Just out of curiosity, I dug out Prager's photographic data for AI Aur (1929KVeBB...6....1P). There are another 100 visual observations published by Beyer (1937AN....262..257B). The 'GuL' says there are 16 additional observations by Koyama in the publications of the Kwasan Observatory and 10 by Kukarkin in a Russian publication. We apparently do not have either of these publications in the Lowell archives. I show below the Prager and Beyer data. Table 1 gives details of the comparison stars, using Tycho-2 photometry adjusted to standard B and V as per Bessell's recent paper (2000PASP..112..961B). The spectral types are from Chuadze's spectral survey of the region (1973AbaOB..44..105C). Table 2 shows the dates of maximum and minimum as given by Beyer from his analysis of both Prager's and his own data. Prager's plates were taken with fast (f/1.8 to f/3.5) telephoto lenses. Table 3 gives his data without any adjustments. It appears that his magnitudes are midway between standard B and V, with a fairly consistent zero-point offset of: B = mb + 0.5. He obviously took plates in quick succession on several nights in order to deal with short-period variables, and the nightly scatter on these data for AI Aur gives a good indication of their consistency. Beyer used only two comp stars, and these are given in the final lines of the first table; his data are in Table 4. Since the comp stars are blue, his values for AI Aur should be about 0.4 fainter than standard V [from: V = mv - 0.2(B-V)], assuming a color for AI Aur close to B-V = 2.0. _However_, notice that his assumed values for the two comp stars are too bright compared to V by about the right amount, and this may just about offset the color term in the visual observations! For what they're worth, I found eight plates in our Pluto Camera archive showing the star, and estimates from these are given in Table 5. One could be forgiven for thinking that the star was constant from these plates. (Yes, I verified the identification!) They may be no good. Table 1 - Data for comparison stars Pr Name RA (2000) Dec GSC mb B V B-V MK Prager (Tycho-2) AI Aur 6 33 49.6 +30 15 18 e HD 259179 6 33 14.0 +30 05 07 2422-0974 9.77 10.20 9.98 0.22 A2III a HD 259704 6 34 53.7 +30 26 08 2422-1255 9.94 10.49 10.38 0.11 A1V b HD 259145 6 33 13.9 +30 21 46 2422-0868 10.16 10.73 9.71 1.02 K0IV c HD 259900 6 35 26.2 +30 09 32 2422-1326 10.16 10.53 10.15 0.38 F2V f HD 259450 6 34 06.6 +29 57 56 1892-0601 10.40 10.77 10.20 0.57 F8III d HD 259801 6 35 14.2 +30 13 14 2422-0753 10.47 10.94 9.80 1.14 K3IV p HD 258961 6 32 33.7 +29 53 31 1891-0142 10.86 11.35 10.13 1.22 K0III l 6 34 52.9 +30 04 40 2422-1169 10.96 11.64 11.18 0.46 G0III n* 6 33 46.8 +30 04 00 2422-1027 11.07 12.0 12.0 0.0 A3V --- star 'n' has a large photometric error in Tycho-2. it is given with V=11.43 and B-V=0.55 in Chuadze. this source has a zero-point offset in this region in V of about -0.15, suggesting V for this star is about 11.6. the raw TASS MkIV data shows mean V ~11.8. Beyer RA (2000) Dec GSC mv V B-V MK p HD 259661 6 34 49.1 +30 15 38 2422-0091 9.19 9.41 0.19 A3V q HD 259704 6 34 53.7 +30 26 08 2422-1255 9.95 10.38 0.11 A1V Table 2 - Dates of maximum/minimum according to Beyer JD 2420000+ max min 5278 5502 5534 5563 5601 5636 5701 5897 5935 5963 5986 6011 6032 6280: 6606 6983 7015 7051 7083 7112 7151 7179 7503 7535 7695 7720 7753 7786 7821 7854 7880 7917 8065 8117 8164 8227 8268 Table 3 - Prager photographic data source: 1929KVeBB...6....1P PRAGER R. Kleine Veroeff. der Univ. zu Berlin-Babelsberg, 6, 1 (1929) Name JD mb AI Aur 2424466.440 10.20 AI Aur 2424492.470 10.14 AI Aur 2424590.343 10.38 AI Aur 2424590.343 10.45 AI Aur 2424849.422 10.51: AI Aur 2424907.396 10.40 AI Aur 2424907.408 10.38 AI Aur 2424907.419 10.38 AI Aur 2424907.431 10.40 AI Aur 2424907.442 10.38 AI Aur 2424907.450 10.48 AI Aur 2424907.459 10.43 AI Aur 2424946.428 10.00 AI Aur 2424946.451 10.14 AI Aur 2424946.473 10.06 AI Aur 2424946.495 10.13 AI Aur 2424946.518 10.08 AI Aur 2424946.540 10.08 AI Aur 2424963.367 10.51 AI Aur 2424963.389 10.43 AI Aur 2424963.416 10.21 AI Aur 2424963.438 10.33 AI Aur 2424963.460 10.63 AI Aur 2424969.321 10.63 AI Aur 2424969.338 10.57 AI Aur 2424975.322 10.61 AI Aur 2424975.344 10.43 AI Aur 2424975.396 10.63 AI Aur 2424975.423 10.63 AI Aur 2424975.449 10.65 AI Aur 2424992.368 10.12 AI Aur 2424992.390 10.20 AI Aur 2424993.368 10.10 AI Aur 2424993.390 10.04 AI Aur 2424998.371 10.24 AI Aur 2424998.393 10.16 AI Aur 2425258.321 10.48 AI Aur 2425271.344 10.52 AI Aur 2425271.374 10.38 AI Aur 2425271.396 10.47 AI Aur 2425271.420 10.37 AI Aur 2425271.443 10.37 AI Aur 2425271.467 10.37 AI Aur 2425271.491 10.34 AI Aur 2425271.513 10.45 AI Aur 2425271.538 10.39 AI Aur 2425271.561 10.41 AI Aur 2425275.550 10.37 AI Aur 2425286.318 10.39 AI Aur 2425298.334 10.90 AI Aur 2425298.360 10.86 AI Aur 2425298.388 10.59 AI Aur 2425298.413 10.65 AI Aur 2425298.444 10.82 AI Aur 2425298.467 10.75 AI Aur 2425298.490 10.79 AI Aur 2425298.516 10.75 AI Aur 2425298.546 10.65 AI Aur 2425300.482 10.67 AI Aur 2425300.510 10.79 AI Aur 2425301.306 10.69 AI Aur 2425301.329 10.67 AI Aur 2425301.357 10.72 AI Aur 2425301.382 10.69 AI Aur 2425301.406 10.67 AI Aur 2425301.433 10.72 AI Aur 2425301.459 10.81 AI Aur 2425301.482 10.65 AI Aur 2425301.509 10.69 AI Aur 2425302.457 10.79 AI Aur 2425302.515 10.82 AI Aur 2425503.534 10.69 AI Aur 2425506.546 10.67 AI Aur 2425556.434 10.53 AI Aur 2425561.426 10.55 AI Aur 2425588.440 10.29 AI Aur 2425588.465 10.24 AI Aur 2425643.271 10.58 AI Aur 2425647.401 10.43 AI Aur 2425650.350 10.24 Table 4 - Beyer visual data source: 1937AN....262..257B BEYER M. Astron. Nach., 262, 257-316 (1937) Beobachtungen und untersuchungen des lichtwechsels von 55 veranderlichen sternen. I. --- visual estimates with 115mm and 142mm refractors Name JD mv AI Aur 2425670.33 9.57 AI Aur 2425671.37 9.34 AI Aur 2425672.39 9.54 AI Aur 2425686.36 9.61 AI Aur 2425687.35 9.76 AI Aur 2425698.39 9.83 AI Aur 2425699.36 9.81 AI Aur 2425705.35 9.73 AI Aur 2425707.36 9.75 AI Aur 2425710.35 9.71 AI Aur 2425714.35 9.66 AI Aur 2425715.34 9.73 AI Aur 2425882.43 9.74 AI Aur 2425883.47 9.77 AI Aur 2425887.43 9.77 AI Aur 2425892.40 9.80 AI Aur 2425900.47 9.79 AI Aur 2425922.37 9.66 AI Aur 2425982.41 9.68 AI Aur 2425936.38 9.62 AI Aur 2425939.34 9.66 AI Aur 2425964.33 9.73 AI Aur 2425984.39 9.54 AI Aur 2426016.48 9.75 AI Aur 2426025.40 9.57 AI Aur 2426026.30 9.52 AI Aur 2426034.31 9.57 AI Aur 2426038.32 9.60 AI Aur 2426213.54 9.71 AI Aur 2426264.44 9.73 AI Aur 2426275.44 9.62 AI Aur 2426281.40 9.62 AI Aur 2426433.35 9.70 AI Aur 2426440.35 9.51 AI Aur 2426584.52 9.54 AI Aur 2426609.43 9.44 AI Aur 2426624.45 9.54 AI Aur 2426976.50 9.39 AI Aur 2426978.50 9.44 AI Aur 2426979.52 9.39 AI Aur 2426984.47 9.37 AI Aur 2426986.56 9.39 AI Aur 2427030.37 9.47 AI Aur 2427040.41 9.39 AI Aur 2427060.38 9.43 AI Aur 2427063.27 9.39 AI Aur 2427068.37 9.41 AI Aur 2427087.38 9.50 AI Aur 2427093.59 9.44 AI Aur 2427098.26 9.38 AI Aur 2427124.44 9.41 AI Aur 2427132.43 9.40 AI Aur 2427145.36 9.50 AI Aur 2427152.45 9.50 AI Aur 2427157.37 9.49 AI Aur 2427176.38 9.43 AI Aur 2427180.37 9.41 AI Aur 2427190.37 9.45 AI Aur 2427195.37 9.49 AI Aur 2427332.56 9.49 AI Aur 2427343.47 9.50 AI Aur 2427359.49 9.50 AI Aur 2427482.39 9.67 AI Aur 2427483.44 9.68 AI Aur 2427506.40 9.55 AI Aur 2427512.40 9.57 AI Aur 2427531.37 9.76 AI Aur 2427533.33 9.80 AI Aur 2427535.38 9.84 AI Aur 2427543.37 9.76 AI Aur 2427554.36 9.73 AI Aur 2427567.38 9.70 AI Aur 2427687.54 9.41 AI Aur 2427689.56 9.39 AI Aur 2427715.47 9.59 AI Aur 2427717.50 9.64 AI Aur 2427728.47 9.50 AI Aur 2427743.42 9.53 AI Aur 2427755.42 9.41 AI Aur 2427781.41 9.65 AI Aur 2427840.53 9.53 AI Aur 2427843.41 9.57 AI Aur 2427858.39 9.60 AI Aur 2427866.42 9.53 AI Aur 2427876.37 9.50 AI Aur 2427907.35 9.64 AI Aur 2427926.36 9.68 AI Aur 2428047.54 9.42 AI Aur 2428053.52 9.38 AI Aur 2428069.52 9.28 AI Aur 2428081.50 9.43 AI Aur 2428096.54 9.57 AI Aur 2428122.45 9.65 AI Aur 2428140.39 9.57 AI Aur 2428180.42 9.52 AI Aur 2428181.42 9.52 AI Aur 2428204.46 9.54 AI Aur 2428237.30 9.57 AI Aur 2428254.36 9.43 AI Aur 2428267.37 9.39 AI Aur 2428282.38 9.44 AI Aur 2428396.57 9.54 AI Aur 2428428.49 9.64 Table 5 - B mags from Lowell Pluto Camera plates (based on Prager sequence stars with B mags.) Name JD B AI Aur 2426331.8 10.9 AI Aur 2426335.8 11.0 AI Aur 2426336.8 11.0 AI Aur 2426337.8 11.0 AI Aur 2437309.81 10.9 AI Aur 2437321.77 10.8 AI Aur 2445380.60 10.8 AI Aur 2446441.69 10.9