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A brief explanation of the options:
- Arc line identification: firehose_ld will by default cross-correlate your arc frame against our NeNeAr template and attempt an automatic wavelength solution. This works fairly well but not 100% of the time. If you trust the software, you can choose "fully automated." Or, you can choose "user reidentify." The latter option generates a first guess ID of "good" lines, and then launches a GUI for the user to check centroiding, and generate the final wavelength fit. Use of this GUI is documented in the Arcs page of the Wiki.
- Flat field interaction: There is not much user-intervention allowed here, but if you choose "inspect results" an atv window will pop up to let you see the quality of the composite flat. Usually this is mostly useful to see whether your red/blue transition row was chosen judiciously.
- Red/blue transition row: As described above, firehose_ld generates a superflat from a composite of dome flats of different lamp voltages. Depending on your exposure times, the temperature of the dome, etc, the row (i.e. the y pixel number) where the transition optimally blends from one flat to the other may vary. We have chosen y=1150 as a default, but the user may set this to another value as needed.
- Object finding: There are four modes available for defining the trace aperture, ranging from fully automated to fully manual. In depth descriptions of each mode are provided on the object finding wiki page.
- Fully automated: firehose will find the brightest object on the slit and trace it, with no user intervention and no feedback to the user.
- Inspect results: as in "fully automated" except an xatv window launches with a black line indicating the trace center and a dotted line the +/- 2sigma aperture
- User initial guess: Useful when the object is faint, or when your object is one of several on the slit. The user defines the global position of the source of interest, and firehose then fits a detailed aperture model to this object. Results are fed back to the user for inspection as in "inspect results."
- User Specify: Here the user dictates the exact position and width of the aperture. No automated post-fit is performed.
- Extraction