ASTEROIDAL OCCULTATION - REPORT FORM

  +--------------------------------+  +----------------------------------------+
  |            EAON                |  |                IOTA/ES                 |
  |                                |  |        INTERNATIONAL OCCULTATION       |
  |     EUROPEAN ASTEROIDAL        |  |           TIMING ASSOCIATION           |
  |     OCCULTATION NETWORK        |  |            EUROPEAN SECTION            |
  +--------------------------------+  +----------------------------------------+

 1 DATE: 24 Apr 2021                              STAR: TYC 6177-00356-1

   ASTEROID: (167601) 2004 BJ124                           

 2 OBSERVERS: 
  Name      : Wojciech Burzynski                    Abrr: BZY
  Address   : 15-345 Bialystok, Poland

 3 OBSERVING STATION: 
  Nearest city : Suprasl
  Station      : Lipowy Most                 Acc.
  Latitude     : 53 12 31.5 N            -   0.1"
  Longitude    : 23 31 37.9 E            -   0.1"
  Altitude     : 145 MSL                 -   1 m

  Datum (WGS84 preferred): WGS84

  Single, OR Double or Multiple station (Specify observer's name): single

 4 TIMING OF EVENTS:  
  +----------------------------------------------+
  |       OCCULTATION RECORDED: POSITIVE         |
  +----------------------------------------------+
  Type of event:
 "S"tart observation   "I"nterrupt-start   "D"isappearance   "B"link   "F"lash
 "E"nd observation     "J"nterrupt-end     "R"eappearance    "O"ther (specify)

  Event   Time (UT)    P.E.   Acc.   
  Code   HH MM SS.ss   S.ss   S.ss
  
  S - 21:46:25.6
  D - 21:47:13.65         +/- 0.16
  R - 21:47:14.30         +/- 0.16
  E - 21:47:34.4  

  Duration: 0.65 s,       +/- 0.23     


  Predicted max. duration (secs) : 0.5
  Predicted max. drop (mag)      : 7.9
  Predicted mid-event (UT)       : 21:47:04
  Predicted error in time        : 12 sec 

  Was your reaction time applied to the above timings? - not relevant
  
 5 TELESCOPE: 
  Type        : NEW  f/4.7                            Aperture   : 254 mm
  Focal length: 1195 mm                               FOV        : 32.37' x 20.23'
  Mount       : equatorial GOTO                       Motor drive: yes

 6 TIMING & RECORDING:
  Time source      : GPS 1PPS  
  Sensor           : QHY 174M GPS
  Mode of recording: 1920x1200, 12 bit SER, Gain=420
  Mode of recording: Contrast=0, Brightness=0, Gamma=1
  Shutter          : 0.321 s
  Recording        : Laptop Dell Latitiude 3540 (Intel Core i5/RAM 8 GB/SSD 128 GB)
  Recording        : SharpCap 4.0.7703

 7 OBSERVING CONDITIONS: 
  Atmospheric transparency          : fair 
  Wind  (m/s)                       : 4
  Temperature (deg C / humid.)      : -1 / 70
  Star image stability              : good 
  Minor planet visible              : no
  Local conditions (degree)         : star altitude: 14, sun altitude: -23 
  Local moon conditions (degree)    : moon altitude: 38, moon distance: 48, moon phase: +92%

 8 ADDITIONAL COMMENTS:
  Observed star                           : TYC 6177-00356-1 
  Star magnitude (mag)                    : 11.3
  Minor planet magnitude (mag)            : 19.2
  Feed                                    : ITALOccult, 2 March 2021
  Rank                                    : 3
  Distance (km)                           : in the 1-sigma zone, 2 km outside the shadow path
  Shadow width (km)                       : 13
  Predicted probability OccultWatcher (%) : 1.7
  Predicted combined magnitude (mag)      : 11.3 
  Faintest star on movie (mag)            : 12.8
  Evaluation with Tangra 3.7.3 and AOTA

  9 REMARKS: 
  JPL HORIZONS (Apr 13, 2021) : probability 4%, in the 1-sigma zone, 66 km N from the center line
  ITALOccult prediction was much more precise.
  Problem with the QHY174GPS camera exposure time during SharpCap (4.0.7703) recording. 
  The time was set as 0.125 s and so it was saved in the settings file generated by the SharpCap. 
  Meanwhile, the real exposure time was 0.31 s, which resulted in a decrease in the accuracy of this observations.