ASTEROIDAL OCCULTATION - REPORT FORM

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

1 DATE: 14 September 2021             STAR: UCAC4 471_110652  (12.8 mag)
  ASTEROID: Pretoria                     No: 790

2 OBSERVER: Name: Marek Zawilski            Abbr:
            E-mail: marek.zawilski@p.lodz.pl
            Address: ul.Julianowska 5/7 m.322, 91-473 Lodz, Poland

3 OBSERVING STATION: Nearest cities: Koło
  Station: Brdów
  Latitude:  52d 20' 41.0" N
  Longitude: 18d 43' 57.9" E
  Altitude:  105 m MSL
  Datum (WGS84 preferred): WGS84

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

                         +----------------------------------+
4 TIMING OF EVENTS:      |                                  |
                         |  OCCULTATION RECORDED: NEGATIVE  |
                         |                                  |
                         +----------------------------------+
  Type of event
  Start observation   Interrupt-start   Disappearance   Blink   Flash
  End observation     Jnterrupt-end     Reappearance    Other (specify)

                                                  Comments
  Event   Time (UT)    P.E.   Acc.   
  Code   HH:MM:SS.ss   S.ss   S.ss
  
    S  - 22:44:43    - N/A  - 1    :
    D  -   -                       :  
    R  -   -                       :   
    E  - 22:46:40    - N/A  - 1    :
  
                          Duration : no occultation 
                         Mid-event : 
               Predicted mid-event : 14 Sep ; 22:45:23 UT  +/- 12 sec

  Was your reaction time applied to the above timings? N/A

5 TELESCOPE: Type: Cassegrain       Aperture: 203 mm    Magnification: ---
             Mount: Equatorial     Motor drive: YES   Foc.length: 2032 mm reduced to 1016 mm

6 TIMING & RECORDING:
  Time source: Laptop time controlled by the GPS TimeBox device (steady time delay 0.190 s, considered in Tangra).
  Sensor: ZWO ASI 120MM, shutter set for 500 ms, image resolution 1024x768 px, gain 70.
  Recording: SHARPCAP v.3.2.6383.0 software

7 OBSERVING CONDITIONS:
  Atmospheric transparency: good   Wind: none            Temperature: +12 deg C
  Star image stability: average    Minor planet visible: yes (as approaching to the star gradually)

8 ADDITIONAL COMMENTS:
 A remote mobile station. The light curve analysis using Tangra and AOTA software and a careful inspection of the screen replay showed no remarkable rapid drop of the star brightness caused by the asteroid to the expected level of brightness (i.e. to about a half of the summed combined brightness of the star and asteroid - Pretoria's magnitude was 13.1). The star image was not very stable both for the occulted and a guiding star; however, there was no occultation longer than 0.5s and the observation has been classified as negative. The lightdrop around 22:45:30 coincides with the prediction plus a 3-6s delay obtained by other positive observations but it could not be confirmed by the AOTA analysis as a real occultation.

  Predicted max 32.0 sec duration at the central line with 0.9 mag drop.
  Event probability at site : 70 %
  Distance from center line : 61 km in 140° direction, inside the predicted path, not far from the eastern limit
  Local * conditions (Alt,Az): 24°, @242° in Aquila
  Moon below the horizon.