1from __future__ import division 

2from datetime import datetime, timedelta 

3import math 

4 

5import palpy 

6 

7__all__ = ["DateProfile"] 

8 

9class DateProfile(object): 

10 """ 

11 This class handles calculating the Modified Julian Date and the Local Sidereal Time for 

12 the internal timestamp and location coordinates. 

13 """ 

14 

15 SECONDS_IN_HOUR = 60.0 * 60.0 

16 

17 def __init__(self, timestamp, location): 

18 """Initialize the class. 

19 

20 Parameters 

21 ---------- 

22 timestamp : float 

23 The UTC timestamp for a given date/time. 

24 location : lsst.ts.dateloc.ObservatoryLocation 

25 The location site information instance. 

26 """ 

27 self.location = location 

28 self.update(timestamp) 

29 

30 def __call__(self, timestamp): 

31 """Modified Julian Date and Local Sidereal Time from instance. 

32 

33 Parameters 

34 ---------- 

35 timestamp : float 

36 The UTC timestamp to get the MJD and LST for. 

37 

38 Returns 

39 ------- 

40 (float, float) 

41 A tuple of the Modified Julian Date and Local Sidereal Time (radians). 

42 """ 

43 self.update(timestamp) 

44 return (self.mjd, self.lst_rad) 

45 

46 def __get_timestamp(self, dt): 

47 """float: Return a timestamp from the datetime instance. 

48 """ 

49 return (dt - datetime(1970, 1, 1)).total_seconds() 

50 

51 @property 

52 def lst_rad(self): 

53 """float: Return the Local Sidereal Time (radians) for the internal timestamp. 

54 """ 

55 value = palpy.gmst(self.mjd) + self.location.longitude_rad 

56 if value < 0.: 

57 value += 2.0 * math.pi 

58 return value 

59 

60 @property 

61 def mjd(self): 

62 """float: Return the Modified Julian Date for the internal timestamp. 

63 """ 

64 mjd = palpy.caldj(self.current_dt.year, self.current_dt.month, self.current_dt.day) 

65 mjd += (self.current_dt.hour / 24.0) + (self.current_dt.minute / 1440.) + \ 

66 (self.current_dt.second / 86400.) 

67 return mjd 

68 

69 def midnight_timestamp(self): 

70 """float: Return the UTC timestamp of midnight for the current date. 

71 """ 

72 midnight_dt = datetime(self.current_dt.year, self.current_dt.month, self.current_dt.day) 

73 return self.__get_timestamp(midnight_dt) 

74 

75 def next_midnight_timestamp(self): 

76 """float: Return the UTC timestamp of midnight for the next day after current date. 

77 """ 

78 midnight_dt = datetime(self.current_dt.year, self.current_dt.month, self.current_dt.day) 

79 midnight_dt += timedelta(**{"days": 1}) 

80 return self.__get_timestamp(midnight_dt) 

81 

82 def previous_midnight_timestamp(self): 

83 """float: Return the UTC timestamp of midnight for the next day before current date. 

84 """ 

85 midnight_dt = datetime(self.current_dt.year, self.current_dt.month, self.current_dt.day) 

86 midnight_dt -= timedelta(**{"days": 1}) 

87 return self.__get_timestamp(midnight_dt) 

88 

89 def update(self, timestamp): 

90 """Change the internal timestamp to requested one. 

91 

92 Parameters 

93 ---------- 

94 timestamp : float 

95 The UTC timestamp to update the internal timestamp to. 

96 """ 

97 self.timestamp = timestamp 

98 self.current_dt = datetime.utcfromtimestamp(self.timestamp)