HAA Skywatch

LAST CHANCE FOR 2008 MESSIER MARATHON

What a beautiful Last Quarter Moon this morning low in the S before dawn! The sky was beautifully clear and the air was not too cold for catching all those morning Messier objects. These are the last few days before the Marathon ends for 2008. How long is your list of Objects Seen?

BRIGHT NOVA DISCOVERED IN SAGITTARIUS, 18 April 2008

Up before the Sun to observe Jupiter low in the pre-dawn SE sky? Catching a view of the spectacular deep-sky objects in Sagittarius and Scutum before the summer haze threatens them? Looking for Pluto?

Why not have a look at the most recent Nova in Sagittarius, discovered just last week, 18 April at RA 18h 06m Dec -27.2 degrees,
just above the spout of the famous "teapot" asterism:

The Nova is getting brighter by half a magnitude per day and is now visible to the naked eye (ie: use binoculars in the city). If you have a go-to scope you can just go to open cluster NGC6540 and then move 1 degree north. The Nova is at the moment, the brightest star in the area shown by the chart below which has a 2 degree field of view:

Here is the discovery image, with stars to about magnitude 13... it pays to use a desert-based rent-a-scope to get a really clear image:

You can read more about this Nova at http://www.skyandtelescope.com/resources/proamcollab/astroalert/18063819.html or you can get (or post) up-to-date A.A.V.S.O. observational information at http://www.aavso.org/cgi-bin/newlcg.pl?name=Nova%20Sgr%202008&lastdays=400&obstotals=on&type=ps&width=600&height=450&style=points&mag1=&mag2=&visualunvalidated=on&visualvalidated=on&fainterthan=on&v=on

MINOR PLANET CERES IN TAURUS, May 11-12

The evening of May 11th Minor Planet (formerly "Asteroid") Ceres, magnitude 8, will appear to enter NGC 1746, a bright open cluster midway between 1st magnitude stars Aldebaran and El Nath in the constellation Taurus. Both the cluster and the planet are visible in binoculars. Here's a chart:

The cluster contains a dozen stars brighter than Ceres. It's an excellent opportunity to catch the movement of the planet over the course of an hour or two. Ceres leaves the cluster moving E through Taurus late on May 12th. Both nights are excellent imaging opportunities. Enjoy!

IF YOU HAVEN'T SEEN AN ASTEROID...

...this spring you have an opportunity to watch 10th magnitude asteroid Kalliope as it moves through the constellation Virgo.

If you are an imager, Kalliope does some excellent galaxy fly-bys:

- this weekend (12-13 April) it is 4' S of M91l
- April 17th the asteroid is just 1' S of M88;
- May 4th it is 1/2 way between M99 and M84-86;
- from June 25-29 it is 40' SW of M49

Here is a chart showing Kalliope's position May 5th:

EARLY EVENING ECLIPSE TUESDAY 8 APRIL

Saturn's bright little moon Dione, usually magnitude 10 is easy to see in a 4" aperture scope (Saturn needs high magnification - it's almost a billion miles away). With Saturn's minimal ring tilt, the inner moons are passing across the face of Saturn in Transit (but you won't see them do that, they are too small) and being eclipsed by Saturn or the huge darkness behind it.

Watch Saturn Tuesday evening from 8:30 pm local time. The bright moons Titan and Rhea are on either side of the planet. Tethys is about to transit Saturn and is lost in the planet's glare. Dione is eclipsed in the planet's shadow, a too faint magnitude 14. But at 8:34 pm Dione moves into sunlight and suddenly appears S of the rings, at magnitude 10.

The chart below has been rotated 90 degrees so it will fit in the blog. After rotating the image, observers using Maks and Cassegrain scopes should flip the image horizontally, to show Titan on the right side and Rhea on the far left. But you probably already know that.

Observers who have watched moons pop into view from Jupiter's shadow (a fairly common event as Jupiter has 4 bright moons always tilted about 3 degrees to us) will be able to see eclipses of Saturn's moons for the next year. Indeed, on a few occasions in early 2009 the huge moon Titan will cast its shadow on bright Saturn and I plan to image that "shadow transit", a very rare celestial event!