OAKLAND ASTRONOMY CLUB

NEWSLETTER

                                                        DECEMBER  2007                                                        

Bill  MacIntosh,  Editor

• Dave Holt and Bill MacIntosh received "Thank You" cards from the Ortonville Scouts for a scope viewing event at an Independence Oaks campground presentation on October 6th.    Signed by many kids, the cards expressed thanks for the "Astrology" program !                                             

  Observations & Presentations

• Bob Berta related details on his trip to the San Jose, California Astrophotography Conference in November.   He was able to meet and talk with famous sky imagers such as widely published Robert Gendler and Adam Block of KPNO.   While there, he learned details about high-end equipment such as the Ceravolo Astrograph and a $10K CHRONOS mount, some models of which can support a 250lb OTA.   Bob circulated a newspaper article on astronomer Alex Filippenko, who dressed himself as a Black Hole for Halloween, and a baseball cap autographed by some astro-notables he met at the conference.

• Mark Jeffery passed around several Moldavite Tektite samples:   two stones that had been cut and polished, a rough hewn chunk of Moldavite and a flat piece of Moldavite with nice flow lines that evidenced its journey through the atmosphere some 15 million years ago.

• Dave Holt brought a whole bag full of collimation devices.   He demonstrated them at the end of the meeting on a 6" Orion reflector that visitor Ed Bacon had brought to the meeting seeking help for it.   This scope has a 3 vane spider supporting the secondary which was badly out of alignment.    Dave made several adjustments based on the views through the collimation implements to bring the scope back into proper sync. 

• Bill Girardin handed out SkyMaps for December and gave the following presentation:

• Comet Tuttle is now in the Northern sky to compete with Holmes for observers.  ( See Chart Below)
• 2008 Independence Oaks Star Parties

Discovered by amateur stargazer John Bevis in 1731, it is one of the few historically observed supernovae in our Milky Way Galaxy, dating back to 1054 A.D., seen by Chinese astronomers as about 4 times brighter than Venus or about mag -6 and visible in daylight for 23 days and 653 nights to the naked eye.     Messier independently found it on August 28, 1758 while looking for comet Halley, and it caused him to begin the compilation of his famous catalog thus becoming M 1.  It was dubbed the "Crab Nebula" from a drawing by Lord Rosse about 1844. In 1968, the known radio and X ray source was identified as a Pulsar by the 300 meter Arecibo radio telescope flashing with a period of 33.085 milliseconds. RA      05:34.5  (h:m) DEC +22:01  (deg:m) Visual Brightness:  Mag  8.4 Overall Apparent Dimension   6x4 arc min Click HERE for more detailed info

Image Credit:   NASA

Constellation:   TAURUS

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Although the Pulsar rotates rapidly, this slow-motion vid slows it down enough to see both the bright pulse and the inter- pulse phases Credit:  Cambridge (UK) LuckyCam

COMET HOLMES CHART

    Still bright and visible in binos, this chart shows the Comet's position for December/January:

COMET TUTTLE RETURNS

Although eyes have been on Comet Holmes recently, Tuttle is again on its way
to compete for northern sky viewing.   Its apparent speed is very fast as seen
in the chart below for positions during December/January.  

Note that toward the end of December, it will appear very near M33 in Triangulum,
offering a unique photo-op for those able to capture such an image.

Interstellar distances are usually considered as a function of light-speed over TIME - ( i.e. light years.)    Yet for distances within the Solar System, the measure is commonly miles or kilometers.    With the advent of planetary probes, it was recognized that radio signals travel at light-speed, so distances for communication lags also needed to be expressed as a TIME function.

The tables below relate the light-speed time from the Sun based on mean orbital distances.  

  Table A.1: Conversion between light-travel time distances and astronomical units (AU), kilometers, and miles. (1 AU = 149 million km = 93 million miles.)
                                                    Distances           
Light-travel Time(AU)                 (kilometers)                       (miles)    

 1 light-second    0.0020              299,792.458               186,322.224   
 1 light-minute    0.1202             17.98 million              11.18 million  
 1 light-hour        7.2143                1.08 billion            670.76 million   
 1 light-day           173.1                 25.9 billion             16.098 billion   
 1 light-week      1212.0               181.3 billion             112.69 billion   
 1 light-month (30 days)           5194.37 billion            482.95 billion   
 1 light-year      63240.2                9.46 trillion                5.89 trillion   

Table A.2: Light-travel distances to some familiar objects in the Universe, as measured from the Sun.

Object     Light-travel distance
   
Mercury   3.22 light-minutes   
Venus       6.01 light-minutes   
Earth        8.32 light-minutes   
Mars        12.7 light-minutes  (Approximate signals to Earth from Mars probes)
Jupiter      43.3 light-minutes   
Saturn       1.32 light-hours     (Cassini average to Earth:  56 minutes at opposition)
Uranus      2.66 light-hours   
Neptune    4.16 light-hours   
Pluto          5.5  light-hours     (about how long it will take for the New Horizons probe to send data back when in arrives in 2013)
Farthest comets    1.58 light-years   
Proxima Centauri (nearest star)    4.3 light-years   
Orion Nebula    1,500 light-years   
Center of the Milky Way    26,000 light-years   
Andromeda Galaxy (farthest naked-eye object)    2.36 million light-years   

 

                                                                   Data from Hayden Planetarium Website

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PERSPECTIVES

Ever wonder what the night sky would look like from a different Star than ours?     The AstroNexus website offers tools that can let you model the sky as seen from various definable stellar locations.  

The sample image below is a view looking our way from the Alpha Centauri system.

Note that the Sun appears just to the left of the Casseopeia "W" in this perspective.  

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FUNZIES

   

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CLUB MEMBER ASTROPHOTO OF THE MONTH

CRESCENT NEBULA

                              NGC 6888                                                       Distance = 4,700 LY                               

Image Credit:   BOB BERTA

Bob's Notes to Above Image:

Located in Cygnus, it is an emission nebula that is a bit less in apparent diameter than the Moon.    There is a Wolf-Rayet star that is due to go supernova in this nebula.

It was taken with a 152mm A&M APO  refractor at  F8 through an SBIG STL 6303e camera with LRGB filters.   The FOV of the image is 1.3 x 9 degrees.    This is about 6 hours of exposure from Cadilac on a very cold night---around 14 degrees F.   The next morning the mount and scope were coated with a sheet of ice.....luckily I used a dew heater.

Some of the last components were taken when the object was very close to a mountain nearby and thus were a bit soft from the atmosphere "murk."   I kept three of these to add to the final shot to make the brightest stars "glow" with their color.  In particular there are two stars close to each other with a strong color contrast which is interesting.    This technic is used by a noted Japanese astrophotograher, although instead of soft pictures he uses a soft focus camera filter for a couple of the sub exposures to achieve the same thing.

 

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CLUB DUES FOR 2008

Membership fees ($35) become due in January each year.
If you are unable to make the next meeting and wish to support OAC
with your 2008 dues, you can mail your check payable to

OAKLAND ASTRONOMY CLUB
600 Shelley Dr
Rochester Hills, MI  48307-4237

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NEXT MEETING:   January 13, 2008, 7:30 PM

           
                                                                        

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ASTRONOMY TECHNOLOGY TODAY

Astronomy Technology Today  - A new startup magazine for equipment geeks features reviews, specs and images from both users and distributers.   They are offering subscriptions for $18 per year.  
Details on their website:   www.astronomytechnologytoday.com

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Wishing all Members and Friends of OAC clear dark skies and fast, accurate GOTOs for 2008 !