Tag: MAPS

Today/tonight Dan and Amali went down, Dan and Oli came up, and Craig and Oli went down. Oli brought up six (6) new negative lenses ranging from f=-100 to -1000mm to test the Vis WFS pupil focus. We took another image set with the current lens (f=-300mm) and then swapped it out for each of the other lenses to see the difference in pupil focus and pupil size/separation. Here is what we saw:

Result: The best are f=-200 & f=-300. Oli’s feeling is the best focal length is going to be around f=-250mm. That lens is not available but can be created by combining two lenses. Furthermore, there are other degrees of freedom that can be used to fine tune… namely the separations between the CCID75, CTL, and Pyramid. By adjusting those distances, the overall magnification (pupil size and separation) will change. This is a much more complicated alignment and is destructive since a move cannot be perfectly reversed. So we may try that another time.

Meanwhile we took some ARIES spectra, then went on to closing the CACAO loop with 50 modes and saving some ARIES images. Unfortunately the seeing was around 2-3” so these won’t be great, but it was also a really good practice session for Lauren and Bianca to run CACAO while Amali coached them remotely from Tucson.

There was a dust storm blowing over from New Mexico. Around 3:45am it got worse, and meanwhile the seeing had blown up to above 3” where we were unable to make much progress anyway, so it was time to close for the night. We have 1 more night but the forecast doesn’t look promising, so we shall see.

The word of the night is TEAMWORK. The MAPS team has done a great job this run covering the various tasks even though various people have had to come and go due to life circumstances. Thanks for the excellent teamwork, MAPS team!

Tonight we worked with the Vis WFS and got up to 50 modes we think. We also made the pupils rounder:

And at the start of the night we took some darks for Suresh to figure out the IR WFS camera:

And we took some MLAT’s with different tuning parameters for Jess.

The word of the night is 霧 (kiri) which means fog. Kiri came up just at the end of the night.

We never opened the dome tonight, due to high winds. And in Yokohama it rained hard all day.

Manny went down and Dan came up.

Dan and Amali measured voltages on various pins of the SAPHIRA under Suresh’s guidance. Based on their measurement, the detector temperature matches what is observed by the cold head. So it is not a temperature issue and likely an electronics issue. The next step was to measure two separate voltages to ensure they are correct. They were all around 5V which is where they were supposed to be. Suresh is now crunching the data to see if it gives any other clues to the IR WFS behavior.

The word of the night is たいふう (Typhoon) because apparently all this rain in Yokohama today was actually a small typhoon.

Tonight we worked more on alignment of the WFS pupils (both WFS’s). At the start of the night we attached a cardboard “knife edge” to the ASM so that we could compare the primary mirror and secondary mirror images.

Here’s the resulting image on the ZWO:

And here’s the result on ARIES:

And here are the Vis pyramid pupils:

Checking optics/focus: double knife edge test using primary mirror cover partially lowered and cardboard over ASM (mounted on posts). VIS: – Expectation: one edge would be sharper if said edge was closer to point of focus. – Observation: neither edge is sharp. Fall off on both edges is about 3 pixels on viswfs_pupils. – Assessment: Focal point is near primary, pupil plane inside topbox is somewhat correct.

Next we worked on the IR WFS. We could see the IR source on the SAPHIRA, but only just barely could see the white-light source, and when we went to a really bright and red star (Arcturus) we couldn’t see it. The dark counts were around 30,000 and looked normal (the full well depth is around 100,000), but when Suresh did an up-the-ramp test (which usually saturates after ~20 steps) it saturated after ~5 steps, and wasn’t enough steps to see if it was linear. So now we think either there is a thermal short or some thermal problem, or perhaps a readout/reset problem. TBD.

So we went back to Vis WFS alignment. Oli and Grant did some experiments changing the negative lens (first adjusting it, then removing it completely). Here is one result:

We were closed for high winds from around 1:50am-3:30. During this time we put the negative lens back in. When we opened again we checked it out:

We also tested going to a fainter (almost 7th mag) star and saw that we have plenty of photons on the CCID-75. Now with the winds close to our limit and having completed our engineering tests, the next thing is to get back to working on AO calibrations, but it was too close to dawn to get anywhere especially fighting the almost-limits-winds, so we called it a night.

Meanwhile at the conference there were great talks by Robin, Eden, and Jacob:

Word of the day: “Sumimasen” — excuse me.

Today was the first day of the conference and my talk: “Commissioning MAPS, the MMT AO exoPlanet characterization System.” It went pretty well and it’s also nice to be done with that right at the start of the week! There were a few MAPS-ers in the audience and here’s a photo by one of them, Suresh:

Meanwhile back at MMTO, Brian had a message from Tim that it would be better to take the large tens-of-arcseconds mount offsets and offload them to the hexapod with zero-coma offsets. After he did that the team tested whether the star was still on the chief ray by rotating the instrument and watching it on ARIES — and it was good!

Oli came up tonight and he and Grant put in the ZWO pupil-imaging camera and did the same test we did yesterday to check if offsetting the star shifted the pupils, meaning they are mis-conjugated. However, they only saw a quarter of a pixel shift, or about 5um, which is about 2um out of tolerance (3um tolerance) and still close enough.

Suresh is also observing remotely from Japan and was in communication with the team about the IR camera weirdness from yesterday — the pressure seems high (or the reading is off), and/or the camera isn’t cool enough — so we turned it off for now and will pump on it all day while sleeping. Before that Grant/Oli/Manny went up to check the seating of the fibers in the Top Box.

Finally we tried to do some CACAO and began working our way through a few software bugs. We realized we needed Jared’s help with the pseudo inverse but he was at the conference reception.

We also started looking at our pupils more and decided to explore the alignment and pupil conjugation further. Oli and Grant tried adjusting the negative lens between the pellicle and pyramid. But even with 3 turns and almost all the way off, there was no noticeable difference in the pupil images:

But isn’t it strange that they still look so raggedy, and we can’t even see the spiders? We were wondering about this. So we decided to try and make something even more obvious to see. Some kind of a sharp edge. Shall we say a knife edge.

So we asked Brian to partially obscure the pupil by putting the primary mirror cover tarp about 1/3 of the way across. And here are the pupil images after this. First the ZWO:

Which looks a lot like ARIES in K-band:

And finally the Vis WFS pupils:

They all have a sharp knife edge from the primary mirror cover tarp. But the central obscuration is fuzzy on the Vis, whereas it is sharp in both ZWO and ARIES. And another curious thing is that the IR pupils have a sharper central obscuration.

It was about dawn and our brains were tired, so we will explore this a bit more tomorrow night. But it is curious that we can get a sharp knife edge on the Vis pupils but not a sharp central obscuration. Furthermore it is curious that the IR pupils did have a sharper central obscuration (last run).

The word of the night is Santoku. “Santoku means ‘Three Virtues’ or ‘To solve Three Problems’. The three virtues are meat, fish and vegetables, or slicing, dicing and mincing depending on your interpretation. This means that the Santoku is an all-around knife, suitable for the amateur home cook and the professional chef alike.” [source]