Young/Old Crescent Spotting Tips
Set up at a site with as much altitude as possible overlooking an unobstructed horizon.
Optimal sky transparency allows the crescent to be detected and tracked down to, or up from, the horizon.
Using a telescope or binoculars (mounted binos are recommended), fine tune the focus on Venus, Jupiter, or one of the brighter stars beforehand.
For dusk attempts, have Sol's setting azimuth on hand- making note after sunset of a random landmark at that position for reference- as well as Luna's altaz position at sunset thru moonset. Accordingly, for dawn attempts, have Luna's altaz info for moonrise thru sunrise.
As dawn slivers have the advantage of possible detection with dark-adapted eyes, wearing sunglasses during the day prior to sunset attempts is recommended for maximum 'dusk' adaptation.
Once the crescent is acquired in binoculars, walk the bino down to the horizon/random landmark in consecutive FOVs for the approximate naked-eye altaz.
A favorable elongation is important. In the 24 hours before or after New Moon, Luna's angular separation from Sol can vary by several degrees. With a favorable ecliptic, net elongations (as altitude) of 6° or more at sunset or moonrise offer the best window for detection. 8-10° is necessary to catch Saber's beads in optimal/deep twilight.
Illuminated fractions of same-age crescents within 24 hours of New Moon can vary by over 200% and more than a full magnitude of brightness. Slivers near perigee provide faster elongations and thicker, brighter lunar profiles for personal record crescent spotting.
Last but not least, don't always count-out a shallow ecliptic. Occasionally our moon's extreme northern or southern declination will compensate for a less than favorable ecliptic angle.
Lunation 1085
New Moon 08 September 2010 1030ut
Areas offering net elongations as altitude of 6° or more
are indicated in gold/green above with corresponding sighting
data provided below.
Angular Size/Distance
@-24hours 33.4'/357759km
@ 00hours 33.3'/358695km
@+24hours 33.1'/361485km
Declination
@-24hours +06°59'
@ 00hours +00°43'
@+24hours -05°34'
Colongitude
@-24h 257.2°
@ 00h 269.3°
@+24h 281.4°
%Illumination/Mag
@-24hours 0.016/-1.36
@+24hours 0.015/-1.36
-24h Waning
lat/long: 20n160w
moonrise/azimuth: 1540ut/83
altaz at sunrise: 8.8/87
sunrise/azimuth: 1628ut/83
age at moonrise: -18h06m
50n120w
1228ut/76
7.4/89
1326ut/80
-22h02m
30n120w
1247ut/81
9.7/88
1343ut/83
-21h43m
50n90w
1021ut/76
8.5/90
1126ut/80
(-24h09m)
30n90w
1041ut/80
10.9/88
1142ut/83
-23h49m
10n90w
1054ut/82
12.4/85
1152ut/84
-23h36m
10n120e
2120ut/79
6.7/87
2154ut/84
-12h39m
10s120e
2137ut/79
(mercury 1.4 deg ene)
6.5/84
2202ut/84
-12h53m
30s120e
2145ut/77
(mercury 1.2 deg e)
6.4/80
2211ut/84
-12h37m
10s150e
1933ut/78
(mercury 0.9 deg se)
7.4/83
2002ut/84
-14h47m
30s150e
1945ut/77
(mercury 0.6 deg se)
7.1/79
2011ut/84
-14h38m
-24h Waning
lat/long: 10n90e
sunset/azimuth: 1206ut/275
altaz at sunset: 7.8/263
moonset/azimuth: 1242ut/265
age at sunset: (25h36m)
10n120e
1006ut/276
6.9/264
1038ut/265
23h36m
10s120e
0959ut/275
9.9/267
1045ut/265
23h29m
30s120e
0951ut/276
12.2/272
1053ut/265
23h21m
10s150e
0758ut/275
9.5/267
0840ut/266
21h28m
30s150e
0750ut/276
11.0/272
0847ut/266
21h20m
Lunation 1086
New Moon 07 October 2010 1844ut
Areas offering net elongations as altitude of 6° or more
are indicated in blue/orange above with corresponding sighting
data provided below.
Angular Size/Distance
@-24hours 33.6'/356159km
@ 00hours 33.4'/357564km
@+24hours 33.1'/360866km
Declination
@-24hours -04°59'
@ 00hours -11°02'
@+24hours -16°23'
Colongitude
@-24hours 255.0°
@ 00hours 267.0°
@+24hours 279.1°
%Illumination/Mag
@-24hours 0.015/-1.36
@+24hours 0.014/-1.36
-24h Waning
lat/long: 10n00e
moonrise/azimuth: 0516ut/97
altaz at sunrise: 6.4/99
sunrise/azimuth: 0549ut/95
age at moonrise: -13h28m
30n30e
0322ut/97
6.1/102
0357ut/96
-15h22m
10n30e
0311ut/96
7.5/98
0349ut/95
-15h33m
10s30e
0302ut/96
8.4/95
0341ut/96
-15h42m
30s30e
0251ut/97
7.6/93
0332ut/97
-15h53m
30n60e
0116ut/97
7.2/102
0157ut/96
-17h28m
30n90e
2309ut/94
8.4/102
2357ut/96
-19h35m
10n90e
2301ut/95
9.8/98
2352ut/95
-19h43m
50n120e
2115ut/93
6.6/107
2212ut/97
-21h29m
30n120e
2104ut/94
9.6/102
2200ut/96
-21h40m
10n120e
2056ut/95
11.0/97
2152ut/95
-21h48m
10s120e
2049ut/95
11.3/93
2144ut/96
-21h55m
30s120e
2041ut/94
9.7/90
2135ut/97
-22h03m
50n150e
1908ut/92
7.6/108
2012ut/97
-23h36m
10s150e
1845ut/94
12.3/92
1944ut/96
-23h59m
30s150e
1838ut/93
10.4/89
1935ut/97
(-24h06m)
-24h Waxing
lat/long: 10n00e
sunset/azimuth: 1750ut/264
altaz at sunset: 6.8/253
moonset/azimuth: 1820ut/255
age at sunset: 23h06m
10n30e
1549ut/264
6.0/253
1615ut/255
21h05m
10s30e
1558ut/264
9.0/256
1638ut/255
21h14m
30s30e
1608ut/263
11.2/260
1703ut/254
21h24m
30s120e
1007ut/263
7.7/259
1046ut/255
15h23m
30s150e
0806ut/263
6.6/259
0851ut/255
13h22m
Lunation 1087
New Moon 06 November 2010 0452ut
Areas offering net elongations as altitude of 6° or more are
indicated in blue/orange above with corresponding sighting
data provided below.
Angular Size/Distance
@-24hours 32.2'/370867km
@ 00hours 32.0'/373689km
@+24hours 31.7'/377444km
Declination
@-24hours -15°54'
@ 00hours -20°03'
@+24hours -22°57'
Colongitude
@-24h 253.2°
@ 00h 265.3°
@+24h 277.5°
%Illumination/Mag
@-24hours 0.014/-1.36
@+24hours 0.013/-1.02
-24h Waning
long/lat: 90w30n
moonrise/azimuth: 1139ut/109
(venus 3.0 deg n)
altaz at sunrise: 6.1/115
sunrise/azimuth: 1219ut/108
age at moonrise: -17h13m
90w10n
1110ut/107
(venus 2.7 deg n)
8.4/109
1153ut/106
-17h32m
60w10n
0905ut/106
(venus 1.3 deg n)
9.5/109
2137ut/254
-19h47m
60w10s
0841ut/106
(venus 1.1 deg n)
9.8/105
0930ut/106
-20h11m
60w30s
0814ut/108
(venus 0.8 deg n)
8.7/103
0904ut/109
-20h38m
00e50n
0605ut/114
(venus 0.9 deg e)
6.0/125
0657ut/114
-22h47m
00e30n
0522ut/108
(venus 1.0 deg se)
9.3/115
0618ut/108
-23h30m
30e50n
0358/114
(venus 2.0 deg se)
6.5/125
0457ut/114
-24h54m
30e30n
0317ut/107
(venus 2.2 deg sse)
10.4/115
0417ut/108
-25h35m
30e10n
0251ut/105
(venus 2.5 deg ssw)
12.8/109
0352ut/106
-26h01m
30e10s
0229ut/105
(venus 3.0 deg sw)
12.7/103
0329ut/106
-26h23m
30e30s
0203ut/107
(venus 3.5 deg wsw)
10.9/101
0303ut/109
-26h49m
60e50n
0152ut/115
(venus 3.0 deg sw)
7.4/126
0256ut/114
-27h00m
60e30n
0112ut/107
(venus 3.5 deg ssw)
11.5/116
0217ut/108
-27h40m
-24h Waxing
long/lat: 160w20n
sunset/azimuth: 0404ut/253
altaz at sunset: 6.2/243
(mercury 2.3 deg nw)
moonset/azimuth: 0438ut/246
age at sunset: 23h48m
90w10n
2339ut/254
6.1/246
(mercury 3.8 deg nnw)
0006ut/248
18h47m
60w10s
2202ut/253
7.3/289
(mercury 4.5 deg nnw)
2234ut/248
17h10m
60w30s
2230ut/251
8.6/250
(mercury 4.1 deg nw)
2312ut/246
17h38m
Lunation 1088
New Moon 05 December 2010 1736ut
Areas offering net elongations as altitude of 6° or more
are indicated in orange/blue above with corresponding
sighting data provided below.
Angular Size/Distance
@-24hours 32.0'/373298km
@ 00hours 31.7'/376922km
@+24hours 31.3'/381250km
Declination
@-24hours -23°46'
@ 00hours -25°01'
@+24hours -24°47'
Colongitude
@-24h 252.5°
@ 00h 264.7°
@+24h 277.0°
%Illumination/Mag
@-24hours 0.013/-1.02
@+24hours 0.011/-0.68
-24h Waning
long/lat: 165w20n
moonrise/azimuth: 1626ut/114
altaz at sunrise: 9.5/119
sunrise/azimuth: 1720ut/113
age at moonrise: (-25h10m)
45e10s
0156ut/114
6.2/112
0229ut/113
-15h40m
75e10n
0027ut/113
6.5/115
0103ut/112
-17h09m
90e10n
2325ut/113
7.2/115
0003ut/112
-18h11m
105e10n
2222ut/113
7.5/115
2303ut/112
-19h14m
120e30n
2201ut/117
6.1/122
2240ut/115
-19h35m
120e10n
2120ut/113
8.2/115
2203ut/112
-20h16m
120e10s
2044ut/113
8.6/112
2129ut/113
-20h52m
120e30s
2002ut/117
8.1/111
2050ut/116
-21h34m
135e30n
2059ut/117
6.3/122
2140ut/115
-21h37m
135e10s
1941ut/113
9.3/112
2029ut/113
-21h55m
135e30s
1900ut/117
8.4/111
1950ut/116
-22h36m
150e10s
1839ut/113
10.0/111
1929ut/113
-22h57m
150e30s
1758ut/116
9.0/111
1850ut/116
-23h38m
-24h Waxing
long/lat: 15w10n
sunset/azimuth: 1912ut/247
altaz at sunset: 11.2/247
moonset/azimuth: 2009ut/245
age at sunset: (25h36m)
00e30n
1701ut/244
7.1/236
1746ut/242
23h25m
00e10n
1739ut/247
9.4/243
1829ut/245
(24h03m)
15e30n
1601ut/244
6.4/236
1643ut/242
22h25m
15e10n
1639ut/247
9.2/243
1727ut/245
23h03m
15e10s
1712ut/247
10.2/247
1804ut/245
23h36m
15e30s
1752ut/243
9.3/248
1847ut/242
(24h16m)
30e30n
1501ut/244
6.2/237
1541ut/242
21h25m
30e10n
1539ut/247
8.5/243
1624ut/245
22h03m
30e10s
1612ut/247
9.5/247
1702ut/245
22h36m
30e30s
1652ut/243
9.0/248
1745ut/242
23h16m
45e10n
1439ut/247
8.2/243
1522ut/245
21h03m
45e30s
1552ut/243
8.4/247
1642ut/242
22h16m
75e10n
1239ut/247
7.2/243
1317ut/245
19h03m
90e10n
1139ut/247
6.5/243
1215ut/245
18h03m
105e10n
1039ut/247
6.2/244
1112ut/245
17h03m
120e10s
1012ut/247
6.5/246
1048ut/245
16h36m
120e30s
1051ut/243
6.4/246
1131ut/241
17h15m
135e10s
0912ut/247
6.2/246
0945ut/245
15h36m
135e30s
0951ut/243
6.1/246
1029ut/241
16h15m
Lunation 1089
New Moon 04 January 2011 0903ut
Areas offering net elongations as altitude of 6° or more
are indicated in orange/blue above with corresponding
sighting data provided below.
Angular Size/Distance
@-24hours 30.6'/390723km
@ 00hours 30.3'/394864km
@+24hours 30.0'/398844km
Declination
@-24hours -24°02'
@ 00hours -22°07'
@+24hours -19°12'
Colongitude
@-24h 253.1°
@ 00h 265.3°
@+24h 277.6°
%Illumination/Mag
@-24hours 0.011/-0.68
@+24hours 0.010/-0.68
-24h Waning
long/lat: 90w30n
moonrise/azimuth: 1218ut/117
altaz at sunrise: 6.0/122
sunrise/azimuth: 1255ut/116
age at moonrise: -20h45m
90w10n
1136ut/114
8.0/116
1217ut/113
-21h27m
75w10n
1033ut/114
8.3/116
1117ut/113
-22h30m
75w10s
0957ut/114
9.1/122
1043ut/113
-23h06
75w30s
0914ut/117
8.2/112
1003ut/117
-23h49m
60w10n
0931ut/114
8.6/116
1017ut/113
-23h32m
60w10s
0855ut/114
9.4/112
0943ut/113
(-24h08m)
60w30s
0812ut/117
8.5/111
0903ut/117
(-24h51m)
-24h Waxing
long/lat: 165w20n
sunset/azimuth: 0435ut/246
altaz at sunset: 7.5/245
moonset/azimuth: 1838ut/108
age at sunset: 19h32m
120w30n
0114ut/244
6.1/242
0151ut/247
16h11m
105e50n
0914ut/234
7.3/227
1021ut/240
(24h11m)
120e50n
0814ut/234
7.1/227
0918ut/240
23h07m
120e30n
0915ut/244
9.4/241
1011ut/248
(24h12m)
120e10n
0953ut/247
10.2/248
1043ut/251
(24h50m)
135e50n
0714ut/234
6.4/228
0815ut/239
22h11m
135e30n
0815ut/244
9.1/241
0908ut/248
23h12m
135e10s
0927ut/246
8.4/252
1009ut/251
(24h24m)
150e10s
0826ut/246
8.3/252
0907ut/251
23h23m
Lunation 1090
New Moon 03 February 2011 0231ut
Areas offering net elongations as altitude of 6° or more
are indicated in orange/blue above with corresponding
sighting data provided below.
Angular Size/Distance
@-24hours 29.8'/401646
@ 00hours 29.6'/403563
@+24hours 29.5'/404971
Declination
@-24hours -17°45'
@ 00hours -13°52'
@+24hours -09°28'
Colongitude
@-24h 254.7°
@ 00h 266.9°
@+24h 279.1°
%Illumination/Mag
@-24hours 0.010/-0.34
@+24hours 0.009/-0.34
-24h Waning
long/lat: 60w10n
moonrise/azimuth: 1011ut/106
altaz at sunrise: 6.1/107
sunrise/azimuth: 1042ut/107
age at moonrise: -16h20m
60w10s
0947ut/106
6.0/105
1017ut/107
-16m44m
45w10s
0824ut/106
6.4/105
0857ut/107
-18h07m
15w10n
0645ut/107
7.3/108
0722ut/107
-19h46m
00e30n
0612ut/109
6.2/114
0649ut/109
-20h19m
00e10n
0543ut/107
7.6/109
0622ut/107
-20h48m
15e30n
0511ut/109
6.4/114
0549ut/109
-21h20m
15e10n
0442ut/107
8.2/109
0522ut/107
-19h49m
15e10s
0416ut/107
8.3/105
0457ut/107
-22h15m
15e30s
0346ut/110
7.2/105
0428ut/110
-22h45m
30e30n
0409ut/109
6.6/114
0449ut/109
-22h22m
30e10n
0340ut/107
8.4/109
0422ut/107
-22h51m
30e10s
0314ut/107
8.6/106
0357ut/107
-23h17m
30e30s
0244ut/110
7.5/105
-23h47m
45e30n
0307ut/110
7.2/115
0349ut/109
-23h24m
45e10n
0238ut/107
9.1/109
0322ut/107
-23h53m
45e10s
0212ut/107
9.3/106
0257ut/107
(-24h19m)
60e30n
0206ut/110
7.3/115
0249/109
(-24h25m)
-24h Waxing
long/lat: 165w60n
sunset/azimuth: 0321ut/237
altaz at sunset: 9.1/232
moonset/azimuth: 0457ut/253
age at sunset: 24h00m
165w20n
0454ut/253
10.4/256
0545ut/261
(25h23m)
120w50n
0059ut/245
9.0/242
0208ut/256
22h28m
120w30n
0140ut/135
9.3/253
0231ut/259
23h09m
105w50n
2358ut/245
8.5/242
0105ut/255
21h27m
105w30n
0040ut/251
9.0/253
0129ut/259
22h09m
90w50n
2259ut/245
8.1.243
0002ut/255
20h28m
90w30n
2340ut/251
8.4/253
0027ut/259
21h09m
90w10n
0006ut/253
7.4/259
0042ut/260
21h35m
75w50n
2158ut/245
7.6/243
2300ut/255
19h27m
75w10n
2306ut/253
7.1/258
2340ut/260
20h35m
60w50n
2058ut/245
7.3/243
2157ut/254
18h27m
60w10n
2206ut/253
6.5/258
2239ut/260
19h35m
00e30n
1739ut/251
6.0/253
1813ut/258
15h08m
raw data generated with WinEphem
*check local listings*
*****
| Lunar |
You've probably seen a very thin sliver of our moon after sunset or before sunrise. Imagine it thinner. And even thinner. Eventually all that's left is sunlight shining off the mountain peaks while leaving the valleys in darkness. This arched 'string-of-pearls' is known as Saber's beads after a comment I made about the visual similarity to what is seen during a solar eclipse.
Just before (and after) the moon passes in front of the sun, light shines at us through the valleys but is blocked by the mountains- the mirrored effect of Saber's beads. After reporting this resemblence, my esteemed stargazing colleagues honored me with its namesake.
While promoted as an outreach term, further scientific study may also provide new insights regarding local albedo values within the lunar libration zones.
*****
EXTREME CRESCENT SPOTTING TIPS
Set up at a site with as much altitude as possible overlooking an unobstructed horizon.
Optimal sky transparency allows the crescent to be detected and tracked down to, or up from, the horizon.
Using a telescope or binoculars (mounted binos are recommended), fine tune the focus on Venus, Jupiter, or one of the brighter stars beforehand.
For dusk attempts, have Sol's setting azimuth on hand- making note after sunset of a random landmark at that position for reference- as well as Luna's altaz position at sunset thru moonset. Accordingly, for dawn attempts, have Luna's altaz info for moonrise thru sunrise.
As dawn slivers have the advantage of possible detection with dark-adapted eyes, wearing sunglasses during the day prior to sunset attempts is recommended for maximum 'dusk' adaptation.
Once the crescent is acquired in binoculars, walk the bino down to the horizon/random landmark in consecutive FOVs for the approximate naked-eye altaz.
A favorable elongation is important. In the 24 hours before or after New Moon, Luna's angular separation from Sol can vary by several degrees. With a favorable ecliptic, net elongations (as altitude) of 6° or more at sunset or moonrise offer the best window for detection. 8-10° is necessary to catch Saber's beads in optimal/deep twilight.
Illuminated fractions of same-age crescents within 24 hours of New Moon can vary by 200% and a full magnitude of brightness. Slivers near perigee help present a thicker and brighter lunar profile for personal record crescent spotting.
Last but not least, don't always count-out a shallow ecliptic. Occasionally our moon's extreme northern or southern declination will compensate for a less than favorable ecliptic angle.
BRACKETING THE SLIVERS
Another rare and challenging notch for ones lunar bedpost is to catch the consecutive waning and waxing crescents within 24 hours on each side of New Moon.
For instance, July 2008's Buck Moon offered such an opportunity as I was able to spot both the -16.5 hour illumination before sunrise on the 2nd and the +23.5 hour sliver just after sunset on the 3rd.
*****
EXTREME CRESCENTS AND COLONGITUDE
A big piece of the puzzle concerning the appearance of a thin crescent's degree of segmentation may be predicted by its colongitude at New Moon which, not suprisingly, can vary by more than 10°, trumping the effects and cycling independently of the apogee-perigee lunar profiles. VMA simulations show New Moon colongs less than 270° to favor segmented waxing crescents while those over 270° favor segmented waning crescents. (Those over 270° would be considered 'early' colongitudinal moons).
Equally important to those hunting Saber's beads, colongitude may also be used inversely to determine the best profiles and visibilities for personal record crescent spotting.
The table below shows the lunation, colongitude at New Moon, duration in hours of the most segmented waxing limb (-280° colongitude), and the duration in hours of the most segmented waning/preceding limb (+260° colongitude). Data derived from thin crescent images and my own experiences with extreme crescents also concur with a 260-280° colong window. Of note; the youngest naked-eye crescent sighting to date (May 1990/aged 15.5 hrs), my May '06 sighting (20.5 hrs), and the Lodriguss example above (27.5 hrs) all have a colongitude of 276-278°.
Exact formations involved may vary at each lunation due to libration and other factors. The illuminations caused by sunlit mountainous regions and/or albedo effects also bear further study.
lun/colong/h-280/h+260
1068 274.7 10 28
1069 273.0 13 25
1070 271.1 17 21
1071 269.3 20 18
1072 267.6 24 14
1073 266.0 27 11
1074 264.9 29 09
1075 264.7 29 09
1076 266.0 27 11
1077 268.5 22 16
1078 271.3 16 22
1079 273.5 12 26
1080 274.7 10 28
1081 274.9 09 29
1082 274.4 10 28
1083 273.3 12 26
1084 271.5 16 22
1085 269.3 21 17
1086 267.0 25 13
1087 265.3 28 10
1088 264.7 29 09
1089 265.3 28 09
1090 266.9 25 13
1091 268.9 21 17
1092 271.1 17 21
1093 273.1 13 25
1094 274.7 10 28
*****
For the record, here's the ELCD from my first observation
of Saber's beads:
New Moon 27 May 2006 0526ut
(@+24hours)
Angular Size/Distance 31.2'/383356km
Colongitude 277.6°
Declination +27°04'
Solar Elongation 13.5°
Mag/% Illumination -1.02/.012
41.5n 90.5w
-24h waxing
moonset window: 01h10m
sunset/azimuth: 0126ut/300*
altaz at sunset: 9.3*/298*
moonset/azimuth: 0236ut/308*
age at sunset: 20h00m
First detected at +20.2 hours, this instance of Saber's beads peaked in deep twilight with the infant crescent hanging 2.0° above the horizon at a solar elongation of 12.2°.
By this time I was fully immersed in the imagery of a total solar eclipse- as if in the next few moments I would either be basking in our sun's corona or forced to turn away from its glare.
This experience left me with the mystery of why the phenomenon had escaped my attention in then over 10 years of diligent young/old crescent spotting, and more so, gone unreported after four centuries of magnified scrutiny.
As a drummer and not a scientist, I've done my best to make some headway into the window parameters for viewing this rare and beautiful lunar aspect.
Note the extreme northern declination and sunset altitude combined with a favorable colongitude and ecliptic which allowed one of the longest moonset windows and highest altitudes at sunset possible for a crescent that age. It is this rarity of catching the fully/near-fully segmented limb in a dark sky that defines the complete phenomenon.
*****
| Lunar |
