The list shows occultations of possible double stars during April. Although the main emphasis remains on stars with separations < 2", now that the more detailed lunar limb profile from LOLA is available, some wider pairs are included. Doubles predicted to be occulted by the Moon during April 2017 and visible from parts of Australia or New Zealand are included. The listing is a very abbreviated version of predictions produced by Occult plus an indication of the region of visibility. Observers need to generate their own precise predictions using Occult.

The list below is generated by OCCULT for a 25cm telescope. Some of the events could be beyond the reach of smaller telescopes. Observations of all pairs in the list are highly desirable. Those showing an OCc number have been reported as non-instantaneous at a lunar occultation. Confirmation or otherwise of any double nature is wanted.

*** Kepler stars: the nights on which they are occulted are indicated. Individual Keplers are only shown if they are also a known or possible double. Light curve of occultations of all Kepler stars are desired.

Please send reports of all observations of these stars to Brian Loader at palbrl@clear.net.nz, including any made in earlier months and not so far reported. And of course if you observe a stepped event for a star, which is not a known double, please report this. More details about reporting follow the predictions.

NEW - ARCHIVING OF OCCULTATION LIGHT CURVES

For ALL lunar occultations: single, double and Kepler K2 stars a csv file should be prepared for archiving. This can be done through the OBSERVATIONS EDITOR of OCCULT.

It will be necessary to generate a light curve using LIMOVIE and save or copy its csv file. You will also need to note the time, hh:mm:ss.sss of one frame and the corresponding frame number.

Then in the Observations Editor select the entry for the star and use the menu bar option to create a Light Curve Report. Follow the instructions on the new screen which appears. There is a help file. It is suggested that light curve reports be emailed in batches rather than singly. They are sent directly to Dave Herald from the program.

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 d P    Star  Mag    %         Double details        WDS or   Area of
Apr      No    v    ill      magnitudes sepn    PA?  OCC #    Visibility
 1 d   *** Kepler Stars occulted, light curves are desired    BCMRST,AkI
 1 d   93958  7.8   22+ : **  9.0  9.0  0.50" 279.0  OCc 532  ,AkW
     93958 is double: ** 9.0 9.0 0.50" 279.0, dT = -1.2sec
 1 D   93962  7.0s  23+ : **  7.0       0.01"  12.7 OCc1235   ,AkChW
   *** 93962 is in the Kepler2 program {ID = 210640991}
 1 D   93967# 7.8   23+ : AB  9.37 8.09 0.06" 235.0 COU 567   ,AkChIW
   *** 93967 is in the Kepler2 program {ID = 210650598}
 1 d X 70180  9.5   23+ : AB  9.5       0.01" 136.6 VVO 394   ,AkChW
   ***X 70180 is in the Kepler2 program {ID = 210652965}
 1 D   94019  6.7   24+ : **  7.9  7.9  0.05"  89.0  OCc 954  R
   *** 94019 is in the Kepler2 program {ID = 246946353}
 2 D   94684  7.2   34+ : AB  7.2 10.9  0.80"  69.5  HDS 749  M,I
 3 D    1006* 7.1   45+ : **  7.7  7.7  0.05" 350.0  OCc1323  BR,Ak
 3 d   *** Kepler Stars occulted, light curves are desired    BCMRS
 4 d   96962* 8.5   56+ : **  9.3  9.3  0.10"  45.0  OCc 326  ,AkChW
 4 d X 11218  9.7   56+ : AB  9.4 10.9  4.0"  126.1  BRT2376  ,Ak
 5 d   *** Kepler Stars occulted, light curves are desired    BCMRS,AkChW
 6 d   98559  9.1   77+ : AB  9.9  9.8  0.7"  266.4  HU  869  ,AkChIW
 7 d   99153  7.2   87+ : AB  7.5  8.6  0.43" 123.7  STT 220  BCMRST
 9 d   *** Kepler Stars occulted, light curves are desired    BCMST,AkChIW
10 d  138962  8.3   99+ : **  9.2  9.2  0.10" 181.0  OCc 666  ,ChW
10 d   *** Kepler Stars occulted, light curves are desired    ,AkChIW

11 r   *** Kepler Stars occulted, light curves are desired    M
13 R    2184  7.3   94- : AB  7.0       0.20" 153.1  CHR  44  R
14 r    2279* 6.1   90- : **  7.0  7.0  0.10"  90.0  OCc1485  B,Ak
16 r   *** Kepler Stars occulted, light curves are desired    ,AkChW
16 r  160678* 7.6   76- : Aab 8.2  8.8  0.10" 230.4  YSC 158  ,AkChIW
                        :  AB 7.71 10.1 0.73"  91.7  HDS2485  ,AkChIW
16 r  160686* 9.3   76- : AB  9.49 11.3 0.19" 129.9  HDS2486  ,ChW
17 r  161463# 8.4   68- : AB  8.6  10.1 0.10" 117.5  CHR 236  ,ChW
17 R    2680* 5.6   67- : **  6.6  6.6  0.10" 322.0  OCc 988  BCMRST,AkChIW
17 R    2686  5.1   67- : Aab 6.0  6.0  0.10"  90.0  OCc  22  CMS,ChI
17 R  161656? 7.7   66- : **  9.0  9.0  0.10"  67.0  OCc 970  BCMRS,AkChIW
18 R    2828* 5.8   58- : **  3.7  6.7  0.02" 106.0  OCc 994  BCMRST,AkChIW
18 r   *** Kepler Stars occulted, light curves are desired    BCMST,AkChIW
18 r  162554  8.7   57- : Aab 9.1  9.3  0.11" 298.0  OCc 461  CMS,ChIW
18 r X 45949? 9.1   57- : AB  9.1 10.2  2.5"   86.4  HWE  48  ,ChIW
18 r X 45974  8.6   57- : **  9.2 10.5  0.32" 299.0  OCc1576  CMS,ChIW
     X 45974 is the B star for S162554 above, separation 23.2" 
18 r X 45992  9.8   57- : AB  9.9 10.3  1.9"  201.2  HLD  35  ,Ak
18 R  162637  7.2   57- : AB  7.2 11.0  0.20" 234.0  TOK 367  BCMRS,AkChIW
   *** 162637 is in the Kepler2 program {ID = 218683659}
19 r    2952  7.5   47- : **  8.8  8.8  0.06"  93.0  OCc 993  BCMRST,AkChIW
19 r  163401  8.5   47- : **  9.8  9.8  0.10" 357.0  OCc 864  BCMRST,AkChIW
19 R X 48192  7.8   46- : AB  8.3  9.2  3.2"  326.8  H N 138  BCMRST,I
     X 48192:  B star is X173991
20 R  164259  8.5   36- : **  9.3 10.6  0.24"   6.8  OCc 589  BCMRST
20 r X 49829  9.8   37- : AB 10.5 10.5  0.40" 261.0  TDT2794  Ak,
21 r   *** Kepler Stars occulted, light curves are desired    BCMRST,AkChIW
22 r  146395  9.5   18- : **  9.4 11.0  0.03"  21.3  OCc 587  CMS,AkChIW
22 R Neptune  7.9   17-                                       BCMRST
     Neptune limb contacts offset by ?2.7 secs
     Both contacts are against the bright limb of Neptune
22 R   *** Kepler Stars occulted, light curves are desired    BCMRST
22 r  146439  9.7   17- : AB  9.9 11.8  1.1"  187.2  RST4712  CMST 
   *** 146439 is in the Kepler2 program {ID = 246103334}
23 r   *** Kepler Stars occulted, light curves are desired    BCMRS,AkChIW
23 R    3514? 5.9   10- : AB  6.7  6.7  0.07" 143.6  FIN 359  BCRST
24 r   *** Kepler Stars occulted, light curves are desired    BCMRST,AkChIW

28 d   *** Kepler Stars occulted, light curves are desired    ,Ak
29 D     764  4.9   11+ : AB  5.8  5.8  0.07" 318.3  A  3010  ,AkChW
29 d   *** Kepler Stars occulted, light curves are desired    BCRS
30 d   *** Kepler Stars occulted, light curves are desired    MRS,ChIW
30 D     940* 5.8   20+ : Aab 5.8       0.10" 294.0  CHR 163  ,ChI
30 d X 84768* 9.7   20+ : AB 10.3 10.6  0.40"  96.0  TDS3638  BCRST,AkChW
   *** X 84768 is in the Kepler2 program {ID = 202059326}
30 d   95446* 9.0   20+ : AB  9.0 11.5  2.9"  102.8  A  2446  BR

======================================================================

Visibility codes:
Australia: B Brisbane, C Canberra, M Melbourne, R Rockhampton, S Sydney, T Tamworth

NZ (following a ,) Ak Auckland, W Wellington, Ch Christchurch, I Invercargill.
----------------------------------------------------------------------
Stars with previous occultation observations: 

#: Observations indicating double - these need further checking
*: Observations not showing double - need confirmation
!: Recent video discoveries - confirmation needed.
?: Uncertain double observation, confirmation or otherwise needed
==================================================================

Reporting Your Observations

The most convenient way of reporting is to use Dave Herald's OCCULT which has a Double Star report option in the Observations editor. Before using it, generate a light curve with Limovie and copy to the clip board. Your graph will be attached to the email which you can then send to palbrl@clear.net.nz.

Otherwise in reporting please include your name and positional data as for other occultations reports, also your telescope type and method of observing and timekeeping.

For each event give the star name and the times of each step of the event with the corresponding accuracy. The limb PA, Rv and Cct of the event would also be useful.

In addition to measures of the PA and separation of binary stars, there is also a need for an estimate of the magnitude difference. An estimate of this can be made from the step sizes shown by Limovie data. So if possible a determination should be made of the size of each step together with an estimate of accuracy.

Please also report cases where a double event is predicted but none detected. These are especially likely with stars shown with an OCc designation

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