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\title{Photometry of $\alpha$ Orionis (October 1994 to April 1996)}

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We present another two year summary of $V$-band photometry of $\alpha$ Orionis
(Betelgeuse).  For previous
data see Krisciunas (1994) and references therein.
The comparison star, as before, was $\phi^{2}$ Ori ($V$ = 4.09, $B-V$ = 0.95).
Transformation to the UBV system was accomplished by means of observations
of red-blue pairs (Hall 1983).

In Table 1 and Figure 1 we give the data points. 
The nightly means are typically the
mean of three differential measures.  Luedeke's data were taken with a
25-cm reflector situated at Albuquerque, New Mexico, and an Optec
SSP-3 photometer.  Krisciunas's data of November 1994 (Julian Dates
2449675 and 2449680) were obtained with the Lowell 0.6-m reflector
at Cerro Tololo, stopped down to a smaller aperture, and using a
dry ice cooled photometer, standard $V$ filter and a
4.5 magnitude neutral density filter.  His data of Julian Dates 
2450128 to 2450191 were obtained with a 15-cm reflector at
the 2800-m elevation of Mauna Kea, Hawaii, using the system described
by Krisciunas (1996).
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Table 1. 
Photometry of Betelgeuse.  Observers: L = Luedeke, 
K = Krisciunas. The given internal errors do not include the
uncertainties attributable to the adopted extinction coefficients
or the transformation coefficient
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\begin{tabular}{rcccrccc}
\hline
Julian Date & $V$ & $\pm$ & Observer & Julian Date & $V$ & $\pm$ & Observer\\
\hline
\\
  $2449656.7973$ & $0.452$ & $0.011$ & L & $2449802.6947$ & $0.831$ & $0.006$ & L \\
  $    666.7642$ & $0.461$ & $0.002$ & L & $    803.6323$ & $0.831$ & $0.006$ & L \\
  $    671.7731$ & $0.487$ & $0.001$ & L & $    808.6166$ & $0.830$ & $0.004$ & L \\
  $    675.6942$ & $0.493$ & $0.001$ & K & $    819.6496$ & $0.841$ & $0.006$ & L \\
  $    680.7669$ & $0.498$ & $0.001$ & K & $    820.6159$ & $0.791$ & $0.005$ & L \\
  $    684.7434$ & $0.518$ & $0.001$ & L & $    832.6117$ & $0.814$ & $0.002$ & L \\
  $    685.7564$ & $0.520$ & $0.001$ & L & $2450017.7919$ & $0.353$ & $0.004$ & L \\
  $    687.7012$ & $0.502$ & $0.004$ & L & $     18.8099$ & $0.371$ & $0.003$ & L \\
  $    696.7644$ & $0.543$ & $0.004$ & L & $     28.7748$ & $0.405$ & $0.001$ & L \\
  $    736.6483$ & $0.663$ & $0.005$ & L & $     30.7372$ & $0.389$ & $0.003$ & L \\
  $    746.6263$ & $0.683$ & $0.002$ & L & $     54.7179$ & $0.452$ & $0.001$ & L \\
  $    748.5894$ & $0.682$ & $0.005$ & L & $    103.5812$ & $0.509$ & $0.002$ & L \\
  $    750.6193$ & $0.702$ & $0.006$ & L & $    106.5515$ & $0.537$ & $0.004$ & L \\
  $    752.6095$ & $0.701$ & $0.001$ & L & $    128.8424$ & $0.562$ & $0.016$ & K \\
  $    754.5968$ & $0.709$ & $0.001$ & L & $    129.6139$ & $0.533$ & $0.003$ & L \\
  $    755.5713$ & $0.702$ & $0.003$ & L & $    153.8236$ & $0.556$ & $0.029$ & K \\
  $    761.6019$ & $0.723$ & $0.003$ & L & $    163.7917$ & $0.460$ & $0.019$ & K \\
  $    765.5867$ & $0.735$ & $0.001$ & L & $    191.7604$ & $0.503$ & $0.002$ & K \\
  $    791.7196$ & $0.813$ & $0.006$ & L & $            $ & $ $ & $ $ &   \\
\hline
\end{tabular}
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Figure 1. 
$V$-band photometry of Betelgeuse. Triangles: data of Luedeke.
Circles: data of Krisciunas.  Except for the Krisciunas data at the
right hand side, the internal errors of the individual points are on
the order of, or smaller than, the size of the points
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Krisciunas also observed $\gamma$ Ori as a check star, in spite
of the fact that it appears to be slightly variable.  The mean of
those measurements gives $V$ = 1.635 $\pm$ 0.010 for $\gamma$ Ori.

Bester {\em et al.} (1996) have recently correlated this and previous
photometry of Betelgeuse with mid-infrared measurements of the
diameter of the star.  Further photometric monitoring is warranted.
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\beginauthors
\authorsrightcol
K. KRISCIUNAS$^{\star}$
K. D. LUEDEKE$^{\star\star}$
\endauthors
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$^{\star}$\ Joint\,Astronomy\,Centre,~660\,N.~A'oh\={o}k\={u}\,Place,
University\,Park,~Hilo,~Hawaii\,96720,~USA\\
e-mail: kevin@jach.hawaii.edu\\
\vskip 2mm
$^{\star\star}$\ 9624 Giddings Avenue NE, Albuquerque, New Mexico\, 87109,
~USA\\
e-mail: 71477.154@compuserve.com\\


\references

Bester, M., Danchi, W. C., Hale, D., Townes, C. H., Degiacomi, C. G.,
$\rm M\acute{e}karnia$, D., and Geballe, T. R., 1996, {\em Ap. J.}, 
{\bf 463}, 336

Hall, D. S., 1983, {\em I. A. P. P. P. Communic.}, No. 11, 3

Krisciunas, K., 1994, $IBVS$, No. 4028

Krisciunas, K., 1996, {\em Sky and Telescope}, {\bf 91}, No. 2, 91


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