[AZ-Observing] Re: Nearby semi-bright asteroid
- From: "Neville Cole" <nevillecole@xxxxxxxxxxx>
- To: az-observing@xxxxxxxxxxxxx
- Date: Thu, 18 Jan 2007 14:17:38 -0700
Hi Brian,
I visited the JPL NEO page around 4PM yesterday and generated my topocentric
ephemeris for 2007 BD. However, I failed to find the object in the sky last
night.
This is my first time trying for one of these, so there was plenty of
opportunity for mistakes on my part. I started searching around 9PM, with
much flopping around. By 11PM I had worked out a better search technique,
which I then applied unsuccessfully for another hour.
Should I have been able to see 2007 BD in a 12" SCT from a valley suburb
with typical light pollution? Also, how reliable are the JPL NEO ephemeris?
Just trying to figure out what I need to do differently next time.
Neville
----Original Message Follows----
From: Brian Skiff <bas@xxxxxxxxxx>
Reply-To: az-observing@xxxxxxxxxxxxx
To: az-observing@xxxxxxxxxxxxx
Subject: [AZ-Observing] Nearby semi-bright asteroid
Date: Wed, 17 Jan 2007 12:41:26 -0700 (MST)
Eric Christensen at Catalina has found a nice NEO that will
be coming within the Moon's distance _tonight_. It will reach
mag 13.5-14 at its brightest, and be well-placed in the mid-evening sky.
Details are here:
http://cfa-www.harvard.edu/mpec/K07/K07B15.html
....which includes an ephemeris, but note that because of the small
distance, you'll need a topocentric ephemeris to find it. Use the
JPL NEO page to get one: http://neo.jpl.nasa.gov/orbits
(2007 BD has just been announced, so isn't in the JPL system as I
write this, but hopefully they'll get it in before the end of the
work day).
Minimum distance is about 200,000 miles at about 10pm local time
this evening. Notional object-size is about 15 meters (house-sized).
The usual 'lore' is that there are one or two such objects always
within a lunar radius from Earth. Usually none are actually
detected. However, at the moment we know of the second one,
also found by Christensen. It is 2007 BB, and will come just within
the Moon's distance in a couple of days. It is both smaller and
more distant, so won't get any brighter than mag 16.5. Details for
that one are here:
http://cfa-www.harvard.edu/mpec/K07/K07B13.html
\Brian
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