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Spectacular Conjunction of Io with a red star!

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#1 Starfleet


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Posted 04 January 2013 - 03:36 PM

Hi all,
I do apologise for cross-posting, but we have cloudy skies here in the UK and I thought this would be of interest to the forum:


Later tonight (January 04, 2013) there will be a rare close alignment of Jupiter's sulfur-bathed red satellite of Io with a similarly red (M0 spectral-type) star, and the two are virtually of the same brightness. I'm really curious if Io looks as red as the star? Even photographically?

Kind regards,

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#2 Darren Drake

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Posted 04 January 2013 - 03:50 PM

Yes and I have pointed out it is actually a challenging double star. The mags are 5.9 and 8.5 with a sep of about 1.9 arcseconds. It makes a most interesting challenge for smaller scopes.

#3 Asbytec


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Posted 04 January 2013 - 05:57 PM

Having observed both, IMO the star is more red than Io.

#4 drbyyz


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Posted 04 January 2013 - 07:56 PM

Just saw this a second ago while setting the scope up...didn't pay attention to color but they are definitely very similar in magnitude. Easily mistaken for a 5th moon, pretty cool.

#5 Patricko



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Posted 04 January 2013 - 09:10 PM

Just came in from seeing this "5th" moon with 11.75x48mm binoculars on accident while locating Vesta. It was located at about 7 o'clock and Io about 8 o'clock using west as 12 o'clock. The star is fainter than Io, it was difficult to get a clear call on colors but it seems the star had a more reddish hue; however, this could be an illusion since it is fainter than Io. Pretty cool :ubetcha:

#6 Ed D

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Posted 05 January 2013 - 10:21 AM

I was observing it again last night (1/4/2013) with my 6" f/8. The star appears red, similar in color to Betelegeuse, whereas the moons appear a bluish white. I did manage to split it, but I want to observe it a few more times before reporting. It is a VERY HARD split, much tougher than the magnitudes and separation would lead one to believe.

Ed D

#7 azure1961p


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Posted 06 January 2013 - 12:08 AM

No it's no illusion, thru my 8" anyway it's pretty obvious, but star colors are never obvious in the poster color way, but it shown with fair regularity.

Abdul, the star was clearly redder than Io. Perhsps 2/3rds more? Io was comparatively more muted, pale peach while this had flecks of rusty orange.


#8 Ira



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Posted 06 January 2013 - 07:01 PM

I saw this when all four moons were on one side and the red star was on the other in the same plane as the moons. It looked like Jupiter had acquired a 5th moon. Truly beautiful. Does anyone know what star it was? It was much redder than any of the other moons.


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