andyc
16-06-2012, 11:03 AM
Amongst lots of other observing over the past few nights (taking me to 432/600 on John Bambury's great list of southern objects), I've managed to take in three bright transients in the sky. They are a good range of challenges for different scopes and settings:
Nova Scorpii 2012: ~mag 10.5.
SN2012cg in Virgo (NGC4424): ~mag 12.0.
SN2012aw in Leo (M95): ~mag 13.8.
First, from urban skies, the nova in Scorpius is bright and easy in a small telescope. The main challenge is to find it amongst the stars near M6 and M7! Using an AAVSO finder chart for the location (RA: 17h50m54s; Dec: -32d37m20s), it's quite bright at about mag 10.5, judging from field stars, particularly the mag 10.6 star 7' SE of the nova.
A trip to the alpine country near New Moon gave me some dark skies, and I picked out two supernovae.
The supernova in M95, SN2012aw is, remarkably, still visible! I thought I'd have a casual look at M95 as Leo was still well up after dusk, and I'd spent long enough looking at the supernova when it was near its maximum a few months ago and I struggled to see any more of the galaxy through light pollution than it's stellar core. To my surprise, with averted vision and in moments of clarity, a little sparkle shone back from the supernova's exact location, this time within the edge of the haze of M95. On checking the bright supernovae page (http://www.rochesterastronomy.org/supernova.html#2012aw), I see that SN2012aw is estimated around 13.8, which seems reasonable given the sky clarity and the faintness of the little sparkle.
A much easier challenge was SN2012cg (http://www.rochesterastronomy.org/supernova.html#2012cg), listed at around 12th mag in NGC4424 in Virgo. In a very pretty field with three galaxies (the image here by Pedro Re (http://www.astrosurf.com/re/sn2012cg_20120612.jpg), with the SN, gives a good impression) - NGC4417 and NGC4442 shared the field, both brighter than the quite faint smudge of NGC4424 that was dominated by the SN. The SN appeared very easy and very bright. From Melbourne last night, I saw the SN again, but this time could see none of the galaxies due to light pollution in the northwest from my location (SE suburbs). The SN itself was barely visible as one of two little specks ESE of a distinctive three-star asterism. Using an AAVSO chart, the other speck is a 12.0mag field star, which gives a reasonable estimate for the brightness of the SN. The difference in visibility from light-polluted and dark skies was pretty stark!
All observations with an 8" dob.
Nova Scorpii 2012: ~mag 10.5.
SN2012cg in Virgo (NGC4424): ~mag 12.0.
SN2012aw in Leo (M95): ~mag 13.8.
First, from urban skies, the nova in Scorpius is bright and easy in a small telescope. The main challenge is to find it amongst the stars near M6 and M7! Using an AAVSO finder chart for the location (RA: 17h50m54s; Dec: -32d37m20s), it's quite bright at about mag 10.5, judging from field stars, particularly the mag 10.6 star 7' SE of the nova.
A trip to the alpine country near New Moon gave me some dark skies, and I picked out two supernovae.
The supernova in M95, SN2012aw is, remarkably, still visible! I thought I'd have a casual look at M95 as Leo was still well up after dusk, and I'd spent long enough looking at the supernova when it was near its maximum a few months ago and I struggled to see any more of the galaxy through light pollution than it's stellar core. To my surprise, with averted vision and in moments of clarity, a little sparkle shone back from the supernova's exact location, this time within the edge of the haze of M95. On checking the bright supernovae page (http://www.rochesterastronomy.org/supernova.html#2012aw), I see that SN2012aw is estimated around 13.8, which seems reasonable given the sky clarity and the faintness of the little sparkle.
A much easier challenge was SN2012cg (http://www.rochesterastronomy.org/supernova.html#2012cg), listed at around 12th mag in NGC4424 in Virgo. In a very pretty field with three galaxies (the image here by Pedro Re (http://www.astrosurf.com/re/sn2012cg_20120612.jpg), with the SN, gives a good impression) - NGC4417 and NGC4442 shared the field, both brighter than the quite faint smudge of NGC4424 that was dominated by the SN. The SN appeared very easy and very bright. From Melbourne last night, I saw the SN again, but this time could see none of the galaxies due to light pollution in the northwest from my location (SE suburbs). The SN itself was barely visible as one of two little specks ESE of a distinctive three-star asterism. Using an AAVSO chart, the other speck is a 12.0mag field star, which gives a reasonable estimate for the brightness of the SN. The difference in visibility from light-polluted and dark skies was pretty stark!
All observations with an 8" dob.