In message , Greg Neill
writes
"Paul Schlyter" wrote in message
...
In article ,
Greg Neill wrote:
A question on observing: What would be the minimum elongation
(angle betwixt a planet and the Sun) that would allow it to be
spotted by naked eye? We can assume the use of filters to save
our eyes.

Does it vary for different naked-eye planets?

It varies with the brightness of the planet and with what instruments
you use. And the Sun should preferably be blocked, because if you use
a solar filter safe for solar viewing, the planet won't be visible...

Hi Paul, yes that makes sense. But what are typical values
of elongation for, say, Mars or Venus? Assume ideal viewing
conditions.

Would it be possible to detect Mars a half degree from
the Sun's limb? A full degree? More? How about Venus?


IIRC, Venus has been seen at conjunction (i.e. when it's between Earth
and sun and either north or south) but I'm not sure how close it was.
We'll have a nice chance to see it close to the sun next year, before
and after the transit :-)
On August 7 1921 an object "brighter than Venus" was seen 3 degrees east
of the sun; it's thought this was a sun-grazer comet or a nova.
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