(10199 - 1997 CU26) Chariklo 03/06/2013

*See updates at the bottom of the page*


Dark gray is night and light gray is astronomical twilight (Sun at less than 18° below the horizon).
Shadow moves from right to left, each red dot is separated by one minute, the nominal occultation time on the map, is for the big red dot, the closest approach
See finding charts bellow.

A similar web page in Spanish can be seeing in this link, by G. Tancredi.

Star J2000 coordinates:
   RA  16 56 06.49
DEC -40 31 30.21

Day coordinates:
  RA  16 56 06.44
DEC -40 31 30.15

Star R mag 12.3
Star K mag 7.2
Magnitude drop in R  > 5
Maximum duration 21 s

Observation tips:

- Observations are requested from 06:20 to 06:30 TU, continuously. 

- Drift-scan observations are welcome too!

Absolute time accuracy is essential to connect together all the observations after the fact. Check the time of your computer with many sources (phone talked hour, different internet sites, ideally with a GPS). As images should be acquired for a long time (10min at least), its advised to check the registered time right after and right before the integrations, so if there is a drift, we can correct it by having the difference.

Beware of the dead time between the images. If you manage an exposure time of 1 sec (for example), but have your camera takes 2 sec to read the image, then there is a 67% chance that you miss the dis(re)-appearance of the star. So it's better to have, for example, a 4 sec integration, so you have 67% chance to get the occultation in one of your exposures.

Finding charts
(North is up, East is left):

from DSS R filter 05 X 05 arc min.

The star is very close to the open cluster NGC 6231:

from DSS R filter
20 X 20 arc min.
Get the 'fits' version of this image here: [ .fits ]

Chart with magnitudes from Starry Night, 2.5 x 3 degrees

Chart with magnitudes from Starry Night, 10 x 5 degrees.

Chart with magnitudes from Starry Night, 60 x 30 degrees.

Astrometric Updates

The first prediction based on the WFI star position:

With images of the star taken at Pico dos Dias Observatory (OPD) on May 1st. by M. Assafin:
[updated on May 02]

Julio Camargo observed Chariklo with the 2.2m ESO telescope plus WFI on the 06 may, and obtained new offset measurements that are consistent with another measurement made middle April. This indicates that the predictions may be very accurate.

With images taken at OPD by Altair Gomes Jr. on May 03.
[updated on May 04]

With images taken at OPD by Felipe B. Ribas on May 05.
[updated on May 06]

With images taken at OPD by Felipe B. Ribas on May 07.
[updated on May 08]

With images taken at OPD by Felipe B. Ribas on May 07.

[updated on May 10]

With images taken with ASH telescope on May, José Luis Ortiz obtained this map.
[updated on May 24]

With images taken at OPD by Julio Camargo and Gustavo Rossi on May 20.
[updated on May 25]

Making a weighted average of the OPD observations, I obtain the following map. The dashed lines indicates the extremes of the above predictions.
[updated on May 27]

Please, see the observation tips at the top!