Prespecified evaluation of the AuroraChaser score, 2026/27 season

The plan for evaluating the AuroraChaser aurora visibility score over the 2026/27 season was fixed before its evaluation period began (10:00 UTC, 10 October 2026). This page publishes the SHA-256 fingerprints of the plan, its source and the frozen parameter file. The files themselves are published here with the April 2027 report; anyone can then check that they are the files fingerprinted below.

Fingerprints (SHA-256)

aurorachaser_prespecified_evaluation_2026-27.pdf ca591079a48dcb18c4087b21d9789c0be485b64d36272483b04f79a4826147b6
aurorachaser_prespecified_evaluation_2026-27.tex 925ea495ad8e0dafb774e8539dbb3f4d253d3330a684a24361dd6b9e12fea11f
score_model_v2.json (parameter file, version 2026-10-02.1) 297f3be19c0b49b80b39c63c8f54caf01328b704bbe65b568e52df70a8280c63

Timestamps

Each fingerprint was timestamped on 8 October 2026 at 21:25 UTC by:

The proofs, a .ots and a .tsr file for each file, are published with the files.

When this page went up

The fingerprints were timestamped 36 hours before the evaluation period began, but this page only went up on 10 October 2026, a few hours after the period began at 10:00 UTC (the Internet Archive's snapshot records when). Page 1 of the plan reads as if both happened before the start. No hour or alert the evaluation can count had begun before 16:00 UTC that day (the sun first reaches -6.7° at a camera site at 16:06 UTC), and the camera data that decide its outcomes are released in 2027 at the earliest.

How to check

sha256sum FILE
ots verify FILE.ots     # or drop FILE and FILE.ots on opentimestamps.org
openssl ts -verify -data FILE -in FILE.tsr -CAfile digicert_trusted_root_g4.pem

Updates

This is the only plan for this evaluation. Changes to it are listed here, each fingerprinted and timestamped, and published with the plan.

21 October 2026: Amendment 1. Sodankylä leaves the camera comparisons, which now run on Kilpisjärvi and Abisko. The calibrated camera at Sodankylä was taken out of service in April 2021, so no 2026/27 intensities can come from it, and under the plan as registered the comparisons would have waited until 30 June 2029. The plan's own data section already showed this when it was registered; we missed it. We have not requested, received or seen any 2026/27 camera intensities. The amendment also corrects how the plan describes the intensities (the mean within 45° of the zenith) and the Abisko camera (the Sodankylä Geophysical Observatory's); neither correction changes a rule or a computation. aurorachaser_prespecified_evaluation_2026-27_amendment-1.txt 3827f0bff420f5e97cc01ff187f6aaf795b7b0d60d3a6f69e2768710bf3f644c Timestamped on 21 October 2026 at 13:41 UTC by OpenTimestamps (Bitcoin attestation pending) and by DigiCert's RFC 3161 timestamp authority (granted at 13:41:46 UTC).

The completion of the analysis code, due by 31 January 2027, will be listed here as a dated, timestamped update.

AuroraChaser, hello@aurorachaser.app