Star: Beta Orionis
Date & Time:  12/26/99 10:48 pm CST
Seeing:  7 <1-10 Seeing Scale (10 best)> 
Location of site: Killeen, TX (Lat 31 N, Elev 600 ft) 
Site classification: Suburban 
Sky darkness: 4.5 <Limiting magnitude> 
Telescope: Orion 6" Dob. 
Magnification: 32x, 48x, 72x, 98x, 144x  
 

Star: Beta Orionis
Date & Time:  1/4/2000 10:22 pm CST
Seeing:  7 <1-10 Seeing Scale (10 best)> 
Location of site: Killeen, TX (Lat 31 N, Elev 600 ft) 
Site classification: Suburban 
Sky darkness: 4.5 <Limiting magnitude> 
Telescope: Orion 6" Dob. 
Magnification: 32x, 48x, 72x, 120x
 

[Update from November, 16th, 1998 - 10:28 pm CST]: Re-visited this to see if I could split it at 120x. I thought I did, but am not really sure. 

[Update from 1/11/99 10:07 pm CST]: Continuing observations for the 33 doubles in Orion project, I re-visited Rigel to see if I could split it with the aid of my 
newly arrived barlow at 240x. However, even at this higher power, I could not split it. 

[Update from 1/25/99 8:48 pm CST]: 

Star: Beta Orionis 
Date & Time:  1/25/99 8:48 pm CST 
Seeing:  7 <1-10 Seeing Scale (10 best)> 
Location of site: Killeen, TX (Lat 31 N, Elev 600 ft) 
Site classification: Suburban 
Sky darkness: 4 <Limiting magnitude> 
Telescope: Orion 6" Dob. 
Magnification: 144X, 98X 

Success tonight at last! After several attempts, I finally was able to split this double. I first used my 17mm w/barlow combination for 144x and it was an easy 
split. I then used my reticle EP (98x) to measure the separation - 15" and PA - 185 degrees. 
 
 

I was able to split this at 120x with some difficulty. I did not attempt to measure this tonight, due to the difficulty. 
 
 
 
 
 
 
 
 
 

I re-observed this pair with the aid of the hexagonal objective mask to see how much it would help in splitting them. I have previously split this pair with 98x without any additional aid. I tiried 48x, 72x, and 120x tonight. I could only split it at the higher power. Without the mask, I could not split it at all, as the conditions were such that the image of Rigel proper was considerably smeared out and obscured the secondary. 

Additional comments: I took my scope to North Carolina, which is quite a ways south of  my usual site in Madison WI, over our holiday weekend called 
Thanksgiving, and had two great nights of observing (11/26-11/27).   At this more southern latitude Orion was much higher in the sky and hence the seeing 
was better. This would apply to Psi, Struve 712, Sigma, Zeta, Sh 49, 59 Ori, Struve 855 and Struve 750. 
 

Clearly split, but the air turbulence was rather heavy, so the “image” was not 
very satisfactory. 
 

No doubt it's a fantastic view!
 

I have actually split this pair with as little as 100x with good seeing and a hexagonal objective mask. 

The B8Ia primary is a brilliant bluish-white and the companion looks white (B5V+), but with this much contrast and this close of spacing, it is difficult to say for sure. I have spotted Rigel B with as little as 100x by using a hexagon-shaped objective mask (per the suggestion in the Webb Society's handbook on Double Stars). This mask breaks up the Airy rings into "spokes" and by rotating the mask, you can rotate the "spokes" so that a dim companion pops out between two spokes. (This was also how I glimpsed Sirius B in 1988.) 

Tycho data suggests a distance of 770 light years, implying luminosities of 48,000 and 90 suns (it is hard to imagine that the little speck to the south of Rigel is 90 times brighter than our Sun!). 

Other intersting tidbits about Rigel: 

The primary is 65 times bigger than the Sun, and 25 times its mass. (If it were in the Sun's place, it would almost fill Mercury's orbit!) Its surface temperature is around 10,000 Kelvins (twice the Sun's 
temperature, and thrice its constellation comrade, Betelgeuse). Each square unit of area of Rigel radiates 15 times as much energy as an equal area on our Sun, and about 100 times as much as ruddy Betelgeuse. It is also an infra-red source. 

Rigel will last on the Main Sequence only 20 million years. 

Rigel B has a surface temperature of 12,000 Kelvins. It is at least 2,500 AU away from Rigel A, is about 2.5 times as massive as the Sun, about twice its diameter, and 90 times as luminous. Rigel B is also a spectroscopic binary (discovered in 1937). 

Rigel C (which I have never glimpsed) is a star 1.9 times as massive as the Sun, 50% larger, 50 times brighter, and of spectral class B9V. 
 

d = 11.0; PA = 205