For those commenting that Voyager 1 will be 1 light day away in November 2026, that's from Earth. My post said from the Sun. That happens on February 3, 2027.

In 1 year from today, Voyager 1 will be one light day from the Sun. 🔭 orbitsimulator.com/gravitySimul...

116 years of Barnard's Star: 1940 to 2056. Proper motion and parallax are visible. The field of view is ~ as wide as the full Moon. #astronomy #astro 🔭

What would happen if you took a full-sky picture every day at noon from San Francisco for a year? I have no idea! It’s too cloudy here. So I simulated it. #astronomy #analemma

Space ambulance: Dragon returns a sick astronaut to Earth. Shot from San Francisco minutes before splashdown off San Diego. Skip to ~1:00 if the slow horizon motion bores you. Thank you @marwellaspaceart.bsky.social for reminding me to look up! pic.x.com/cuXLHH2N2h

Comet 3I/ATLAS, our interstellar visitor, poses for my eVscope from San Francisco. @unistellar.bsky.social @unistellarusa.bsky.social

The first 4 asteroids discovered this year are 2026 AA 2026 AB 2026 AC 2026 AD

Finally! Tens of thousands of asteroids are found each year. Yet 2026 had ZERO through Jan 6. The drought is over. Possibly as big as a jet liner. Possibly as large as a football field. Meet 2026 AA. Blame the Full Moon for the drought.🌕 Expect many more soon.

Polaris is not always the North Star. Due to Earth's precession, over the course of 26,000 years, Polaris, Alderamin, Vega, and Thuban take turns as the closest prominent star to the celestial pole.

Flying into Orion’s Belt at 0.001c 🌌 The hunter isn’t flat. It’s a real 3D region of space. (Upgraded animation!) #astronomy 🔭

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Taurus is prominent in January's evening sky. The Hyades star cluster forms its familiar V-shape, and Aldebaran appears to belong to the cluster. But over ~100,000 years of proper motion, the illusion breaks: Aldebaran is moving to its own beat.

18 asteroids passed closer than the Moon in November. And every one of them was discovered this month. #Astronomy

Newly-discovered asteroid 2025 WZ₃ is currently passing through Earth's anti umbra 3 days before making a close approach of 1.15x the Moon's distance.

Asteroid 2022 RD₂ may become a mini-moon not once, but three times in 2043–2044. This may not exactly look like an orbit, But during each capture, if the Sun suddenly vanished, RD₂ would remain gravitationally bound to Earth indefinitely. iopscience.iop.org/article/10.3...

Comet C/2025 D1 (Groeller) has a perihelion over 14 AU, making it too dim for my backyard telescope. But it looks nice in Orbit Simulator. #Astronomy

The ESCAPADE mission to Mars is about to launch. It will stay near Earth for about 1 year before using an Oberth maneuver to send it to Mars.

Potentially Hazardous #Asteroid (PHA) 3361 Orpheus is an Apollo-class Near-Earth Asteroid (NEA). Last night it posed for a 30-minute image taken with my eVscope from San Francisco. Dim, mag 15.9 it is centered in the image. @unistellar.bsky.social

The asteroid is now known as 2025 UC11. This animation shows where the observations were made. #astronomy

A quick trip through the thermosphere turns newly-discovered asteroid ST25J47 from an Apollo to an Aten. It is no bigger than a meter.

After billions of years heading towards us, interstellar comet #3IATLAS is currently at its closest approach to the Sun right NOW. Perihelion. #astronomy #comet

Another mini-moon? Maybe. Newly discovered 2025 US6 is officially listed as an asteroid. Unlike our quasi-moon 2025 PN7, this one is actually bound to Earth, for now. Its orbit is pure chaos. Enjoy it while it lasts. It’ll probably be demoted to space junk.

Some YouTubes, even one by a famous astrophysicist, confuse mini-moons with quasi-moons. Simple test: 🔴 Delete the Sun. – Still orbiting Earth, even years later? Mini-moon (bound), like 2024 PT5. – Gone forever? Quasi-moon, like 2025 PN7.

What was 'quasi-moon' 2025 PN7 doing before it entered its quasi state? It was tracing horseshoe orbits. Horseshoe orbits are called that because some people think they look like horseshoes.

Watch Earth’s newest quasi-moon in motion. 🌍🌀 The new paper “Meet Arjuna 2025 PN7” confirms #asteroid 2025 PN7 is trapped in a quasi-satellite orbit, looping around Earth (in a rotating frame) from the 1960s to the 2080s. iopscience.iop.org/article/10.3...

Two Near-Earth Asteroids (NEAs) in the same field of view in my eVscope @unistellar. 2004 FN18 (middle) and 2000 EZ148.

2 Near EarthAsteroids in 1 FOV? Last night I imaged 2000 EZ148 at mag 15.1, and 2004 FN18 at mag 15.6 from San Francisco with my eVscope. Tomorrow night (Friday around 11pm PDT), they will be of similar brightness as they pass only 0.33 degrees from each other. 2000 EZ148 is the left image.

What if Juno left Jupiter to get a closer look at interstellar comet 3I/ATLAS? With a couple of burns, Juno can get as close as 25 million km. Purely hypothetical, fun orbital mechanics! 🔭 Thanks @adamsspaceresearch.bsky.social for the research and trajectory data. @i4interstellar.bsky.social

After last week's asteroid buzzed over Antarctica, the North Pole gets its turn. Newly-discovered #asteroid 2025 TQ2 (2-4 meters wide) passed 3,000 miles above the Fortress of Solitude. #Astronomy

Interstellar #comet 3I/ATLAS is hidden on the far side of the Sun from Earth. But today it sweeps past Mars, where orbiting spacecraft have ringside seats. Let’s hope they look up. #astronomy #NASA

An #asteroid passed just 300 km above Antarctica earlier today. It was not discovered until hours after close approach.

10 #asteroids passed closer than the Moon in a 5-day period from September 23-28. All were discovered this month. The largest up to 41 meters wide. #astronomy

October's comets. SWAN C/2025 R2, and Lemmon (C/2025 A6). Our interstellar visitor 3I/Atlas aka C/2025 N1, is unfortunately on the wrong side of the Sun for viewing, but I included it anyway because... well... it's interstellar. #Astronomy

#Asteroid 2024 YR4 has a ~4 % chance of hitting the Moon on Dec 22 2032. A strike could spike micrometeoroid flux in low Earth orbit ~1000×, endangering satellites—so researchers even study nuclear disruption. arxiv.org/pdf/2509.12351 My sim: 2000 clones; 72 hit.

Yesterday, newly-discovered #asteroid 2025 SU4 🦒passed closer than our geostationary satellites.

#SanFrancisco Earthquake just now. Shaking started before the cell phone alert sounded.

In the last 6 days, 9 asteroids passed inside the Moon’s orbit. Estimated sizes: ~1–38 m. All were discovered this month, a reminder that countless small, faint NEOs slip by unnoticed until they make a close pass.

It might seem scary that two mega-Chelyabinsks passed closer than the Moon this week. Good news: Earth is a small target. Even with gravitational lensing, our planet is only about 80% the size of a dartboard’s bullseye compared to the board itself. In fact, 2013 was the last time I had a bullseye.

El recientemente descubierto #asteroide #2025RJ2 pasará a solo 13.000 km de la #Luna. Cada vez el rastreo con los programas de seguimiento digitales son más efectivos. Vivimos una auténtica revolución como explico en: theconversation.com/la-revolucio... @planetarysociety.bsky.social #PlanetSci 👇

Tomorrow, newly-discovered #asteroid 2025 RJ2 will miss the Moon by 13,000 km. Shortly before close approach, it will pass through the Moon's shadow.

A simulation of Earth's present and former quasi satellites as described in the Carlos de la Fuente Marcos and Raúl de la Fuente Marcos paper iopscience.iop.org/article/10.3... including newly-discovered 2025 PN7, first recognized as quasi by @AdrienCoffinet

Tomorrow is a #LunarEclipse2025 . 6 months ago I was clouded out. This time I'm in the wrong hemisphere Good luck to the Eastern Hemisphere.

#Asteroid (669952) Kootker, named after @LisetteKootker, was discovered by @marcolangbroek.bsky.social‬ and @sarneczky. Most named asteroids are common main-belters. Not Kootker. It is in an 8:11 librating resonance with Mars. So in a rotating frame, it traces a striking path. #astronomy

In the past 3 days, two asteroids — 2025 PF2 and 2025 PU1 — passed closer than the geostationary satellites delivering our preseason #NFL games this weekend. #asteroid #astronomy

A spacecraft that loops endlessly between Earth & Moon without extra fuel? See this 1:1 Earth–Moon cycler from @RossDynamicsLab’s “Stable, Low-Energy Prograde Earth–Moon Cycler Orbits” 📄 ross.aoe.vt.edu/papers/ross-... 🖥️ Simulation: orbitsimulator.com/gravitySimul... #astronomy

There is a big difference between the two

#SanFrancisco, a 1-foot tsunami is not the same as a 1 foot tide. It is a wall of water in motion. It's the energy, not the height, that's dangerous. Don't go to the beach to watch this. #tsunami #LosAngeles #SanDiego, #Seattle

Trans Neptunian object 2020 VN40 is in a 10:1 resonance with Neptune. Here is an animation holding Neptune stationary so you can see this resonance. iopscience.iop.org/article/10.3...

A community of amateur astronomers using @unistellar.bsky.social smart telescopes have been observing comet C/2025 N1 (ATLAS) – also designated 3I/ATLAS – and have managed to captured images of the interstellar comet. www.skyatnightmagazine.com/news/unistel...

July 10's Full Moon, competes with June's full Moon for lowest full Moon in years. Many northern hemisphere locations will not see it at all. Here's the waxing gibbous from #SanFrancisco today.