Observatory Logo

From: TerryMoselat signaol.com
Date: 17 June 2007 02:27:17 Jun 2007
Subject: Young TV astronomers wanted; Venus Occultation on Monday

Hi all,

1. BBC TV is looking for keen young astronomers from N.I. who can talk
on TV. Children's BBC are doing a programme called "Do Something
Different" over the summer holiday, from a different location each week.
They will be coming to Armagh in w/c 24 July, and they want to focus on
astronomy, via the Observatory & Planetarium.

They are looking for children from N.I. (Sorry about the rest of you,
but it is BBC!)* aged between 7-12** interested in astronomy & space,
who could talk to camera about their interest, with some props such as a
telescope. The important thing is that they are keen & enthusiastic
& know enough to be able to talk - at children's level of course - and
that they would be confident & articulate enough to do so.  

This is not 100% certain yet, so if you know of anyone don't raise their
hopes that they are guaranteed TV stardom, but it's very likely to go

Please reply to me on this asap: email me to this address and to
Terry.Moseleyat signnio.x.gsi.gov.uk, or ring me on 028 90253637 (W) or 028
90587658 (H), asap.

*If you live close to the border, they might just stretch the rules a
bit, but that's not up to me!

** If they can't get any aged between 7 - 12, they might just stretch it
to a year or so older, but no more!


On Monday 18 June the Moon will occult brilliant Venus, mag -4.4, at
about 13.50 (14.50 BST). The exact time of the occultation will depend
on your location - the further West you are, the earlier it will occur,
so be prepared up to 5 minutes before these times. All times in BST from
now on, to avoid confusion!    The Moon will be a thin crescent, 14.4%
illuminated, so it won t be all that easy to see in the bright noontime
sky. Venus will lie almost directly in the Moon s path, so once you see
it, bisect the angle of the  horns  and look for Venus ahead of where
the front of the full moon s disc would be.     In fact, it might be
just as easy to see Venus first: at 14h 30m it will be at R.A. 08h 59m
50s; Dec. +18° 57' 16". From Dublin it will be at altitude 47°  36 , Az
131°  34' . If you find it, the Moon will lie to the right and slightly
above it.    Another way to try to locate it is to set your telescope up
at about 11.30, and locate the Sun, being careful not to look directly
at it, and certainly DO NOT look through the telescope at it, UNLESS YOU
HAVE A PROPER SOLAR FILTER! See any astronomy observing book or check
the web if you are not sure how to do it.     What you are aiming to do
is aim your 'scope to a point in the sky where Venus & the Moon will be
just before the occultation. For this purpose, I'm taking that as 14.40
BST, about 10 minutes before the occultation, to allow you to select
your best eyepiece, or attach your camera etc, before the event begins.
   From Dublin, at 14.40 BST, the Moon will be at altitude 49° ,  azimuth
134°  51'; and Venus will be at essentially the same altitude, azimuth
134°  39'.    The Sun gets nearest to this position at 11.37 BST, when it
will be at altitude 53°  42', azimuth 134°  47'. So at 11.37, the Sun's
azimuth will be just about right, but it will be about 4°  40' higher up.
So, at 11.37, centre the Sun in the scopes' field of view, then move it
down towards the horizon by 4°  40'. How do you do that in daylight?
Either use the declination circles if your scope has them, or check the
night before how many turns of the declination slow motion handle move
it through that amount. Note that declination is not the same as
altitude, but in this case it should be close enough to get the Moon in
the field of a wide field eyepiece, and it will give you an extra minute
or two location time.   Leave the telescope locked in this position, and
at about 14.40 the Moon & Venus should appear in the field of view of a
WF eyepiece.    Then unlock the clamps, and follow Venus as it moves due
to earth's diurnal rotation, until the occultation starts. The visible
occultation will take just under a minute to occur - obviously you will
only see the occultation of the visible part of Venus' disc! Venus will
be 44% illuminated, so it will appear just under 'half' phase. The S tip
of Venus' thick crescent will be the last to disappear.     Venus will
reappear from behind the Moon s bright trailing limb at about 16h 10m
BST.    For observers N or S of Dublin, just adjust those altitude
figures by the difference in your latitude from that of Dublin - usually
no more than 1 or 2 degrees.

Good Luck.

Clear Skies,

Terry Moseley


Last Revised: 2007 June 19th
Go to HOME PageHome Page