Heads Up Eros Close Approach

[jjjnettie]

Minor Planet Eros is currently making it's closest approach since 1975.

http://www.heavens-above.com/MinorPlanet.aspx?desig=433&lat=0&lng=0&loc=Unspecified&alt=0&tz=CET

I can't seem to suppress the giggles though....Eros is in Sextans. It's childish I know. :P :lol: (and yes, I realise it means a Sextant)

[gary]

Hi JJJ,

Thanks for the heads-up.

The 1900/1901 opposition of Eros proved particularly seductive for astronomers.
It was the first time parallax measurements were made of it and from that one
could refine the value for the solar parallax. In other words, more accurately peg
the distance from the Earth to the Sun.

At the time, there were troubling discrepancies in some of the solar parallax
measurements that had been made either by direct or indirect means, so the
discovery and then the subsequent opposition of Eros were seen as timely
in helping solve the question.

The parallax observations were a major international effort, entailing
58 observatories including 18 photographic telescopes. To aid in the reduction
process, a catalog of 871 reference stars was compiled using the meridian
observations of 30 observatories.

As I touched upon during my talk at the IceInSpace AstroCamp last October,
one remarkable devotee to this exercise was the English astronomer Arthur Robert Hinks.
For three continuous months, he stayed up all night until dawn at the Cambridge
Observatory, trying to get exposures of Eros. The weather was particularly
lousy (sounds familiar) and he only got six clear nights, but he managed to
obtain 500 exposures. A remarkable effort when one contemplates the manual
handling of photographic plates at the time.

But his efforts didn't end there. Using the data collected from the observatories
around the world, he spent the next 13 years devoted to reducing it all. Part of the
complication was Eros fluctuated in magnitude with a period of 2 hours and 38 minutes,
from which astronomers deduced that Eros was likely to have an irregular shape (http://en.wikipedia.org/wiki/File:Eros_rotation_Dec._3-4_2000.gif).
Trying to eliminate sources of systematic error such as this was a massive undertaking
to which Hinks personally devoted all his energies. No computers, no high speed
broadband network, no image processing. Just pen and paper.

The value he came up with for the solar parallax was 8.807" +/- 0.0027"
and the ratio of the mass of the Earth to that of the Moon 81.53 +/- 0.047.

In 1912 Hinks was awarded the Gold Medal of the Royal Astronomical Society
and was elected as a Fellow of the Royal Society in 1913 for his efforts.

However, in 1914 he was passed over for promotion at The Cambridge Observatory in
favour of Arthur Eddington. Eddington was younger but had a firm grasp of
the theory of relativity which had become the new "in thing". Somewhat dismayed,
Hinks resigned.

As a footnote, in 1922 Hinks was Secretary of the Mount Everest Committee and
recommended Englishman George Mallory and vetoed the selection of Australian
George Finch (father of actor Peter Finch). Mallory and his climbing companion,
Irvine, died on their third summit attempt. But that's another story!

Today, amateur groups such as Astronomers Without Borders are helping co-ordinate
amateur astronomer's observations of the opposition of Eros as part of an
educational opportunity.
See http://www.astronomerswithoutborders.org/projects/eros-parallax-project.html