A beautiful day in the planetary neighborhood

Jupiter is still visible in June, low in the west after sunset. The best bet for observers is to set up a scope at sunset and start observing before the sky is fully dark. Jupiter is bright enough that you can still observe it in a twilit sky, and catching it before it gets low will help in seeing more detail.

Pluto is at opposition on June 9th, shining at magnitude 13.8. Now is the best chance to catch our dim farthest planet, so if you've always wanted to find Pluto, get your finder charts, find a dark sky and try it!

The most reliable finder charts for Pluto are the ones in the RASC Observer's Handbook. To illustrate the problems with finding Pluto, compare the chart in the published RASC handbook to the chart they publish on their web site: http://www.edmontonrasc.com/pluto.html . The chart on the web site was made using Guide 7 (an excellent program for planetary predictions) but if you pick a date and compare the two charts, you'll see significant differences in the nearby stars plotted. In fact, I highly recommend that beginning Pluto hunters try this exercise of getting several charts and comparing them. It's good practice for what you'll be doing in the eyepiece, but in addition, you'll become much more familiar with the star patterns nearby so you'll remember them better when you're looking in the dark, which means a lot less back-and-forth between the eyepiece and the chart. I'm definitely going to try this myself as preparation beforehand the next time I look for Pluto!

Mars, in Aquarius, rises before midnight, but doesn't get very high in the sky before morning twilight. It's growing in apparent size — about as big as Saturn (without the rings) — and you might be able to make out some details on it on a steady night, at least fairly prominent features like Hellas and Syrtis Major, and possibly the south polar cap (SPC). The southern hemisphere of Mars (the one currently tilted toward us) is in spring right now, so the polar cap should be fairly substantial, but shrinking. Use a reliable program if you have one (XEphem, Guide, and Starry Night are good for Mars features), or a globe and a Mars ephemeris (there's one in this year's RASC Observer's Handbook) to figure out what features are pointed toward us, and be careful not to confuse Hellas and the SPC. Then keep an eye on the SPC — can you see it shrink over the next month?

Uranus and Neptune are hanging out on either side of Mars — Uranus just barely visible to the naked eye and easily in a telescope, while Neptune, two magnitudes fainter, requires a telescope. They'll get easier to see over the next few months.

Saturn, Mercury and Venus are too close to the sun to be observable this month.

I was hoping I could end this month's column with some information on how to observe one of our newest-named asteroids, asteroid 26858 Misterrogers. Unfortunately, 26858 Misterrogers is in Orion this month, and sets before twilight ends. At magnitude 16.5, that means it's going to be a tough target in amateur scopes! It's a main-belt asteroid with an estimated diameter of about 10 km, and will next be at opposition on May 3, 2004 at magnitude about 16.6. (It's fainter at opposition than it is now? That doesn't make sense to me either, so maybe it's a misprint and really should be 15.6, since its last opposition had a magnitude of 15.8. Regardless, it's very faint!)