After being a little cloudy for the first few days after #sunrise, the winterovers are finally starting to see a little bit of #Sun at the #southpole! Pic by winterover Sim Bash! @NSF

This weekend was official #sunrise at the #southpole! Which happens at the autumn equinox. Unfortunately, the weather was very overcast, as you can see from this picture (credit: winterover Sim) during the official sunrise day! #whiteout @NSF @NOAA #Antarctica

SPT-3G 1500d D1 MCMC Chains are now available on @NASA_LAMBDA lambda.gsfc.nasa.gov/product/spt/...

NOAA scientist Ian Crocker on top of the atmospheric monitoring tower at the #southpole (Pic by Kevin Leung). @noaa.gov (formerly the US Weather Bureau) have been monitoring weather there since January 1957! #Antarctica

Picture from winterover Sheryl Seagraves. The view from station out to the Dark Sector. Getting much brighter outside about 2-weeks before #sunrise. The red "night" lights from the telescope are becoming less visible against the brightening sky. #Antarctica @NSF

Getting closer to #sunrise at the #southpole, with official sunrise still nearly three weeks away. Winterover Sim capturing a picture of the horizon behind the ceremonial South Pole with his rubber duck on top. #Antarctica

SPT winterover Sim Bash attempting to play #chess outside at the #southpole during the annual Pole #Olympics, in -30 deg F temps and 30 knot winds. Sim unfortunately reigned after too many pieces blew away. Pic by Zach.

Nice article describing the devastating impact of the President's Budget on the US Antarctic science program: www.scientificamerican.com/article/u-s-...

A group of winterovers, including SPT's Karia Dibert, posing in front of the #southpole marker (pic by Kevin Leung). The long exposure helps to see signs of the #sunrise at Pole, but with the stars overhead there will still be some decent night sky viewing. @NSF

It's still about a month away from official #sunrise at the #southpole, but they are starting to see signs of the Sun on the horizon! Picture by winterover Zeke Mills from the deck on the station! @NSF #southpole

Another picture from winterover Zach Tejral of SPT observing a couple weeks ago, with some nice #aurora and the #milkyway just overhead. #Antarctica #southpole @NSF

Picture from Winter Site Manager Zach Tejral of the Dark Sector Lab (DSL), which hosts the BICEP-3 experiment, and the South Pole Telescope! #ANTARCTICA @NSF @doescience #nsfunded #doefunded

New SPT-3G constraints on early dark energy: "combining with DESI ... we get fEDE=0.071+0.035−0.038 at 68% CL and a weak preference for AEDE over ΛCDM. this shift is a manifestation of the discrepancy present between DESI and CMB experiments in ΛCDM" arxiv.org/abs/2507.23355

Quick picture by SPT winterover Sim Bash on their way out to the telescope, with the red glow from the station lights in the background, and some nice #aurora overhead! #Antarctica @NSF

The SPT winterovers recently hosted an open house and tour of the telescope. Since SPT is 1-km from station, many winterovers don't make it out often, so it's nice to have open houses to help learn about the science they are supporting! Pic by Kevin Leung @NSF @doescience

It's a couple weeks late, but South Pole recently celebrated mid-winter at the #southpole. Mid-winter is a big milestone for the winterovers, who are spending a year at the South Pole. Attached is the official mid-winter photo, and dinner announcement from this season!

SPT/SPT-3G collaboration meeting taking place this week at @UChicago! Great to see everyone and having great discussions about all the ongoing science analyses of SPT data! @NSF @doescience #Antarctica

Photo by Kevin Leung. SPT winterovers watching #aurora at the "End of the World", the unofficial end of the extent of the South Pole station infrastructure footprint. #southpole @NSF

Tonight at 530pm in Harold Washington Library #Chicago, SPT scientist and former winter over Dr Matt Young is giving a free public lecture, learn about the science of SPT and what its like to live/work at the South Pole #Antarctica! @UChicago t.co/uHlpPlchRA

SPT-3G D1 Webinar: CMB TT/TE/EE power spectra and cosmology from 2019-2020 observations from SPT-3G Main Field - Now Live!!! youtu.be/TRJ5sfAwnao @NSF @doescience @UChicago #NSFfunded #DOEfunded #Antarctica

On Wed, June 25, the SPT collaboration will release major new results from SPT-3G, via a pre-recorded webinar at 9.30am CDT on youtube youtube.com/@southpolete..., with the paper released at Noon CDT, on the SPT-3G website pole.uchicago.edu @NSF @doescience #Antarctica

SPT winterover Karia Dibert pictured under a nearly full moon (or moondog) at the #southpole (Pic by Toshin Rao). On a 2-mile thick ice sheet in many directions the horizon is featureless, and the moon beautifully highlights the sastrugi. @NSF @doescience #Antarctica

New SPT-3G data release of the Euclid Deep Field-S taken in Nov-2024, with maps and source catalogs. In 57 deg^2, achieved depth of 4/4/13 uK-arcmin at 95/150/220 GHz, about 10x deeper than Planck, finding 114 dusty DSFGs and 217 galaxy clusters. @NSF arxiv.org/abs/2506.00298

With all the #aurora going on in the northern hemisphere right now, our winterovers Karia and Sim also thought it would be a good time to pull up a couch and watch them near the #southpole! Pic by Kevin Leung. @NSF @NOAA

This week, the south pole winterovers had a zoom call with Apollo 13 @NASA astronaut Fred Haise! People were thrilled to talk to him, hear his stories, and impressed by this 91-year old! @NSF #MemorialDay2025

Picture of some #southpole winterovers enjoying a walk to the "end of the world", marking the edge of the official station footprint, and enjoying some winter #aurora. Pic by SPT's Sim Bash! @NSF @doescience

Congrats to former SPT winterover Aman Chokshi for being recognized as one of Nature's top photos of 2025 for "scientific fieldwork"! www.nature.com/immersive/d4...

SPT getting ready for observations last week. Weather has been great recently and entering the best part of the observing season. The #aurora are also picking up, with the #Sun still near solar maxima. Picture by SPT winterover Karia last week. #southpole @NSF @doescience

Been clear skies and great observing weather the past week at the #southpole. SPT winterover Karia Dibert was able to get to a visit this nice picture at the RF communications dome, showing some impressive #aurora! @NSF @doescience

New SPT-3G B-mode spectrum and r-constraint! "demonstrates a white noise level of 9.3 (6.7) µK-arcmin at ℓ∼500 for the 95GHz (150GHz) data, with a 1/ℓ noise knee at ℓ= 128 (182) with a statistical uncertainty on r of σ(r) = 0.067" arxiv.org/abs/2505.02827 @NSF @doescience

New joint SPT, ACT, & Planck CMB lensing power spectrum & cosmology results! The CMB measurements are consistent, when combined place new leading constraints on cosmic structure, the Hubble constant, and the neutrino mass! @NSF @doescience #southpole arxiv.org/abs/2504.20038

Now that we are past Sunset at the #southpole, and its actually dark in the Dark Sector, our winterovers Sim and Karia decided to stage an epic #starwars light saber battle in front of the South Pole Telescope! #NSF

More #aurora lighting up the sky at the #southpole, again captured by SPT winterover Sim Bash! Technically we are still in nautical twilight, but we should still be in solar maximum this year, so should be a great winter for aurora! @noaa.gov @NSF.gov #NSF

First aurora of the 2025 winter season! Picture by SPT winterover Sim Bash! @noaa.gov #NSFfunded

Picture by @noaa.gov winterover Ian Crocker, of a drifting sastrugi wave, with the #sunset behind the ceremonial #southpole and the profile of the SPT and dark sector telescopes in the distance on the right.

Two-weeks after #Sunset, the sky is getting darker at the #southpole. Pic of SPT winterover Karia Dibert by Sim Bash, outside doing the greasing of the SPT elevation gears of the telescope, that they still need to do every two weeks, even during the depths of winter. @NSF

Picture of SPT winterover Karia Dibert cleaning the snow off the cabin roof of the telescope, a few days after #equinox #sunset at the South Pole! #Antarctica @NSF

Unfortunately it was pretty cloud during #Sunset this year at the South Pole, but our winterover Sim managed to catch this picture just before the weather got bad, with the moon over SPT! #southpole #Antarctica

SPT 2026 Winterover job advertisement is now live on the AAS Job Register! Circulate to any astronomer or physicist or engineer friends to whom 1-year in Antarctica might sound particularly appealing right now! aas.org/jobregister/...

New @TheNRAO press release describing @almaobs measurements of SPT-discovered protocluster SPT2349-56, work led by SPT scientist Dazhi Zhou from U. of British Columbias! Hidden Cosmic Fuel Tank Found in Infant Galaxy Cluster public.nrao.edu/news/hidden-...

We are looking for SPT 2026 winter overs — please encourage candidates to apply at the link below and to contact us directly. #Antarctica #southpole @NSF 2026 South Pole Telescope (SPT) position: uchicago.wd5.myworkdayjobs.com/External/job...

Picture by SPT winterover Sim Bash, showing the sun shining behind SPT, taken near end of February! #sunset is only a couple weeks away, and the sun is about 4-degrees above the horizon. @NSF #Antarctica

Nice aerial view of SPT and the Dark Sector Lab, from @BICEP_Keck scientist Matthew Petroff!

Im guessing we will be closer to midnight

About 20-days until the last flight of the Austral summer and start of winter operations. One last SPT team picture before people started leaving, pictured here: Adam, Amy, Jessica, Matt, Sim, Karia, Maclean, Pernic, and Sasha! #southpole #Antarctica

Final SPTpol TE, EE power spectrum from full 4-year data set! "dataset is well-fit by the ΛCDM model, for which we find H0=70.48±2.16 km/s/Mpc and Ωm=0.271±0.026 using only the SPTpol data" Great PhD thesis work from Jody Chou! #southpole @NSF arxiv.org/abs/2501.06890

-Dannie Heineman Prize for Astrophysics Lecture: Past, Present, and Future Cosmic Microwave Background Surveys, John E. Carlstrom (UChicago) 11:40am -RAS Gold Medal Lecture: From the Cradle: Applying Basic Physics to Astrophysical Fundamental Questions, Gilles Chabrier (ENS-Lyon) 3:40pm #AAS245 ✨🔭

The SPT team at Pole represented us well at the annual Race Around the World, the 3-km race around the #southpole on #Christmas. SPT'ers Adam and Jessica came in first and second in the race, and also made some of the best costumes! #Antarctica

New SPT-3G paper (Chichura et al. 2024): "Pointing Accuracy Improvements for the South Pole Telescope with Machine Learning" tested with in situ test observations during the @ehtelescope observing campaign in 2024 April. #southpole #Artificial_Intelligence #ML @NSF arxiv.org/abs/2412.15167

SPT-SLIM team at the #southpole in front of the assembled focal plane! Read more about SLIM at: arxiv.org/abs/2304.00973 arxiv.org/abs/2111.04631 #Antarctica #LIM