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17P Holmes Ic 20 2x2 Annotated 800x500.gif (173020 bytes) The Comet 17P/Holmes, discovered by the British astronomer Edwin Holmes in 1892, underwent a great transformation in late October of 2007.  This comet is normally a magnitude 17 object orbiting about 235 million miles from the sun [about 2.5 times the distance from the earth to the sun].   It's present position is between the orbits of Mars and Jupiter and it is headed back out into the depth of the solar system.  A few days ago, it appears that the comet broke into several pieces and released much of its internal ice to space.  The ice began to evaporate and the light from the sun made the water vapor glow brightly.  This process changed the comet from a 17 magnitude to a 2.5 magnitude object.  [Its brightness increased by a factor of 590,000 times!]  It is easily visible with the naked eye in the east in early evening sky.  This 20 second image was taken on a 0.41m f/8.5 telescope in the near infrared band and shows star-like the nucleus of the comet with a bright coma just to the south-east of the nucleus.     
IMG_3868Cropped.jpg (1449425 bytes)   This picture of comet 17P/Holmes was taken on November 30.  At this point, the comet is the largest object [by diameter] in the solar system.  On this date, the comet was 1.6 AU from the earth [one AU is 93 million miles].  It is headed away from earth so we are looking up the tail and into the head of the comet as a 2-dimentional plane, which is one reason that the comet is so bright: 1.1 mag. or nearly as bright as the star Vega.   The comet is now much too large to image using a conventional telescope.  This image was taken using a Canon 400D digital camera with a 200mm f/2.8 lens.  Exposure time was 120 seconds.   The image was captured an RAW format and processed in Photoshop.  In this image, the diameter of the comet can be measured at 0.72o.  Since we know that the comet is 148 million miles away, a little math indicates that the diameter of the comet is 1,800,000 miles.  The diameter of the sun is a paltry 870,000 miles.  About 100 years ago, this same comet had a similar explosion, also in November, on its travel away from the Sun, just like it has done this year.  It had another outburst in January of the following year.  We will have to wait and see if this happens again.
Minor Planets [asteroids] are bits of tumbling rock in space that range in size from a few inches to a few miles.  The minor planet pictured to the right, 764 Gedania, is in the multi-mile category.  Gedania orbits between Mars and Jupiter and was 293 million  miles from earth when these images were taken. These objects move several arcminutes across the sky during an evening of observation.  That makes it difficult, but not impossible to measure their light curves.  Determining the light curve leads to knowing the shape of the object.  The average shape of Gedania is shown at http://obswww.unige.ch/~behrend/r000764b.png.    The movie to the left indicates that the asteroid moved ~ 4360 miles during the 5 hours of observation.  The asteroid starts in about the center of the image and moves up and to the right.  
2004 NM4.jpg (92022 bytes) The minor planet [asteroid] 2004 MN4 has been in the news lately.  This 1000 ft wide rock is predicted to have a close encounter with Earth on Friday, April 13 2029 [Friday the 13th...Classic!].  Close Encounter means MN4 will slide by the earth at a distance of 15,000 to 25,000 miles [about 1/10th the distance to the moon].  In astronomical terms, that is like having a bullet whiz by your head!  Here is an image of 2004 MN4 taken on April 16th when it was at a distance of ~50 million miles and headed back out into the solar system.  The brightness of 2004 MN4 was 20th mag.
Cuppy Summed and Flat.jpg (69110 bytes) This is an image of the minor planet [asteroid] 15017 Cuppy.  The image is R filtered and is the sum of 5 x 180 second exposures.  The magnitude of this object is R 19.1.  The image was taken on July 1, 2004 at 02:29:50 UT.  Its coordinates were RA 14:58:58  Dec -17:07:17 J2000.  BTW, this minor planet was named after the humorist Will Cuppy.  For more on the man, click here.
Starkey Moving Object.gif (150621 bytes)  I was doing some deep sky imaging on March 10, 2003 UT.  When I processed the images, I noticed an object moving across the lower right hand corner of the image set.  It turns out that the object was the Minor Planet 2003 VO.  These are 300 sec Rs filtered exposures.  The estimated magnitude of the MP is 18.2.  Click on the image at the left to run a movie of the whole 4 hours of images in just a few seconds.  The Movie file plays well on Windows Media Player and is about 977k in size.  [BTW: The three black dots in the image are "burn In" areas of the chip from aligning on a very bright star at the start of my dark frame run.]
hyku.jpg (27340 bytes) This photo of the comet Hyakutake was taken in Mar 22, 1996. The bright star in the tail is Zeta Bootes. North is to the left. 5 second exposure using Kodak Royal Gold 1000 ASA 200mm telephoto at f4.5.



C2002 O4 Hoenig  composite.jpg (622175 bytes) This is a composite of three images of comet C/2002 O4 [Hoenig] taken on Aug. 02, 2002.  The comet is 1.03 AU from earth and is mag 11.  The comet is moving ~0.05 arc sec/sec at this point in time.  Each image is a 5 minute exposure, unfiltered through a C-14 at f/11.  Air mass is a fairly high 2.18 .