在 Cloudynights 上看到一段比較詳細的描述,我再用The Sky 模擬一下,似乎觀看這彗星時機有不少限制,情況比97年我在興隆觀測站看Hale Bopp的要差一點,或許好不過三月的C2011 L4太多?
http://www.cloudynights.com/ubbthreads/ ... art/2/vc/1Quote
"...So will it be as bright as the full moon? Maybe or maybe not, in any event when it reaches maximum brightness, it will be for the most part obscured by the Sun so at it's brightest we won't see it. I created an ephemeris for my location in southeast Louisiana courtesy of the Minor Planet Center. Their maybe conservative calculations suggest a max brightness of about -7.3 on 11/29/13 and this coupled with other data suggest a comet very hard to see due to it's proximity to the Sun (and morning and evening twilight) between about 11/22/13 and 12/4/13. Outside of this date range, the brightest estimate is +1.8 on approach to the Sun and +1.0 after whipping around the Sun. Only time will tell.
One month before it's date with the Sun, the estimated magnitude is about 7.0. It brightens steadily at the end of October 2013 reaching magnitude 6.0 by about 11/3 or 11/4, and then on to magnitude 5.0 by about 11/9. By about
11/20 to 11/21 it is up to magnitude 2.0 but morning twilight is becoming a factor so it will be hard to see.
When it moves away from the Sun during December, much of it's distance from the Sun from our perspective will be in azimuth, not altitude so for awhile it will be settting in twilight. For instance look at my plot for 12/20/13 when at sunset the comet is only 7 degrees in altitude, but about 50
degrees north of the Sun in azimuth. At that time it will be back up to a magnitude of about +3.5 (estimated)...."
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