Saturday, August 17, 2013

MODS2 passes its preliminary acceptance tests at OSU

MODS2 is the second of a pair of Multi-Object Double-beam Spectrographs designed and built for LBTO by the Department of Astronomy at Ohio State University. 

MODS1, the first of the pair, has been offered to the LBTO users for regular observing since the last quarter of 2011.
MODS1 at LBT's left direct gregorian focus 

On the second week of August 2013, forty months after MODS1, it was the turn of MODS2 to go through its laboratory acceptance tests, which it passed with flying colors! The instrument was cleared for shipping to the observatory on Mt Graham. MODS2 is expected to be on the mountain by mid-October 2013.

Rick Pogge, current MODS PI, in a show and tell in front of MODS2

Rick at the MODS2 control laptop with LBTO reviewers Olga Kuhn and Mark Wagner

Daniel Pappalardo (OSU) doing some explaining for Mark Wagner and Joar Brynnel (LBTO)

MODS2 is a near-perfect twin of MODS1, something which should make for a smooth integration at the telescope. The few changes made on MODS2 are actually improvements which will eventually be retrofitted to MODS1.

The lab acceptance of MODS2 is for LBTO a very important step, as it marks the completion of the construction phase of the first generation of facility instruments. LUCI2 was partially accepted in Europe in early June (only one of the cameras, still missing, will be completed in early 2014) and is now at the observatory.

The coming semesters will be very intense commissioning-wise and it is too early to give a tentative date for final acceptance on the sky of either LUCI2 or MODS2. More news on this when time comes! 

Saturday, August 10, 2013

Summer shutdown: SX primary recoating... and much more!

Monsoon season is summer shutdown time for the observatory. Don't think that not looking at the sky means nothing much happening under the LBT enclosure on Mt Graham! Much work is going on to clean, repair, maintain, or upgrade many of the components of the observatory.

Every year, one of the two 8.4m primary mirrors gets a facelift, I mean a fresh aluminum coating. This year, it is SX (the left mirror's) turn. On most telescopes, the mirror would be removed from the telescope and carried to a near-by lab to be cleaned and re-aluminized in a vacuum chamber. At LBT, the mirror stays on the telescope. The old coating is removed and the mirror washed while in its cell. The vacuum chamber, actually half of it (the bell jar) comes to the mirror and mates to its cell to form the vacuum chamber. 

The bell jar waiting in the high bay to be lifted to the telescope floor

The bell jar on the SX primary mirror

Once the aluminizing is done, the bell jar goes back to its storage place on the first floor of the observatory. The mirror got a new shiny coating without leaving the telescope... The whole process went very smoothly. Kudos to all involved!

The three SX bent gregorian focal stations  (from left, Linc-Nirvana, LBTI, and LUCI1) (top), 
and their reflection in the freshly recoated SX primary (bottom)

Done with realuminizing the SX primary mirror (on the right on this picture)

Here are some of the many activities are going on for this 2013 shutdown:
- Replacement of the hoses bringing glycol to the many chillers cooling mirrors, instruments, and their electronic cabinets. Not an easy task, as these hoses are going through the telescope azimuth cable wrap!
- Servicing the LBC's (Large Binocular Cameras)
- Adding or replacing sensors and valves in the ICS (Instrument Cooling System)
- Removing the tertiary mirrors, sending them out for recoating... and installing them back!
- Building a new stand for the 4D interferometer for the recalibration of the AdSec-DX at the end of the month...

Working on the filter wheel of LBCB

Plumbing work in progress on the instrument cooling system

Installing the 4D interferometer stand for AdSec-DX recalibration