The eruption was first seen on May 31st 2011, by
French amateur Amédée Riou who noticed a previously absent
14th-magnitude star in a image of the M51 galaxy. He had compared
the new image to a previous one take and decided that it had to
be a supernova because of its blue color and the fact that it was
missing in previous images.
Shortly there after, others had also spotted the
supernova among them the robotic
Transient Factory and the
Zoo's supernova hunters.
Measurements take of the hydrogen gas ejected from
SN2011dh indicates that its traveling at astonishing speed of
17,600km per second.
I am attempting to monitor and calculate its magnitude
(dimness) over time. As you can see by the graph below, from the
time I started to monitor it on June 4th 2011 it had increased in
brightness 'till June 7th when it started do decline in intensity a bit.
Please note that the smaller the magnitude number the brighter the
I will keep this graph updated by getting at least one image a night
(weather permitting) till it is no longer visible.
If you are interested in how to convert ADU
( Analog Digital Units)
values to a Magnitude value, check out this link
You will need the ADU and Magnitude numbers for a reference star
in the same field as the primary object as well as the ADU value of the
object in question. I use Nebulosity to get the ADU figures.
(This Page was last
These measurements were taken in the visible light
without any color filters using an Orion SSP V2 on a SN8 at 5 minute
exposure dark subtracted and flat applied.
I'd Like to thank the following for providing images for