Cahill Rooftop Observatory

The Moon

The Moon can look spectacular, although you will need to use the polarizing filters to cut down the brightness to bearable levels. Lunar features look best at quarter phase, when sunlight hits them at a low angle and casts long shadows. You can find lists of good features on S&T's Moon page.

Planets

The major planets – Venus, Mars, Jupiter, Saturn – make for excellent visual and CCD targets. RDRO observers have spotted the phases of Venus, moons and bands of Jupiter, and rings and moons of Saturn. Some have claimed to have also seen the Martian polar caps. Uranus and Neptune, while much less impressive, are visible as well. The locations of the planets can be determined most readily from Sky & Telescope's Sky at a Glance page, or from the hard copy S&T in the library (which should be borrowed for only as long as it takes to xerox, not for a night's observing run).

The S&T website has dozens of other useful tools, including:

• Stargazer's Almanac: planetary coordinates, magnitudes, and phases
• Transit times of Jupiter's Great Red Spot
• Jupiter's Moons: positions, transits, and eclipses
• Saturn's Moons: positions

Mercury has not been reported in the RDRO observing logs, but should be readily visible at certain times.

Comets

The IAU Minor Planet Center maintains a complete list of cometary ephemerides, although many of these will be far beyond the capabilities of our telescopes. This list is incorporated into Starry Night's database as part of its update process.

If there's a good comet around, it will likely be featured on S&T's Sky at a Glance page or its comets page.

Asteroids

S&T lists the best asteroids at any given time on its asteroid observing page. True to their name, though, even the "best" asteroids still look like stars!

The IAU Minor Planet Center maintains a complete list of asteroid ephemerides and look up tools. Starry Night regularly updates its own asteroid data as well.

Earth Orbit

The International Space Station, Hubble Space Telescope, and Space Shuttle are some of the brightest satellites in low Earth orbit. S&T has a calculator that can predict when these three satellites will be visible. For other satellites, or more detailed predictions such as finder charts, your best resource is Heavens Above. Heavens Above can also predict Iridium flares, but you'll have to give your position to within a few miles – just saying "Los Angeles" won't cut it.

Double/Multiple Stars

Open Clusters

Open clusters are a safe target on hazy nights because they're not extended sources. The individual stars are less sensitive to light pollution than nebulosity or unresolved starlight would be.

Globular Clusters

Globular clusters can look quite nice on a clear night, and make spectacular CCD targets.

Nebulae

Extragalactic

Alignment Stars

The following list of easy-to-find stars will be useful for calibrating a telescope's setting circles or GO-TO system. All of the stars listed here are on the C-14's Bright Star List, accessible from Objects->Strs or from within the Star-Sync or 2-Star calibration routines.

Color Calibrators

Anyone who wants to do "true-color" astrophotography needs to worry about color balance. To human vision, sunlight appears white, so solar twins serve as an excellent white-light standard to set the relative scaling of the red, green, and blue frames.