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[ STARGAZER HOME]: (216) Kleopatra stellar occultations 2018 Nov 7th and 2018 Dec 7th

Table-1: Circumstances of the occultations

Date...................Obs from ..................Star..........................Mag............RA / Dec (2000)...........Alt / Azimuth........Magnitude drop.....Max duration (estimated)

2018 Nov 7 .....0113 to 0117UT.......UCAC4 487-41241....11.5 (r)......07 38 38 +07 15 33.........26 / 119...............0.5 red..................20 s

2018 Dec 7......0234 to 0238UT.......TYC 0183-02277-1....10.0 (r)......07 38 29 +03 05 24.........37 / 170...............0.9 red..................12 s


Occult 4 prediction for Nov 7th................SkyMap (1 x 1.2deg) indication a finder star.........Map and approximate limits of observation
The ellipse illustrates the approximate orientation of the asteroid within the path shown in "More Information, 1)"

Fig-1.............................................................Fig-2.......................................................................Fig-3

 

 

Occult 4 prediction for Dec 7th................SkyMap (1 x 1.2deg) indication a finder star.........Map and approximate limits of observation

Fig-4..........................................................Fig-5.......................................................................Fig-6

 

Tips for observers / recorders:

1. Planning:
1) Let the writer know if you plan to observe (even if you don't in the end). occultations AT stargazer DOT me DOT uk
2) Please do observe even if you are outside the limits drawn in red and blue lines (Fig 3 and 6). These observations may be negative or short duration.
3) If you are a visual observer, then please submit a report. All observations will be acknowledged. Pls Note: The Nov 7th event is not suitable for visual.
4) Allow enough time to find the correct star. About 30 min before occultation, the target star and asteroid will look like a close unequal double star.
5) If you use a mobile telescope, then make notes on its location so that we can get its coordinates from Google Earth.

2. Planetary Cameras:
1) Use the native instrument focal length, and where possible use a focal reducer to get F4 to F7 or thereabouts.
2) Download and install Dimension 4 software and use it to update the computer clock to +/- 0.1 sec.
3) Use the camera software control to add the UT time stamp to the frames. This can be done with SharpCap and FireCapture (or other products).
4) Often there is a log file function. Use this to add extra info.
5 ) Select an integration time that records the target clearly without over-exposure. e.g. 5 FPS or 200 ms. Use trial and error to get best result beforehand
6) Try to avoid exposures longer than 330ms, 50ms to 200ms is optimal, depending on aperture.
7) Record in the format (SER or AVI) which shows the time stamps clearly.
8) Observe/record during the start and end times in Table-1
9) If possible arrange to have at least one other star in the field of view. This is used to monitor seeing conditions during analysis.
10) A mono camera will be more sensitive than colour.
11) The desired UT accuracy is +/-0.1 s but even good observations are subject to errors we can't always quantify with certainty.

3 Reporting:
1) The observer should play back the file and note the approximate times of any events. A software analysis will be needed to extract the exact times.
2) There is a free software tool (TANGRA) if the observer does the analysis, otherwise send the file to the writer for analysis (drop box etc).
3) Negative result (no occultation) are as important as the positives. Please report negatives or "unsure".
4) There is standard report to fill out. Contact me if you have a successful recording.

 

Fig-7 The path of Kleopatra in Canis Minor from November 7 to December 7, 2018

 

This page will update if required.

Tim Haymes: occultations AT stargazer DOT me DOT uk

Assistant Director, BAA Asteroids and Remote Planets Section, Occultations.

 

[ PS: I try to get the details right. If you see anything suspect, drop me an email :) thanks. ]

More information:
1) https://echo.jpl.nasa.gov/asteroids/shepard.etal.2018.kleopatra.pdf
2) Kleopatra has two known satellites.
3 ) Predictions are prone to errors and prediction paths may be updated. Check this page for any updates.

About occultations and this page:
This is a personal web page to support occultation observers. There is a Yahoo! group: UKoccultations which observers are welcome to join. .
An observation sent to the writer is checked and forwarded to the BAA which will perform a preliminary analysis prior to submission to IOTA-ES.

Page created: 2018 Aug 13