www.youtube.com/watch?v=Vdz7njiLvM0) really becomes apparent here. You can see a YouTube assemblage of many Metsavianio sims here (https://www.youtube.com/watch?v=MLqqKiA_oxs).
=Dana in S Africa
Susan has posted three impressively detailed observing reports of supernova remnants on her blog Sand & Stars (http://sandandstars.co.za/2016/08/21/about-me/):
Sh 2-91 (http://sandandstars.co.za/2017/07/26/cygnus-other-snr/)
Cygnus Loop & Veil (http://sandandstars.co.za/2017/07/23/the-veil-nebula/) (http://sandandstars.co.za/2017/07/23/the-veil-nebula/)
Vela SNR (http://sandandstars.co.za/2017/04/22/velas-snr-neighbourhood/)
Of these, Sh 2-91 is the most interesting because the object is so seldom observed . It's the oldest SNR visible in amateur instrument; estimates range from 240,000 to 470,000 years. By compare, the Cygnus Loop is a tyke at 5,000–8,000 years old; the Vela SNR is 11,000–12,300 yro; and Simeis 147 in Taurus is ~40,000 yro.
In the professional literature Sh 2-91 is the least studied of all SNR: SIMBAD links only 6 papers, dating from 1976 discovery paper (http://simbad.u-strasbg.fr/simbad/sim-ref?bibcode=1976A%26AS...25...25D) up to a spectral study of all the Sharpless H II emission nebs in 1995. (http://simbad.u-strasbg.fr/simbad/sim-ref?bibcode=1995ApJS..100..389C) The most informative study is Reich et al 1979 (http://simbad.u-strasbg.fr/simbad/sim-ref?bibcode=1979A%26A....72..270R). While it is a radio continuum study and depicts emission unseen by us, Section 7 starting on p.27 provides quite a bit of interesting facts on Sh 2-91 and SNRs in general. Frankly, I learned more from Susan's blog than all the SIMBAD papers combined.
The Finnish artist/sim producer named J-P Metsavianio (https://astroanarchy.blogspot.co.za/) (https://astroanarchy.blogspot.co.za/)has done a superb 3D full-rotation sim of the Cygnus Loop, as though we were at standoff radius watching it all happen. The eggshell-like surface configuration of SNRs (https://www.youtube.com/watch?v=Vdz7njiLvM0) really becomes apparent here. You can see a YouTube assemblage of many Metsavianio sims here (https://www.youtube.com/watch?v=MLqqKiA_oxs).
=Dana in S Africa