Whats Up, Ron? is a monthly almanac for Northern American astronomersastras

WHAT'S UP?

by Ronald A. Leeseberg, the Star Geezer

June 2011 - Vol. 15 No. 6

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Features: Calendar | Lunar Almanac | Monthly Topic

This Month's Night Sky - NOTE: The next paragraph describes the sky as it appears at 10 pm EST (11 pm EDT) near mid- month. The sky also looks this way at 11 pm EST (midnight EDT) during the beginning of the month and at 9 pm EST (10 pm EDT) by month's end.

Angular Measurement Review: It is interesting to note that the relationship between the angle subtended by combinations of fingers on your fully outstretched arm are the same for all viewers. This is due to the fact that the hand's size is proportional to the arm's length. A shorter arm is attached to a smaller hand while a longer arm is attached to a larger hand, thus the angle measured remains the same. If you hold your arm fully outstretched, your little finger, when sighted down your arm, is one degree wide. Your three middle fingers is five degrees, your fist, 10 degrees, and the distance between your little finger and your pointer finger is 15 degrees no matter what your age or size.

Arcturus (Bootes) shines high overhead as Night falls. Spica (Virgo) glows in the SW while Regulus (Leo) vanishes over the W horizon before midnight. The "big dipper" (Ursa Major's asterism) now stands on its "handle" in the N. Antares (Scorpius) is low on the S horizon. The E sky is dominated by the "summer triangle" asterism: Deneb (Cygnus), Vega (Lyra) and Altair (Aquila). An interesting star tour begins at the last star of the big dipper's handle, Alkaid. Following the curve of the handle, "arc to Arcturus". Now, following the same curve, "spike to Spica"and "continue to Corvus", its distinctive four star, kite-shaped, asterism. NOTE: since you are looking upwards into the "bowl" of the sky instead of down at a map, E is to the LEFT and W is to the RIGHT.)

Unfortunately, neither the partial solar eclipse on the first nor the total lunar eclipse on the 15th. With not be visible in our corner of the world.  MERCURY may be visible, very low on the NW horizon after Sunset during the last week of this month.  Bright VENUS should be visible in the NE about an hour before Sunrise.  Faint MARS should be visible in the NE about two hours before Sunrise and will slowly drift E before its lost in the rising Sun's glare.  JUPITER becomes visible in the NE about three hours before Sunrise.  It will also drift to the E before being lost in the Sun's glare.  All of the early morning planets will be quite low on the horizon.  SATURN, the queen of the night sky, appears about half way up in the S at Sunset.  It gradually moves to the W before setting shortly after midnight.  Its rings are now about 7 degrees edgewise and will widen to about 10 degrees before disappearing into the Sunset glow in mid September.

Calendar of Events

NOTE: For those observers not in the ET zone, convert the calendar times to your zone's time by subtracting one hour for CT, two for MT and three for PT. Don't forget to adjust for Daylight Savings Time when necessary by subtracting one hour from your planisphere's time.; Dawn and dusk times must also be corrected. See your local newspaper, TV news, or cable TV's Weather Channel for sunrise and sunset times. Unfortunately some of these events may occur during daylight hours in your area.

DATE EVENT
18
Look NE at 4 AM to see a pseudo-conjunction (5 degrees) of Venus and the bright star, Aldebaran (Taurus).
19-22

Dim Mars and M45, the Pleiades of Taurus, fit in the same 5 degree binocular view. Look low on the ENE horizon, well below bright Jupiter, early in the morning.

21
Our solstice occurs. Welcome to summer in our hemisphere!
26
Look ENE at 5 AM to see a conjunction (5 degrees) of Jupiter and the Moon.
27-28
The Bootid Meteor Shower peaks at early in the morning of the 28th. This is a "broad" shower and observers report seeing these meteors before and after the peak. Itís radiant is in the Constellation Bootes, which that will be nearly overhead at the peak. Over 100 events/hour were reported in 1998 and about 50/hr. in 2004. These "outbreaks" are unpredictable; this might be the year!!
29
Look ENE at dawn (about 45 minutes before Sunrise to see the triangle formed by the thin crescent Moon, Mars and the bright star Aldebaran.
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Lunar Almanac for June 2011

Phases of the Moon Phase and Date(s)

Best viewed before local midnight

New
01

Deep Space Objects

1st. Qtr
08

Planets & Moon

Full
15

Moon

Last
Qtr 23

Deep Space & Planets

Topic of the month: Telescopic Finders

It is quite difficult to find an object in the sky when looking through a telescope. This is because the telescope has a very small field of view. So, for most of the history of the telescope, a smaller telescope of low magnification but with a large field of view, was used to "find" the object for view though the main instrument. Thus the term, FINDER. Of course the finder must be carefully aligned to the optical axis of the telescope to be useful!

focal reducer with extension

Finder "A" is typical optical finder, although its size is overkill for most amateur telescopes at 11 power by 80 mm (11X80). Most finders are between 6X30 to 8X50. Remember, the greater the magnification, the smaller the field of view. The second number refers to the diameter of the finder's objective (front lens) and is related to the brightness of its image (the bigger, the brighter). This particular finder has a diagonal (right angle attachment) making it easier to use when the telescope is aimed near the zenith (straight up). Its ocular (eyepiece) contains a fine cross hair, making it easier to bring the target into the telescopes field of view. (Its diagonal uses a special prism that corrects its image. Although it absorbs a bit more light than the typical mirrored diagonal, it is far easier to use!)

Finders "B" and "C" are examples of the more recent zero power or unity finders or aiming devices. Both operate using the same principle, a half silvered mirror that superimposes a glowing series of red concentric circles "B" or a red dot "C" on the object viewed without any magnification. With the advent of the computer controlled "Goto" telescopes, the unity finders are beginning to replace the optical finders for casual use.

Finder "D" is the latest aiming device to appear on the scene. This particular unit attaches to the same "red dot" mount found on many telescopes. The cylinder is a very powerful green laser that appears to shine on the object to be viewed in the telescope regardless of where the observer is standing, eliminating the sore neck many observers develop while attempting to move the telescope rapidly during group observing (sidewalk astronomy).

BE VERY CAREFUL WHERE YOU POINT ANY LASER. IF YOU HAPPEN TO SHINE IT ON A PASSING AIRCRAFT, YOU COULD GO TO JAIL! However, as a street astronomer, I believe they are the best things since sliced bread!!

NOTE: I will defer the discussion of a sun finder, used when locating the Sun during solar astronomy, until our topic of the month is "solar astronomy".

--See you next month!
Ron, the star geezer

This installment of "Whats Up?" is ©2011 Ronald A. Leeseberg, encoded by Dawn Jenkins for Astra's Stargate. Images used in this installment of "Whats Up?, Ron"are ©2011 by Ronald A. Leeseberg.

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