Tour of the Sky: April 2007

Download this month's sky map!

Kym Thalassoudis does a wonderful job creating accurate and easy to use star maps every month! Visit his site at www.skymaps.com for skymaps and links to other useful astronomical sites. Also a great portal for astronomical gifts!

Northern hemisphere sky map
Southern hemisphere sky map

Those in the Southern Hemisphere should also visit James Barclay's site for a great tour of the Southern Hemisphere December sky.

Another great site for Southern Hemisphere viewers is the Royal Astronomical Society of New Zealand's Southern Hemisphere Calendar can be found at the RASNZ site
Ian Musgrave has a very handy Southern Hemisphere site called Southern Sky Watch.

Download "What's up 2007: 365 days of Skywatching" by Tammy Plotner, published by Universe Today (Faser Cain) it is a fantastic and it is free!

Planets for April 2007

• Mercury-Continues good morning viewing for Southern Hemisphere observers until mid-month when it sinks lower in the dawn sky. Poor viewing for Northern latitudes but those of you closer to the equator should still give it a try 0.0 mag (1st) to -0.8 mag (21st)
• Venus-Brilliant in the evening sky all month passing very close to the Pleiades and Hyades between the 10th and 18th. For mid to high northern latitudes Venus is almost 40 deg high at sunset. -3.9 mag (1st) to - 3.9 mag (21st)
• Mars-Starts out the month not far from Neptune at the Capricorn/Aquarius border and ends the month(28th) extremely close to Uranus in Aquarius 1.1 mag (1st) to 1.0 mag (21st)
• Jupiter-After the 6th Jupiter begins its retrograde loop within southern Ophiuchus -2.3 mag (1st) to -2.4 mag (21st)
• Saturn-Absolutely beautiful in Leo almost at the Cancer border. Saturn's rings are tipped 15 deg from edgewise towards us so take advantage of these beautiful rings. The axial tilt of Saturn produces Saturian season the same way our tilt does but from our perspective here on Earth it also accentuate the changing view of the rings tilting above or below the horizontal plane between us. So now, Saturn's rings are closing their tilting pattern. A good illustration of that tilt can be seen at the Hubble Heritage site. Saturn returns to regular motion (prograde) on the 20th heading back towards Regulus 0.2 mag (1st) to 0.3 mag (21st)
• Uranus-In Aquarius 5.9 mag (1st) to 5.9 mag (21st)
• Neptune-Will camp out in Capricorn all year long and is currently masked by the glare of the sun. 8.0 mag (1st) to 8.0 mag (21st)

For more information, and illustrations, on retrograde motion visit these links:
LaSalle University Astronomy class website
University of Illinois Astronomy project

Key Dates for April 2007

Days and Times in UT (help with time)
Observations are for 8pm for the mid-northern latitudes and for 10pm for the mid-southern latitudes.

Great site for sunrise and sunset times and a downloadable toolbar application by Steve Edwards

Astronomical Highlights

April
2	- Full Moon 17:15 UT Spica shines to its lower left with bright Arcturus is much farther to their left. This will be the smallest Full Moon (in angular size) of the year!
3	- Moon at apogee (farthest from Earth) 9:00 UT distance 406,329 km angular size 29.4'
	- Moon near Spika at 17:00 UT
4	- Happy Birthday Mom!
5	- Double shadow transit on Jupiter 20:07 UT
6	- Jupiter stationary
7	- Moon near Antares 13:00 UT, Occultation visible from E. Australia, N.Z. and S.South America check IOTA for occultation at your location
8	- Moon near Jupiter 8:00 UT
10	- Last Quarter Moon, 18:04 UT
10-12	- Great photo opportunity with Venus very close to the Pleiades (evening western sky)~ 2.6 deg apart
13	- Double shadow transit on Jupiter 00:05 UT
13-14	- Moon close to Mars in the morning sky. The waning crescent moon will move from the west to the east of Mars on these two mornings. Occultation visible from Yemen and Somali check IOTA for occultation at your location
16	- Moon near Mercury at 6:00 UT (morning sky)
17	- New Moon 11:36 UT and Moon at perigee (closest to Earth) at 357,135 km and an angular size of 33.5'
	- Large tides
17-24	- National Dark Sky Week! Start spreading the word and post fliers in your neighborhood and host a star party!
19-20	- Look for the Moon, Venus, the Pleiades, Capella and Aldebaran to be all together with the Moon shifting from west to east in the arrangement. Good potential photo op!
20	- Saturn stationary 1:00 UT
21	- Astronomy Day 2007! Check out what is happening in your area or create your own event! This is also
22	- Lyrid meteor shower peaks at 22:00 UT. For more information.....
24	- First Quarter Moon 6:36 UT
25	- Moon very near Saturn at 10:00 UT. Occultation visible in Alaska, Western and Northern Canada and AAGG-land! check IOTA for occultation at your location
26	- Moon very near Regulus at 9:00 UT Occultation visible in N.E. Siberia and N.W. North America (but not here at the AAGG home!) check IOTA for occultation at your location
29	- Mars (1.0 mag) 0.68 deg from Uranus (5.9 mag) at 4:00 UT
30	- Moon at apogee 11:00 UT 406,209 km and angular size 29.4'

Monthly Messier*

This month highlights galaxies and gets us ready for the big spring galaxy push of the Virgo Cluster later in the month. Most of these can be detected in binoculars or small telescopes and I recommend doing so just for the practice of navigation, averted vision and patience! Then you can pull out the big dog and make these galaxies bark!

• M40 - This is a pair of faint stars located in Ursa Major. They are a tough find in binoculars, and you will be challenged to split them with binoculars. In telescopes, they appear to be an identical pair of stars and easy to split even at low power. There is enough dark space around them that even in a smaller telescope they look like a pair of eyes staring back at you.
• M108 - This galaxy will appear as a thin streak of light in telescopes, there is a definite brightening towards the middle. M108 is a very tough object for the largest binoculars. In a smaller scope the spindle shape helps identify M108.
• M97 - This planetary nebula in Ursa Major, also called the Owl nebula, appears as a fairly large, round, hazy patch of light in a telescope. It is in the same field of view as M108 at low to medium powers. Use averted vision to see the faint glow of the Owl nebula through binoculars. The two dark eyes do not become apparent until you throw some aperture into the mix but if you are patience and well dark adapted (and in dark skies) you can just start to see the eyes in a 10" or so.
• M109 - This spiral galaxy in Ursa Major appears as a small, oval patch of light. It can be found in the same field of view as Gamma UMa at low to medium power in a telescope. Use large binoculars under good conditions for a chance of seeing this one. Its bright center and bar pop out first in smaller scopes and you can detect a 'halo' around the core. Adding more mirror will bring out the spiral arms.
• M106 - This galaxy in Canes Venatici appears as an oval patch of light, larger than M109, with a fairly bright core. A tough, but possible binocular target. In smaller scopes look for the brighter edge points around the halo that mark clustering in the middle spiral arms.
• M95 - This galaxy in Leo appears as a faint round patch of light with a bright nucleus. Large binoculars and good conditions are a must. Larger scopes will bring out the spiral arms which make this look more like an oval with a dot in the middle than your typical spiral.
• M96 - Look for M96 in the same low power telescope field as M95. Another round patch of light, slightly larger and brighter than M95, it too has a stellar core. Binocular advice for M96 is the same as M95. This is the galaxy I see first as a bright blob, even with a larger telescope the blobbiness stays about the same.
• M105 - This is a small elliptical galaxy in Leo, and can be found in the same low power field as M96. It looks like a small fuzzy star. M105 has a close companion galaxy, NGC 3384, which is only slightly smaller and fainter than M105. To prevent confusion, M105 is the closer of the pair to M96. Not possible in binoculars, except maybe with averted "imagination". This is the proto-typical UFO (unidentified fuzzy object)
• M65 - A small, but relatively bright galaxy in Leo. It is an elongated oval patch of light with a bright stellar core. A tough, but possible binocular target. This galaxy's spindle shape helps distinguish it from....
• M66 - A close companion galaxy to M65, it can be seen in the same low to medium power field as M65. M66 is another oval patch of light, brighter and slightly wider than M65. Another possible binocular target. While you are here be sure to look for a thin streak of light, which is the galaxy NGC 3628. It can be found north of M66 in the same low power telescope field as both M65 and M66. Now once you finish with M66 in your smaller scope go find someone with a big scope and take a look..or just follow the like provided. The is a beautiful galaxy 'up close' and appears to be twisting in on itself.

*Monthly Messier information gleaned from the Royal Astronomical Society of Canada, Moncton Centre Quebec and from the Astronomy Connection website.

Historical and Current Events

...Did you know?
April
2	-First photograph of the sun taken (1845)
5	-10th Anniversary (1997), Galileo, Ganymede 7 Flyby
11	-William Wallace Campbell's 145th birthday (1862)-pioneer observer of stellar motions and radial velocities
12	-Yuri Gagarin became the first man in space (1961)
	-Columbia became the first Space Shuttle launched
	-Edward Mauder's 156th Birthday (1851)
14	-Christian Huygens' 348th Birthday (1629)
16	- Wilbur Wright's 140th Birthday (1867)
	- Leonardo DaVinci's 555th Birthday (1452)
	-35th Anniversary (1972), Apollo 16 Launch (Manned Moon Landing)
17	-40th Anniversary (1967), Surveyor 3 Launch (Moon Lander)
19	-25th Anniversary (1982), Salyut 7 Space Station Launch
22	-Sir Harold Jeffreys' 117th Birthday
23	-Max Planck's 149th Birthday
24	-17th Anniversary (1970), China's first satellite (Shi Jian 1)
28	-Jan Oort's 107th Birthday
30	-Johann Carl Frederich Gauss' 230th Birthday

Astronomical Highlights for 2007

Earth's major motions for 2007

Perihelion		Jan 3 20h(UT)
First Cross Quarter Day		Feb 2-6
Equinox		Mar 21 00:07(UT)
Second Cross Quarter Day		May 4-7
Solstice		June 21 18:06(UT)
Aphelion		July 4 00h (UT)
Third Cross Quarter Day		Aug 5-8
Equinox		Sept 23 19:51(UT)
Fourth Cross Quarter Day		Nov 5-8
Solstice		Dec 22 06:08(UT)

Planet Positions for 2007

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Venus

Sgr

Aqr

Psc

Ari

Tau

Gem

Leo

Sex

Cnc

Leo

Leo

Vir

Mars

Oph

Sgr

Cap

Cap

Aqr

Psc

Ari

Tau

Tau

Gem

Gem

Gem

Jupiter

Oph

Oph

Oph

Oph

Oph

Oph

Oph

Oph

Oph

Oph

Oph

Oph

Saturn

Leo

Leo

Leo

Leo

Leo

Leo

Leo

Leo

Leo

Leo

Leo

Leo

Uranus

Aqu

Aqu

Aqu

Aqu

Aqu

Aqu

Aqu

Aqu

Aqu

Aqu

Aqu

Aqu

Neptune

Cap

Cap

Cap

Cap

Cap

Cap

Cap

Cap

Cap

Cap

Cap

Cap

Eclipses for 2007

March 19 - partial solar eclipse (see map, times, and animation!): The first solar eclipse of 2007 occurs at the Moon's ascending node in Pisces and is visible from eastern Asia and parts of northern Alaska

September 11 - partial solar eclipse (see map, times, and animation): The last eclipse of 2007 is a partial solar eclipse at the Moon's descending node in southern Leo. Its visibility is confined to parts of South America, Antarctica and the South Atlantic

March 3-4 - total lunar eclipse (see map): The beginning of the umbral phase visible in the Arctic region, Africa, Europe, Asia except for extreme eastern region, most of Indonesia, western Australia, Queen Maud Land of Antarctica, extreme eastern South America, Greenland, the Indian Ocean, the South Atlantic Ocean, and the eastern North Atlantic Ocean; the end visible in Africa, Europe, western Asia, Queen Maud Land of Antarctica and Antarctic Peninsula, South America, eastern North America, Greenland, the Arctic region, the Atlantic Ocean, the western Indian Ocean, and the extreme eastern South Pacific Ocean.

August 28 - total lunar eclipse (see map): The beginning of the umbral phase visible in North America, South America except extreme east, Antarctica except for Enderby Land, New Zealand, eastern Australia, extreme northeastern Asia, the Pacific Ocean, and the western Atlantic Ocean; the end visible in New Zealand, Australia, most of Antarctica except Queen Maud Land, Indonesia, eastern Asia, western North America, the Pacific Ocean, and the southeastern Indian Ocean.

Eclipse information from: NASA Eclipse Homepage, Eclipses Online (HM Nautical Almanac Office, UK in coordination with the U.S. Naval Observatory)

Meteor Showers for 2007

As luck would have it, all the major meteor showers reach their peaks in 2007 with the Moon out of the sky. Any of these showers can produce dozens of shooting stars each dark hour leading up to dawn.

Mark your calendar to look for...

• Lyrids on April 23rd
• Perseids on August 13th
• Orionids on October 21st
• Leonids on November 18th
• Geminids on the night of December 13-14 (Meteor enthusiasts are keenly awaiting the Geminids in 2007 because their progenitor, the defunct comet Phaethon, precedes them in a flyby of Earth on December 10th.)

Comets for April

Gary Kronk's comet and meteor pages
Skyhound Comet pages

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