1st & 2nd September 2011
M101 Supernova 2011fe
|On 1st September the sky was quite clear so more
exposures could be made of M101.
I noticed that the Aug 31st images were
overexposed and the supernova was saturating so exposures were reduced
drastically to 100 seconds.
I also converted each image to mono with a
'boxcar' filter which should give better magnitude estimates.
On 2nd Sep
cloud cover allowed only three exposures but this was enough for a magnitude
Aug 31 10.98
Sep 1 10.63
supernova continues to brighten. Exposures at 100 seconds were too long and
were reduced to 60 and 70 seconds.
The magnitude was measured (average of 24
images) at 9.999, lets call it 10.0.
|2011fe is now the brightest supernova for nearly 20
SN1993J reached magnitude 10, and 2011fe may get even
39 years ago SN 1972E reached mag 8.5.
2011fe is a type
1a supernova. These always have the same energy
when they explode and so can be used to measure distance.
is only 20million light years away, hence the apparent brightness of the
Some clear spells in the early
evening. 46 exposures taken of M101, all less than 60 seconds.
magnitude of the supernova is 9.918
|Still brightening, but the peak must occur fairly
|Bright Moon conditions. The Supernova in M101 was
measured at magnitude 9.89 which is its brightest so far. AAVSO values seem to
show that it has passed the maximum, contrary to my
|Supernova measured at magnitude
This is slightly dimmer than the preceeding night so it
would appear that the maximum has been
Bright Moon conditions made imaging faint objects
impossible, hence another look at the Ring Nebula.
This is 22x5
minutes with re-focusing every 5 frames in an attempt to get the maximum detail
The Mira variable RX
Lyrae near M57 is near peak value.
|I dug out an image from Sept 2010 when it was
near minimum, and plotted my values with AAVSO readings.
For some reason
there is a large gap in CCD
M101 Supernova 2011feThis is 2x10 minutes. Clouds
prevented any more frames being taken.
|The supernova is showing a very
gradual drop in brightness since the peak a few days ago.
recorded tonight was 10.098
It would appear that the combination
of my colour camera and light pollution filter gives a magnitude reading a
little higher than the true value.
|Adding 0.1 to all my readings gives a much
better agreement with the AAVSO values.
I have also figured out
how to turn the graph upside
22nd September M101
|Sky conditions were appalling. Lots
of cloud and even the gaps were filled with high level haze.
seconds were taken but only 4 frames were of any use.
reading was 10.356
25th September M101
|Sky conditions still
All images were shot through cloud.
The 29 best were used for
finding the magnitude.
The magnitude reading was
Short break in the
Magnitude measured at 10.694
27th September IC5070
8x 10 minutes
Only the top part of the Pelican
fits in the frame.
|Sky conditions much
The magnitude reading was
NebulaAnother 17x10 minutes taken. Total now is 300minutes. A lot more
background stars are showing up.
A central crop shows some of the wispy green stuff
extending outwards from the nebula.
NebulaTotal now is 600 minutes. I suspect that adding more data will not
improve the image much.
The opalescent caste in the 28th September version
is probably poor management of curves. I don't think the colours are
This is probably a better rendition.
|M101 supernova now at