VI/132C Lunar Occultation Archive (Herald+ 2022)
Lunar Occultation Archive
Herald D., Gault D.
International Occultation Timing Association (IOTA) (2010-2022)>
ADC_Keywords: Occultations
Description:
Lunar occultation timings from 1623 to the present time are brought
together in a consistent format. The observations have been processed
and reviewed to correct a range of data errors. Provisional reductions
of the observations are provided. The reductions are based on the
JPL-DE440 ephemerides, with limb corrections derived from satellite
altimetry from the Lunar Orbiter Laser Altimeter of the Lunar
Reconnaissance Orbiter. Almost all star positions are from Gaia EDR3,
Hipparcos2, or UBAD.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
lunarocc.dat 347 493085 Lunar occultation archive
doc.txt 77 1224 Detailed information concerning the derivation
of the data, the corrections applied, and the
basis of the reductions
--------------------------------------------------------------------------------
See also:
http://occultations.org.nz/index.htm/ : IOTA home page for Australasia
http://www.iota-es.de/ : IOTA home page for Europe
http://astro-limovie.info/jclo/index.html : IOTA home page for Japan
http://www.lunar-occultations.com/IOTA : IOTA home page for North America
https://pds-geosciences.wustl.edu/lro/lro-l-lola-3-rdr-v1/lrolol_1xxx/
data/lola_gdr/cylindrical/img/ : The LRO-LOLA data used for limb
corrections
Byte-by-byte Description of file: lunarocc.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
[ Group 1 Time and Object - including any corrections]
--------------------------------------------------------------------------------
1- 4 I4 yr Obs.Y [1623,2022] Year of the observation
5- 6 I2 "month" Obs.M [1,12] Month of the observation
7- 8 I2 d Obs.D [1,31] Day of the observation
9- 10 I2 h Obs.h [0,23] Hour of the observation
11- 12 I2 min Obs.m [0,59] Minute of the observation
13- 18 F6.3 s Obs.s [0,59.999]? Second of the observation.
19 A1 --- CatID [APRSXU] The star catalogue or object type (1)
20- 25 I6 --- CatNum [0,999999] Number in catalogue (2)
26 A1 --- WDS [A-Z, a-z] Double star component identifier (3)
27 A1 --- Phen [BDEFMORSX?] Phenomena type (4)
28 A1 --- Limb [DBU?] Bright or dark limb (5)
29 A1 --- Graze [G?] Flag for grazing occultation event (6)
30- 33 F4.2 --- PE [0.00,9.99]? Personal equation.
34 A1 --- PEApp [ABESUX?] Application of Personal equation (7)
--------------------------------------------------------------------------------
[ Group 2 ILOC observation codes - mainly used after 1980]
--------------------------------------------------------------------------------
35 A1 --- Meth1 [CEGKMOPSTVX?] First method of timing and
recording 1 (8)
36 A1 --- Meth2 [ACEGKMOPSTVX?] Second method of timing and
recording (8)
37 A1 --- Time [CMNGORT?] Time source (9)
38- 42 F5.3 s Accur [0.000,9.999]? Accuracy of time.
43 A1 --- Cert [0123?] Certainty (10)
44- 46 F3.1 --- SN [0.0-9.9]? Signal-to-Noise ratio (11)
47 A1 --- Double [BEFNSUW?] Double star or unidentified star (12)
48- 52 F5.3 s Durn [0.000,94]? Duration of non-instantaneous
event (13)
53 A1 --- LLevel [TF?] Light level at event (14)
54 A1 --- Stabil [123?] Sky stability (1=good, 3=poor) (15)
55 A1 --- Transp [123?] Sky transparency (1=good, 3=poor) (15)
56 A1 --- Remark [123456789?] Remarkable circumstances (17)
57- 59 I3 degC Temp [-49,+50]? Temperature, degrees Celsius
--------------------------------------------------------------------------------
[ Group 3 RGO observation codes - mainly used before 1981]
--------------------------------------------------------------------------------
60 A1 --- Acc [123456789?] Accuracy (18)
61 A1 --- Cond [123456789?] Condition (19)
62 A1 --- Ad_Dbl [28?] Time adjusted; Double star (20)
63 A1 --- TMeth [0123456789?] Timing method (21)
--------------------------------------------------------------------------------
[ Group 4 Compilation/Edit codes]
--------------------------------------------------------------------------------
64- 69 A6 --- --- ?=? Reserved for future use
70 A1 --- EGraze [G?] Graze - additions from original
reports (22)
71 A1 --- Graze2 [2?] Graze observed at 2nd Limit (23)
72 A1 --- Srce [AHIMNOPQRSX] Source of observation (24)
73 A1 --- DupErr [DIKX?] Duplicate/erroneous observation (25)
74 A1 --- Valid [ABCDEFGSTUWXYZ?] Observation validity (26)
75- 78 I4 yr GZyear [1706,2022]? Graze identifier - year (27)
79- 81 I3 --- GZnum [1,150]? Graze identifier - number in year (27)
--------------------------------------------------------------------------------
[ Group 5 Site location - including any corrections]
--------------------------------------------------------------------------------
82 A1 --- Long.- [-+]? Site location: sign of longitude
83- 85 I3 deg Long.d [0,180]? Site location: degrees of longitude
86- 87 I2 arcmin Long.m ? Site location: minutes of longitude
88- 92 F5.2 arcsec Long.s ? Site location: seconds of longitude
93 A1 --- Lat.- [-+]? Site location: sign of latitude
94- 95 I2 deg Lat.d [0,89]? Site location: degrees of latitude
96- 97 I2 arcmin Lat.m ? Site location: minutes of latitude
98-102 F5.2 arcsec Lat.s ? Site location: seconds of latitude
103-104 I2 --- HDatum ? Horizontal datum code (28)
105-110 F6.1 m Alt [-999.9,+9999.9]? Altitude
111 A1 --- VDatum [ME] Vertical datum code (29)
112-120 A9 --- ILOCst ?=? ILOC Station + Telescope code
121-127 A7 --- RGOst ?=? RGO station + Observer code
128-177 A50 --- Town ?=? Closest town or landmark, and Country.
--------------------------------------------------------------------------------
[ Group 6 Telescope details]
--------------------------------------------------------------------------------
178 A1 --- Tel [*CNORX?] Type of telescope (30)
179 A1 --- Mount [*AEX?] Telescope mounting (31)
180 A1 --- Drive [*DMX?] Telescope drive (32)
181-184 I4 cm Apert ? Telescope aperture
185-188 I4 cm FL ? Telescope focal length
--------------------------------------------------------------------------------
[ Group 7 Observer names]
--------------------------------------------------------------------------------
189-213 A25 --- Name ?=? Observer name
--------------------------------------------------------------------------------
[ Group 8 Original date/time]
--------------------------------------------------------------------------------
214-217 I4 yr Src.Y [19,2094]? Year in source data
218-219 I2 "month" Src.M [0,91]? Month in source data
220-221 I2 d Src.D [0,31]? Day in source data
222-223 I2 h Src.h [-1,+98]? Hour in source data
224-225 I2 min Src.m [0,99]? Minute in source data
226-231 F6.3 s Src.s [0,99.95]? Second in source data
--------------------------------------------------------------------------------
[ Group 9 Original object]
--------------------------------------------------------------------------------
232 A1 --- SrcCat [AHMOPRSXU?] Star catalogue or object type
in source data (1)
233-238 I6 --- SrcNum ? Number in catalogue in source data (2)
--------------------------------------------------------------------------------
[ Group 10 Original site coordinates]
--------------------------------------------------------------------------------
239 A1 --- SrcLg.- [-+] Sign of longitude in source data
240-242 I3 deg SrcLg.d [0,180]? degrees of longitude in source data
243-244 I2 arcmin SrcLg.m [0,72]? minutes of longitude in source data
245-249 F5.2 arcsec SrcLg.s [0,92.0]? seconds of longitude in source data
250 A1 --- SrcLt.- [-+] Sign of latitude in source data
251-252 I2 deg SrcLt.d [0,89]? degrees of latitude in source data
253-254 I2 arcmin SrcLt.m [0,59]? minutes of latitude in source data
255-259 F5.2 arcsec SrcLt.s [0,65.0]? seconds of latitude in source data
260-261 I2 --- SrcHDt ? Horizontal datum code in source data (28)
262-267 F6.1 m SrcAlt [-999.,+9999.9]? Altitude in source data
268 A1 --- SrcVDt [EM?] Vertical datum code in source data (29)
--------------------------------------------------------------------------------
[ Group 11 Computed values]
--------------------------------------------------------------------------------
269-277 F9.2 deg LibLon Longitude libration
278-283 F6.2 deg LibLat Latitude libration
284-290 F7.2 deg AA Axis Angle
291-296 F6.3 --- Scale Ratio of the apparent to mean lunar radius
297-303 F7.3 arcsec LimbH Apparent height of the lunar limb at the
contact point.
304-313 F10.3 arcsec OC O-C residual - computed height of the star
above the lunar limb.
314-320 F7.2 deg PA [0,360] Position Angle of the contact point
on the lunar limb.
321-327 F7.2 arcsec/s dOC change in the O-C residual for a time
difference of +1.0 second.
328-333 F6.2 arcsec/s dMoon Apparent rate of motion of moon
334-340 F7.2 deg PAmoon Position Angle of direction of motion
of the moon
341-347 A7 --- RefCat Catalogue source of the star position (33)
--------------------------------------------------------------------------------
Note (1): The star catalogue code is used to identify the star, planet or
asteroid. The source of its position is given in columns 340-345.
The star catalogue code is designated as follows:
R = Zodiacal Catalogue [ADS ref 1940USNAO..10..169R 1940USNAO..10..169R]
S = SAO catalogue [I/131]
X = XZ80Q catalogue [I/291]
A = Numbered asteroid
P = Planet and planet satellites
U = Unidentified star
The following codes are additionally referred to in the source data
(column 232):
H = a catalogue used internally by ILOC
M = PPM catalogue [I/146, I/193]
O = an unpublished catalog of faint stars used for lunar eclipses
Note (2): The star catalogue number is used to identify the star. The source
of its position is given in columns 340-345.
The number for catalogues A, P and U are:
A = the asteroid number
P = the number is formed as pmmm, where: p is planet number
and mmm is moon number. For an occultation of the planet, mmm=000
Examples: Mercury=1000, Jupiter=5000, Ganymede=5003, Titan=6006
U = always 0
Note (3): the WDS code is the component identifier the star in a
double star system listed in the WDS [B/WDS]
Note (4): the code for the Phenomena type is as follows:
D = disappear
R = reappear
B = Blink. The mid-time of a blink event. Usually only occurs during
a graze, but can occur in near-graze situations. Duration is
specified at col 48.
(video) partial disappearance (always >25% of full light).
(visual) a short disappearance-reappearance - too close to
separately time.
F = Flash. The mid-time of a flash event. Usually only occurs during
a graze, but can occur in near-graze situations. Duration is
specified at col 48.
(video) partial reappearance (always <25% of full light).
(visual) a short reappearance-disappearance - too close to
separately time.
M = Miss. The time when the star was adjacent the highest point on the
observed or predicted graze profile - although the time might also
be simply the mid-time of the graze. Usually only used when other
observers in a graze observation have recorded D and/or R events
S = Start or resume. Only used in a graze observation, to indicate
periods when the observer was observing.
E = End or pause. Only used in a graze observation, to indicate
periods when the observer was not observing.
O = Other [used by ILOC instead of S or E]
X = Missing data. A grazing occultation of this star was known to have
been successfully observed on this date, but no observations are
available. The time and site coordinates are indicative only.
Note (5): the Bright or dark limb code is:
D = dark limb
B = bright limb (including lunar eclipse penumbra)
U = umbra of lunar eclipse
Note (6): The Graze flag is set to G if the event is part of a grazing
occultation. An ordinary occultation occuring within 4.5° of the
tangent point is treated as a graze observation.
Note (7): the code for the Application of personal equation is:
S = personal equation has been subtracted from the observed time.
A = same as S, but PE listed is an assumed value [compatibility for
ILOC observations]
B = same as S, but the value of the PE applied is unknown
[compatibility for RGO observations]
U = personal equation has not been subtracted from the reported time.
E = personal equation not relevant to the method of timing
(eg video, eye-ear)
X = Not known whether any PE has been applied.
Note (8): the code for the method of timing and recording is:
G = Video with time insertion, times extracted by frame analysis
V = Video with other time linking, times extracted by frame analysis
M = Video with other time linking, times extracted by replay
S = Stopwatch (visual)
T = Tape recorder (visual)
E = Eye and ear
P = Photoelectric
K = Key-tapping - including computer keyboards
X = Chronograph
C = Camera and clock
O = Other [details reported to ILOC, but not captured.]
A = Time base corrected using adjacent observers.
This is only used in Meth2.
Note (9): the code for the Time source is:
G = GPS (using 1PPS output, NOT GPS screen display)
R = Radio signal (standard time signal)
N = Network Time Protocol (using NTP software)
C = Clock(adjusted by standard time signal)
T = Telephone
M = Some medium related with standard time signal
O = GPS screen display, computer clock not using NTP software
(poor accuracy).
Note (10): the code for Certainty is the following:
1 = Sure
2 = Possibly spurious
3 = Most likely spurious
Note (11): Signal to noise is only given for video or photoelectric
observations.
Note (12): the code for Double star or unidentified star is:
W = Preceding (west) component
E = Following (east) component
N = North component
S = South component
B = Brighter component
F = Fainter component
U = Unidentified star
Note (13): the duration of the event relates to both Fresnel diffraction
effects, and the effects of stellar diameter. The duration of event
does not apply to the time difference between the occultation of both
components of a close double star.
Note (14): the code for Light level at event is:
T = 25% light level (consistent with Fresnel diffraction)
F = 50% light level (consistent with stellar diameter effects)
The code is only applied where the occultation was recorded by video
or photometer.
Note (15): the code for Sky stability/transparency is:
1 = Good
2 = Fair
3 = Poor
Note (17): the code for Remarkable circumstances is the following:
1 = Gradual [not instantaneous] event
2 = Dark limb visible
3 = By averted vision
4 = Star faint
5 = Through thin cloud
6 = Many clouds
7 = Strong wind
8 = In strong twilight
9 = In daylight (sun altitude >-6° {civil twilight})
Note (18): the code for Accuracy (RGO) is:
1 = excellent, very good (±0.1s, ±0.2s)
2 = good, certain (±0.3s, ±0.4s)
3 = fair, satisfactory (±0.5s to ±0.7s)
4 = poor, uncertain (±0.8s, ±0.9s)
5 = very poor, very doubtful (±1s)
6 = star faint
7 = perhaps early
8 = perhaps late
9 = uncertain by tens of seconds
Note (19): the code for Condition (RGO) is:
1 = clear, good conditions
2 = haze, mist, thin cloud
3 = cloud
4 = difficult conditions
5 = not instantaneous, gradual
6 = dark limb visible
7 = by averted vision
8 = during lunar eclipse
9 = obvious mistake corrected on report
Note (20): the code for Time adjusted; double star (RGO) is:
2 = reported time adjusted by integral number of minutes,
hours, etc, for obvious mistake
8 = component of double star (Observations of components
of double or compound star systems which do not have
positions in the ZC or SAOC are indicated by an '8')
Note (21): the code for Timing method (RGO) is the following:
1 = photoelectric
2 = eye-and-ear
3 = chronograph
4 = stopwatch and time-signal
5 = stopwatch and telephone time-signal
6 = camera and clock
7 = eye-and-ear with sidereal chronometer
8 = chronograph and sidereal clock
9 = tape recorder and time signal
0 = not known
Note (22): the code for Graze - additions from original reports is:
G = graze observations that were missing from the data sources
used to create the archive, with the observations being added
from original reports obtained from the observers or
coordinators.
Note (23): on rare occasions a star is observed to graze at both
the northern and southern limbs of the moon. Those grazes are
distinguished by one of them being assigned the code 2.
Note (24): the code for the Source of observation is the following:
A = New observation reports
H = RGO grazing occultations, OCR'd from RGO Bulletin 192 (1984)
I = ILOC computer records - annual consolidations
M = Miscellaneous sources (grazes before 1960, + missing grazes)
N = S. Newcomb: Researches on the Motion of the Moon (APAE, 1878)
O = grazes in the files of Occult
P = re-processed ILOC reports after 2002
R = RGO computer records - ordinary occultations
S = Graze reports collected by Mitsuru Soma - up to 2007.
X = ILOC computer records after 2000, where no site code was allocated
Note (25): the code for Duplicate/erroneous observation is the following:
D = Observation is a duplicate, and is to be ignored in favour of
another observation. Observation can be removed from the dataset.
I = Observation is a graze observation that is inconsistent with
other observations. Presumably an erroneous observation.
However the observation is to be retained in the dataset
K = Observation is a duplicate, and is to be ignored in favour
of another observation. However observation is to be retained
in the dataset
X = Missing data. A grazing occultation of this star was known
to have been successfully observed on this date, but no
observations are available.
Note (26): the code for Observation validity is the following:
A = Valid, after adjustments to the date/time.
B = Valid, after adjustments to the star number.
C = Valid, after adjustments to both the date/time AND star number.
D = Valid, after adjustments to site coordinates (*)
E = Valid, after adjustments to site coordinates AND date/time (*)
F = Valid, after adjustments to site coordinates AND star number (*)
G = Valid, after adjustments to site coordinates AND star number
AND date/time (*)
S = Unknown site location [Used for RGO and ILOC data, where
there is no site data for the specified station.]
T = Poor time base [for events before 1850]
U = Unidentified star
W = Invalid site location. The site location is definitely
in error (eg site located in the sea, or all observations
from the location have large residuals), and the
correct location cannot be deduced (eg no obvious transposition
of digits in the reported site coordinates).
X = Assessed as an invalid observation. On investigation,
confident the relevant occultation and observing location
has been identified, with a conclusion that the event was
not actually observed for some reason - such as difficult
conditions.
Y = limb-corrected residual greater than about 4". This is
a flag automatically generated to indicate the computed
residual is unsatisfactory. The exact criteria applied
depends on the basis for correcting the limb for its
irregularities. Events with this flag have not been
individually investigated to determine whether there is
an error in the reported data, or whether the observation
was adversely affected by poor observing conditions
(that is, is invalid).
Z = Unresolved data errors. After considering the
possibility of errors in several of date + time, star,
and site location, the reported observation cannot be
plausibly associated with a relevant occultation.
(*) NOTE for codes D, E, F and G: Adjustments to site coordinates
are made on the basis of ALL observations made from a site,
and not on an event-by-event basis.
Note (27): The graze identifier year and number in year provides
a simple means to extract all observations of a particular
grazing occultation. Use column 71 to distinguish events
when the graze was observed at both limbs.
Note (28): the code for Horizontal datum is the following:
0 = unknown (WGS84 used)
1 = RGO code 1 = 'geodetic, referred to one of the following
major datum blocks; 1927 North American Datum, European
Datum or Australian Geodetic Datum'
2 = RGO code 2 = 'geodetic, either referred to one of the
secondary datum blocks, such as Tokyo Datum or African
Arc Datum, or are referred to a national datum, such as
the 1936 Ordnance Survey of Great Britain'
3 = RGO code 3 = 'probably geodetic'
4 = RGO code 4 = 'probably astronomic'
5 = RGO code 5 = 'astronomical'
10 = 'GoogleEarth' (WGS84)
12 = Christmas Island Astro 1967
13 = Chua Astro (Brazil Geodetic)
14 = Corrego Alegre (Brazil)
15 = Easter Island Astro 1967
16 = European 1950
17 = Graciosa Island (Azores)
18 = Gizo, Provisional DOS
19 = Guam
20 = Heard Astro 1969
21 = Iben Astro, Navy 1947 (Truk)
22 = Indian
23 = Isla Socorro Astro
24 = Johnston Island 1961
25 = Kusaie Astro 1962,1965
26 = Luzon 1911 (Philippines)
27 = Midway Astro 1961
28 = New Zealand 1949
29 = North American 1927
30 = Cape Canaveral
31 = White Sands
32 = Old Bavarian
33 = Old Hawaiian
34 = Ordnance Survey of Great Britain 1936
35 = Pico de las Nieves (Canaries)
36 = Pitcairn Island Astro
37 = Potsdam
38 = Provisional South American 1956
39 = Provisional South Chile 1963
40 = Pulkovo 1942
41 = South American 1969
42 = Southeast Island (Mahe)
43 = South Georgia Astro
44 = Swallow Islands (Solomons)
45 = Tananarive
46 = Tokyo
47 = Tristan Astro 1968
48 = Viti Levu 1916 (Fiji)
49 = Wake Island Astro 1952
50 = Yof Astro 1967 (Dakar)
51 = Palmer Astro 1969 (Antarctica)
52 = Efate (New Hebrides)
53 = Marcus Island 1965
54 = Canton Astro 1966
56 = Yap Island
58 = Kourou (French Guiana)
59 = Ordnance Survey of Great Britain 1970
60 = Qornoq (Greenland)
61 = Adindan (Ethiopia)
62 = American Samoa 1962
63 = Arc-Cape (South Africa)
64 = Argentine
65 = Ascension Island 1958
66 = Australian Geodetic
67 = Bermuda 1957
68 = Berne 1898
69 = Betio Island 1966
70 = Camp Area Astro 1961-62 USGS
71 = Batavia (Java)
72 = Palestine (Israel,Jordan)
73 = Hermannskogel (Austria,Czech.,Yugoslavia)
74 = Kandawala (Ceylon)
80 = ETRS89 (European Terrestial Reference System)
81 = Amersfoort 1885 (Netherlands)
82 = NAD83/NAD1983 (= WGS84)
84 = WGS84
85 = JGD2000 (= WGS84)
86 = GDA94 (= WGS84)
87 = NZGD2000 (= WGS84)
88 = NGRF2000 (= WGS84)
89 = KDG2000 (= WGS84)
90 = Hartebeesthoek94 (= WGS84)
91 = TWD94 (= WGS84)
Note (29): the code for Vertical datum code is:
M = Mean Sea Level
E = Ellipsoid [for use when the altitude obtained using a GPS unit was
NOT corrected for the difference between Ellipsoid and Mean Sea
Level altitudes. Most GPS units apply this correction by default.]
Note (30): the code for Type of telescope is the following:
R = Refractor [including Achromatic, Apochromatic, binoculars,
and camera lenses]
N = Newtonian reflector [including Dobsonian, Schmidt-Newtonian,
Maksutov-Newtonian, Jones-Bird, Schiefspiegler]
C = Cassegrain (including Schmidt-Cassegrain, Maksutov,
Ritchy-Chretien, Dall-Kirkham)
O = Other, including naked eye.
Note (31): the code for Telescope mounting is:
E = Equatorial mounting
A = Alt-Azimuth mounting
Note (32): the code for Telescope drive is:
D = Driven
M = Manual
Note (33): the code for the catalogue used for the star position, and the
number of records using that catalogue:
EDR3 = Gaia EDR3 (454982 records)
Hip2 = Hipparcos2 (20571 records)
UBAD = United States Naval Observatory Bright-Star Astrometric
Database 2022 [VizieR catalogue J/AJ/163/131] (8498 records)
DR1 = TGAS, from Gaia DR1 (305 records)
XZ80Q = XZ80Q catalogue [VizieR catalogue I/291] (8014 records)
DE440 = JPL DE440 ephemeris, for planets (710 records)
JPLhor = JPL Horizons system, for the satellites of planets, and asteroids
(138 records)
--------------------------------------------------------------------------------
Acknowledgements:
This catalog was prepared with the assistance of Breit D., Coles K.,
Dunham D., Loader B., Manek J., Miyashita K., Sandy R., and Soma M.
* 25-Oct-2010: Original version, prepared by IOTA (461692 occultations)
* 01-Sep-2012: Version 'A', from Dave Herald [IOTA]. The changes are:
-- addition of 2 years of observations (467974 occultations)
-- reduction of the pre-1800 observations using DE422 (rather than DE414)
* 06-Oct-2015: Version 'B', from Dave Herald [IOTA], 2015-Sep update
(478843 occultations)
* 94-Jul-2022: Version 'C', from Dave Herald [IOTA], 2022-Jun update
(493218 occultations). The changes are:
-- addition of observations up to end of 2021
-- star positions from Gaia EDR3, Hipparcos-2 and UBAD
-- reduction using DE440
-- lunar limb height derived from LRO LOLA data.
-- positions of planetary satellites and asteroids from the JPL Horizons
system
(End) Dave Herald [IOTA], Patricia Vannier [CDS] 01-Jul-2022