Tuesday, July 30, 2013

Lab tests completed: AdSec-DX is good to go!

The AdSec-DX unit passed all its lab tests with flying colors and is now in the clean room tent on the integration stand awaiting its reintegration with the hub. An amazing achievement by an amazing team of people from Arcetri, LBTO, UofA, and MicroGate!

The last step of the lab tests followed the integration of a mylar patch over the mouse hole (a feature of the thin shell #4), which can be seen on the before and after pictures below before and after the patch was applied.

 Before... the mouse hole is just above the inner hole of the shell. 
Through the hole, one can see the reference and a couple of actuator holes under the shell.

 After... The hole is patched

Testing included static setting of the shell, dynamic elevation slew testing (zenith to 70 degrees off zenith), thermal testing at zenith and 70 degrees off zenith and testing of thin shell rotation while setting at various elevation angles. The results of all tests were favorable and the DX AdSec is now ready for integration with the telescope.

The unit will be reintegrated on its hub in the middle of August and is scheduled to be back on the telescope around Aug 21 for a lot of day time work before seeing the sky after the shutdown and restart of the telescope, sometime in mid-September. Stay tuned...

In case you wonder what this mouse hole is about... TS4 developed a couple of fractures following an incident during the edging of the inner hole. These cracks were quickly stopped through drilling and then a circular hole (the mouse hole) was ground to remove the damaged area. Six years later, a patch was finally designed and installed to cover the mouse hole!

  The mouse hole as seen right after the aluminizing of the thin shell (April 2013)

Thursday, July 11, 2013

The shell is integrated.. and doing well!

The final goal of this week's campaign objectives were to integrate TS4 with the reference body and successfully flatten the shell.

The campaign objectives were met and the shell was flattened this morning (Jul 11). Further, the shell has been centered and the inner ring is secured. Additional tests were performed remotely from Italy to obtain a feed forward calibration matrix.

Kudos to the main players of the week: Roberto Biasi (MicroGate), Armando Riccardi (Arcetri), Michael Wagner and Michael Lefebvre (LBTO).
We are now closer to the ultimate objective of reinstalling the DX adaptive secondary on the telescope and getting back on sky.

AdSec-DX with its new shell

One proud Michael Wagner ;)

Roberto Biasi (left) with Guido Brusa (center) and Julian Christou (right)

Tuesday, July 9, 2013

All 672 actuators good to go...

The unit has been electrically tested and after some actuator repairs, appears to be fully functional. All 672 actuators were successfully measured with a fixed capacitance, coil current checked, and replaced actuators were checked for correct polarity.

Next step: integration of the new thin shell (TS4)

Testing the actuators one by one...


Monday, July 8, 2013

Unit reassembled (without the shell)

Since mid-Saturday (Jul 6) and up to Thursday, much work is scheduled around AdSec-DX with the visit of Roberto Biasi from Microgate assisted by LBTO staff and remotely by the Arcetri group.

So far, the team is on schedule. The system has been fully reassembled without the shell and partially tested (first power-up and test of a selection of actuators to validate the flat cables connection). Some time was also spent analyzing the actuators depth variations versus elevation angle (more to come on this later).

 Pressure tests of the cooling system.  The unit is inverted for protection 
of the actuators, cold plate, and reference body in the event of a leak.