Summary Table of Open and Available Time

This table simple summarizes the amount of possible time each semester and the amount of time the APF was allowed to be open. The A semester runs from February 1 to July 31, while the B semester runs from August 1 to Jan 31. The large loss in 2022B was because of downtime from a mirror recoating and other technical issues. The time lost in 2020B due to the large fire at Lick Observatory was not recorded.

• Total represents the total number of hours of darkness, defined as between -9 degree sunset to -9 degree sunrise, over the month.
• OK gives the number of hours it was determined to be ok to open the telescope. Reasons for closure may include weather or engineering issues.

Year	A Total(hr)	A OK(hr)	B Total(hr)	B OK(hr)
2015			1571.50	735.79
2016	1682.38	1122.25	2094.87	1139.91
2017	1644.95	963.06	2106.26	1260.57
2018	1652.69	1026.23	2068.34	1052.32
2019	1676.17	800.36	2119.24	1208.31
2020	1636.00	941.66	2095.15	650.61
2021	1680.60	1087.95	2106.79	1113.87
2022	1663.50	1115.13	1386.26	460.66
2023	1663.36	729.71	2092.42	854.86
Average	1662.45	973.33	1960.09	942.06

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