Observing Tips from the Amateur Astronomers' Association of Princeton

Helpful hints for skywatchers in central New Jersey and the Delaware Valley.

This current satellite image comes from CNN Interactive/Accu-Weather.
For forecasts and current conditions, see Weather below.

What to See

Interesting Sky Sights and planetary positions for the week are featured in Sky & Telescope's Sky at a Glance.

Local Rising and Setting Times for the sun, moon and planets are featured in Princeton Online's EYE ON THE SKY Princeton Almanac.

How Much Moonlight tonight? The U. S. Naval Observatory will show you a virtual reality image of the current moon phase.

The Brightness of the Planets can be found in Philadelphia's Franklin Institute Science Museum and Fels Planetarium Planetary Magnitude Almanac, from EYE ON THE SKY.

AAAP's Simpson Observatory

AAAP Public Starwatches with the John W. H. Simpson Observatory's two telescopes are held every Friday that the weather permits (if it's not too cold, the sky is mostly clear, and the park road isn't covered with snow or ice). Call (609) 737-2575 to verify that the observatory will be open at the time you want to be there. Keyholders usually open the observatory shortly before dark and stay until the last person is through observing. You may want to bring extra layers of warm clothing, a flashlight (especially one that has a red filter to preserve your night vision), and insect repellent.

To Get to the Observatory, which is located about ten miles north of downtown Trenton in New Jersey's Washington Crossing State Park, take New Jersey Route 29 (River Road) north from Trenton or Interstate 95 to New Jersey Exit #1 (Lambertville exit), and then:

• Go 3.8 miles north of I-95 on New Jersey Route 29 to the second traffic light (Church Road).
• Turn right on Church Road and go 1 mile to the northern entrance of Washington Crossing State Park (Brickyard Road).
• Turn right on Brickyard Road (it is unmarked and called Fiddlers Creek Road north of Church Road). Drive slowly and watch out for deer.
• You will come to a gate that may be closed but not locked. If the gate is locked, you will be unable to drive to the observatory. If the gate is closed but not locked, open the gate, drive through, and close the gate behind you.
• Go down and up a small hill and turn right. Simpson Observatory is on your right. Park along with the other cars, and carefully walk to the observatory -- this is where you may need the flashlight.

The Observatory houses two telescopes, a 6" refractor and a 12.5" Newtonian reflector. Both telescopes are on motor-driven equatorial mounts, and the 12.5" is equipped for astrophotography. For convenience, the observatory has a toilet (summer use only), a heated "warming room" in winter and a telephone. The observatory is open for use at anytime for any member who is a keyholder (keyholders take a short course in observatory operation and agree to accept scheduled duty on a Friday night about once each season).

Weather

• Weather Underground (NWS) conditions and short-term forecast for Trenton (text only)
  
  
• NOAA National Weather Service current conditions for New Jersey
  
• NOAA National Weather Service short-term forecast for New Jersey
  
• Other NOAA National Weather Service forecasts and information for New Jersey
  
  
• WebWeather (NWS) Trenton forecast and report
  
• New Jersey Online (Accu-Weather) Trenton forecast and report
  
• USA Today Trenton forecast
  
• The Weather Channel Trenton forecast and report (graphics-intense)
  
  
• CNN Interactive/Accu-Weather regional radar image (less detailed)
  
• NBC News/WSI Corporation regional radar image (more detailed; Trenton is TTN)
  
  
• NBC News/WSI Corporation regional satellite image
  

Definitions of terms used by NOAA National Weather Service for its public forecasts and reports, from the NWS Operations Manual:

Clear

Opaque clouds cover less than 1/10 of the sky.

Mostly Clear

Opaque clouds cover 1/10 to 2/10 of the sky.

Partly Cloudy

Opaque clouds cover 3/10 to 6/10 of the sky.

Mostly Cloudy

Opaque clouds cover 7/10 to 8/10 of the sky.

Cloudy

Opaque clouds cover 9/10 to 10/10 of the sky.

Variable Cloudiness

Amount of opaque cloudiness is expected to vary anywhere from 2/10 to 9/10 during the forecast period.

Fair

Less than 4/10 of the sky is covered by opaque clouds, with no precipitation and no extremes in wind or temperature.