We’re well into Noctilucent Cloud territory – see one of my sightings here, some faqs here, a page on NLCs at Cumbrian Sky and one of my posts here, so keep your eyes on the North at twilight times for these night shining clouds (as well as aurora, which have been lighting up some skies for the past few days). As ever, this post is illustrated with a few sky charts showing midnight on the first, last and fifteenth day of the month. The dots represent brighter stars, green circles are star clusters, nebulae, galaxies and the like and the very brightest stars, the Moon and the planets are named when they appear. Sky charts provided using Stellarium.
Solar system
The Moon will be in the last quarter phase on the 4th, new on the 11th, first quarter on the 18th and full on the 26th. On the 8th, the Moon will pass by the Pleiades cluster.
The middle of the month sees the start of the Perseid meteor shower, which will peak in the middle of next month. On the 28th-30th, there may be a couple of Delta Aquarid meteors about, but these are best seen in the southern hemisphere, and the Moon will be spoiling things with its brightness.
Heavens above presently lists six comets above magnitude 12 and ten asteroids above magnitude 10 in the hours of darkness. The comets are: C/2009 R1 McNaught at 4.6 just above Gemini and making for the horizon; 10P Tempel 2 at 8.3 in Aquarius; C/2009 K5 McNaught at 11.6 in Camelopardalis; C/2010 A1 Hill at 11.6 in Leo; 43P Wolf-Harrington at 11.8 in Orion and 2P Encke at 11.9 in Taurus. Details on the future movements and changing brightness of the comets can be found here. The asteroids are 1 Ceres at 7.5 in Ophiuchus, this month passing in front of the Barnard 78 dark cloud, which helps when viewing it, it will also pass by a 6th magnitude star on the 6th, allowing motion to be seen over a few hours; 4 Vesta at 7.9 in Leo; 15 Eunomia at 9.2 in Sagittarius; 2 Pallas at 9.2 in Boötes; 6 Hebe at 9.3 in Aquarius; 29 Amphitrite at 9.6 in Sagittarius; 7 Iris at 9.7 in Taurus; 63 Ausonia at 9.8 in Sagittarius; 3 Juno at 9.9 in Gemini and 8 Flora at 10.0 in Aquarius.
The Planets
Mars is on the home stretch to the Sun now. It shines at +1.4, falling to +1.5 by the end, appearing in the south-west as the sun sets. Its angular size falls from 5.2 arcseconds to 4.8 arcseconds in the same period, making details impossible to spot. However, it will appear in a line with Saturn and Venus on the 15th and make a close grouping with those two in the dying days of the month.
Venus is now prominent in the evening skies just after sunset. Shining at magnitude -4.0, it is the brightest thing in the night sky after the Moon. It appears in the south-west once the Sun has gone down and has an angular diameter of 16 arcseconds, showing phases like the Moon, rising to almost 18.7 arcseconds by the end of the month. Due to the Earth’s inclination, it now appears lower down in the evenings despite getting further from the Sun.
Mercury will shine in the evenings for about half an hour after sunset from the middle of the month when its 80% illuminated 5.6 arcsecond disc shines at -0.5. By the end of the month, the size of the disc is 6.8 arcseconds, but it shines in a half Mercury phase, the brightness dropping to +0.1. Hard to spot, six degrees above the horizon.
Saturn will remain at an angular diameter of around 17 arcseconds and will shine at +1.1 over the course of the month. The angular size of the slender rings extending to ~38 arcseconds, the tilt increasing to 3 degrees, compared to 1.7 in May. The bright moon Titan shines at 7.8 and will be easily visible in small scopes and binoculars (unless it is in front of or behind the planet at the chosen viewing time).
Jupiter has returned as the King of the Planets as the others hide in sunset. It rises shortly after midnight at the start of the month, shining at -2.6, and appears at 23:30 by the end, shining at -2.7. The single band is visible already through telescopes like mine (5/6 inches), the red spot without its accompanying band is also easier to see and has intensified its actual colour too and the Galilean moons should be visible in even small telescopes.
Uranus lies a couple of degrees west of Jupiter and shines at 5.7.
Neptune is also in the morning skies, shining at 7.9 with a 2.3 arcsecond disc in the middle of Aquarius.
A few things outside the solar system
The constellations of Leo, Virgo and the Big Dipper are all home to galaxies, details here. This is not a good month to look at faint things as the all-night twilight obliterates detail and contrast.
The Usual Stuff
If you want to watch satellites flaring or passing in the sky (even sometimes during the day), then go to Heavens Above to get times and directions. If you need assistance in deciding where things are in the sky, why not install the free program Stellarium, which does all the work for you? Finally, to avoid the dreaded clouds, Met Check gives a quick forecast and the Met satellites or other satellites can be used to track breaks in the cloud. For an indication of auroral or solar activity, SpaceWeather.com is an invaluable resource. If the stars aren’t available, there’s always solar astronomy. Projections of the Sun onto white card can show sunspots, when properly focused. A good filter (not an eyepiece filter) or a dedicated solar telescope will show better details. Never observe the Sun without filters and never with an inadequate, inappropriate or old (and therefore possibly with holes in) filter.
Public events
For young astronomers (ages 9-16) Space Explorers is run in Kendal Museum on the third Saturday of most months from 2:30-4:00 pm. The next meeting is on Saturday the 17th, when we’ll look at more to do with the Sun, the spectrum and gravity. The Society for Popular Astronomy also has a sky map for young astronomers for May here.
Plus why not pop along to the Eddington Society, which meets at Kendal Museum on the first Monday of each month, this month it is on the 5th, with member’s projects the subject of the meeting. There will also be a public observing event in Abbot Hall park on the 16th from 10:00pm – as advertised in the Sky at Night Magazine.
Don’t forget to check back here and on my twitter account for the latest astronomical events in this area.
Where the Sun hits the sky 