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Proposal Preparation

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GHOST

Announcements

First pipeline reduced GHOST observations & available data

GHOST expected Special Call in 2023B, none in 2023A
View All GHOST News

Phase I Checklist

A Phase I Tool (PIT) tutorial video is available here

  • Instrument configuration:

    • Is the chosen resolution mode sufficient for your science?
    • Is the sky IFU sufficient for your sky subtraction? Or do you need an additional science IFU observation for sky subtraction (the latter suitable in dense fields). If so, please only use single target observations for your science.
    • If you are observing dual targets, are your targets separated by more than 102 arcsec, and less than 7.34 arcmins? This must include the correction for proper motions to an approximate time of observation. Please include only the faint target when proposing.
    • If you are interesed in proposing for dual targets, please only include the faint target in your proposal; and ensure the other target is within the field of view.
    • If you are observing dual targets, are your observations not binned by more than 8 in the spatial direction to avoid potential cross-talk
    • For dual targets, please only enter the coordinates of the faintest target.

  • Guiding

    • Guiding is only possible with the peripheral wavefront sensor 2 (P2WFS). Please ensure that a guide star is available. The position angle of the instrument can be rotated to ensure one is reachable. Please check that not vignetting is caused by P2WFS. In principle, there must be a P2WFS guide star within 6.75' for two IFUs, (and for a single target within 9.85').
    • Additional fine guiding on target is provided by dedicated microlenses surrounding the science IFUs, for bright targets.

  • Calibrations

    • Are the baseline calibrations sufficient for your science? If not, additional observing time must be requested for calibrations.
    • All observations requesting flux calibrated spectra require conditions better than CC50, and IQ70 for standard resolution observations. These must also include time for a spectrophotometric standard.
    • If you require removal of telluric lines for your science, please include a telluric standard in your time request.
    • If your observations require a radial velocity standard, please include this in your time request.
    • Do you need additional standards for calibration of your data for your science goals?

  • Observing time:

    • Please confirm the S/N achievable in your desired conditions, and the exposure time required using the ITC
    • Please include overheads for additional calibrations in your proposal, these may include time needed for spectrophotometric calibration, telluric, or radial velocity standards.
    • If you are planning to observe with a non-standard acquisition mode (blind-offset, slave guiding), or have non-standard targets (extremely faint targets (V-band magnitudes ≥19 mag), non-sidereal, extended objects, diffuse emission), you may need to include larger overheads to account for the decrease in observing efficient. Currently such modes are available on a best-effort basis, and need to be discussed with the instrument team beforehand. Please contact the instrument team in this case.

  • Observing conditions requested (for queue-scheduled observations):

    • Please consider whether the chosen IQ bin is appropriate for your science, given the wavelength range of interest, and the likely airmass of your observations. Remember the airmass and wavelength roughly degrade from the zenith seeing (measured in the V-band) by an exponent of 0.6, and −0.2 approximately. Given the finite width of the input aperture, the throughput degrades strongly as a function of seeing
    • The night sky significantly increases in brightness shortward of the R-band during bright moon phases. If your science needs observations at short wavelengths, please consider strong SB constraints to ensure enough S/N in the blue.
    • The level of cloud cover needed for your science depends on the combination of the brightness of your target, wavelength range needed for your science, and the S/N desired. Most spectroscopic observations of medium-bright targets at all wavelength ranges are sufficient when taken in thin cirrus or worse conditions. If you required accurate spectrophotometric calibration, please indicate by choosing clear conditions.
    • Please ensure the observing conditions requested match your science goals.