Last chance to image the great galaxy clusters for 2012
Although now moving westwards, galaxy-rich areas surrounding the constellation of Virgo still dominate the early evening sky, with Virgo directly overhead just after sunset.
The Sombrero galaxy (M 104) and the Sculptor galaxy (M 83) are highly recommended targets for those using SPIRIT to image galaxies for the first time. The fascinating radio galaxy Centaurus A (NGC 5128), together with the edge-on spiral galaxy NGC 4945, are also worthy early evening targets. East of the meridian, with plenty of time to spare, is another bright spiral galaxy: NGC 6744. Stellarium and other planetarium programs provide plenty of options for those wishing a last chance to image galaxies at this time of year.
Like May, June is a good time of the year for imaging NGC 5139, the great Omega Centauri globular cluster. It is high in the southern sky in the early evening and can be easily imaged using exposures less than 20 seconds.
While in the south, you may want to pay a visit to the Jewel Box cluster (NGC 4755). Exposures of less than 10 seconds through red, green and blue filters will provide more advanced users with enough data to create a colour image of this bright open cluster.
The hydrogen-rich nebula Eta Carina (NGC 3372) is just past the meridian and moving westwards early in the evening. It’s your last chance to image this bright region before it disappears for the year.
For those with late bookings (11:30 pm and later), consider being the first for the 2012 season to image the bright Sagittarius nebulae. They include M 16, M 17, the Trifid nebula (M 20) and the Lagoon nebula (M 8). The H-a filter on SPIRIT I will reveal a wealth of detail in these bright emission nebulae.
Saturn dominates Virgo, and although the SPIRIT telescopes are not optimised for planetary imaging, a filtered exposure of less than 5 seconds will reveal its unusual shape and some of Saturn’s brighter moons. Mars is the bright red object in the north west. Don’t forget to wander outside in the early evening to view Mars and Saturn high in the evening sky.
With the approach of winter and the centre of the Milky Way rising, now is also the time of the year to consider imaging globular clusters. More on these next month.
The Moon is full on June 4th, so the best dates to image deep-sky objects fall between June 11th and June 27th.
The Perth night sky facing south at 7:30 pm on June 15
(click on image to enlarge)