Tuesday, January 16, 2007

forecasting crescents in 2007

Chasing the crescent moons.

Chasing crescent moons is becoming a favorite pastime for me. The challenge of "can we detect it or not?" is addictive. Catching both crescents that embrace the New Moon. Knocking on the door of a 36 hour interval between the opposing crescents. Anticipation that nature agrees with my perseverance. However, being in the right place at the right time is true way to challenge the physically possible. Earth, Moon, Sun and obliquity of the ecliptic all play a role. It's a confluence of circumstances which the Babylonian astronomers were aware. But for us New Yorkers, most times that right place/right time is somewhere else on the globe.

The best interval for opposing crescents this year with the slightest chance of success is 37 hours 24 minutes. In the Astronomical Calendar, Guy Ottewell reports that Stephen J. O'Meara holds the naked eye record of 35h 42m and the binocular record goes to Don Pearce 35h 14 m. Nonetheless what follows is where we observe and my predictions for this year. Naturally, these are for weather permitting dates.

Favorite spots to observe these events are
- Carl Schurz Park at 86th St. for old crescents rising in the wee hours
- Great Lawn, Central Park, somewhere along the eastern sidewalk for young crescents setting shortly after the Sun
- Battery Park, near the East Coast Memorial for really low western horizon for young crescent

This year I am making some predictions. Last year I was able to come within the intervals measured in minutes for those crescents observed. Sometimes Charlie caught it first, other times I did, but in all cases we all observed it. If I remember correctly, even pedestrians we share the oculars with had seen it. On one young crescent event I claimed to have seen the crescent naked eye but Charlie and Kin had not.

Beginning 2007 Daylight Saving Time (DST) will begin on the second Sunday in March (11 March 2007) and end the first Sunday in November (04 November 2007). This is a result of the Energy Policy Act of 2005 that President Bush signed on 08 August of that year.

Bracketing the New Moon
16 Apr & 17 Apr
Interval - 37h24m
Extremely Difficult

14 Jun & 15 Jun
Interval - 39h
Best chance

Old crescents
16 Apr :: predicted sighting 05:45 ~ 05:50 EDT
Age :: 28d7h (-25.3h prior to New Moon)
1.8% illuminated
15° 29' W elongation
Easy; altitude at predicted time 1° 07'

14 Jun :: predicted sighting 04:40 ~04:45 EDT
Age :: 28d13h (-17.7h prior to New Moon)
1.0% illuminated
11° 39' W elongation
Moderate; altitude at predicted time 1° 41'

10 Oct :: -predict no sighting-
Age :: 28d21h (-17.9h prior to New Moon)
0.7% illuminated
Extremely Difficult
In terms of absolute age, this crescent will be the closest to a New Moon observed in y2007

Young crescents
19 Jan :: predicted sighting 17:10 ~ 17:15 EST
Age :: 18h09m
0.8% illuminated
10° 22' E elongation
V. Difficult; altitude at predicted time 2° 58'

19 Mar :: predicted sighting 19:10 ~ 19:15 EDT
Age :: 20h26m
1.1% illuminated
12° 17' E elongation
Easy; altitude at predicted time 9° 44'

17 Apr :: predicted sighting 19:50 ~ 20:00 EDT
Age :: 12h18m
0.5% illuminated
8° 16' E elongation
Extremely Difficult (why not % D); altitude at predicted time 4° 01'

15 Jun :: predicted sighting 20:50 ~ 20:55 EDT
Age :: 21h24m
1.2% illuminated
12° 50' E elongation
Easy; altitude at predicted time 6° 30'

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