# restToLSRK

Uses the CASA measures tool to convert a rest frequency, LSRK velocity, and observing date/direction to the corresponding frequency in the LSRK frame. See also topoToLSRK, restToTopo, and topoToRest.

### Usage:

```au.restToLSRK(restFrequency, velocityLSRK, datestring, ra, dec, equinox='J2000', observatory='ALMA', prec=4, verbose=True)
```
Inputs:
• restFrequency: floating point value in Hz or GHz, or a string with units
• velocityLSRK: floating point value in km/s
• datestring: "YYYY/MM/DD/HH:MM:SS"
• ra: string "HH:MM:SS.SSSS"
• dec: string "DD.MM.SS.SSSS" or "DD:MM:SS.SSSS" (colons will be replaced with .)
• prec: only used to display the value when verbose=True
Returns: the LSRK frequency in Hz

### Examples:

```CASA <5>: au.restToLSRK(230.538, -7, '2015-10-10-10:12:00','05:35:20','-05:00:20')
Warning: replacing colons with decimals in the dec field.
Frame: Epoch: 57305::10:12:00.0000 (TDB = 57305.4, UT1 = 57305.4, TT = 57305.4)
Position: [1761.87, -4307.63, -1977.71]
(Longitude = -1.18255 Latitude = -0.399415)
Direction: [0.107011, 0.990422, -0.0872523]
(J2000 = [83.8333, -5.00556] deg)
LSRK freq = 230543382943.9565Hz = 230.5433829439565 GHz
TOPO freq = 230547826724.3049Hz = 230.5478267243049 GHz
TOPO doppshift = -12778.7082m/s = -12.7787082 km/s
Out[5]: 230543382943.95654
```

-- ToddHunter - 2016-05-11
Topic revision: r1 - 2016-05-11, ToddHunter

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