At LBTO, first-generation instruments are deployed in pairs. The Multi-Object Double Spectrograph for the Large Binocular Telescope (MODS1 and MODS2) pair is the second one to have been fully installed and commissioned on the telescope. The Large Binocular Cameras have been in binocular mode since 2008.
MODS2 was reunited with MODS1 on Mt Graham in April 2014. Following commissioning, completed by mid-2015, MODS2 was used for science in the second half of 2015, when only one eye of the telescope was available. With the telescope back to two-eye mode at the end of 2015, it was time to move forward and test MODS1 and MODS2 in binocular mode.

Snapshot of the telescope monitoring screen with the two MODS in action (guider and primary mirror active optics wave-front sensor images displayed for each). The red “ADSEC-OFF” on the right side shows that the rigid secondary is used while the right-side adaptive secondary is being serviced.

As a first step, MODS Principal Investigator Richard Pogge (Ohio State University) worked on the interface between the instruments and the telescope to make possible the use of single-MODS scripts for a binocular observation where each MODS is actually doing the same observation, opening the possibility to reduce by nearly a factor of two the time needed for an observing program. While still in early engineering mode, this is an important step toward a more efficient use of MODS telescope time, which is one of the raisons d’être of the binocular nature of LBT!

There is more work ahead to make this mode user-friendly enough to be used by observers. LBTO could offer binocular observations with MODS in shared risk toward the end of the semester. Stay tuned…

The “official” MODS1+2 binocular first-light: a long-slit spectrum of the Seyfert galaxy NGC1068
(3x5mn exposures on each side).