HS50EXR and F900EXR reviews ...

Started Mar 27, 2013 | Discussions thread
alexisgreat Veteran Member • Posts: 6,459
Re: part 8 -- astro (starry fields and looking forward to Comet ISON)

Kim, both the moon and Saturn looking breathtaking! This lens really is sharp and it looks like it even shows detail on Saturn at ISO 3200!  I hope it will surprise with its long exposure (starry field) performance too.  I want to use it on that Great Comet we have coming in November (it's supposed to be the brightest comet in over 100 years, brighter than the  full moon and even visible by daylight!) Its tail is going to pass through both Saturn and Mars- what wonderful photo ops!


During August 2013, it should become bright enough to be visible through small telescopes or binoculars, becoming visible to the naked eye by late October or early November and remaining so until mid-January 2014.[7][12]

In October, the comet will pass through the constellation Leo, passing near Leo's brightest star Regulus and then passing near Mars in the night sky, and these brighter objects might make the comet easier to locate.[11] In November, when the comet is brighter, it will sweep another bright star in our sky, Spica in the constellation Virgo, and another planet, Saturn.[13] Around the time the comet reaches its perihelion on 28 November, it may become extremely bright if it remains intact, probably reaching a negative magnitude.[5] It may briefly become brighter than the full Moon.[7][8]

It is expected to be brightest around the time it is closest to the Sun; however, it may be less than 1° from the Sun at its closest, making it difficult to see against the Sun's glare.[14] In December, the comet will be growing dimmer, but, assuming that it remains intact, it will be visible from both hemispheres of Earth, possibly with a long tail.[11]

Predicting the brightness of a comet is difficult, especially one that will pass so close to the Sun and be affected by the forward scattering of light. Comet Kohoutek and C/1999 S4 did not meet expectations, but if comet C/2012 S1 does not fragment, it could look similar to the Great Comet of 1680, the Great Comet of 2007, or C/2011 W3 (Lovejoy).[5][15] The brightest comet since 1935 was Comet Ikeya–Seki in 1965 at magnitude −10.[16] Comet C/2012 S1 (ISON) will be well placed for observers in the northern hemisphere during mid to late December 2013.[17]

In a recent study, 1,897 observations were used to create a secular light curve. The resulting plot shows the comet increasing its brightness relatively quickly at R+4.35 [Unit?].[18] If this continues up to perihelion, the comet could reach magnitude −17, brighter than the full moon.

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 alexisgreat's gear list:alexisgreat's gear list
Olympus C-7070 Wide Zoom Fujifilm FinePix HS20 EXR Fujifilm FinePix HS50 EXR Olympus E-520 Olympus PEN E-PL6 +3 more
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