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Observation aids

Altitude limits
Exposuretimes
Focus values
Reference count
Sun and moon
Sky brightness

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Altitude limits

Combination	Full aperture	30cm upper aperture on mask	30cm lower aperture on mask
Lower hatch closed	42	32	41
Lower hatch open, wind cloth mounted	13	physical	12
Lower hatch open, wind cloth dismounted	8	physical	7

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Exposure times

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Focus values

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Tab. Estimated background saturation times for 0.5m². Conversion factors can be found here.

Alt	Az	Az from Sun	Sun alt	Filter/set	CCD temp	Ambient temp	ST1001E
20		180	50	U/2	-15	20	0.13
20		180	50	B/2	-15	20	0.013
20		180	50	V/2	-15	20	0.010
20		180	50	R/2	-15	20	0.0083
20		180	50	O/2	-15	20	0.0024
70		180	48	U/2	-15	20	0.19
70		180	48	B/2	-15	20	0.021
70		180	48	V/2	-15	20	0.017
70		180	48	R/2	-15	20	0.013
70		180	48	O/2	-15	20	0.0037
67		146	36	U/2	-15	20	0.26
67		146	36	B/2	-15	20	0.027
67		146	36	V/2	-15	20	0.023
67		146	36	R/2	-15	20	0.018
67		146	36	I/2	-15	20	0.017
22		140	32	U/2	-15	20	0.19
22		140	32	B/2	-15	20	0.018
22		140	32	V/2	-15	20	0.014
22		140	32	R/2	-15	20	0.0099
22		140	32	I/2	-15	20	0.0081
18		97	28	U/2	-15	20	0.17
18		97	28	B/2	-15	20	0.016
18		97	28	V/2	-15	20	0.012
18		97	28	R/2	-15	20	0.0096
18		97	28	I/2	-15	20	0.012
76		132	26	U/2	-15	20	0.32
76		132	26	B/2	-15	20	0.033
76		132	26	V/2	-15	20	0.027
76		132	26	R/2	-15	20	0.021
76		132	26	I/2	-15	20	0.019

Tab. Conversion factors for diffrent appertures in respect to the saturation times in the background count table.

Main mirror	Secondary block diameter	Tertiary block diameter	Other	Conversion factor	Comment
90	41.6	< 41.6		1.00	Normalized
90	40	< 40		0.98	Secondary test buffle
90	30	< 30		0.88	Original settting
80	30	< 30		1.2	Primary test ring and original secondary buffle
30	30	< 30		7.1	One Sub-aperture mask main hole
22	30	< 30		13	A Sub-aperture mask hole
14	30	< 30		32	A Sub-aperture mask hole
10	30	< 30		64	A Sub-aperture mask hole

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Sun and Moon

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Sky brightness

Sky brightness in units of mag arcsec^-2

Alt	Az	Sun alt	Sun dist	Moon alt	Moon phase	U	B	V	R	I	dU	dB	dV	dR	dI	U-B	B-V	V-R	V-I	d(U-B)	d(B-V)	d(V-R)	d(V-I)	CR	Order	Reference
					no moon				18.5	18.7														18.9
					phase 10 days				18.1	18.3														18.5
54.1		15.5	101.1			4.6988	4.7230	4.7726	4.8812	3.8760	0.0247	0.0040	0.0036	0.0033	0.0037										1	110719
54.1		15.5	101.1			4.6202	4.7782	4.6676	4.9273	3.8865	0.0130	0.0038	0.0067	0.0139	0.0035										2	110719
28.6		17.3	132.1			4.0750	4.0174	4.0032	4.1956	3.7069	0.0534	0.0036	0.0025	0.0025	0.0036										1	110719
28.6		17.3	132.1			3.9964	4.0726	3.8982	4.2416	3.7173	0.0141	0.0028	0.0106	0.0152	0.0034										2	110719
31.9		19.1	113.0			4.1831	4.1731	4.1910	4.3823	3.8185	0.0201	0.0031	0.0027	0.0027	0.0035										1	110719
31.9		19.1	113.0			4.1045	4.2283	4.0860	4.4283	3.8289	0.0105	0.0029	0.0050	0.0070	0.0037										2	110719
59.1		21.2	69.0			4.3884	4.3920	4.3302	4.3259	3.2525	0.0467	0.0038	0.0030	0.0026	0.0028										1	110719
59.1		21.2	69.0			4.3098	4.4471	4.2252	4.3719	3.2630	0.0142	0.0033	0.0083	0.0102	0.0044										2	110719
73.1		23.0	73.7			4.4853	4.5422	4.5271	4.5345	3.4038	0.2350	0.0102	0.0035	0.0029	0.0030										1	110719
73.1		23.0	73.7			4.4067	4.5974	4.4221	4.5805	3.4143	0.0491	0.0035	0.0168	0.0081	0.0085										2	110719
77.1		25.3	73.2			4.4561	4.5344	4.5457	4.5404	3.3263	0.0178	0.0037	0.0033	0.0029	0.0030										1	110719
77.1		25.3	73.2			4.3775	4.5896	4.4407	4.5864	3.3367	0.0115	0.0036	0.0055	0.0135	0.0029										2	110719
19.1		27.4	87.0			3.7951	3.7164	3.5978	3.6448	2.7386	0.0230	0.0027	0.0022	0.0021	0.0024										1	110719
19.1		27.4	87.0			3.7165	3.7715	3.4928	3.6908	2.7491	0.0093	0.0025	0.0059	0.0125	0.0022										2	110719
43.2		29.7	101.2			4.1042	4.1880	4.2341	4.3268	3.2947	0.0341	0.0033	0.0028	0.0026	0.0032										1	110719
43.2		29.7	101.2			4.0256	4.2431	4.1291	4.3728	3.3051	0.0115	0.0030	0.0087	0.0198	0.0027										2	110719
47.4		31.6	91.2			4.1555	4.2593	4.3154	4.4134	3.3952	0.1579	0.0073	0.0031	0.0030	0.0033										1	110719
47.4		31.6	91.2			4.0769	4.3145	4.2104	4.4594	3.4057	0.0337	0.0034	0.0181	0.0126	0.0064										2	110719
22.3		32.8	113.0			3.8457	3.8262	3.7402	3.7014	2.2561	0.0356	0.0030	0.0025	0.0027	0.0023										1	110719
22.3		32.8	113.0			3.7672	3.8813	3.6352	3.7474	2.2666	0.0112	0.0026	0.0079	0.0145	0.0027										2	110719
22.1		33.2	113.0			3.7595	3.7360	3.6924	3.6017		0.0360	0.0035	0.0040	0.0026											1	110719
22.1		33.2	113.0			3.6809	3.7911	3.5874	3.6477		0.0129	0.0031	0.0088	0.0146											2	110719
67.8		35.7	73.3			4.1936	4.3032	4.3119	4.2731	2.9339	0.0182	0.0035	0.0031	0.0026	0.0030										1	110719
67.8		35.7	73.3			4.1150	4.3584	4.2069	4.3191	2.9443	0.0106	0.0034	0.0059	0.0165	0.0028										2	110719

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