The nearest supernova of its type to be discovered for more than 40 years is expected to reach its maximum brightness around the 8th and 9th of September 2011.

The supernova (named PTF11kly) was discovered by British astronomers on the 24th August 2011 using the famous 48-inch Schmidt telescope at Mount Palomar. Operating the telescope remotely they found a "new" 17th mag. star lying within one of the spiral arms of M101 in Ursa Major. It has now brightened significantly and as of the 8th September the supernova hovers around magnitude 10, which is bright enough to be seen with an 80mm (3.1 inch) telescope under dark skies or even with good binoculars.

Discovery image of supernova PTF11kly (Peter Nugent/PTF collaboration)

But here comes the warning, although M101 has a relatively bright mag of +7.9, it is orientated almost exactly face on to Earth. As a result it has a low surface brightness and is therefore much more difficult to observe than its magnitude suggests. Even with just a small amount of light pollution, M101 is a notoriously difficult object to locate. This is especially true for binocular and small telescope observers and such is the case that it is often not even included in some beginners observing guides. So unless you live under exceptional dark skies, well away from any light pollution, spotting M101 and its supernova with a small instrument will be challenging if not impossible.

The chart below shows how to find M101. It is easy to locate the general area where M101 lies as it forms one corner of a triangle with well-known Plough stars Mizar and Alkaid.

M101 Supernova Star Chart

M101 Supernova Star Chart - pdf format

PTF11kly is located 22 Million light-years from Earth and the spectrum suggests it to be a Type 1a supernova, which occurs when a white dwarf star in a binary system explodes. For comparison, Tycho's Supernova of 1572 was of the same type and supernova 1987a in the Large Magellanic Cloud was of the much rarer Type II-P.

M101 Data

NameM101
ConstellationUrsa Major
Type Spiral Galaxy SAB(rs)cd
RA (J2000)14h 03m 12s
DEC (J2000)+54d 20m 55s
Apparent Dimensions 29' × 27'
Apparent Magnitude7.9
Distance (light-years)22 Million
Diameter (light-years)180,000

M101 Supernova Data

NamePTF11kly
RA14h 03m 5.81s
Dec+54h 16m 25.4s

Sky Highlights - July 2017

The Planets
This Month's Guide

Algol Minima
Algol eclipse dates and times for July

Meteor Shower
Southern Delta Aquariids (Aquarids) meteor shower peaks on July 29

Northern Hemisphere
Evening
West:- Mercury (mag. -0.5 to +0.3) (second half of month)
Southwest:- Jupiter (mag. -2.0)
South:- Saturn (mag. +0.2)
Midnight
West:- Jupiter
South:- Saturn
East:- Neptune (mag. +7.8)
Morning
Southwest:- Saturn
South:- Neptune
Southeast:- Uranus (mag. +5.8)
East:- Venus (mag. -4.1)

Southern Hemisphere
Evening
West:- Mercury (second half of month)
Northwest:- Jupiter
East:- Saturn
Midnight
West:- Jupiter
North:- Saturn
East:- Neptune
Morning
West:- Saturn
North:- Neptune
Northeast:- Venus, Uranus

Deep Sky

Small telescopes:-
Messier 13 - M13 - Great Hercules Globular Cluster
Messier 92 - M92 - Globular Cluster
Messier 11 - M11 - The Wild Duck Cluster (Open Cluster)
Messier 7 - M7 - The Ptolemy Cluster (Open Cluster)
Messier 6 - M6 - The Butterfly Cluster (Open Cluster)
Messier 4 - M4 - Globular Cluster
Messier 8 - M8 - Lagoon Nebula (Emission Nebula)
Messier 16 - M16 - Eagle Nebula (Emission Nebula with Open Cluster)
Messier 20 - M20 - Trifid Nebula (Emission and Reflection Nebula)

Shop at Amazon US

Contributions

If you like the website and want to contribute to the running costs then please do so below. All contributions are most welcome.

PayPal - The safer, easier way to pay online.