ESO received 913 valid proposals for observations in Period 116 (1 October 2025 - 30 April 2026, with a duration of 7 months). The deadline for proposal submission was 20 March 2025. On the VLT, the most demanded ESO instrument was MUSE with a request of 3034.5 hours (i.e. 379.3 nights of an average duration of 8 hours), followed by ESPRESSO with 2594.8 hours, and XSHOOTER with 2221.2 hours. HARPS/NIRPS on the ESO 3.6-metre telescope was the most demanded instrument at La Silla, with a combined request of 3277 hours. The plot above shows the number pf ESO Proposals/PIs since Period 62. The fluctuations in the recent years are due to Large Programmes being offered only in even periods since P106. The peak in P106 is due to the extension of the proposal submission deadline during the pandemic.
ESO Period 116 Proposal Submission Statistics
Published: 11 Apr 2025
In Paranal, the telescope with the highest oversubscription is Yepun (UT4), with a total request of 4240.2 hours, followed by Melipal (UT3; 3415.3 hours). Visitor Mode was requested by 11.9% of VLT programmes. ESO received 8 VLTI/I-ALMA joint proposals this Period.
The distributed peer review (DPR) is reviewing proposals requesting a total telescope time of 16h or less, which is 50.2% of submitted proposals in this Period, covering 15.8% of all the requested time. The rest of the proposals are being reviewed by the Observing Programmes Committee and its Expert Panels. Proposing teams can expect to be informed of the outcome of the review process by early July 2025.
The percentages of submitted proposals across science categories were:
- Cosmology and Intergalactic Medium 7.7%
- Galaxies 23.5%
- Interstellar Medium, Star Formation, and Planetary Systems 37.0%
- Stellar Evolution 31.8%