NOTES FROM OBSERVATORIES

A PHOTOVISUAL COMPARISON SEQUENCE FOR AE AQUARII

George H. Herbig Lick Observatory

The variable AE Aquarii1 has recently been found by Joy2 to be a spectroscopic binary as well as to possess the spectro- scopic characteristics of a U Geminorum-type variable. The range in photographic given by Zinner is from 9.7 to 11.7. The variable at minimum is one of the brightest of this class ; it is an easy object for small telescopes. Continuous observations of its brightness should be of considerable interest. The photovisual magnitudes of a sequence of comparison stars (Table I) have been determined with the Schraffierkassette

TABLE I Comparison Stars for AE Aquarii

Alger ph. Photo- B.D. Io, 20h 36m Δα cos5 Δδ visual Star ■ Magnitude

C —lo4021 No. 231 — 9^.3 — ÖM 9.79 h —lo4018 215 —18.3 — 0.7 9.96 d 250 + 4.8 + 9.7 10.49 m —lo4022 235 — 6.0 —18.1 10.67 e 253 + 7.8 + 1.0 10.90 η 233 — 7.1 —17.4 11.11 f 237 — 4.7 — 7.1 11.15 k 245 + 0.7 —10.0 11.44 9 -f 0.7 — 3.3 12.19 I + 7.4 — 2.7 12.72

at the Crossley reflector ; they are based upon S direct compari- sons with the North Polar Sequence. The emulsion used was Eastman 103-G behind a yellow filter. The plates were measured

ι a(1900) = 20h 35^0, 0(1900) =-1° 13'; Alger ph. -Io, 20* 36^, No. 244. 2 Puh. AS.P., 55, 283, 1943.

48

© Astronomical Society of the Pacific · Provided by the NASA Astrophysics Data System NOTES FROM OBSERVATORIES 49

with the Ross photoelectric photometer. The mean probable error of a magnitude, from the agreement of the individual ob- servations, is 0.024 mag. Stars g and I were measured on only 2 plates. AE Aquarii is the origin of co-ordinates. In addition to the 5 Schraffierkassette plates used in deriving this sequence, 5 direct photographs and 2 Schraffierkassette plates of inferior quality are available for the determination of magnitudes of AE Aquarii itself (Table II).

TABLE II Photovisual Magnitudes of AE Aquarii

J.D. Magnitude Plate J.D. Magnitude Plate

2431269.96 11.0 D 2431317.82 11.40 54 1292.89 11.2 D 1317.83 11.42 5 1292.95 11.0 D 1411.66 11.07 5 1298.88 11.3 D 1411.67 11.07 5 1298.89 11.2 D 1411.72 11.2 s 2431317.78 11.42 S 2431411.73 11.2 s

In the third column, D signifies a direct photograph, 54 a good Schraffierkassette plate, and ^ a poor Schraffierkassette plate.

January 8, 1945

VISUAL MAGNITUDES OF PUPPIS 1942

Edison Pettit Mount Wilson Observatory

The determination of visual magnitudes of Nova Puppis 1942 has been continued with the wedge photometer as pre\'riously described.1 Each magnitude in Table I is from 8 comparison stars and 2 sets of measures on the nova with the 6-inch refractor in Pasadena, except where noted. The comparison stars were Nos. 5, 6, 7, 8, 12, 13, 14, and 16 of a previously published table

ι Pub. AS.P., 55, 14, 1943.

© Astronomical Society of the Pacific · Provided by the NASA Astrophysics Data System