Photometric analysis of the TYC 1839-00696-1 occultation by (212)Medea.

Jan. 10 , 2011
Kazuhisa Miyashita


Obsrvation with Non-integrated video

1. Suzuki at Hamamatsu




Event time : Disppearance = 11h48m13.44s +/- 0.03s ; Appearance = 11h48m31.22s +/- 0.03s   (UTC)

2. Uchiyama at Owase




Event time : Disppearance = 11h48m35.48s +/- 0.03s ; Appearance = 11h48m52.74s +/- 0.03s   (UTC)

3. Ikari at Moriyama




Event time : Disppearance = 11h48m33.68s +/- 0.03s ; Appearance = 11h48m43.76s +/- 0.03s   (UTC)

4. Ishida at Taikicho




Event time : Disppearance = 11h48m31.50s +/- 0.03s ; Appearance = 11h48m49.86s +/- 0.03s   (UTC)

5. Kitazaki at Musashino




Event time : Disppearance = 11h47m45.49s +/- 0.03s ; Appearance = 11h48m04.31s +/- 0.03s   (UTC)

Obsrvation with Integrated video

1. Asai at Hokuseicho, Inabe




8 frames integration.
Event time : Disppearance = 11h20m25.44s +/- 0.14s ; Appearance = 11h20m38.45s +/- 0.14s   (UTC)

Step is due to the appearance of the star in the middle of integrated frame exposure. This is not an aspect of double.

2. Ida at Mihamacho, Mie




8 frames integration.
Event time : Disppearance = 11h48m41.49s +/- 0.14s ; Appearance = 11h48m55.20s +/- 0.14s   (UTC)


Step is due to the appearance of the star in the middle of integrated frame exposure. This is not an aspect of double.

3. Watanabe at Inbencho, Inabe




8 frames integration.
Event time : Disppearance = 11h48m24.39s +/- 0.14s ; Appearance = 11h48m38.99s +/- 0.14s   (UTC)


Step is due to the appearance of the star in the middle of integrated frame exposure. This is not an aspect of double.

110108_212Medea_Ooba_Takashima_Kashiwa.png

4. Takashima & Ohba at Kashiwa




2 frames integration.
Event time : Disppearance = 11h47m40.31s +/- 0.03s ; Appearance = 11h47m58.91s +/- 0.03s   (UTC)

Step is due to the appearance of the star in the middle of integrated frame exposure. This is not an aspect of double.

Calculating the event time.

Below is an example of calculation of event time from integrated video observed by Takashima and Ohba.
----------------------------------------------------------------
Disappearance

From Limovie's light curve.

No.  Frame Centre  End
477  20h47m40.36s  40.38s   ..... The last frame of full brightness.
                   ~~~~~~
To = 20h47m40.38s           ..... The base point for this calculation

In the case of disappearance, the event time is given as:
T = To + (f * Hi) / R - C(f)
  To : base point obtained as the LAST frame of full bright.
  f  : number of integrated frame
  Hs : height of intermidiate frame(integration) expressed as percent
  R  : frame rate. =29.97 (NTSC)
  C(): delay correction
      C(0) = 0.033 seconds
      C(1) = 0.042
      C(2) = 0.075
      C(4) = 0.141
      C(8) = 0.275
      C(16)= 0.542
      C(32)= 1.084

Hence,
T = To + (2 * 0.156) / 29.97 - C(2)
  = To + 0.010 - 0.075 = To - 0.065
  = 20h47m40.31s +/- 0.03
---------------------------------------------------------------
Appearance
1033 20h47m58.91s  58.93s   The last frame of minimum brightness.
                   ~~~~~~
To = 20h47m58.93s

In the case of appearance, the event time is given as:
T = To + (f * (1-Hi)) / R - C(f)

T = To + (2 * (1-0.111)) / 29.97 - C(2)
  = To + (2 * 0.889) / 29.97 - C(2)
  = To + 0.059 - 0.075 = To - 0.016
  = 20h47m58.91s +/- 0.03
---------------------------------------------------------------

Fitting the light change to diffraction simulation

1. Suzuki's observation





2. Ishida's observation





3. Uchiyama's observation





4. Ikari's observation





5. Kitazaki's observation