Pallas to occult TYC 5240-00433-1 on October 12th / evening

Forums Asteroids Pallas to occult TYC 5240-00433-1 on October 12th / evening

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    Tim Haymes

    Invitation to observe.

    Bright events are uncommon, so this is worth looking out for if you are anywhere in S, SE, E, NE, England.
    The event is not without its little challenges though. As the asteroid moves in on the star, the combined magnitude before occultation is 8.4, and when the star is covered the asteroid will be at mag 9.1.  So the drop in brightness is 0.7.  This may or may not be seen by eye.  I have replayed videos of other events with this drop, and 0.7 can be seen, but its a different matter when the eye is looking through an eyepiece.

    To record what is seen, an observer could use a mobile phone voice recorder and an accurate watch to make time announcements at start and end of the recording. I welcome any visual observation reports.

    I would also like to see some videos. If the video frames have accurate time stamps  ( UT +/- 0.1sec), then so much the better.  (The recording software should allow the PC time to be overlayed on the frames.)

    The prediction is made by IOTA:
    Star RA/DEC:  22 49 07 -7 07 55 (2000) is due South in Aquarius.

    The time to observe is from  2138 to 2140 UT In England, and the duration is up to 37 seconds centered on 2139 UT – all being well with the prediction. The uncertainty is small in this case,  +/- 3 sec. 

    Readers on mainland Europe will also have an opportunity (Portugal, Spain, France).

    Good luck, and I hope the weather is favourable for you.


    Grant Privett

    Something to look forward to – if the rain ever stops.

    Tim Haymes

    Grant: Yes, time dependent events like this are particularly prone to weather conditions. There are 25 observers across Europe, 7 in the UK that i know off.  Best of luck to them all.   A number of chords across the asteroid will help refine its shape. We have no direct imaging, and based on light curves its not spherical.

    Tim Haymes

    I was clouded out and this is the same story for many. However there are a few lucky observers in Europe who got a clear view of the occultation.  Thanks to all who peeped outside.  There are few opportunities to see (2) Pallas occult a star of sufficient brightness.  This was one of them. 

    There are many asteroids and many stars, and the best place to look for predictions for favourable event is Steve Preston’s pages:

    The Asteroids and Remote Planets Section will be pleased to receive your observations.


    Alex Pratt

    Hi all,

    Eric Frappa has now added the observed chords to the Euraster website and fitted them to a DAMIT shape model – 2021 European Asteroidal Occultation Results

    Clear skies,


    Tim Haymes

    These are good observations from our European friends. British observers were on chords near position (3) on the DAMIT shape model (see Link from Alex) where the duration was about 25 seconds. This area of the profile was sparsely covered as a result of obscuration by cloud.

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