6. New V 1794 Cyg photometry

The new photometry of V 1794 Cyg was made between July, 1989 and December, 1995 at the Mount Hopkins, the Mount Maidanak, the Mount Laguna, the Kvistaberg, and the Royal Swedish La Palma Observatories (Table 3: "This paper'').

1. Mount Hopkins Observatory (APT)

The first part of new data is the differential UBV photometry made at the Mount Hopkins Observatory between September, 1989 and December, 1995 with the (Automatic Photoelectric Telescope) Phoenix 10 inch telescope. Each observation is a mean of three ten second integrations. The average internal standard deviation of the differential magnitudes was $0\hbox{$.\!\!^{\rm m}$ }008$, $0\hbox{$.\!\!^{\rm m}$ }004$ and $0\hbox{$.\!\!^{\rm m}$ }005$ in U, B and V, respectively. All observations with an internal error greater than $0\hbox{$.\!\!^{\rm m}$ }02$are automatically discarded by the APT. The respective external errors in UBV are $0\hbox{$.\!\!^{\rm m}$ }023$, $0\hbox{$.\!\!^{\rm m}$ }014$ and $0\hbox{$.\!\!^{\rm m}$ }012$(e.g. Strassmeier & Hall 1988b; Boyd et al. 1990). These external errors agree with the accuracy for the C₁ magnitudes during individual subsets of APT data (see Table 2). The APT suffered from problems with the U-band filter between July, 1991 and September, 1992. Thus only the BV-photometry of that time interval is given in Table 4. The APT observing routines have been described in detail, e.g., by Boyd et al. (1984). The C₁ for L. Jetsu was SAO 50205, while that for B.W. Bopp and H.L. Nations was SAO 50313. The long-term UBV magnitudes of these two C₁(Table 2) were added to the differential magnitudes. The C₂ in all new APT photometry was 57 Cyg. Every SET of these new APT data has the same C₁, i.e. overlapping data with different C₁ were not combined (e.g. SET=64 and 65). This ensures the data homogeneity, and if necessary, enables simple future LTM-corrections.

2. Mount Maidanak Observatory

The second part of new data is absolute UBVR photometry made at the Mount Maidanak Observatory between July, 1989 and September, 1994. The two most frequently used C₁, SAO 50313 and SAO 50205, were also observed in November, 1989 (Table 2: SET=47). The observations were made with the 48 cm AZT-14 telescope. Each observation in Table 4 is an average of 3-5 ten second integrations in each UBVR passband. A set of standard stars was observed to determine the nightly extinction coefficients and the transformation into the standard Johnson UBVR system. The upper limit of external errors for the standard Johnson BVR ( $\pm 0\hbox{$.\!\!^{\rm m}$ }015$) and U ( $\pm 0\hbox{$.\!\!^{\rm m}$ }030$) magnitudes have been determined, e.g., by Kilyachkov & Shevchenko (1976) and Shevchenko (1980), who described the Mount Maidanak Observatory photometric observing routines, instrumentation, reductions, and transformations.

   

Table 3: The collected photometry of V 1794 Cyg: The observing time interval, the subset number (SET), the observatory, the primary comparison star (C₁), the secondary comparison star (C₂), the reference and the number of observing nights (N)

Interval	SET	Observatory	C1	C2	Reference	N
3.-12.11.1975	1	McDonald Observatory	SAO 50313	-	Bopp 1982	7
5.-11.10.1976	2	Kitt Peak National Observatory	SAO 50260	-	Bopp et al. 1983	6
26.6.-17.8.1980	3	Cloudcroft Observatory	SAO 50313	SAO 50257	Bopp et al. 1983	14
12.9.-13.10.1980	4	Cloudcroft Observatory	SAO 50313	SAO 50257	Bopp et al. 1983	9
11.5.-18.6.1981	5	Cloudcroft Observatory	SAO 50313	SAO 50257	Bopp et al. 1983	4
15.9.-8.10.1982	6	Crimean Astrophysical Observatory	SAO 50205	-	Huovelin et al. 1987	10
2.-5.11.1982	7	Kitt Peak National Observatory	SAO 50313	-	Paper II	4
23.4.-31.5.1983	8	Kitt Peak National Observatory	SAO 50313	-	Paper II	6
22.-24.8.1983	9	Kitt Peak National Observatory	SAO 50313	-	Paper II	3
8.-16.9.1983	10	Crimean Astrophysical Observatory	SAO 50205	-	Huovelin et al. 1987	8
20.3.-17.5.1984	11	Kitt Peak National Observatory	SAO 50313	-	Paper II	2
17.-29.8.1984	12	Ostrowik Observatory	SAO 50313	SAO 50257	Kaluzny 1984	9
5.9.-10.11.1984	13	Kitt Peak National Observatory	SAO 50313	-	Paper II	4
30.4.-9.6.1985	14	Kitt Peak National Observatory	SAO 50313	-	Paper II	8
6.8.-4.9.1985	15	Mount Hopkins Observatory	SAO 50313	-	Nations & Seeds 1986	16
5.9.-4.10.1985	16	Mount Hopkins Observatory	SAO 50313	-	Nations & Seeds 1986	20
9.10.-1.11.1985	17	Mount Hopkins Observatory	SAO 50313	-	Nations & Seeds 1986	17
2.-22.11.1985	18	Mount Hopkins Observatory	SAO 50313	-	Nations & Seeds 1986	13
1.-27.12.1985	19	Mount Hopkins Observatory	SAO 50313	-	Nations & Seeds 1986	13
3.-29.5.1986	20	Mount Hopkins Observatory	SAO 50313	57 Cyg	Paper II	12
5.-20.6.1986	21	Mount Hopkins Observatory	SAO 50313	57 Cyg	Paper II	13
5.-17.9.1986	22	Crimean Astrophysical Observatory	SAO 50205	-	Paper II	7
28.9.-28.11.1986	23	Mount Hopkins Observatory	SAO 50313	57 Cyg	Paper II	16
3.-30.5.1987	24	Mount Hopkins Observatory	SAO 50313	57 Cyg	Paper II	9
16.6.-8.7.1987	25	Mount Hopkins Observatory	SAO 50313	57 Cyg	Paper II	10
11.-19.8.1987	26	Crimean Astrophysical Observatory	SAO 50205	-	Paper II	5
28.9.-27.10.1987	27	Mount Hopkins Observatory	SAO 50313	57 Cyg	Paper II	13
4.-12.10.1987	28	Crimean Astrophysical Observatory	SAO 50205	16 Cyg B	Paper II	5
8.11.-23.12.1987	29	Mount Hopkins Observatory	SAO 50313	57 Cyg	Paper II	10
25.4.-22.5.1988	30	Mount Hopkins Observatory	SAO 50313	57 Cyg	Paper II	16
28.5.-17.6.1988	31	Mount Hopkins Observatory	SAO 50313	57 Cyg	Paper II	13
5.9.-17.10.1988	32	Crimean Astrophysical Observatory	SAO 50205	-	Paper II	8
11.9.-6.10.1988	33	Mount Hopkins Observatory	SAO 50313	57 Cyg	Paper II	20
7.10.-1.11.1988	34	Mount Hopkins Observatory	SAO 50313	57 Cyg	Paper II	14
2.-21.11.1988	35	Mount Hopkins Observatory	SAO 50313	57 Cyg	Paper II	17
28.11.-25.12.1988	36	Mount Hopkins Observatory	SAO 50313	57 Cyg	Paper II	18
28.4.-27.5.1989	37	Mount Hopkins Observatory	SAO 50313	57 Cyg	Paper II	15
11.-15.5.1989	38	Crimean Astrophysical Observatory	SAO 50205	SAO 50313	Paper II	3
31.5.-24.6.1989	39	Mount Hopkins Observatory	SAO 50313	57 Cyg	Paper II	14
3.7.-1.8.1989	40	Mount Maidanak Observatory	Absolute	Absolute	This paper	27
2.-31.8.1989	41	Mount Maidanak Observatory	Absolute	Absolute	This paper	28
1.-30.9.1989	42	Mount Maidanak Observatory	Absolute	Absolute	This paper	22
10.-30.9.1989	43	Mount Hopkins Observatory	SAO 50313	57 Cyg	This paper	11
1.-28.10.1989	44	Mount Hopkins Observatory	SAO 50313	57 Cyg	This paper	12
3.-28.10.1989	45	Mount Maidanak Observatory	Absolute	Absolute	This paper	13
1.-20.11.1989	46	Mount Hopkins Observatory	SAO 50313	57 Cyg	This paper	15
2.-30.11.1989	47	Mount Maidanak Observatory	Absolute	Absolute	This paper	13
23.11.-22.12.1989	48	Mount Hopkins Observatory	SAO 50313	57 Cyg	This paper	11
4.-31.5.1990	49	Mount Hopkins Observatory	SAO 50313	57 Cyg	This paper	11
4.5.-2.6.1990	50	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	11
16.-26.5.1990	51	Mount Laguna Observatory	SAO 50313	SAO 50326	Heckert & Stewart 1992	6
1.-26.6.1990	52	Mount Hopkins Observatory	SAO 50313	57 Cyg	This paper	11
5.-26.6.1990	53	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	11
6.6.-2.7.1990	54	Mount Maidanak Observatory	Absolute	Absolute	This paper	20
8.7.-8.8.1990	55	Mount Maidanak Observatory	Absolute	Absolute	This paper	27
9.8.-9.9.1990	56	Mount Maidanak Observatory	Absolute	Absolute	This paper	26
9.9.-12.10.1990	57	Mount Hopkins Observatory	SAO 50313	57 Cyg	This paper	9
10.9.-11.10.1990	58	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	9
10.-28.9.1990	59	Mount Maidanak Observatory	Absolute	Absolute	This paper	19
4.10.-7.11.1990	60	Mount Maidanak Observatory	Absolute	Absolute	This paper	15

 

Table 3: continued

Interval	SET	Observatory	C1	C2	Reference	N
12.10.-9.11.1990	61	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	17
13.10.-15.11.1990	62	Mount Hopkins Observatory	SAO 50313	57 Cyg	This paper	24
8.11.-8.12.1990	63	Mount Maidanak Observatory	Absolute	Absolute	This paper	17
12.11.-19.12.1990	64	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	17
16.11.-20.12.1990	65	Mount Hopkins Observatory	SAO 50313	57 Cyg	This paper	14
15.12.1990-14.1.1991	66	Mount Maidanak Observatory	Absolute	Absolute	This paper	11
30.4.-30.5.1991	67	Mount Hopkins Observatory	SAO 50313	57 Cyg	This paper	15
12.-26.5.1991	68	Mount Laguna Observatory	SAO 50313	SAO 50326	Heckert & Stewart 1992	11
15.5.-8.6.1991	69	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	17
3.-30.6.1991	70	Mount Hopkins Observatory	SAO 50313	57 Cyg	This paper	20
11.6.-3.7.1991	71	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	14
11.6.-12.7.1991	72	Mount Maidanak Observatory	Absolute	Absolute	This paper	19
15.7.-15.8.1991	73	Mount Maidanak Observatory	Absolute	Absolute	This paper	26
16.8.-18.9.1991	74	Mount Maidanak Observatory	Absolute	Absolute	This paper	27
19.9.-18.10.1991	75	Mount Maidanak Observatory	Absolute	Absolute	This paper	13
29.9.-20.10.1991	76	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	18
11.10.1991	77	Royal Swedish La Palma Observatory	Absolute	Absolute	This paper	1
21.10.-25.11.1991	78	Mount Maidanak Observatory	Absolute	Absolute	This paper	13
26.10.-17.11.1991	79	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	15
6.5.-6.6.1992	80	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	13
12.-20.5.1992	81	Mount Laguna Observatory	SAO 50313	SAO 50326	This paper	6
9.6.-6.7.1992	82	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	21
15.7.-14.8.1992	83	Mount Maidanak Observatory	Absolute	Absolute	This paper	28
6.-9.8.1992	84	Mount Laguna Observatory	SAO 50313	SAO 50326	This paper	2
17.8.-18.9.1992	85	Mount Maidanak Observatory	Absolute	Absolute	This paper	23
6.-10.9.1992	86	Royal Swedish La Palma Observatory	Absolute	Absolute	This paper	4
19.9.-19.10.1992	87	Mount Maidanak Observatory	Absolute	Absolute	This paper	18
1.-23.10.1992	88	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	17
22.10.-11.11.1992	89	Mount Maidanak Observatory	Absolute	Absolute	This paper	11
2.11.-1.12.1992	90	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	11
26.11.-29.12.1992	91	Mount Maidanak Observatory	Absolute	Absolute	This paper	4
24.5.-30.6.1993	92	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	26
2.-29.6.1993	93	Mount Maidanak Observatory	Absolute	Absolute	This paper	14
6.-31.7.1993	94	Mount Maidanak Observatory	Absolute	Absolute	This paper	21
24.-27.7.1993	95	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	4
26.7.-2.8.1993	96	Mount Laguna Observatory	SAO 50313	SAO 50326	This paper	6
1.-28.8.1993	97	Mount Maidanak Observatory	Absolute	Absolute	This paper	18
5.-25.8.1993	98	Kvistaberg Observatory	Absolute	Absolute	This paper	3
30.8.-24.9.1993	99	Mount Maidanak Observatory	Absolute	Absolute	This paper	21
3.9.-3.10.1993	100	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	19
9.-10.9.1993	101	Royal Swedish La Palma Observatory	Absolute	Absolute	This paper	1
18.9.-27.10.1993	102	Kvistaberg Observatory	Absolute	Absolute	This paper	6
28.9.-28.10.1993	103	Mount Maidanak Observatory	Absolute	Absolute	This paper	17
13.10.-1.11.1993	104	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	9
21.11.-15.12.1993	105	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	9
8.6.-15.7.1994	106	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	15
13.6.-8.7.1994	107	Mount Maidanak Observatory	Absolute	Absolute	This paper	20
11.7.-5.8.1994	108	Mount Maidanak Observatory	Absolute	Absolute	This paper	21
7.8.-1.9.1994	109	Mount Maidanak Observatory	Absolute	Absolute	This paper	17
2.-28.9.1994	110	Mount Maidanak Observatory	Absolute	Absolute	This paper	14
9.6.-11.7.1995	111	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	21
21.9.-19.10.1995	112	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	22
20.10.-16.11.1995	113	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	16
17.11.-15.12.1995	114	Mount Hopkins Observatory	SAO 50205	57 Cyg	This paper	16

3. Mount Laguna Observatory

The third part of new data consists of the differential UBV(RI)_C photometry made between May, 1992 and August, 1993 with the 24 inch telescope at the Mount Laguna Observatory. The comparison stars SAO 50313 (C₁) and SAO 50326 (C₂) were as in Heckert & Stewart (1992). Each observation is an average of four 10 seconds integrations through a diaphragm of 19'' or 26'', depending on the seeing conditions and/or background brightness. The internal error is $\leq 0\hbox{$.\!\!^{\rm m}$ }01$ in every passband. The standard stars (Landolt 1983) were observed to determine the transformation into the standard Johnson UBV and Cousins RI systems. The weighted mean UBVR magnitudes of SAO 50313 in Table 2 were used to derive the magnitudes of V 1794 Cyg. The Cousins R magnitudes were transformed into the standard Johnson system (Bessel 1979). The standard Johnson I magnitudes could not be derived, because I of SAO 50313 is unknown. The Mount Laguna Observatory observing routines and instrumentation have been described, e.g., in Heckert & Stewart (1992) and Heckert (1993).

4. Kvistaberg Observatory and Royal Swedish La Palma Observatory

The fourth part of the new data is absolute UBV photometry made between October, 1991 and October, 1993 with the 40 cm telescope at Kvistaberg Observatory and the 60 cm telescope at Royal Swedish La Palma Observatory. These observations were obtained during a survey of medium magnitude UBV standard stars at positive declinations (between 15$^{\circ}$ and 45$^{\circ}$), i.e. V 1794 Cyg was "accidentally'' included into a list of standard stars, before being identified as a variable. As an exception, the first observation (SET=77) was made during a study of late-type stars in the Milky Way. The reductions by T. Oja are essentially the same for both instruments. Each observation is a mean of three ten second integrations. The transformation into the standard Johnson UBV is determined, and continuously verified, with respect to standard star measurements, as described, e.g., by Oja (1983). The external accuracy is about $0\hbox{$.\!\!^{\rm m}$ }021$ in V, and $0\hbox{$.\!\!^{\rm m}$ }011$ in B-V and U-B. The V magnitudes of V 1794 Cyg were reduced relative to three standard stars using the values given in the parenthesis: BD+44$^{\circ}$3604 (V=9.420), BD+45$^{\circ}$3310 (V=8.647), and BD+54$^{\circ}$3220 (V=8.297), while the B-V and U-B of V 1794 Cyg are absolute.