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| current moon phase comes from the U. S. Naval Observatory | weather report comes via the Weather Underground |
Peyton Hall Observatory holds public starwatches led by students of Princeton University's Department of Astrophysical Sciences and are scheduled for 8 to 9 p.m. on the second Wednesday of each month. In case of cloudy skies the starwatch is rescheduled to the third Wednesday.
Local Moonrise, Moonset and Astronomical Twilight times for the Peyton Hall Observatory are featured in the Eye on the Sky® Almanac.
Detailed Weather Information (including forecasts and current conditions) for the Princeton area can be found on the Eye on the Sky® Weather Page, including a link for hourly forecasts for up to three days from AccuWeather.
Interesting Sky Sights and planetary positions for the week are in the Sky & Telescope feature Sky at a Glance.
A Customizable Map of the sky seen from Peyton Hall Observatory can be found at Your Sky Sky Map.
Which Satellites are Visible from the Peyton Hall Observatory tonight? Heavens-Above will calculate the visibility of all bright satellites (including space shuttles and the International Space Station) brighter than 4.5 magnitude and of sighting opportunities for Iridium flares. Some nighttime launches of space shuttles are visible from here, and the Kennedy Space Center provides a schedule and countdown timer for all shuttle launches.
Aurora Borealis can be seen from our area (if the sky is clear and dark) an average of 60-130 days every 11-year solar cycle, especially if the Kp Index is 8 or greater and the Auroral Activity Index is 10 or greater (according to Aurora Chasers, the minimum Kp Index for an aurora to be seen at least 20 degrees above the northern horizon at local midnight is 7.4). The current solar cycle began about May 1996 and peaked about April 2000. Middle-latitude auroral activity warnings and watches are available from Solar Terrestrial Dispatch, and Intellicast (Weather Services International Corp.) reproduces the current auroral forecast map from the Geophysical Institute of University of Alaska Fairbanks.
If You're Using Computer Software to plan your skywatch, it may be helpful to know that the location of the Peyton Hall Observatory is 40° 20' 48" north latitude (or +40.3466°), 74° 39' 05" west longitude (or -74.6516°).

First Visibility of young crescent moons from the Peyton Hall Observatory is based on the International Lunar Dateline work of Islamic astronomer Dr. Monzur Ahmed. Last visibility of old crescent moons is based on the research of Dr. Leroy Doggett of the U. S. Naval Observatory. Data is from MoonCalc 5.2 by Dr. Ahmed.
| Last Visibility | New Moon | First Visibility | First Quarter | Full Moon | Last Quarter |
|---|---|---|---|---|---|
| January 2 | January 4 | January 10 | January 18 | January 25 | |
| January | February 1 | February 2 | February 9 | February 16 | February 23 |
| March 2 | March 4 | March 11 | March 18 | March 24 | |
| March | April 1 | April 2 | April 9 | April 16* | April 23 |
| April | May 1 | May 2 | May 9 | May 15 | May 22 |
| May | May 30 | June 1 | June 7 | June 14 | June 21 |
| June | June 29 | June 30 | July 6 | July 13 | July 21 |
| July | July 29 | July 30 | August 5 | August 11 | August 19 |
| August | August 27 | August 29 | September 3 | September 10 | September 18 |
| September | September 25 | September 27 | October 2 | October 10 | October 18 |
| October | October 25 | October 26 | November 1 | November 9 | November 16 |
| November | November 23 | November 25 | November 30 | December 8** | December 16 |
| December | December 23 | December 24 | December 30 | 1/7/04 | 1/14/04 |
| Last Visibility | New Moon | First Visibility | First Quarter | Full Moon | Last Quarter |
| Event | Date | Time (EDT) |
|---|---|---|
| Penumbral eclipse begins | May 15 | 9:05 p.m. |
| Partial eclipse begins | " | 10:02 p.m. |
| Total eclipse begins | " | 11:13 p.m. |
| Greatest eclipse | " | 11:40 p.m. |
| Total eclipse ends | May 16 | 12:06 a.m. |
| Partial eclipse ends | " | 1:17 a.m. |
| Penumbral eclipse ends | " | 2:14 a.m. |
| Event | Date | Time (EST) |
|---|---|---|
| Penumbral eclipse begins | November 8 | 5:15 p.m. |
| Partial eclipse begins | " | 6:32 p.m. |
| Total eclipse begins | " | 8:06 p.m. |
| Greatest eclipse | " | 8:18 p.m. |
| Total eclipse ends | " | 8:30 p.m. |
| Partial eclipse ends | " | 10:04 p.m. |
| Penumbral eclipse ends | " | 11:21 p.m. |
No Twilight or Nighttime Occultation of a bright planet or first-magnitude star by the moon is visible from the Peyton Hall Observatory this year.
Major Meteor Showers peak at the following times, according to International Meteor Organization (IMO). Neil Bone of the British Astronomical Association estimates that under perfect conditions an average of about 3-8 sporatic meteors per hour are visible to the naked eye. Bone says the best place to look for meteors from a specific meteor shower is about 50° above the horizon and 40° to either side of the radiant.
| Shower | Peak Date | Peak Time | Radiant Alt/Az | Lunar Phase (percent illuminated) / Magnitude / Elongation | Meteors per Hour* |
|---|---|---|---|---|---|
| Quadrantids | Jan. 3 | 7 p.m. | 1°/NNW | waxing crescent (2%) / -5.5 / 97° | 0 |
| Eta-Aquarids** | May 6 | 7:30 a.m. | 46°/SSE | waxing crescent (22%) / -8.5 / 120° | 6 |
| Perseids | Aug. 13 | 12:40 a.m. | 34°/N | waning gibbous (99%) / -12.4 / 44° | 9 |
| Orionids** | Oct. 21 | 5 p.m. | -33°/N | waning crescent (18%) / -8.2 / 96° | 0 |
| Geminids | Dec. 14 | 6:40 a.m. | 34°/WNW | waning gibbous (73%) / -11.0 / 36° | 10 |
* at local peak time(s), calculated by reducing zenithal hourly rate (ZHR) to a limiting magnitude of 4.5 and factoring in the distance of the radiant from the zenith (but does not include the effects of moonlight, sunlight or time of day), based on the International Meteor Organization's 2003 Meteor Shower Calender.
** Eta-Aquarids and Orionids are listed because they are associated with Halley's Comet (Comet 1P/Halley).
The best conditions for watching a meteor shower occur when the radiant at the shower's peak appears high in a dark sky between local midnight and the beginning of astronomical twilight.
| Shower | Peak Time | Local Midnight | Astronomical Twilight Begins | Moon Rise/Set | Moon Above Horizon At Dawn? | Meteors per Hour* |
|---|---|---|---|---|---|---|
| Quadrantids | Fri Jan 3 7 p.m. | 12:03 a.m. | 1/4 5:44 a.m. | Set 1/3 5:33 p.m. Rise 1/4 9:06 a.m. | No | 0 |
| Perseids | Wed Aug 13 12:40 a.m. | 1:04 a.m. | 4:25 a.m. | Rise 8/12 8:48 p.m. Set 8/13 7:23 a.m. | Yes | 9 |
| Geminids | Sun Dec 14 6:40 a.m. | 11:53 p.m. | 5:35 a.m. | Rise 12/13 8:55 p.m. Set 12/14 11:34 a.m. | Yes | 10 |
Space Shuttles launched at night and at high inclinations (such as toward the International Space Station at 51.6°) can be seen from Princeton during the last minute or so before Main Engine Cut-Off (MECO, which occurs about eight-and-a-half minutes into the mission). The Kennedy Space Center provides a schedule and countdown timer for all shuttle launches, all of which are under review following the tragic loss of the orbiter Columbia February 1, 2003. Shuttle launches are usually carried live by local radio stations KYW-AM (1060 kHz, Philadelphia) and WINS-AM (1010 kHz, New York City). Our thanks to NASA Flight Dynamics Officer Daniel R. Adamo for "guidance" and use of his MacMission Control software for the following calculations of the nighttime visibility of an average flight of a shuttle to the ISS as seen from Trenton.
| Mission Elapsed Time (mm:ss) | Altitude | Azimuth | Range (Statute Miles) |
|---|---|---|---|
| 06:45 | 5° | South | 478 |
| 07:00 | 6° | South | 448 |
| 07:15 | 6° | South | 418 |
| 07:30 | 7° | SSE | 391 |
| 07:45 | 8° | SSE | 367 |
| 08:00 | 8° | SSE | 350 |
| 08:15 | 9° | SE | 298 |
| 08:30 | 8° | ESE | 302 |
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