After the successful upgrade of two of the three GMOS-S CCDs, the instrument is back on the telescope and undergoing recommissioning. The long-slit mode has been released for taking science data. However, updates for the data reduction packages in IRAF and DRAGONS are pending testing after the full commissioning data set has been collected and will likely not be available until the May/June timeframe.
GMOS-S will be removed from the telescope on Friday, July 21st for the CCDs intervention, with the purpose of replacing the faulty CCD2.
The instrument is scheduled to come back during late August for the commissioning of the upgraded detector array, and expected to be available for Science by September.
The GMOS-N B600 grating sensitivity has recently degraded significantly. This overall degradation is in addition to the blue sensitivity loss reported previously. Since the new B480 grating is now available for GMOS-N, we recommend changing B600 programs to the B480 grating. The B480 grating offers a wider wavelength coverage than B600 at a a slightly reduced spectral resolution.
GNIRS has been reinstalled on the telescope after the extended shutdown and is ready for science use as of June 6, 2023. All slit spectral modes along with imaging are available. Both the Low Resolution and High Resolution IFUs are now installed and are undergoing commissioning. They will be released for science use at a later date.
We are pleased to present the first GHOST science observations that have been reduced with the GHOST pipeline. We are releasing the spectrum of XX Oph (Be + Red Supergiant; V= 8.59-10.2 mag) as an example to showcase the spectral range, spectral resolution, and overall quality of data that GHOST can provide in standard resolution mode (R=50000; with a total integration time of 240s, and a wavelength range of 347 to 1060nm).
GHOST has not yet been fully commissioned and information such as sensitivities is pending. For this reason GHOST is not offered as an instrument for regular science in 23B. We expect most modes to be fully commissioned late 23A, and for there to be a special Call for proposals in 23B. We will post an announcement as soon as we have more details on the special call in 23B.
Since November 'Alopeke has now a Halpha filter. The specifications are identical to the one installed at Zorro. The filter is available to anyone applying to 'Alopeke time.
After the GMOS-S detector troubleshooting earlier this semester, the physical location of the array has shifted by a small amount in the -direction. While this did not have harmful consequences, the Y-shift has the effect of the MOS mask slits as defined on the MDF appearing with a small (~20 pix) yet systematic offset with respect to the actual location of the spectra.
After successfully assembling and testing the spectrograph and enclosure from April through June, the team was able to observe with GHOST on-sky for only two good nights at the end of June due to poor weather conditions. A few more good nights in September resulted in further commissioning progress. Presently, the team is working on improving the data deduction pipeline software and the telescope control software to remedy issues determined during these commissioning runs. These improvements are expected to be complete by early 2023.
It has recently been noticed that the sensitivity of GMOS-N B600 observations at wavelengths blueward of 500 nm is significantly lower than predicted by the Exposure Time Calculator. Historic data of spectrophotometric standard stars show that this reduction in sensitivity is largely attributed to a decrease of the B600 grating response, which started to develop around 2013 to 2014.
