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Interlude: Installing new cold stops and a J-band filter into Clio2

Meanwhile, back in Tucson… We interrupt the NAS Fitcheck program to bring you this update on the Clio2 infrared camera.

After the Pre-Ship Review for Clio2 in Amsterdam in July, we have been completing preparations to receive diffraction-limited near-IR to thermal-IR photons from MagAO. Yesterday and today we installed the new J-band filter, and the cold pupil stops sized for Magellan. This was done in a CAAO lab at Steward Observatory in Tucson, where Clio2 is undergoing its final testing before shipment.

Cold pupil stops: Clio2 used to be “Clio” and was installed on the MMT telescope in Arizona. The MMT, like Magellan, is a 6.5-m telescope, but the Magellan secondary is 0.85m while the MMT secondary is 0.7m. Therefore, because the pupil is different, we needed two new cold stops for Clio2 on Magellan. A cold stop is a cryogenically-cooled metal mask located at an image of the telescope pupil, and its purpose is to block stray light (heat sources in the dome cause a lot of background thermal light) from contaminating the infrared image. Here is a picture of the pupil wheel with the new cold stops:

Clockwise from Phil's hand: 3-hole non-redundant aperture mask (NRM); 6-hole non-redundant aperture mask (NRM); Wide-camera cold stop (home); M-band apodized-phase plate (APP); L'-band apodized-phase plate (APP); Narrow-camera cold stop.

We also added a new J-band filter, taking out the old 3-5um Janostech filter from filter-wheel 1:

Clockwise from the red arrow: J (new), Blocked (for darks), Open (home), MKO M', Barr M, Direct vision prism, 3.1um, Barr L'.

We updated the Clio2 user manual at http://zero.as.arizona.edu/groups/clio2usermanual/ so that we can repeat this in Chile if need be.  Note the tools required: Most of the wrenches were found in a standard set of Allen keys, except for the 0.035” driver which is a special size.

Tools required for changing Clio2 filters: Phillips/flat head, 0.035, 5/64, 3/32, 7/64, and 9/64 inch Allen keys.

It took about 3 hours to take it apart and insert the new filter and pupil stops, including finding new spacers, etc.  It took about 1 hour to put it all back together.

 

T.J. Rodigas (foreground) and Andy Skemer (background) helped take Clio2 apart.
The box labeled 3 and 4 contains filter wheels 1 and 2. The box labeled 2 contains the cold pupil stops. We disconnected the wires and unscrewed the bellows (those keep the shafts straight at cryo temperatures) to access the filter and pupil wheels.
The same view as the previous image, with the filter and pupil wheels removed.
Two by two, hands of blue
Opening the pupil box to put in the new cold stops, and also Phil put in a new home switch. (Otherwise we could have just inserted the new cold stops through the port and not had to open it all the way.)
Oli Durney putting Clio2 back together

 

NAS Fitcheck Day 3: Cold, Pressurized, and Telecentric

The weather has taken a turn for the worse at LCO. It is currently 1.8C and blowing at 32.7 mph. And getting colder.

Speaking of cold, we installed the new liquid cooling system in the W-Unit today.

Jared and Laird installing the brass cold-plates on our CCDs.
Jason getting ready to install the shutter. Jason first assembled the shutter heatsink and mounting system nearly 2 years ago.
Jared checking the shutter mounting. It is a tight fit, and we don't want any metal-metal contact because the shutter vibrates. A lot.
The team at work on the NAS, under appropriate supervision.
The finished product.
The test gauge for the CCD cooling system.

The other big accomplishment in world of the NAS today was Laird installing the Telecentric Lens. This almost flat lens lets us work off-axis, away from the guide star.

The new telecentric lens.
View past the cube, through the new telecentric lens. That's L1 there.
After installing new glass, we checked the system. Everything looks great - the wavefront is flat and our i' PSF is 3.2 pixels. Click for more pixels.

We also got some time in the dome, and did a little work on the Clay telescope. The vane-end trays are installed, and the leak preventing solenoid valve was plumbed and tested.

Jason and Juan working on the solenoid.
Installing the vane end trays.

This hawk was hanging out over the observatory at lunch today.

A hawk over Magellan. Click for full wingspan.

Tonight’s pretty pictures are from Alan Uomoto, who spent some time messing with his camera’s settings today.

The beginning of the weather. Note the top of the fog in the valley below. Click for bigger.
A panoramic view of the hotel and Las Campanas itself. Click for more awesome.

Days without a motherboard failure: 2

NAS Fitcheck Day 2: Plumbing

Today our big plumbing efforts started in earnest. The cooling system that Jason assembled in Tucson was unpacked today, and the complete circuit was put together. It is currently holding pressure (20#), and we’ll see if it holds all night.

Jason Lewis applies thread sealant to a fitting.
Laird, Jason, and Alan discuss routing of glycol, and Tyson is installing some fittings.
Jason and Tyson conducting a soap bubble test.

Still no big animals. The Viscacha was on its perch this morning. Povilas saw a fox (a.k.a. Zorro) recently, so we are on the lookout. I hear they used to be very common here.

I missed sunset tonight, but this was the mountain top after breakfast.
That's Las Campanas behind the hotel. They have finished blasting now, and you can really tell how flat it is. The future home of the GMT.

Days without a motherboard failure: 1

NAS Fitcheck Day 1: All Back Together

The VisAO electronics box is completely back together and running, so you can stop worrying and get back to working on your 22 milli-arcsecond science case.

The VisAO box fully assembled.

In addition to rebuilding the computer, I took the opportunity to organize cables and make everything look tidy. I also turned on the W-Unit and tested everything out. It all still works. The only real excitement today happened when I turned on the old vizcacha computer to check a few files from the unpacking run, and a capacitor exploded. It turns out that’s why that model of motherboard was on the scrap heap here – they make loud noises and give off smoke.

Laird, Alan, and Jason arrived today. That means a lot more work will be getting done, and hopefully more pictures will get taken. I’ve so far seen neither hide nor hair of our larger 4 legged friends, so you’ll have to settle for another sunset.

That's the 100 inch telescope in the fg.
Same sunset, but looking more towards the south.

NAS Fitcheck Day 0: Empanada Sunday

Lunch on Sunday is always empanadas here at LCO, and it’s cold enough that a big bowl of hot soup hits the spot.

My lunch today.

Today was spent rebuilding VisAO after the cooling box interference and the motherboard fiasco from unpacking. It’s almost back together (and I have 2 spare motherboards just in case). But sadly that meant it was time to say goodbye to vizcacha, the stand-in VisAO computer. As if to mark the occasion, our old friend the cleanroom Viscacha said hello this morning.

He still seems pretty skeptical of me.

Here’s the VisAO cooling box, modified so it can stay installed on the handling cart. It used to be a rectangle.

The VisAO cooling box, with modification to fit on the handling cart.

Tonight’s pretty picture:

The moon at sunset from outside the cleanroom.

The grown ups arrive tomorrow, so I guess that means we’ll start using positive numbers.