Geminids and Betelgeuse

And one from an hour ago Paul. Generally my DSLR enhances the brightness of red stars, but it looks about equal to Bellatrix here. And once more, fainter with the naked eye.



Finbarr.

Fermidox wrote: There are two estimates on the AAVSO from last night of mag 1.2 and the next estimate is 1.6... that's about a 25% difference! And there's even a 1.7 which is fainter than Bellatrix. The wide variety is quite surprising, considering a reasonable level of expertise is assumed before submitting to the AAVSO I would have thought.

Hi Finbarr. 

I reckon there are some people who are not very good at estimating magnitudes of variable stars.  
They simply are not being advised to compare Betelgeuse with other important bright stars which are nearby. Bellatrix is the obvious one to start with. Castor and Pollux are also good - as are Aldebaran, Elnath and Alhena. 

Amateur astronomers need to compare all these stars when Orion has a good altitude somewhere high in the the southern sky.   

But do keep checking Betelgeuse over the coming months, Finbarr. 

Clear skies, 

Aubrey. 
 

Last night was the clearest for a while Aubrey, and I had it marginally brighter than Bellatrix. There is something called the 'Purkinje effect' which makes stars appear artificially bright if you stare too long at them; I think I might be falling prey to that... I did my manage to snag my 31st comet, C/2017 T2 PanStarrs, at an estimated mag of 9.3 in Perseus. It's already passed by closest approach to Earth but could reach mag 8 around perihelion in May.

Finbarr. 

Yes, there is always the Purkinje Effect, Finbarr.
But then there are some "petrified" amateurs who are so frightened to estimate a variable star they decide to give these stars a much lower magnitude.
I have spoken about that on Cloudy Nights.
Some agreed with my point.
I am of the persuasion that owners of apochromatic refractors have less reasons to be scared of Purkinje.
Just go with the flow and do our estimates freely without any stress.
Sure it's all fun!

By the way, I am feeling much better today of my recent dose.

Clear skies,

Aubrey.