From: TerryMoselaol.com
Subject: Astronomy @ Castle Espie; ISS; Close asteroid
Date: 23 March 2007 01:31:56 GMT
Hi all,
Òš
1. Another reminder about:
ÒšIAA 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 &Òšportable telescopes if you have them.
Òš
2. 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
Òš
3. CLOSE ASTEROID FLYBY.
ÒšÒšÒš 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:
Òš
Asteroid 2006 VV2 passes close to the Earth at the end of March and early April.Òš 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.Òš Observers should be able to see it through modest telescopes as it reaches 10th magnitude on March
31st and April 1st.
Òš
It will move almost due South,Òšfrom 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.
Òš
Since it willÒšbe 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.
ÒšÒš 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 Link.
For a high accuracy ephemeris: Link
Further details are on: Link
Òš
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.Òš 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.
ÒšÒšÒš 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 0.6029924ÒšÒš
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
ÒšÒš DateÒš ÒšÒšÒšÒšÒš UTÒš Òš RA (J2000) Decl.Òš ÒšÒš DeltaÒš Òš Òš rÒš Òš ÒšÒšÒšÒš El.ÒšÒš Ph.Òš Òš VÒš Òš "/minÒšÒšÒš P.A.
2007 03 25 0000Òš 00 56 22Òš +82 13.6ÒšÒš 0.065Òš 0.989ÒšÒš 80.8Òš 95.5Òš 14.2ÒšÒš 7.76 Òš037.1
2007 03 26 0000Òš 02 24 30Òš +84 43,2ÒšÒš 0.056Òš 0.993ÒšÒš 83.6Òš 93.2Òš 13.7Òš 10.28 Òš058.7
2007 03 27 0000Òš 06 11 45Òš +85 13.2ÒšÒš 0.047Òš 0.997ÒšÒš 87.5Òš 89.8Òš 13.2Òš 14.41Òš 115.0
2007 03 28 0000Òš 08 53 39Òš +80 11.0ÒšÒš 0.039Òš 1.001ÒšÒš 93.2Òš 84.6Òš 12.6Òš 21.14 Òš154.8
2007 03 29 0000Òš 09 49 31Òš +70 20.8ÒšÒš 0.031Òš 1.005Òš 101.9Òš 76.3Òš 11.9Òš 32.23 Òš168.1
2007 03 30 0000Òš 10 14 23Òš +54 42.0ÒšÒš 0.026Òš 1.010Òš 115.2Òš 63.5Òš 11.0Òš 48.43Òš 173.4
2007 03 31 0000Òš 10 28 10Òš +32 31.9ÒšÒš 0.023Òš 1.014Òš 132.6Òš 46.4Òš 10.3Òš 61.58 Òš175.6
2007 04 01 0000Òš 10 36 54Òš +08 27.3ÒšÒš 0.024Òš 1.019Òš 146.9Òš 32.4Òš 10.0Òš 56.00Òš 176.4
2007 04 02 0000Òš 10 42 58Òš -10 35.2ÒšÒš 0.028Òš 1.024Òš 149.6Òš 29.6Òš 10.3Òš 39.11 Òš176.5
Appulses
2007 Mar 28 20:04Òš 27 UMa (V=5.1), Asteroid (V=12.0) 6' west of star
2007 Mar 29 01:20Òš Messier 82 (V=9.2), Asteroid (V=11.8) 25' east of galaxy
2007 Mar 29 02:20Òš Messier 81 (V=7.8), Asteroid (V=11.8) 15' east of galaxy
2007 Mar 30 19:51Òš Beta LMi (V=4.2), Asteroid (V=10.4) 15' west of star
2007 Mar 30 22:42Òš 30 LMi (V=4.7), Asteroid (V=10.3) 22' east of star
OCCULTATION !!!
2007 Mar 31 20:38Òš HIP 51892 (V=7.25), Asteroid (V=10.0)
ÒšÒš This is a K2-type star and the track crosses the UK passing Ayr, Chester, Shrewsbury, Gloucester and
Salisbury.Òš The exact position is uncertain so observers within say 50-100 km either side of the nominal
position may witness a positive event.ÒšÒš 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.Òš The drop in brightness
is expected to be close to 3 magnitudes.ÒšÒš(Roger Dymock, Director Asteroids and Remote Planets Section)
Òš
HIP 51892Òšalso has the following alternative designations (the following information is from Skymap Pro 11):
Òš
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
Òš
Equatorial co-ordinates (epoch J2000.0, ICRS)
Right Ascension: 10h 36m 06.7378s
Declination: +11ÒÀ 36' 52.378"
Òš
This star is a DOUBLE STAR, with the following details (position for component 1):
RA (J2000.0): 10h 36m 06.7s
Dec (J2000.0): +11ÒÀ 36' 52"
Number of measurements: 13
Date of first observation: 1880
Position angle: 339ÒÀ
Separation: 55.7"
Date of last observation: 2002
Position angle: 332ÒÀ
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
Òš
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.
ÒšÒšÒš Any such observation would produce really valuable information, so anyone with suitable equipment
should prepare to try to record it if at all possible.Òš I'll give an update if further information becomes
available.
ÒšÒš (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.)
Òš
Clear skies,
Òš
Terry Moseley
aol.com Subject: Astronomy @ Castle Espie; ISS; Close asteroid Date: 23 March 2007 01:31:56 GMT Hi all, Òš 1. Another reminder about: ÒšIAA 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 &Òšportable telescopes if you have them. Òš 2. 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 Òš 3. CLOSE ASTEROID FLYBY. ÒšÒšÒš 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: Òš Asteroid 2006 VV2 passes close to the Earth at the end of March and early April.Òš 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.Òš Observers should be able to see it through modest telescopes as it reaches 10th magnitude on March 31st and April 1st. Òš It will move almost due South,Òšfrom 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. Òš Since it willÒšbe 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. ÒšÒš 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 Link. For a high accuracy ephemeris: Link Further details are on: Link Òš 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.Òš 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. ÒšÒšÒš 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 0.6029924ÒšÒš 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 ÒšÒš DateÒš ÒšÒšÒšÒšÒš UTÒš Òš RA (J2000) Decl.Òš ÒšÒš DeltaÒš Òš Òš rÒš Òš ÒšÒšÒšÒš El.ÒšÒš Ph.Òš Òš VÒš Òš "/minÒšÒšÒš P.A. 2007 03 25 0000Òš 00 56 22Òš +82 13.6ÒšÒš 0.065Òš 0.989ÒšÒš 80.8Òš 95.5Òš 14.2ÒšÒš 7.76 Òš037.1 2007 03 26 0000Òš 02 24 30Òš +84 43,2ÒšÒš 0.056Òš 0.993ÒšÒš 83.6Òš 93.2Òš 13.7Òš 10.28 Òš058.7 2007 03 27 0000Òš 06 11 45Òš +85 13.2ÒšÒš 0.047Òš 0.997ÒšÒš 87.5Òš 89.8Òš 13.2Òš 14.41Òš 115.0 2007 03 28 0000Òš 08 53 39Òš +80 11.0ÒšÒš 0.039Òš 1.001ÒšÒš 93.2Òš 84.6Òš 12.6Òš 21.14 Òš154.8 2007 03 29 0000Òš 09 49 31Òš +70 20.8ÒšÒš 0.031Òš 1.005Òš 101.9Òš 76.3Òš 11.9Òš 32.23 Òš168.1 2007 03 30 0000Òš 10 14 23Òš +54 42.0ÒšÒš 0.026Òš 1.010Òš 115.2Òš 63.5Òš 11.0Òš 48.43Òš 173.4 2007 03 31 0000Òš 10 28 10Òš +32 31.9ÒšÒš 0.023Òš 1.014Òš 132.6Òš 46.4Òš 10.3Òš 61.58 Òš175.6 2007 04 01 0000Òš 10 36 54Òš +08 27.3ÒšÒš 0.024Òš 1.019Òš 146.9Òš 32.4Òš 10.0Òš 56.00Òš 176.4 2007 04 02 0000Òš 10 42 58Òš -10 35.2ÒšÒš 0.028Òš 1.024Òš 149.6Òš 29.6Òš 10.3Òš 39.11 Òš176.5 Appulses 2007 Mar 28 20:04Òš 27 UMa (V=5.1), Asteroid (V=12.0) 6' west of star 2007 Mar 29 01:20Òš Messier 82 (V=9.2), Asteroid (V=11.8) 25' east of galaxy 2007 Mar 29 02:20Òš Messier 81 (V=7.8), Asteroid (V=11.8) 15' east of galaxy 2007 Mar 30 19:51Òš Beta LMi (V=4.2), Asteroid (V=10.4) 15' west of star 2007 Mar 30 22:42Òš 30 LMi (V=4.7), Asteroid (V=10.3) 22' east of star OCCULTATION !!! 2007 Mar 31 20:38Òš HIP 51892 (V=7.25), Asteroid (V=10.0) ÒšÒš This is a K2-type star and the track crosses the UK passing Ayr, Chester, Shrewsbury, Gloucester and Salisbury.Òš The exact position is uncertain so observers within say 50-100 km either side of the nominal position may witness a positive event.ÒšÒš 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.Òš The drop in brightness is expected to be close to 3 magnitudes.ÒšÒš(Roger Dymock, Director Asteroids and Remote Planets Section) Òš HIP 51892Òšalso has the following alternative designations (the following information is from Skymap Pro 11): Òš 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 Òš Equatorial co-ordinates (epoch J2000.0, ICRS) Right Ascension: 10h 36m 06.7378s Declination: +11ÒÀ 36' 52.378" Òš This star is a DOUBLE STAR, with the following details (position for component 1): RA (J2000.0): 10h 36m 06.7s Dec (J2000.0): +11ÒÀ 36' 52" Number of measurements: 13 Date of first observation: 1880 Position angle: 339ÒÀ Separation: 55.7" Date of last observation: 2002 Position angle: 332ÒÀ 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 Òš 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. ÒšÒšÒš Any such observation would produce really valuable information, so anyone with suitable equipment should prepare to try to record it if at all possible.Òš I'll give an update if further information becomes available. ÒšÒš (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.) Òš Clear skies, Òš Terry Moseley
