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Bruce Macintosh

@bmacastro.bsky.social
1.8K followers 559 following 558 posts

Astronomer working on imaging extrasolar planets, instrumentation, and science policy. Spare time: hiking with a golden retriever, and not playing enough boardgames. Director, University of California Observatories, but opinions are my own. He/him

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Bruce Macintosh @bmacastro.bsky.social · 07/10/2026
Triangle sign hates particle sign.
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Bruce Macintosh @bmacastro.bsky.social · 06/10/2026
One last thing: my absolute favorite figure from the paper isn't the "hey, we made a star look small" picture, but this: a temporal power spectrum of the wavefront error with and without AO, laser and natural. If you know what those words mean we can be friends.
Graphs showing the power spectrum of the wavefront; y axis (log scale) is how much wavefront error there is, x axis (log scale from 0.01 to 100 Hz) is how fast the turbulence is moving. Upper panel compares the uncorrected atmosphere with correction on a bright natural guide star, lower panel compares uncorrected atmosphere with correction from a laser guide star, which did about as well.
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Bruce Macintosh @bmacastro.bsky.social · 03/09/2026
I love this figure.
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Bruce Macintosh @bmacastro.bsky.social · 09/06/2026
I feel like the people in their astronomy department might need to revisit the whole “telescopes: do they go indoors?“ question
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Bruce Macintosh @bmacastro.bsky.social · 16/05/2026
For me I suppose this one has a certain amount of definitiveness in direct imaging, at least until we get an Earth.
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Bruce Macintosh @bmacastro.bsky.social · 08/05/2026
The star HR8799 orbited by several Vole Dwarfs
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Bruce Macintosh @bmacastro.bsky.social · 12/04/2026
we can see the outer equivalent - like Kuiper belt dust - around dozens of other stars; mostly younger stars whose small bodies haven’t settled down and so are colliding thousands of times more than our system. This gallery is from GPI (Esposito et al.) vcresearch.berkeley.edu/sites/defaul...
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Bruce Macintosh @bmacastro.bsky.social · 15/03/2026
Best it could find was He II . Is ionization hell?
A whiteboard covered with astronomy. The word “hell”does not appear. He II does. For weird historical reasons, astronomers refer to singly ionized helium as He II pronounced “Helium two”. Double ionized would be “He III”,  pronounced “Helium 3”, not to be confused with the isotope He 3 pronounced “Helium 3”. Fortunately most astronomers don’t build things where this confusion could result in something exploding.
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Bruce Macintosh @bmacastro.bsky.social · 10/03/2026
Lovely images! So many beautiful galaxies. Are the images black-on-white negatives (a) to bring out faint structure, or (b) to give a deliberately retro photographic plate vibe? Please say b.
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Bruce Macintosh @bmacastro.bsky.social · 10/02/2026
We all show this figure, but I seriously agree with Peter that we need to rethink that. It tells a story but doesn't actually convey more than one or two important facts. It's almost ritualistic.
Plot showing the planetary mass vs orbital semi-major axis of known exoplanets, colorcoded by discovery technique. Mostly it doesn't actually tell you anything useful. If you take your glasses off it looks like two upside down dinosaurs.
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Bruce Macintosh @bmacastro.bsky.social · 22/01/2026
@lickobservatory.bsky.social update: the dome is now sealed! Thanks to the summit staff, contractors, and main-campus staff for an amazing amount of work over the past four months. Now we can catch our breath and plan how to checkout/repair the telescope and the dome.
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Bruce Macintosh @bmacastro.bsky.social · 02/01/2026
And then finally Dr. Gates dug up this terrifying video of the actual fall striking sparks as it hits the parking lot. Plus lightning flashes. Sad to watch but nice use of multi-messenger science to track down the event.
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Bruce Macintosh @bmacastro.bsky.social · 02/01/2026
Firewatch cameras show the shutter on the dome at 3:16 and on the ground at 3:18
Camera image from 3:16 with the dome and shutter barely visible Camera image two minutes later with the dome and the shutter torn off
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Bruce Macintosh @bmacastro.bsky.social · 02/01/2026
Weather records show the highest winds then, and a disturbingly large drop in barometric pressure
Wind speeds from various Mt. Hamilton sensors. Barometer readings at Mt. Hamilton showing a sharp pressure drop
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Bruce Macintosh @bmacastro.bsky.social · 02/01/2026
One nice piece of detective work for the Christmas morning shutter failure at Lick - staff astronomer Dr. Elinor Gates (with others) figured out exactly what time the shutter fell down. The first major clue: records from the seismometer in the building. There's a sharp red spike just after 3:16 AM.
Seismograph readings from Lick Observatory showing a sharp shock just after 3:16 AM
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Bruce Macintosh @bmacastro.bsky.social · 31/12/2025
Yesterday's update - contractors and staff (working almost to midnight) got the roof holes patched and the floor protected, though the dome itself is going to have to remain open until we have several days without rain.
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Bruce Macintosh @bmacastro.bsky.social · 29/12/2025
Pictures from when I was up there over the weekend, protecting things as best we can.
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Bruce Macintosh @bmacastro.bsky.social · 29/12/2025
You don't really appreciate how big the shutter (and the dome) are until you see them on the ground.
Shutter in the parking lot with two people standing near it. The shutter is huge. Photo by Jamey EriksenShutter in the parking lot with a view of the crane
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Bruce Macintosh @bmacastro.bsky.social · 29/12/2025
Lick updates: We got a crane up there Friday and the winds dropped enough by Saturday to get the shutter off the roof.
Large crane going up the narrow road. Photo by Jamey EriksenCrane attaching to the shutter. Photo by Elinor GatesCrane lowering the shutter into the parking lot. Photo by Elinor Gates
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Bruce Macintosh @bmacastro.bsky.social · 27/12/2025
Mountaintop staff worked heroically all day Christmas to protect the telescope as best they could and remove water and secure and assess the building. The shutter (probably about two tons) also did significant damage to the roof of the historic main building.
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Bruce Macintosh @bmacastro.bsky.social · 27/12/2025
In not-very-good news, extreme winds (114 mph gusts) on the early morning of the 25th caused significant damage to the 36" Great Refractor at Lick Observatory. Half of the main shutter broke off and landed on the main building.
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Bruce Macintosh @bmacastro.bsky.social · 08/12/2025
Movie you’ve watched more than six times with a gif. Hard mode (no Star Wars or Star Trek, LOTR, Marvel, Disney, or Pixar)
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Bruce Macintosh @bmacastro.bsky.social · 08/11/2025
Nexus
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Bruce Macintosh @bmacastro.bsky.social · 04/11/2025
This is a pretty darn important election here in California for an odd-numbered year. Get out there!
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Bruce Macintosh @bmacastro.bsky.social · 29/10/2025
...yes you do static.wikia.nocookie.net/memoryalpha/...
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Bruce Macintosh @bmacastro.bsky.social · 24/10/2025
This is going to sound corny, but to me, @ucmerced.bsky.social 's vibe was...hopeful. Building something excellent and new for the very best of reasons, to teach the students of California. Also the adorable bobcat is now tied with the UCSC slug for my favorite UC mascot.
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Bruce Macintosh @bmacastro.bsky.social · 11/08/2025
SGL is the most likely one I was thinking of (though to be fair 10km is hard.) See for example arxiv.org/abs/2002.11871 or arxiv.org/abs/2204.13811
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Bruce Macintosh @bmacastro.bsky.social · 04/05/2025
Other highlights include the mandatory chile enchiladas with egg, and a very nice hike up Tortuga Mountain with Eric Nielsen and the students of the exoplanet/young stars group, including excellent corgis.
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Bruce Macintosh @bmacastro.bsky.social · 04/05/2025
Fortunately there's actually a considerable literature on extrasolar plants, for example O'Malley-James & Kaltenegger 2019.
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Bruce Macintosh @bmacastro.bsky.social · 04/05/2025
Back from a nice visit to New Mexico State University. Based on the departmental poster I realized the audience might want something different so I responded accordingly.
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Bruce Macintosh @bmacastro.bsky.social · 29/04/2025
Does it look something like this?
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Bruce Macintosh @bmacastro.bsky.social · 20/02/2025
Meanwhile: we're doing the first full cooldown of the upgraded spectrograph for the Gemini Planet Imager.
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Bruce Macintosh @bmacastro.bsky.social · 30/12/2024
We got a couple of pounds of fresh mochi from a friends' church that does a large-scale Mochisuki. (Pre-covid we helped out on the assembly line.)
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Bruce Macintosh @bmacastro.bsky.social · 29/12/2024
Bluesky didn't seem to animate the previous GIF so here's a movie version. Kept in this loop forever. I'm pretty sure I am human, but what do I know?
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Bruce Macintosh @bmacastro.bsky.social · 29/12/2024
Researchgate ("The Pinterest of science") seems utterly unwilling to believe I am human and I am peculiarly insulted.
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Bruce Macintosh @bmacastro.bsky.social · 25/12/2024
These are model Gundams from Bandai. Snap together, decorate with stickers and markers so no painting (at least for me). This one is a super-deformed (chibi) version of the XV-016 Aerial.
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Bruce Macintosh @bmacastro.bsky.social · 13/12/2024
Build (adorable) model mecha
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Bruce Macintosh @bmacastro.bsky.social · 01/12/2024
Note that is unknown whether most extrasolar planets are coated with a thin layer of olive oil, so these are not perfect analogs. But promising! I have added the cauliflower boundary to this figure from a great paper by Kielan Hoch, arxiv.org/abs/2212.04557
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Bruce Macintosh @bmacastro.bsky.social · 01/12/2024
Result: cauliflower heated to temperatures lower than the typical hot jupiter loses 40% of its mass, almost half of its water, and hence a lot of its oxygen. This gives a C/O ratio of 0.35, consistent with the hot jupiters.
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Bruce Macintosh @bmacastro.bsky.social · 01/12/2024
This is similar to many extrasolar planets. See for example this figure from the excellent Thorngren, @jjfplanet.bsky.social et al arxiv.org/abs/1511.07854 to which I have helpfully added what I hope will be known going forward as the the Macintosh-Marley Cauliflower Boundary.
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Bruce Macintosh @bmacastro.bsky.social · 16/11/2024
We used the PSDI propagation software to model GPI, and worked with an EUVL-inspired vendor (Precision Asphere) to polish individual mirrors in GPI to < 1 nm RMS. (Measurement here is just from a commercial Zygote)
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Bruce Macintosh @bmacastro.bsky.social · 16/11/2024
We used this technology to characterize optics for GPI, especially the MEMS deformable mirror, and show that we could flatten the DM to <1 nm absolute accuracy, precision, and stability.
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Bruce Macintosh @bmacastro.bsky.social · 16/11/2024
LLNL also developed what was probably the world's most advanced precision interferometer, the lensless phase-shifting diffraction interferometer (PSDI). Led by the brilliant Gary Sommargren, it used a tiny perfect pinhole to make a perfect spherical wavefront, embedded in a superpolished surface
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Bruce Macintosh @bmacastro.bsky.social · 14/11/2024
NSF CV-generation submittal certification is disturbingly specific.
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Bruce Macintosh @bmacastro.bsky.social · 17/07/2024
Since we're doing SL9 anniversary, here's the Keck Observatory sequence of an impact - the fireball (1300 km high!) becomes visible over the edge of Jupiter. Raw IR data with a terrible camera and a small field of view and still amazing. (Imke de Pater, James Graham, Mike Liu, and @plutokiller.com
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Bruce Macintosh @bmacastro.bsky.social · 16/06/2024
And, finally, the awesome coronagraph(sitting quietly in its box under an extra layer of dust protection because it is that special.)
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Bruce Macintosh @bmacastro.bsky.social · 16/06/2024
The snoot-shield somewhat later as they tested stowing/deploying it.
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Bruce Macintosh @bmacastro.bsky.social · 15/06/2024
The six black round things are reaction wheels - the big gyroscopes that provide torque to change the direction of the telescope. (Three, plus three spares.) I dislike these intensely. (Ask me why!)
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Bruce Macintosh @bmacastro.bsky.social · 15/06/2024
The main spacecraft bus. Full of electronics and propulsion (not yet installed) and all the things that a spacecraft needs that aren't actual telescope bits.
Hexagonal spacecraft bus, about the height of a human being. Space in the middle for the propulsion module to go.
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Bruce Macintosh @bmacastro.bsky.social · 15/06/2024
Avionics panels. I love how much these look like giant printed circuit boards.
Giant printed circuit boards taller than a personDiagram showing how the six circuit panels wrap around the spacecraft bus
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