Asteroid occultations anyone?

[lukebl]

Hi,

Does anyone ever observe asteroid occultations? Never observed one myself. I see that tonight 16th magnitude asteroid Menestheus occults an 11th magnitude star for 4.5 seconds in a path which crosses central England and Wales at about 1am.

In the 'old days' amateur observation of the timing of these events was useful in determining the shape and size of these objects, but I guess these days we amateurs don't have some much to offer? Here's the path of the occultation:

[Hypernova]

Very interesting, the detailed finder charts here suggest that it might just be visible from my location. The only problem is that it is currently cloudy and the bbc is forecasting fog all night

The 11 mag star to be occulted is in Cetus near to M77 and will at around 28 degrees altitude when the occultation occurs. A healthy alt but it would force me to observe from my front garden which happens to be plagued by street lights

[LeoLion]

There have been two recent UK positives , Sapho and Elektra in 2010 http://www.euraster.net/results/2010/20100604-Sappho-crd_temp.gif and http://www.euraster.net/results/2010/20100220-Elektra-crd_temp.gif . The Asteroid & Remote Planets BAA Assistant Section Director is ill and currently enquiries should be to Tim Haymes ,Acting Assistant Director (Occultations)

Hill Rise, Knowl Hill Common, Reading RG10 9YD.

Well observed negatives provide valuable size/shape information in addition to the positives. More information here Asteroids and Remote Planets Section Asteroid Occultations

Hope this helps

[lukebl]

Thanks for the info, LeoLion. Just wondered if useful observations can be made with amateur equipment, and it looks like the answer is yes.

The next most interesting event is a 10th magnitude star which will be occulted by (93) Minerva for 14 seconds on the morning of 10th December, for viewers along the east coast. Probably just misses me, but I'm sure there must someone here along the path:

[LeoLion]

Hi again, It may be worth you downloading Hristo Pavlov's Occult Watcher software (free) here for ground track updates/info etc Occult Watcher . It looks like you could be inside the 1 sigma zone - you do not need to be on the centre line (and it is not so precise either ) and also ideally not duplicate the chord of another observer- more chords from a positive - better shape etc. The fact that the star does not dissappear tells you where the asteroid ' was not ' in space !

When you get a positive you have been in the genuine shadow of an asteroid and the light that casts that shadow is light years away !!

[TimH]

Hi stargazers,

To introduce myself, my main astronomical interests are asteroid occultations and super nova searching. I did look out for Menestheus last night but it was too cloudy here in Berkshire. I have a 30cm F/4 from Orion Optics (UK), and a Watec120N for videoing the occultation “suspect” coupled with a video time inserter to get the times of any Dis- and Re-appearance. Visual timings (stop-watch etc) negative or positive are very useful indeed. There are never enough observers to cover an event.

Asteroid occultation monitoring depends largely on the work of enthusiastic amateurs like ourselves. Result are published here: http://www.euraster.net/

Typical instrument are 6” and above – all depends on the brightenss of the star being occulted. I currently help co-ordinate the BAA observations. There is a similar group within the SPA.

Visual observing and timings are very valuable (negative and positive)

Try [348] May 08 Dec 2345UT and [302] Clarissa on 09 Dec 0211UT

http://www.asteroidoccultation.com/2010_12/1209_302_21554.htm

http://www.asteroidoccultation.com/2010_12/1208_348_21553.htm

93 Minerva is a good one, for North East observers – thanks Lukebl

Later in the year 503 Evelyn and 634 Ute favour Southern UK observers. A full list of European events with regular updates can be got from OccultWatcher software ( see reply by LeoLion )

Good luck. I will post any results I get Tim