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Summary of Lunar Occultations for 1994

More about occultations.

Introduction

During 1994, there are many hundred lunar occultations potentially observable from East Anglia, although many involve faint stars. There are two grazing occultations of stars, but no occultations of planets, visible from the region.

This article summarises the circumstances of the best occultations during the year. It provides details for the location of Orwell Park Observatory; differences will in general be negligible for locations throughout East Anglia.

Occultations of Bright Stars

Table 1 lists occultation events during the year, of stars brighter than magnitude 5.0, where the circumstances are favourable. These events should be readily visible in small telescopes or binoculars.

The first two columns of the table list the date and time (UT) of the occultation. Column three specifies the phenomenon: "D" denotes a disappearance and "R" a reappearance. The table lists circumstances of D and/or R as dictated by the visibility of each phenomenon (determined by altitude, lunar phase, etc). Column four details the lunar phase (positive waxing and negative waning). Columns five and six give the altitude of the Sun and the star, both in degrees. (A negative solar altitude means that the Sun is below the horizon.) Columns seven and eight provide the star's magnitude and catalogue number.
 

Date
2002
Time
(UT)
D
R
Lunar
Phase
Sun
Alt (°)
Star
Alt (°)
Mag Star
16 Jan19:28
20:19
D
R
0.23+-29
-37
20
13
4.9κ Psc
22 Jan21:25
22:27
D
R
0.78+-45
-52
55
48
4.9ω Tau
28 Apr01:22
02:33
D
R
0.92--21
-15
16
16
4.4ω Oph
21 Jun22:26
22:37
D
R
0.97+-12
-14
17
15
4.4ω Oph
18 Jul20:54
22:06
D
R
0.81+-6
-13
17
13
4.3ω2 Sco
20 Jul22:27
23:36
D
R
0.95+-15
-17
17
15
3.8μ Sgr
24 Aug21:39
22:22
D
R
0.87--20
-24
16
23
4.4δ Psc
13 Oct22:40
23:34
D
R
0.72+-44
-46
15
9
4.5ν Cap
23 Oct02:11
03:34
D
R
0.89--39
-28
57
54
3.5ε Tau
14 Nov18:10
18:58
D
R
0.89+-19
-26
32
38
4.4δ Psc

Table 1. Occultations of stars brighter than magnitude 5.0.

Note that on 18 July, some 18 minutes before the disappearance of ω2 Sco, the brighter ω1 Sco (magnitude 4.1) is occulted. However, at this time, the Sun is only 4° below the horizon so the observation will be hampered by a twilight sky.

The best opportunity for observing occultations with a young Moon is on the evening of 15-16 January, when three stars are occulted (two of magnitude 6.4, one of magnitude 4.9) and the lunar phase is 20% waxing.

There are lunar eclipses on 25 May (partial, central time 03:30 UT) and 18 November (penumbral, central time 06:46 UT). The reduced lunar glare during an eclipse should make possible the observation of occultations of dimmer stars than would ordinarily be the case. No stars brighter than magnitude 8.0 are occulted during either eclipse.

Grazing Occultations

The tracks of two grazing occultations cross East Anglia during the year. Table 2 summarises the circumstances. Columns one and two give the date and time of the graze and column three specifies the lunar limb involved. Column four indicates the distance between Orwell Park Observatory and point X on the track, on land, where the distance between the two is least; column five links to a plot of the lunar limb profile visible from X. Column six specifies a north or south displacement of the observer's position, relative to the track, based upon inspection of the limb profile, to maximise the chances of witnessing multiple disappearance and reappearance events. Column seven links to an on-line Google Earth plot of the track and column eight links to an off-line image of it. (The plot and image illustrate the nominal track, with no displacement applied.) Column nine details the lunar phase (positive for waxing, negative for waning) and column 10 the altitude of the Sun (a negative solar altitude means that the Sun is below the horizon). Columns 11 and 12 provide the horizontal co-ordinates of the star (azimuth in the order N→E→S→W). Columns 13 and 14 specify the star and its magnitude.
 

Date
1994
Time
(UT)
Limb Dist
OPO
(km)
Limb
Profile
Track
Shift
(km)
Google
Earth
Track
Google
Earth
Image
Lunar
Phase
Sun
Alt
(°)
Star
Alt
(°)
Star
Azi
(°)
Mag Star
30 Sep 03:39 S 9 Profile 0.8 N Track Track 0.29- -21 30 107 6.5 ZC 1237
25 Oct 04:53 S 9 Profile 0.5 N Track Track 0.74- -16 55 204 6.6 ZC 943

Table 2. Grazing lunar occultations.


James Appleton