Thursday 29 March 2007

WWT Event

Yet another totally clear sky graced the IAA's public observing night at WWT, Castle Espie, last Saturday. A large crowd of people were thrilled with stunning views of the almost First Quarter Moon, and of course the showpiece of the sky, Saturn, as well as Deep Sky treats. We had binoculars and telescopes up to 16" aperture, and the amazing views were appreciated by all who attended.

Quantum Leap

Dave McDonald of Kildare Ast Soc. & IFAS has recorded a piece for RTE Radio 1 which will be broadcast on The Quantum Leap on Thursday 29th March at 20:01. That piece should air around 20:15-ish. Dave covered 2006 VV2 and Nova Cygni as well as giving tips to those who are interested in getting into astronomy.

EAAS Lecture

The next EAAS meeting will be a 'Beginner's Night', to be given by Dr Andy McCrea of the IAA. It will be at 8 p.m. on Monday 2 April, in Ballyclare High School. Admission £3.

ASGI

The spring meeting of the Astronomical Science Group of Ireland (ASGI), will be on Tuesday 3 & Wednesday 4 April, in the Physics Dept, Queen's University, Belfast. Please note that this is a professional level meeting, not suitable for the average amateur! Members of affiliated societies, such as the IAA, are entitled to attend, but with the caveat above! Details are on http://star.arm.ac.uk/asgi/qub2007/Programme.html Admission is free, but please let them know if you plan to attend, so that they can gauge numbers: email either matt.redman@nuigalway.ie, or M.Mathioudakis@qub.ac.uk.

IAA Lecture

The next IAA public lecture, and last one for this season, will be on Wednesday 4 April, when the inimitable 'Rocketman' Ash McFadden from Greencastle Planetarium will give a talk entitled "Selling Science and Comets in the Classroom". It will be in the usual venue, Lecture Room 5, Stranmillis College, Stranmillis Road, Belfast, at 7.30 p.m. If you heard Ash's talk at Cosmos last year you'll know that we have a treat in store! Admission free, including light refreshments.

Friday 23 March 2007

IAA Public Observing Evening, WWT, CASTLE ESPIE

The Irish Astronomical Association will be hosting another in its very successful series of public observing evenings at Castle Espie on Saturday 24 March. We'll be observing a nice waxing Moon, Saturn, & other sky attractions, with indoor alternatives if cloudy. All welcome, and bring your own binoculars & portable telescopes if you have them.

ISS

The ISS is now making another series of passes visible from Ireland in the early morning hours: details as usual on the excellent, free, www.heavens-above.com

CLOSE ASTEROID FLYBY

There was an error in the text of my last email (not guilty, as I just copied & pasted!) in that a decimal point had been omitted in the estimated diameter of the asteroid! The true diameter is about 2.2km, not 22km! I reproduce most of the details here for convenience, with some further information:
Asteroid 2006 VV2 passes close to the Earth at the end of March and early April. At its closest, on March 31, it will be 0.0226 AU away (8.8 lunar distances). This will be the closest known approach by an object this intrinsically bright until May 2036, when binary asteroid (66391) 1999 KW4 (H=16.4) approaches within 6 lunar distances. Observers should be able to see it through modest telescopes as it reaches 10th magnitude on March 31st and April 1st.
It will move almost due South, from Ursa Major, through Leo Minor, into Leo. Its greatest apparent motion will be on 30/31 March, when it will be moving at more than 1 minute of arc per minute of time.
Since it will be so close, parallax effects will be considerable: thus you will need to plot its position against the star background for your own location to locate it accurately. The orbital elements below can be 'plugged into' many computer programmes such as Skymap Pro, & it will then generate the track against star charts for your, or any chosen, location.
If you can't do that, you can get the same results as follows. First obtain your latitude and longitude as accurately as possible. Then visit
http://neo.jpl.nasa.gov/cgi-bin/db?name=2006+VV2
For a high accuracy ephemeris:
http://neo.jpl.nasa.gov/cgi-bin/db?name=2006%20VV2#ephemeris
Further details are on: http://homepage.ntlworld.com/roger.dymock/index.htm
If you can't get those details, look for it at the time of the close appulses to the stars identified below (" v " = visual magnitude).

Between 01:00 and 03:00 UT on March 29 the asteroid passes within 25 arc min of galaxies M82 and M81 and between 19:00 and 21:00 UT on March 31 it approaches within 3 degrees of galaxies M105, M96 and M95. A list of close appulses is given below, along with the details of a possible occultation event visible from the UK on the evening of March 31.
2006 VV2 will be a very strong radar target and observations are scheduled at Goldstone (March 27, 30, and April 1-3) and Arecibo (March 31 and April 1). VV2's physical properties are unknown, but its absolute magnitude of 16.7 suggests a diameter within a factor of two of about 2.2 km and there is roughly a 1- in- 6 chance that it is a binary system. Astrometric and photometric data are requested in support of the radar observations.

Orbital elements
Epoch 2007 Apr. 10.0
Semimajor axis, a 2.3913823 AU
Eccentricity, e 0.6029924
Inclination of orbit, i 23.63379 deg
Argument of perihelion 144.91495 deg
Long. ascending node 10.04975 deg
Mean anomaly, M 9.67407 deg
Period of orbit, P 3.70 years (1350.7 days)
Perihelion distance 0.949 AU
Aphelion distance 3.833 AU
Absolute magnitude, H 16.7

Ephemeris
Date UT RA (J2000) Decl. Delta r El. Ph. V "/min P.A.

2007 03 25 0000 00 56 22 +82 13.6 0.065 0.989 80.8 95.5 14.2 7.76 037.1
2007 03 26 0000 02 24 30 +84 43,2 0.056 0.993 83.6 93.2 13.7 10.28 058.7
2007 03 27 0000 06 11 45 +85 13.2 0.047 0.997 87.5 89.8 13.2 14.41 115.0
2007 03 28 0000 08 53 39 +80 11.0 0.039 1.001 93.2 84.6 12.6 21.14 154.8
2007 03 29 0000 09 49 31 +70 20.8 0.031 1.005 101.9 76.3 11.9 32.23 168.1
2007 03 30 0000 10 14 23 +54 42.0 0.026 1.010 115.2 63.5 11.0 48.43 173.4
2007 03 31 0000 10 28 10 +32 31.9 0.023 1.014 132.6 46.4 10.3 61.58 175.6
2007 04 01 0000 10 36 54 +08 27.3 0.024 1.019 146.9 32.4 10.0 56.00 176.4
2007 04 02 0000 10 42 58 -10 35.2 0.028 1.024 149.6 29.6 10.3 39.11 176.5

Appulses
2007 Mar 28 20:04 27 UMa (V=5.1), Asteroid (V=12.0) 6' west of star
2007 Mar 29 01:20 Messier 82 (V=9.2), Asteroid (V=11.8) 25' east of galaxy
2007 Mar 29 02:20 Messier 81 (V=7.8), Asteroid (V=11.8) 15' east of galaxy
2007 Mar 30 19:51 Beta LMi (V=4.2), Asteroid (V=10.4) 15' west of star
2007 Mar 30 22:42 30 LMi (V=4.7), Asteroid (V=10.3) 22' east of star

OCCULTATION !!!
2007 Mar 31 20:38 HIP 51892 (V=7.25), Asteroid (V=10.0)
This is a K2-type star and the track crosses the UK passing Ayr, Chester, Shrewsbury, Gloucester and Salisbury. The exact position is uncertain so observers within say 50-100 km either side of the nominal position may witness a positive event. The duration of any event is expected to be less than 0.2 sec but this can be recorded using a video camera given that the star is so bright. The drop in brightness is expected to be close to 3 magnitudes. (Roger Dymock, Director Asteroids and Remote Planets Section)
HIP 51892 also has the following alternative designations (the following information is from Skymap Pro 11):
Tycho catalog number: TYC 842-486-1
Hipparcos catalog number: HIP 51892
PPM catalog number: PPM 127542
SAO catalog number: SAO 99198
HD catalog number: HD 91785
BD number: BD +12 2235
WDS designation: BIG 1

Equatorial co-ordinates (epoch J2000.0, ICRS)
Right Ascension: 10h 36m 06.7378s
Declination: +11° 36' 52.378"

This star is a DOUBLE STAR, with the following details (position for component 1):
RA (J2000.0): 10h 36m 06.7s
Dec (J2000.0): +11° 36' 52"
Number of measurements: 13
Date of first observation: 1880
Position angle: 339°
Separation: 55.7"
Date of last observation: 2002
Position angle: 332°
Separation: 59.3"
Magnitude of first component: 7.40
Magnitude of second component: 9.67
Spectrum: K2
Proper motion in RA: -0.013 "/year
Proper motion in dec: 0.006 "/year
Secondary PM in RA: -0.085 "/year
Secondary PM in dec: 0.013 "/year
DM number: +12 2235

IRELAND: Given the present uncertainty in the track, there is a slight chance that the extreme ENE coast of N Ireland could witness this occultation - the NE coasts of Co Antrim & Co Down lie within about 100 km of the track. If the asteroid is a binary, then the chances of an occultation visible from here are slightly greater.
Any such observation would produce really valuable information, so anyone with suitable equipment should prepare to try to record it if at all possible. I'll give an update if further information becomes available.
(Even though the star is a double star, there is little chance that the G-type 9.7 mag secondary component could be occulted as seen from Ireland.)

Tuesday 20 March 2007

NOVA CYGNI


As promised in my last email, here's a chart for Nova Cygni, position shown at the tip of the arrow. It lies approx 1/3 of the way from Gamma to Alpha Cygni. Stars are shown to magnitude 10. Latest estimates suggest it is about magnitude 8, so it may not brighten any further.


(From the BAA) Close Approach of Asteroid 2006 VV2

Asteroid 2006 VV2 passes close to the Earth at the end of March and the early part of April. At its closest, on March 31, it will be 0.0226 AU away (8.8 lunar distances). This will be the closest known approach by an object this intrinsically bright until May 2036, when binary asteroid (66391) 1999 KW4 (H=16.4) approaches within 6 lunar distances. Observers should be able to see it through modest telescopes as it reaches 10th magnitude on March
31st and April 1st.

Between 01:00 and 03:00 UT on March 29 the asteroid passes within 25 arc min of galaxies M82 and M81 and between 19:00 and 21:00 UT on March 31 it approaches within 3 degrees of galaxies M105, M96 and M95. A list of close appulses is given below, along with the details of a possible occultation event visible from the UK on the evening of March 31.
2006 VV2 will be a very strong radar target and observations are scheduled at Goldstone (March 27, 30, and April 1-3) and Arecibo (March 31 and April 1). VV2's physical properties are unknown, but its absolute magnitude of 16.7 suggests a diameter within a factor of two of about 22 km and there is roughly a 1- in- 6 chance that it is a binary system. Astrometric and photometric data are requested in support of the radar observations.

Orbital elements
Epoch 2007 Apr. 10.0
Semimajor axis, a 2.3913823 AU
Eccentricity, e 0.6029924
Inclination of orbit, i 23.63379 deg
Argument of perihelion 144.91495 deg
Long. ascending node 10.04975 deg
Mean anomaly, M 9.67407 deg
Period of orbit, P 3.70 years (1350.7 days)
Perihelion distance 0.949 AU
Aphelion distance 3.833 AU
Absolute magnitude, H 16.7

Ephemeris
Date UT RA (J2000) Decl. Delta r El. Ph. V "/min P.A.

2007 03 25 0000 00 56 22 +82 13.6 0.065 0.989 80.8 95.5 14.2 7.76 037.1
2007 03 26 0000 02 24 30 +84 43,2 0.056 0.993 83.6 93.2 13.7 10.28 058.7
2007 03 27 0000 06 11 45 +85 13.2 0.047 0.997 87.5 89.8 13.2 14.41 115.0
2007 03 28 0000 08 53 39 +80 11.0 0.039 1.001 93.2 84.6 12.6 21.14 154.8
2007 03 29 0000 09 49 31 +70 20.8 0.031 1.005 101.9 76.3 11.9 32.23 168.1
2007 03 30 0000 10 14 23 +54 42.0 0.026 1.010 115.2 63.5 11.0 48.43 173.4
2007 03 31 0000 10 28 10 +32 31.9 0.023 1.014 132.6 46.4 10.3 61.58 175.6
2007 04 01 0000 10 36 54 +08 27.3 0.024 1.019 146.9 32.4 10.0 56.00 176.4
2007 04 02 0000 10 42 58 -10 35.2 0.028 1.024 149.6 29.6 10.3 39.11 176.5

Appulses
2007 Mar 28 20:04 27 UMa (V=5.1), Asteroid (V=12.0) 6' west of star
2007 Mar 29 01:20 Messier 82 (V=9.2), Asteroid (V=11.8) 25' east of galaxy
2007 Mar 29 02:20 Messier 81 (V=7.8), Asteroid (V=11.8) 15' east of galaxy
2007 Mar 30 19:51 bet LMi (V=4.2), Asteroid (V=10.4) 15' west of star
2007 Mar 30 22:42 30 LMi (V=4.7), Asteroid (V=10.3) 22' east of star

OCCULTATION !!!
2007 Mar 31 20:38 HIP 51892 (V=7.25), Asteroid (V=10.0)
This is a K2-type star and the track crosses the UK passing Ayr, Chester, Shrewsbury, Gloucester and Salisbury. The exact position is uncertain so observers within say 50-100 km either side of the nominal position may witness a positive event. The duration of any event is expected to be less than 0.2 sec but this can be recorded using a video camera given that the star is so bright. The drop in brightness is expected to be close to 3 magnitudes.
Roger Dymock, Director Asteroids and Remote Planets Section
IRELAND: Given the present uncertainty in the track, there is a slight chance that the extreme ENE coast of N Ireland could witness this occultation - the NE coasts of Co Antrim & Co Down lie within about 100 km of the track. If the asteroid is a binary, then the chances of an occultation visible from here are slightly greater.
Any such observation would produce really valuable information, so anyone with suitable equipment should prepare to try to record it if at all possible. I'll give an update if further information becomes available.

Further detail can be found on the Asteroid and Remote Planets Section website at: http://homepage.ntlworld.com/roger.dymock/index.htm

Monday 19 March 2007

NOVA in CYGNUS

A fairly bright Nova has been discovered in Cygnus by Akihiko Tago in Japan on the evening of March 15 at magnitude 7.4. Another estimate next evening indicated a magnitude of 6.7. It may still be brightening or may have already reached maximum, so observe it if you can. At around 7th magnitude, it's within easy reach of binoculars, but it lies in the Milky Way so it's in a crowded starfield, and may not be that easy to identify at first.
A nova is a star, usually a member of a close binary system where one star is accreting material from another, and undergoes a a colossal explosion, blowing off the outer layers of the star, increasing its brightness by may thousands of times.
This nova is circumpolar in Ireland, but it it's quite low when at lower culmination (due North). It's best seen later in the night: by midnight it will be 10-14 degrees up (depending on your latitude) in the NNE. Its position is:
R.A: 20h 28m 12.5s
Dec: +41 deg, 48' 36.5" (2000.0 co-ordinates)
I'll send a map out separately shortly for those of you without deep star atlases or a PC sky programme

IAA Lecture: BELFAST: Wed 21 March

Irish Astronomical Association Public Lecture: "The Virgo Cluster: Stepping Stone to Infinity" by Tony O'Hanlon. 7.30 p.m., Lecture Room 5, Stranmillis College, Belfast. Admission free, including light refreshments. All welcome.

IAA Public Observing Evening, WWT, CASTLE ESPIE

The Irish Astronomical Association will be hosting another in its very successful series of public observing evenings at Castle Espie on Saturday 24 March. We'll be observing a nice waxing Moon, Saturn, & other sky attractions, with indoor alternatives if cloudy. All welcome, and bring your own binoculars & portable telescopes if you have them.

Programme re Dunsink

Re my last E/M alert, please note that the programme is on RTE1 RADIO next Thursday, 8.30pm

BAA Tribute to Sir Patrick Moore

On April 24, the BBC's Sky At Night programme and Sir Patrick Moore (a BAA member for more than 70 years) celebrate 50 years of continual broadcasting: the world's longest running television programme with the same presenter.
Many astronomers, amateur and professional alike, have been inspired by Patrick and the programme over the years. Following a suggestion by one of the BAA's younger members, Philip Jennings, they are giving members and others an opportunity to send a personal greeting to Patrick on this unique achievement. Visit this webpage where you can add your name and also send a personal greeting or message. The address is: http://www.britastro.org/skyatnight50
They plan to present Patrick with his "Sky at Night at 50" greetings card and read out some of your messages on the anniversary date. Hopefully this will come as a pleasant surprise for him. (via Richard Miles, BAA President)

Thursday 15 March 2007

UCD SEMINAR: (SORRY FOR THE SHORT NOTICE - I ONLY SAW THIS TODAY!)

Astronomy seminar to be held in UCD:
Title: Massive Star Formation along the Hubble Sequence
Speaker: Prof. Nicholas Devereux, Fulbright scholar, NUI Galway
Date: Thursday, March 15th, 2007
Time: 3.30pm
Room: 128 UCD School of Physics, Science Centre North, Belfield
Tea afterwards in the common room
All welcome

Abstract:
New results, based on one of the most comprehensive H-alpha imaging surveys of nearby Sa-Sab spirals completed to date, reveals early-type spirals to be a diverse group of galaxies that span a wide range in massive star formation rates. While the majority of Sa-Sab galaxies in our sample are forming stars at a modest rate, a significant fraction (~29%) exhibit star formation rates greater than 1 Msolar yr-1, rivaling the most prolifically star-forming late-type spirals. A similar diversity is apparent in the star formation history of Sa-Sab spirals as measured by their H-alpha equivalent widths. Consistent with our preliminary results presented in the first paper in this series, we find giant H II regions [L(H?)>=10^39 ergs s-1] in the disks of ~37% of early-type spirals. We suspect that recent minor mergers or past interactions are responsible for the elevated levels of H-alpha emission and, perhaps, for the presence of giant H II regions in these galaxies. Our results, how ever, are not in total agreement with the H-alpha study of Kennicutt & Kent, who did not find any early-type spirals with H-alpha equivalent widths >14 Ã…. A close examination of the morphological classification of galaxies, however, suggests that systematic differences between the Revised Shapley-Ames Catalog and the Second Reference Catalogue may be responsible for the contrasting results.

LECTURES BY JERRY STONE

"See attached schedule of talks by Jerry Stone. I was at his talk in Queen's. He is a very good speaker and certainly knows his stuff, excellent value for a £5-00. The talk lasted for 2 and a quarter hrs! Terry, Can you broadcast on your circulation list?
You can also get more info by 'Googling' him.
Regards, Pat"

Further details from Malcolm Samuel : 02870 326389
or Jerry Stone : spaceflight_uk@yahoo.co.uk
www.geocitites.com/spaceflight_uk

LIGHT POLLUTION SURVEY

(From Al White):
"The 'Globe At Night' survey is running until 21 March. This is a survey designed to record the limiting magnitude of the night sky across the world. If you could pass this on to your mailing list perhaps people could report their observations.

More info can be found at the following URL's
http://www.globe.gov/GaN/
Also here:
http://media.skytonight.com/documents/200704042045.pdf

Cheers,
~Albert
_________________
Albert White BSc. FRAS
Chairperson, International Dark Sky Association - Irish Section
http://www.ilpac.eu "

Saturday 3 March 2007

Saturn & Moon appulse image


Thanks to Peter Paice for this image of Saturn's recent close encounter with the Moon.
Posted by Picasa

Friday 2 March 2007

HAIL STORM DAMAGE GROUNDS ATLANTIS

A sudden, explosive thunderstorm on Monday battered the shuttle Atlantis' external fuel tank with wind-driven, golf ball-sized hail, causing extensive damage to the tank's protective foam insulation. NASA managers said engineers will have to move the shuttle back to the Vehicle
Assembly Building for repairs, delaying launch on a space station assembly mission from March 15 to late April.

Moon Grazes Saturn

We will have a spectacular near-miss on March 2 at about 02.36 when the almost full Moon will just skim past Saturn’s N Pole! It will be so close that in fact from N & E parts of Ireland it will occult Saturn’s Moons Rhea and Iapetus, at about 02.36 and 02.37, but I doubt if you’ll see them with the very bright Moon so close. Rhea will be magnitude 9.7, and Iapetus about mag 10.2.

Don't forget the Total Lunar Eclipse on Saturday night!

A Total Eclipse of the Moon occurs when the Moon passes into the shadow of the Earth. It can only happen at Full Moon, but it doesn't happen every Full Moon because the Moon's orbit is tilted to ours by about 5 degrees, and so usually it passes above or below Earth's shadow, rather than through it. And sometimes it only passes through the edge of the shadow, giving a partial eclipse. The next total one visible from Ireland will be on Feb 21, 2008.

But this is a good one for Ireland, with all stages of the eclipse visible, and the main part occurs before midnight! If it's clear we'll see the Moon turn a glorious reddish colour - anything from a sort of ochre, to deep red. The exact colour can't be predicted, which is one of the fascinating things about such eclipses. The colour is due to the Sun's light passing through the Earth's atmosphere, which acts like a giant lens, focussing the light onto the Moon so that it never goes totally dark.


The Moon starts to enter the Penumbra, Earth’s faint partial outer shadow at 20.18, and then begins to enter the darker main shadow or umbra at 21.30. It will be completely inside the umbra, i.e. the eclipse will be total, from 22.44 to 23.58, with Mid Eclipse at 23h 21m.

It will have left the umbra at 01.00, and will finally exit the penumbra at 02.24, marking the end of the eclipse.

The penumbral stages are barely noticeable, and it will probably be a few minutes after the start of the umbral phase before you'll notice the lower left side of the Moon start to darken slightly: say about 21.35.

This darkness will gradually spread across the Moon until by about 22.45 it will all be immersed in the shadow of the Earth. However, it won't all appear equally dark, as the Moon does not pass through the centre of the shadow, and even at mid-eclipse at 23h 21m you'll notice that the top left of the Moon won't be as dark as the bottom right, which will be closest to the centre of the shadow.

The Moon will be quite high up in Southern Leo, near Chi Leonis, with Saturn about 24 deg away to the upper right.

The Moon will occult 5th magnitude 59 Leonis after the total phase ends, at about 00.43 for observers in Belfast, and about 00.30 for observers in Cork. That event would be visible in a small telescope.

LIGHT POLLUTION PETITION: "Save the night sky"

Please sign this petition to save the night sky, and save vast amounts of
wasted energy. Also please forward to anyone relevant and especially to
science interest groups (You must be a UK resident)

>> http://petitions.pm.gov.uk/starry-night/