Tag: 2012B

Here at LCO, we spend a lot of time staring at the sky, and not just with our instruments! I’ve noticed, for example, that the Belt of Venus is quite prominent and beautiful at sunrise and sunset. For those of you who’ve never noticed it, the Belt of Venus is the pink band of light that stretches all along the horizon at sunrise and sunset. It’s most interesting if you look opposite the setting or rising sun. There, you’ll see a dark band spread up from the horizon at sunset or recede into the horizon at sunrise. This is the Earth’s shadow! You’re seeing a place on earth where the sun has already set (or not yet risen).

I also took a video panning around the horizon at both sunrise and sunset so that you could see the full effect.

[Video coming soon]

We also have a tradition of looking for the green flash at sunset from the Clay balcony. A few days ago, we finally saw it, and I managed to capture a picture!

Here’s a zoomed-in version:

There are lots of misconceptions about the green flash, and I’ve looked for it many times before, but this is only my second time seeing it. It should happen just AFTER the red setting sun drops below the horizon. What you are seeing is earth’s atmosphere acting like a prism and refracting (bending) different colors of light by different amounts. The blue/green limb of the sun sets last.

You can actually see this effect even during the day if you (carefully!) create a large image of the sun. Here, for example, is a picture of the red limb of the sun taken at a teen Astronomy Camp:

That’s all for today, but I’ve been practicing my astrophotography too, so stay tuned for some nighttime shots!

The return of the Crow part II:

Edgar Allen Poe—
Once upon a midnight dreary, while I pondered weak and weary,
Over many a quaint and curious volume of forgotten lore…
…Only this, and nothing more:

The excerpt from the poem “The Raven” is brought to you by the Return of the Crow part II.

That is, we put the CRO back on this afternoon, so that we could spend the evening and night making new interaction matrices. We used a new pattern file from Charlie from SciMeasure, and were able to do bins 3, 4, and 5 — the faint modes — as well as testing the chromaticity of the interaction matrices. Tomorrow we will go back on sky to try them out!

We also spent a lot of time making sure we understand our data. We *still* weren’t certain about the orientations of our respective cameras — Jared, Kate, and Laird spent a lot of time disagreeing about which way to rotate the VisAO images to get North up. And T.J., Katie, and Phil spent some time with the Clio FITS headers and with Clio read noise. Our night-lunch sandwiches are wrapped in tinfoil, and T.J. scavenged it to wrap some wires to reduce electrical noise.

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Tyson has left and we miss him — Tyson, when will we see that special blog post of yours?

“I’m not interested in discoveries.  I just want to take data.” – T.J.  (6am after staying up all night)

“It’s a binary. No look, it’s a binary!” – T.J.

Things are always exciting here on the MagAO project. But nothing – not earthquakes, viscacha attacks, not even non-orthogonal basis sets – can keep us from doing what we came here to do. Now that we are on-sky, we are taking advantage of the *amazing* 0.5 arcsecond seeing common at LCO to take some nice pictures. Last night we were looking at the Trapezium cluster to calibrate our plate-scales, and we took a few moments to take this image:

We didn’t cheat – no shift and add or other tricks.

After we solved last night’s communication problems, we did some engineering work, specifically getting Coma-offloading to work. I hate rotation matrices. Later, seeing calmed down, and we took some fantastic images. Here’s a screen grab from VisAO working at 0.982 microns. It’s a log stretch, and captures a single 0.28 second frame on a bright star.

And here’s our M-band PSF from tonight:

We tested turning off the Clio pump to reduce vibrations in the 25-milli-arc-second VisAO PSF.  But since the Clio folks were observing at M-band, a 0.5-degree increase in temperature of Clio’s inner dewar caused a 3% increase in their thermal background.  Therefore, we turned the pump back on again, and the sky background settled back down as the detector cooled.  Here’s a curve showing the effect on Clio of turning off and on the pump:

Runa Briguglio, who is here from Florence helping us take care of the shell, suggests that we operate by this guideline:

Some quotes:
“If I’m doing what I think I’m doing, I’m an idiot. Yes! I’m doing what I think I’m doing!” – Glenn Eychaner, who came up the mountain today just to help us debug our TCS-MagAO communications problem. Thanks Glenn!

Tonight started with a hard to understand communications problem between our AO system and the telescope control system (TCS). It’s been working for days, but tonight we started having some messages get dropped. We have to keep the elevation of the telescope above a certain value to keep our delicate mirror safe, and this communications problem was causing us to stop getting elevation often enough. So our mirror RIP-ed, which means rest-in-peace. We don’t know what’s going on, but we hacked our way out of it by changing some timings. Troubleshooting begins again tomorrow after supper – I can’t wait.

After that, we had a very productive night. We looked at a standard star to calibrate our filters, and also looked at some well known clusters of stars to calibrate the plate-scales of our camera. Both cameras also had their foci checked. Kind of boring scientifically, but it’s important that we characterize our new instruments on real stars.

Katie and I were charged by a Viscacaha on our way down the mountain this morning. They’re turning against us.

And as I’m typing this we just got hit with an earthquake:

We also saw a hare this morning, a MagAO first.

“I’m a fan too, not just your families. I miss viscachas.” – Prof. Dan Marrone, captain of the Steward Observatory softball team and MagAO enthusiast.

“Keep calm and carry on.” – Runa Briguglio.

Our ranks are thinning — Alan Uomoto left today and I didn’t even get to say goodbye.  Bye Alan!  Thanks for all your help in getting us up and running!!

We are still engineering our many modes on sky and debugging telescope and instrument problems.  One of our exciting new modes is Simultaneous Differential Imaging (SDI), which we tried out on-sky tonight!

Our ASM is a beautiful piece of advanced technology, keeping our wavefronts flat at 1000 times/second (read Kate’s post for why!).  But occasionally the slopes being sent cause the ASM shell to go into its safe position.  It’s either the switch BCU or the BCU 39.  We have a spare switch BCU (see below), but don’t have a spare BCU 39 with us. Hang in there BCUs.

My mom would like to know what a vizcacha is — They are these little rodents, basically a rabbit, squirrel and kangaroo in one package, that live here at LCO and entertain us sunning themselves on the wall or hopping like kangaroos across the rocks!  The official mascot of VisAO is Vizzy the Vizcacha:

And speaking of mascots, the Clio team have been wearing our UA Wildcat pride here at LCO: