Photometric monitoring of late-type stars has proven to be a powerful tool to discover cool starspots and to measure precise stellar rotation periods with, in some favorable cases, even differential rotation on the stellar surface (Hall [1972], [1994]). The way the light and colors of a spotted star vary with time traces the evolution of its starspots. Time-series light and color curves can then be used to determine the approximate distribution of spots on the stellar surface, their temperature contrast, and even their appearance and disappearance marking the beginning and ending of a spot cycle similar to the Sun's 11-year cycle. In the past decade several studies were presented that attempted to model long-term light-curve variations with an evolving spot distribution on the basis of one stellar rotation to the next. Much literature could be cited here but instead let us selflessly draw your attention to our own series of papers on "Time-series photometric spot modeling'' and the many references therein. Paper I on the RS CVn binary VY Ari (Strassmeier & Bopp [1992]) included a description of the modeling technique and were followed by Strassmeier et al. ([1994a]) on 15 years of photometry of HR 7275, Olàh et al. ([1997]) on 30 years of HK Lac and Olàh et al. ([1999]) on 10 years of V833 Tau. A particularly important spot parameter extractable from these data is the spot's lifetime and one result, still lively debatted, is that there is no linear decay law for starspots as there is for sunspots, i.e. the larger a sunspot the longer it lives ( ${\rm d}A/{\rm d}t$ = const; A being the spot area). Various physically similar stars in terms of rotation period and spectral type can host spots or spot groups with a wide range of lifetimes. For a set of four spotted RS CVn stars, Henry et al. ([1995a]) observed individual spot lifetimes between 0.5 years and over 6 years. The same range of lifetimes was found for the stars in our previous papers mentioned above. Maybe not surprising, the spotted star with the longest photoelectric history (RS CVn with 45 years of broad-band data) also shows the longest time scale: a cyclic change of the total spotted area with a period of 20 years (Rodonó et al. [1995]). All these phenomena are suggestive of a significantly non-solar magnetic field topology and a dynamo process that might operate on many different timescales.

Clearly, continuous photometric monitoring for a long period in time is needed for conclusive analyses and automatic photoelectric telescopes (APTs) are ideally suited for such a task. In this paper, we present multicolor data from our two 0.75-m University of Vienna twin APTs (Strassmeier et al. [1997b]) and the 0.25-m Phoenix-10 APT (Boyd et al. [1984]) for 1996/97. Altogether, 47 program stars were observed in either by, UBV, or $V(RI)_{\rm C}$ . Some special cases were targeted in all of these bandpasses but with varying time and phase coverage on the individual telescopes. Others had been observed only briefly and their aim was mostly to support spectroscopic observations for Doppler imaging with large telescopes (see, e.g., Rice & Strassmeier [1998]). Table 1 presents a summary of the program stars and their commonly known stellar parameters. A period analysis for all stars from each individual telescope gives a homogeneous set of stellar rotation periods and the associated rotational light variations.

**Table 1:** Program stars
Star	V	Spectral type	Binary?	$P_{\rm orb}$	$P_{\rm phtm}$	$v\sin i$	Radius	Variable type
	(mag)		(SB/S)	(days)	(days)	(kms^-1)	( $R_\odot$ )
HR 5B (V640 Cas)	6.6	G8V	SB1	39.5	n.det.	4.7	...	solar-type SB
SAO 91772 (LN Peg)	8.6	G8V	SB2	1.844	1.851	23	$\geq$ 0.84	RS CVn
HD 4502 ( $\zeta$ And)	4.1	K1IIIa	SB1	17.769	17.637	41	$\geq$ 14.3	RS CVn + ell.
HD 12545 (XX Tri)	8.1	K0III	SB1	23.98	23.87	18.2	$\geq$ 8.6	RS CVn
HD 17433 (VY Ari)	6.8	K3-4IV	SB1	13.198	16.23	10	$\geq$ 3.2	RS CVn
HD 22468 (V711 Tau)	5.7	K1IV	SB2	2.8377	2.837	40	3.9	RS CVn
HD 26337 (EI Eri)	7.0	G5IV	SB1	1.947	1.913	50	$\geq$ 1.9	RS CVn
HD 283518 (V410 Tau)	11.2	K4	S	...	1.872	77	3.0	WTTS
HR 1362 (EK Eri)	6.3	G8III-IV	S	...	(306.9)	1.5	9	single giant
HD 283571 (RY Tau)	10	F8V	S	...	n.det.	49	...	CTTS
HD 283572 (V987 Tau)	9.3	G5	S	...	1.529	78	$\geq$ 2.3	WTTS
HD 283750 (V833 Tau)	8.2	K5V	SB1	1.788	1.806	6.3	$\geq$ 0.22	BY Dra
HD 282624 (SU Aur)	8.9	G2	S	...	n.det.	66	$\geq$ 3.9	CTTS
HD 31964 ( $\epsilon$ Aur)	3.0	F0Ia	ECL	27yr	n.det.	...	...	puls. supergiant
HD 31993 (V1192 Ori)	7.5	K2III	S	...	26.7	33	$\geq$ 17.4	single giant
HD 33798 (V390 Aur)	7.0	G8III	S	...	9.69	33	$\geq$ 6.3	single giant
HD 291095 (V1355 Ori)	8.7	K1IV	SB1	?	3.87	46	$\geq$ 3.5	RS CVn-type
HD 43989 (V1358 Ori)	8.5	G0IV	S	...	(3.2:)	42	$\geq$ 3.2	RS CVn-type
HD 51066 (CM Cam)	7.2	G8III	SB1	3770.	16.0	47	17.4	eff. single giant
HD 62044 ( $\sigma$ Gem)	4.3	K1III	SB1	19.604	19.615	27	12	RS CVn
HD 81410 (IL Hya)	7.5	K1III	SB2	12.905	12.674	26.5	8.1	RS CVn
HD 82443 (DX Leo)	7.0	K0V	S	...	5.432	5	$\geq$ 0.54	BY Dra
HD 82558 (LQ Hya)	7.8	K2V	S	...	1.60	28	0.94	BY Dra
HD 98230 ( $\xi$ UMa B)	3.8	G5V	SB1	3.980	n.det.	2.8	...	solar-type SB
HD 106225 (HU Vir)	8.6	K0III-IV	SB1	10.39	10.66	27	$\geq$ 5.7	RS CVn
HD 111395 (HR 4864)	6.3	G5V	S	...	15.80	2.9	$\geq$ 0.90	solar type
HD 111812 (31 Com)	4.9	G0III	S	...	6.96:	57	$\geq$ 7.8:	single giant
HD 112313 (IN Com)	8.0	G5III-IV	SB1	?	5.90	67	$\geq$ 7.8	RS CVn
HD 112989 (37 Com)	4.9	G9III	S	...	n.det.	4	...	single giant
HD 117555 (FK Com)	8.1	G2III	S	...	2.4067	160	$\geq$ 7.3	FK Comae
HD 129333 (EK Dra)	7.5	G0-1V	S	...	2.598	17.5	0.92	solar type
HD 136901 (UV CrB)	7.2	K2III	SB1	18.665	18.657	42	$\geq$ 15.5	RS CVn + ell.
BD-08 $^\circ$ 3999 (UZ Lib)	9.3	K0III	SB1	4.77	4.75	67	$\geq$ 6.3	RS CVn
HD 139006 ( $\alpha$ CrB)	2.2	A0V+G5V	SB	17.4	n.det.	$\leq$ 14	...	eclipsing
HD 140436 ( $\gamma$ CrB)	3.8	A0V	VB	91yr	0.44534	100	$\geq$ 0.88	Maia type
HD 141714 ( $\delta$ CrB)	4.6	G3.5III-IV	S	...	57	5	$\geq$ 5.8	single giant
HD 152178 (V2253 Oph)	8.2	K0III	SB1	314.	22.07	28.8	$\geq$ 12.6	RS CVn
HD 171488 (V889 Her)	7.3	G0V	S	...	1.337	33	$\geq$ 0.87	solar type
HD 199178 (V1794 Cyg)	7.2	G5III-IV	S	...	3.342	67	$\geq$ 4.4	FK Comae
HD 208472 (V2075 Cyg)	7.3	G8III	SB1	22.6	22.42	19.7	$\geq$ 8.7	RS CVn
HD 209813 (HK Lac)	6.9	K0III	SB1	24.428	24.15	20	$\geq$ 9.5	RS CVn
HR 9024 (OU And)	5.9	G1III	S	...	24.2	20	$\geq$ 9.6	single giant
HD 216489 (IM Peg)	5.6	K2II-III	SB1	24.65	24.45	28.2	$\geq$ 13.6	RS CVn
HD 216672 (HR Peg)	6.3	S	S	...	irr.	...	...	semiregular
HD 218153 (KU Peg)	7.6	G8II-III	SB1	1411.	25.9	29	$\geq$ 14.8	RS CVn
HD 224085 (II Peg)	7.4	K2-3IV	SB1	6.724	6.725	23.1	$\geq$ 3.0	RS CVn

**Table 2:** Identification of comp and check stars and number, n, of differential observations
Variable	Comparison	Check	Time range	$n_{\rm Wolfgang}$	$n_{\rm Amadeus}$	$n_{\rm Phoenix}$
			2 400 000+	by	VRI	UBV
HR 5B (V640 Cas)¹	HD 663	HD 224784	50395 - 50635	52	...	...
SAO 91772 (LN Peg)	SAO 91775	HD 977	50409 - 50635	35	...	...
HD 4502 ( $\zeta$ And)¹	HD 5516	HD 3690	50395 - 50635	105	...	...
HD 12545 (XX Tri)	HD 12478	SAO 55178	50395 - 50500	...	116	53
HD 17433 (VY Ari)	HD 17572	HD 17361	50386 - 50516	...	...	55
HD 22468 (V711 Tau)¹	HD 22484	HD 22796	50395 - 50490	132	109	...
HD 26337 (EI Eri)	HD 25852	HD 26584	50395 - 50529	...	128	...
HD 283518 (V410 Tau)	HD 27159	HD 27570	50395 - 50525	...	125	...
HR 1362 (EK Eri)¹	HD 27197	HD 26409	50395 - 50500	...	122	...
HD 283571 (RY Tau)	HD 27159	HD 27570	50395 - 50529	...	128	...
HD 283572 (V987 Tau)	HD 27570	HD 28447	50395 - 50532	179	115	...
HD 283750 (V833 Tau)	HD 283749	HD 29169	50395 - 50521	...	127	...
HD 282624 (SU Aur)	HD 31565	HD 31305	50395 - 50534	...	147	...
HD 31964 ( $\epsilon$ Aur)	HD 33167	...	50395 - 50426	100	...	...
HD 31993 (V1192 Ori)	HD 32191	HD 32073	50395 - 50536	...	140	...
HD 33798 (V390 Aur)	HD 34248	HD 33443	50396 - 50540	...	26	...
HD 291095 (V1355 Ori)	HD 41433	HD 40347	50492 - 50551	36	64	...
HD 43989 (V1358 Ori)	HD 44517	HD 44019	50492 - 50554	34	39	...
HD 51066 (CM Cam)	HD 48840	HD 45947	50486 - 50562	...	103	...
HD 62044 ( $\sigma$ Gem)¹	HD 60318	HD 58207	50395 - 50536	471	...	...
HD 81410 (IL Hya)	HD 81904	HD 80991	50395 - 50594	...	235	...
HD 82443 (DX Leo)	HD 83098	HD 83821	50392 - 50604	...	...	161
HD 82558 (LQ Hya)	HD 82477	HD 82508	50395 - 50593	...	202	145
HD 98230 ( $\xi$ UMa)¹	HD 98262	HD 94600	50408 - 50614	244	...	...
HD 106225 (HU Vir)	HD 106270	HD 106332	50410 - 50633	...	191	56
HD 111395 (HR 4864)¹	HD 111469	HD 111812	50429 - 50636	...	257	...
HD 111812 (31 Com)	HD 111469	HD 111395	50401 - 50636	...	...	169
HD 112313 (IN Com)	HD 112299	HD 112706	50419 - 50636	168	226	...
HD 112989 (37 Com)¹	HD 111469	HD 111812	50415 - 50635	...	274	...
HD 117555 (FK Com)	HD 117567	HD 117876	50421 - 50632	132	...	...
HD 129333 (EK Dra)	HD 129390	HD 129798	50437 - 50576	...	183	143
HD 136901 (UV CrB)	HD 136643	HD 136655	50492 - 50636	90	146	...
BD-08 $^\circ$ 3999 (UZ Lib)	SAO 140587	SAO 140589	50451 - 50635	...	139	...
HD 139006 ( $\alpha$ CrB)²	HD 140436³	HD 141714⁴	50458 - 50568	267	...	...
HD 152178 (V2253 Oph)	HD 152501	HD 151179	50468 - 50636	...	120	...
HD 171488 (V889 Her)	HD 171286	HD 170829	50395 - 50636	93	179	...
HD 199178 (V1794 Cyg)	HD 199956	HD 199870	50395 - 50635	...	67	...
HD 208472 (V2075 Cyg)	HD 208341	HD 208916	50395 - 50635	...	96	...
HD 209813 (HK Lac)	HD 210731	HD 208728	50395 - 50635	...	86	...
HR 9024 (OU And)¹	HD 223848	HD 222451	50395 - 50635	...	89	...
HD 216489 (IM Peg)	HD 216635	HD 216672⁵	50395 - 50635	...	73	...
HD 218153 (KU Peg)	HD 218610	SAO 91066	50395 - 50635	...	75	...
HD 224085 (II Peg)	HD 223332	HD 224895	50395 - 50635	...	26	...

¹With 1 $.\!\!^{\rm m}$ 25 neutral-density filter for Var, Comp, and Check.
²With 3 $.\!\!^{\rm m}$ 75 neutral-density filter for Var and Comp, and 2 $.\!\!^{\rm m}$ 5 for Check.
³This is the variable star $\gamma$ CrB (see discussion).
⁴This is the variable star $\delta$ CrB (see discussion).
⁵This is the variable star HR Peg = HR 8714 (see discussion).

1 Introduction