How visible is Sirius B from Sirius A?

On 03/05/14 00:15, Mike Dworetsky wrote:
Brad Guth wrote:

Sirius(b) is mostly emitting photons in the UV spectrum, so don't
expect any human visual capability of even telescope aided views of
that one.

Which of course does not explain why Sirius B was discovered visually in
the 1860s during testing of a new Alvan Clark refractor, and I myself
saw it through the Mt Wilson 60-in telescope in the 1970s. It's faint,
but the main viewing difficulty is its proximity to bright Sirius, not
its low luminosity.


I also saw Sirius B through through the 60-inch, but I did it about a
year ago -- and through thin clouds to boot. Piece of cake. You could
drive a metaphorical truck between A and B.

-- Bill Owen

Many thanks indeed for the responses to my question - it's all been very helpful!

On Wednesday, March 5, 2014 12:15:54 AM UTC-8, Mike Dworetsky wrote:
Brad Guth wrote:



Sirius(b) is mostly emitting photons in the UV spectrum, so don't

expect any human visual capability of even telescope aided views of

that one.



Which of course does not explain why Sirius B was discovered visually in the
1860s during testing of a new Alvan Clark refractor, and I myself saw it
through the Mt Wilson 60-in telescope in the 1970s. It's faint, but the
main viewing difficulty is its proximity to bright Sirius, not its low
luminosity.

--

Mike Dworetsky

(Remove pants sp*mbl*ck to reply)

I stand corrected, as only a good 90% of its illumination energy is in the UV. The 10% in the visual spectrum should be visible, though barely.

What's the photosphere/atmosphere of Sirius(b) made of?

So, where's all of those terrific photosphere images of Sirius A?

In article ,
John writes:
... a massive effort to probe
Europa with absolutely guaranteed sterile robots should be made as
soon as practicable. Or sooner. [And "absolutely sterile" *must* be
guaranteed before we even consider how to do it. Terran life is hardy
stuff.]

"Absolutely sterile" is impossible. When the time comes to design a
Europa lander or penetrator, I'd expect debate over how nearly
sterile is good enough. There's an IAU group cognizant of such
issues, but it won't surprise me if the debate is escalated to
political authorities.

--
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