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measures.separation - Function

1.4.1 get separation angle between two directions


Description

separation will give the separation of a direction from another as an angle.

Arguments

Inputs

m1

direction of source (direction measure)

allowed:

record

Default:

m2

direction of other source (direction measure)

allowed:

record

Default:

Returns
record

Example

 
 
print "\t----\t separation Ex 1 \t----"  
a=me.direction(’j2000’,’0deg’,’70deg’)  
b=me.direction(’j2000’,’0deg’,’80deg’)  
print me.separation(a,b)  
#{’value’: 9.9999999999999893, ’unit’: ’deg’}  
tim = me.epoch(’utc’,’today’)              # set the time  
print me.doframe(tim)  
#True  
pos = me.observatory(’ATCA’)               # set where  
print me.doframe(pos)  
#True  
c=me.measure(b,’azel’)                     # try with different type  
print me.separation(a,c)  
#{’value’: 10.000000000062277, ’unit’: ’deg’}  
 
### the example below is how to calculate  
### the parallactic angle  
me.doframe(me.epoch(’utc’,’2015/06/30/19:30:40’)))  
me.doframe(me.observatory(’ALMA’))  
mydir = me.direction(’J2000’,’17h28m00’,’-28d00m00’ )  
#convert direction to AZEL  
mydirazel=me.measure(mydir, ’AZEL’)  
hadecpol=me.direction(’HADEC’, ’00h00m00’, ’90d00m00’)  
### no need to convert north pole direction to AZEL  
### as it will coverted to the frame of mydirazel  
parAngle=me.posangle(mydirazel, hadecpol)  

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