Getting dark quickly at the #southpole now, roughly 1-month past #Sunset, and our winterovers are starting to see some signs of Southern Lights! Below is a pic from Michel using his iphone walking back from the telescope this week. @NSF @doescience
Nearly a month after Sunset, its much darker at the #southpole, but you can still see a little twilight on the horizon with a medium exposure on an #iphone. Here is a pic from winterover Michel towards the Dark Sector on the walk out to SPT. #Antarctica @NSF @doescience
Pic by Winterover Anjali of SPT, about 2-weeks after #Sunset, even with the Sun several degrees below the horizon there is still a light glow in its direction. Great observing weather recently too, as you can also see in this pic. #Antarctica @NSF @doescience
Another pic by winterover Michel. Taken from the station looking SPT and DSL, which are 1-km away, and small in the distance roughly below the nearly full moon. The view shows how featureless the landscape is at #southpole. #Antarctica @NSF @doescience
The South Pole ceremonial marker, pic by winterover Michel. Still bright enough to see a little bit of Sun on the horizon in the reflection off the marker, but the moon is the brightest thing in the sky right now. #Antarctica @NSF @doescience
About 2-weeks after #sunset at the South Pole, our winter overs Michel and Anjali are getting some great views of the darkening skies. Here SPT and DSL are being backlight by a nearly full moon. #Antarctica @NSF @doescience
Another pic from last week of #southpole #Sunsets, by winterover Anjali, this time looking from the station towards the Dark Sector and SPT. Its 1-km distance between this pic location and SPT, with the sastrugi well lit by the backlight.
@NSF @doescience #Antarctica
Picture of SPT obserivng last week, with the Sun finally almost fully below the horizon. Since then the Sun has fully set, and #southpole winter has begun and SPT began 2026 observations of its 1500d Main field! @NSF @doescience #Antarctica
New SPT-3G D1 data release, providing maps and ancillary data products from the first two years of the Main survey, now public on the SPT website! @doescience @NSF #Antarctica pole.uchicago.edu/public/Home....
Another pic last week by winterover Michel, showing the view out to DSL, but this time with the Sun behind the camera still only a degree above the horizon. On top of DSL, the BICEP calibration source is reflecting the Sun back towards the camera. #Antarctica @NSF @doescience
The Sun has set at the #southpole since we are past the #equinox. However, last week, this was one of the last pictures taken by winterover Michel of the Sun spiraling towards the horizon in the direction of SPT and DSL buildings. @NSF @doescience #Antarctica
@argonne Postdoc Wei Quan presenting at APS today about the new SPT-3G D1 map release! New paper is public on the SPT website here: pole.uchicago.edu/public/Home.... @NSF @doescience #Antarctica
Only four days until #sunset with SPT still looking #golden with the setting Sun. The moon is also up right now at the South Pole, visible at low elevation in the distance, near where SPT is currently observing. Pic by winterover Anjali. #Antarctica @NSF @doescience
Within a week of #sunset at the #southpole. Pic by winterover Anjali with SPT looking #golden backlight by the Sun, which is now only about 1.5 degrees above the horizon. We will start our Main survey observations later this week after Sunset. @NSF @doescience
Cloudy earlier this week at #southpole. Pic from Michel of SPT & DSL, with the newly installed winter flag line from DSL back to station. On the roof, can also see the 20-ft tall BICEP calibration tower, which will be coming down this week before #sunset. @NSF @doescience
With the Sun getting low in the horizon there are lots of nice pictures like this from winterover Michel, the ice crystals in the air creating a #sundog, the backlight showing the #sastrugi and the flag line to @uw_wipac ICL building leading to the right. @NSF @doescience
SPT observing last week (picture by SPT winterover Michel!) Less than 2-weeks away from #sunset at the #southpole, with the Sun about 5 degrees above the horizon. The sky is dry & clear enough in summer that we continue to take science observations ! @NSF @doescience
Even though @NSF #southpole station "officially" closed for winter, last week 2 final twin otter flights stopovered at Pole before heading North! They mainly serve other bases on station, wrapping up work a couple weeks after the last LC130s. Pic by Anjali. #Antarctica
One of the annual #southpole traditions at the start of winter is watching John Carpenter's #thething in the gym. A fitting start to over 8 months of isolation for the 40 winterovers after becoming officially stranded at a remote Antarctic base! #Antarctica
"Last flight" of the official #southpole Austral summer has taken off and winter has begun! SPT is now in charge of the capable hands of Wwinterovers Anjali and Michel for the next 8.5 months! Pic by Anjali . @NSF @doescience #Antarctica #WinterOlympicGames
New SPT-3G paper and data release! "SPT-3G D1: Compton-y maps using data from the SPT-3G and Planck surveys" @doescience @NSF arxiv.org/abs/2602.11279 #Antarctica #southpole
New SPT-3G paper! "Measurement of the Full Shape of the Thermal Sunyaev-Zel’dovich Power Spectrum from South Pole Telescope and Herschel-SPIRE Observations" that finds the "tSZ power spectrum measured at 9.3σ in both MV and CIB-min maps." arxiv.org/pdf/2602.10107 @NSF #southpole
Last week, the South Pole celebrated a wedding! This marks the fourth time in recorded station history for a couple to be married at the #southpole. Pic by SPT winterover Michel. #Antarctica #wedding @NSF
Last week a contingent of @NSF representatives and six US Senators from @SenateCommerce @commercedems visited the #southpole, getting a tour of the science on station, including SPT's very own Sasha Rahlin and Winterover Anjali Sehrawat! @doescience
"First constraints on causal sources of primordial gravitational waves from CMB B-mode data" SPT-3G helps break degeneracies between Inflationary, lensing, and causal sources of B-modes to provide first constraints! #southpole @doescience @NSF arxiv.org/abs/2601.20958
New SPT-3G constraints on CMB secondary anisotropies, including the thermal and kinematic SZ effect! "At ℓ=3000, we find thermal SZ power at 143 GHz of DtSZ=4.91±0.37μK2 and kinematic SZ power of DkSZ=1.75±0.86μK2" @NSF #southpole #Antarctica arxiv.org/abs/2601.20551
Picture of the @uw_icecube Upgrade team photo this season! Congrats to IceCube collaboration for a successful upgrade deployment this season! @NSF #southpole #Antarctica
Interesting history from Josh Frieman about
@theDESurvey: "In 2003, we started thinking about how to do (DES) .. a major motivation was a new cosmic microwave background telescope being built at the South Pole - the South Pole Telescope" phys.org/news/2026-01...
Nice article by @doescience summarizing the recent SPT-3G result by Yujie Wan, which discovered two flaring objects near the #Galactic center! @NSF @NSF_NSB #southpole www.energy.gov/science/arti...
Exciting new result from SPT-3G by Yujie Wan from Illinois! Detection of transient white dwarves, near the Galactic center!
@NSF #Antarctica #southpole
www.ncsa.illinois.edu/2026/01/20/r...