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The action, whether it is a slew or dither, is composed of three independent actions; TCS command, filter move, and an exposure. The input is a pattern file:

#title=true ra=true dec=true exposureTime=true numExposures=true filter=true muRA=true muDec=true epoch=truefalse dRA=true dDec=true rotatorPA=true rotatorFrame=true xi=true eta=true comment=true
#
"Vega - Alpha Lyrae" 18:36:56.336 +38:47:01.28  10.0  3  V 10 5 2000 2 1 0.0 Target 30 60 "Comment 1"
"Vega - Alpha Lyrae" 18:36:56.3   +38:47:1.3    20.0  3  R 10 5 2000 2 1 0.0 Fixed  10 20 "Comment 2"

Each input line may be composed of 

• object title - string composed of any valid ASCII character surrounded by double quotation (")
• Right Ascension (hh:mm:ss.sss)
• Declination (+dd:mm:ss.ss)
• exposure time - float/double (seconds)
• number of exposures - integer
• filter name - string that has to match the display filter name (no spaces allowed)
• Proper Motion in RA - float/double (mas/yr) - this is the angular measurement used by most catalogs: μα×cos(δ)
• Proper Motion in DEC - float/double (mas/yr)epoch - float/double - μδ
• differential track rate in RA - float/double (arc-seconds/hour)
• differential track rate in DEC - float/double (arc-seconds/hour)
• rotator Position Angle - float/double (degrees)
• rotator Frame - literal string (Fixed or Target)
• offset 1 (xi) - float/double (arc-seconds)
• offset 2 (eta) - float/double (arc-seconds)
• comment - string composed of any valid ASCII character surrounded by double quotation (") - optional

The input is not fixed width and there is some validation when loaded. The first 2 lines are meta data and have to be present in the exact form stated above. The boolean value (true or false) for each parameter tells the loading function what to expect and what to validate. All the input files lines have to follow the format indicated by the meta data.

The validation checks for correct number of parameters, correct numerical format and correct filter names. Obviously not all combination of parameters are legal. For instance if both RA/DEC and Xi/Eta are present, the slew command will take precedence and the offset command will not be issued.

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The function may be used without any slewing or dithering. For instance, it can be used for taking exposures at different filters on the same object while guiding. In this special case, the guide state will not change. By default guiding will turn off when an offset command is received by the TCS and there is no guided offsets are available at this timenot currently supported.

Another special case is when exposure time is set to 0. In this case the command will not be sent to LOIS. This can be used for resetting the system back to an initial state by issuing 0 offsets and moving the filter wheels without any exposure.

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