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[Centaur]

At Cloudy Nights we've been discussing the mutual occultations and transits of planets. That motivated me to create a graphic demonstrating the transit of Mars over Saturn on 1477 OCT 09 as viewed from Anchorage. To see it, click:
www.curtrenz.com/astronomical.html

[Chicago Astronomer - Astro Joe]

That must have been quite a sight, two bright bodies merging into one. It would be a great event today to witness this...and how errie it would be in our collective telescopes and imagers to see one world sliding in front of another.

Too cool and thanks for the graphic!... ;D

[Centaur]

admin said:

It would be a great event today to witness this...

Apparently you missed the last mutual planetary event when Venus transited Jupiter in 1818. Did you forget to set the alarm? Well then keep yourself in shape, Joe, in preparation for another transit of Venus over Jupiter in 2123, although the pair will only be 18° east of the Sun.

The next really good event without solar interference should be easy to see if you can hold out for an additional century to the night when Mars transits Jupiter in 2223. There will be events in 2065, 2067, 2079, 2088, 2094, 2104, 2126 & 2133, but they all will either occur less than 12° from the Sun or involve a telescopic planet.

Actually, only one person has ever reported witnessing such an event since the invention of the telescope. That was an English amateur named John Bevis who had access to the Royal Greenwich Observatory. During the evening of 1737 MAY 28 he observed Mercury extremely close to Venus. After clouds briefly intruded, he could only see Venus since Mercury had already moved behind. The pair then set beneath the horizon before he could see Mercury reemerging.

[Chicago Astronomer - Astro Joe]

After clouds briefly intruded, he could only see Venus since Mercury had already moved behind. The pair then set beneath the horizon before he could see Mercury reemerging

Ain't that the curse of the astronomer...eh? Here he had an observatory at his use and the skies fought him.

Hey Curt...What would you consider a comfortable distance from the Sun for a decent viewing of no particular object? 25º or so?

[Centaur]

admin said:

..What would you consider a comfortable distance from the Sun for a decent viewing of no particular object?

The usual standard after sunset or before sunrise is an elongation of 15°, but that can vary considerably due to a number of circumstances, including the angle at which the line from the object to the Sun strikes the horizon, the object’s brightness, atmospheric conditions, and the observer's expertise. Of course a transit or occultation is not instantaneous, so extra leeway would be required to witness the entire event. Also, small elongations limit the number of locations available for witnessing the event during nighttime.