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Alpha ori

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MDP's picture
Alpha ori

I  notice that Betelguese is down to about 1.1. This hasn't happened in a while. According to Australian aboriginal legend this means that the lusty hunter's magic has been overwhelmed by the elder sister of the girls he is pursuing.

Bikeman's picture
Also recently :  http://www
This thread in Twitter

This thread in Twitter analyzes alpha Ori's AAVSO data, rejecting outliers. In doing so, the user says that this dimming is unprecedented. This is the direct link to processed the light curve.

Bikeman's picture
more updates:
stellakafka's picture
More data is needed!!



Looking at the visual data from the AAVSO database, Betelgeuse reached 2nd mag in 1985, so this current event is not unique. However, we have the chance to observe it in unprecedented detail ... so I would like to request as many observations (in as many bands) possible!


Thank you in advance for your time and consideration!

Best wishes - clear skies,


MUY's picture
Comp stars

Hi Stella,

I guess which comp stars we will use when it goes supernova... smiley



tcalderw's picture
Monday Night

I have V=1.281  B=3.082  on JD=2458841.7.  My data for this season show a trend of ~10mmag/day fading.

The visual~=2.0 magnitudes in 1985 are from two particular observers and are considerably outside the norm.

tcalderw's picture
Historical Visual Data

Brian Skiff pointed me at the attached MNRAS from 1911.  It has long-term visual estimates from two 19th century observers, Baxendell and Argelander.  I also attach VStar-compatible csv files if people want to play around with the data.  I have re-reduced (almost) all of Baxendell's data with modern V magnitudes for the comparison stars.  They show a pretty good 460-day phase plot.  Argelander's estimates cannot be re-reduced with the information provided, and his data seem messy in comparison.

The fading of Betelgeuse appears to be slowing in UBV.



weo's picture
alf Ori (Betelgeuse) observing campaign - Alert Notice 690

AAVSO Alert Notice 690 requests photometry and spectroscopy of alpha Ori (alf Ori, Betelgeuse) during and beyond its current minimum. Please see the notice for details and observing instructions.

Many thanks, and Good observing,

Elizabeth O. Waagen, AAVSO HQ

mmontarges's picture
Please observe also in other filters.

Dear all,

Thanks a lot for this observing campaign. We got Betelgeuse data on VLT/SPHERE and soon on VLTI/GRAVITY. We are currently looking at the possibility of observations with other instruments. I would like to emphasize the necessity of monitoring at other wavelengths than V (most interesting would be R, J, H and K).

Clear skies to all !


tcalderw's picture
Latest BV light curve (CTOA)

See attached.



File upload: 
Sebastian Otero
Sebastian Otero's picture
Alpha Orionis special visual charts updated

Dear observers,

even when Betelgeuse seems to be already rising now, due to all the attention it has been receiving, we considered it a good time to update the 10 Star Tutorial charts.
Since comparison stars are widespread over a large area, observers in the different hemispheres may find it useful to have comparison stars higher in their skies so there are two version of the charts, one for the Southern hemisphere (including eps CMa which at V= 1.50 is very useful now) and another one for the Northern hemisphere (which also works to estimate eta Geminorum).
You can download them from here:

VSP is not useful to create charts for Betelgeuse due to its limited field of view so these charts are recommended.
A list of accurate V magnitudes for the comparison stars follows:

01 bet Ori  V= 0.13* (Rigel)
04 alp CMi V= 0.36  (Procyon)
09 alf Tau V= 0.87*  (Aldebaran)
11 bet Gem V= 1.14 (Pollux)
15 eps CMa V= 1.50 (Adhara)
16 alp Gem V= 1.58 (Castor)
16 gam Ori V= 1.64 (Bellatrix)
18 zet Ori V= 1.76* (Alnitak)
19 gam Gem V= 1.93 (Alhena)
21 kap Ori V= 2.06* (Saiph)

* only for visual use. Small amplitude variables:

bet Ori - ACYG V= 0.08 - 0.20
alf Tau - LB: V= 0.86 - 0.89
zet Ori (NSV 2553) - VAR V= 1.74 - 1.77
kap Ori (NSV 2641) - ACYG V= 2.04 - 2.09

Remember this chart is only for visual use.

Unfortunately we don't have stars with the same colours of the variable, we have to use what is available.

Good observing and keep an eye to see if Betelgeuse is going to recover smoothly or not from this fading!

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