“NIRSpec includes the multi-object spectroscopy (MOS) mode, where spectra of dozens to hundreds of science targets will be observed at one time. During instrument commissioning, the excellent performance of WATA has been demonstrated on the sky for all four of the NIRSpec observing modes: integral field unit imaging spectroscopy, fixed slit spectroscopy, bright object time series, and multi-object spectroscopy.
Spectrum locations software#
The software on-board the Webb telescope autonomously calculates an offset to move the telescope and accurately position either this target or another nearby target at the optimal location in NIRSpec to spread the light into a spectrum. “The WATA process takes an image of a single astrophysical target through the wide ‘S1600A1’ fixed slit to determine its position on the sky as seen through the instrument. NIRSpec has two methods for target acquisition (TA): the Wide Aperture Target Acquisition (WATA) and the Micro-Shutter Assembly (MSA) -based Target Acquisition (MSATA). “In addition to the gratings and a prism, the NIRSpec GWA also has a mirror that is primarily used to ‘acquire’ targets – to image them and place them at the proper locations in the instrument to observe a spectrum. Study of the intensity or brightness of light across the wavelengths can provide key diagnostic information about the nature of various objects across the universe – from extrasolar planets around distant stars, to faint galaxies at the edge of the universe, and objects in our own solar system. The NIRSpec Grating Wheel Assembly (GWA) uses diffraction gratings or a prism to separate the wavelengths of incoming light into a spectrum. “The Near-Infrared Spectrograph (NIRSpec) is the instrument on the Webb telescope that observes spectra of astrophysical and planetary objects at near infrared wavelengths. This week we asked Tracy Beck, Tony Keyes, and Charles Proffitt, all NIRSpec instrument scientists at the Space Telescope Science Institute (STScI), to tell us about how Webb gets the targets lined up for observation with the NIRSpec instrument.
The team has started to take some of the first science data, getting it ready to release starting July 12, 2022, which will mark the official end of commissioning Webb and the start of routine science operations.
As we ramp down the final commissioning activities, some openings in the schedule have appeared. The Webb team has now approved 10 out of 17 science instrument modes since last week we added (14) MIRI imaging, (2) NIRCam wide-field slitless spectroscopy, and our final NIRISS mode, (10) single-object slitless spectroscopy.