NEWS FLASH: [B.O.L.O.] BETELGEUSE DIMMING AGAIN!!!!

[OzEclipse]

Many of you will remember Betelgeuse's 2019 episode of dimming. The episode was explained by theory that a large amount of material was ejected from the star and absorbed the light in the direction of Earth.

https://www.skyatnightmagazine.com/news ... -explained

Well I've just heard a rumour from my connections in the IRA, that it's at it again.

Look and see for yourself. A refreshing change, this is a project you can do in full moon, or from a moderately light polluted city.

I have found that Rigel, Procyon and Aldebaran are excellent comparison stars for visual naked eye observations. Betelgeuse [Mv0.50] should be about midway in brightness between Rigel [Mv 0.13] and Aldebaran [Mv 0.86] and very close to Procyon. Here are the magnitudes of other stars visible in the night sky at the same time. Acrux and Achernar are not visible from higher latitudes in the northern hemisphere. For southern hemisphere observers, Betelgeuse is midway between and closer to the brightness of Procyon [Mv 0.34].

For southern hemisphere observers, Betelgeuse [Mv 0.50] is nicely and closely bracketed in between Achernar [Mv 0.46] and Hadar [Mv 0.61].

Here's a list of comparion stars and brightnesses (Wikipedia)

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I've included a finder chart.

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Joe

[DeanD]

This is not easy naked eye, as they are so far apart; but from a quick look just now, I felt that Betelgeuse was only marginally brighter than Aldebaran: closer to that than to Procyon. A wild approximation, but I would say it is more like 0.6-0.7 than 0.5.

Of course, the giant bat nebula that filled my fov while looking in the binos probably didn't help!
For a second I thought I was in Mordor with a giant Nazgul darkening the sky. For the confused among you, it was a fruit bat.

[OzEclipse]

This is not easy naked eye, as they are so far apart; but from a quick look just now, I felt that Betelgeuse was only marginally brighter than Aldebaran: closer to that than to Procyon. A wild approximation, but I would say it is more like 0.6-0.7 than 0.5.

Of course, the giant bat nebula that filled my fov while looking in the binos probably didn't help!
For a second I thought I was in Mordor with a giant Nazgul darkening the sky. For the confused among you, it was a fruit bat.

Hi Dean,
I found that if I stand facing south, I can quickly turn my head from Betelgeuse to Achernar to Hadar and back. I think speed is the key. Moving a scope from one to the other would take too long. I do have two ST80’s. I can envisage pointing one at Betelgeuse and one at Achernar with the eyepieces next to each other. But the eyepieces would also need to be identical matches and I don't have any bino pairs.


Read my observation report in the observing reports sub forum.
viewtopic.php?f=6&t=33631
Visually, I couldn’t pick up any dimming. I then performed a simple photographic photometry experiment that also found no dimming.
Joe

[messier 111]

for some time now, I have found that it is fading, its brilliance seems to be on the decline.
I'm happy that you made a post on just that, I'll be on the lookout even more. thx.

[DeanD]

I think photometry is the way to go, especially for a red star like Betelgeuse, so well done Joe!

A visual comparison with a star of similar brightness but a different colour like Procyon is very difficult not just because they are relatively far apart in the sky, but also because our eyes are less sensitive to the red end of the spectrum. In fact this could be why I felt it was closer in brightness to Aldebaran than Procyon, even when I tried in and out of focus.

Keep up the good work!

Dean

[Graeme1858]

And some sensors are sensitive beyond the red end of the visual spectrum.

And Betelgeuse is the brightest star in the sky in near infrared.

Graeme

[OzEclipse]

I did describe it as a crude method. I’m not suggesting that I can work out a precisely correct magnitude. Provided I am consistent with the equipment and methods then I will get a representative light curve of relative brightness over time.

The linear regression has a correlation of 0.998 between measured star intensity and listed magnitude. This is far better than I expected. Almost too good to be true.

Joe

[OzEclipse]

I have attempted to track down the source of the dimming prediction this week. No luck. This may be a false alarm.

Joe

[DeanD]

Here you go: https://earthsky.org/brightest-stars/be ... e432f48741