Exoplanet Observations from Taurus Hill Observatory for the Season 2024–2025

Clear nights were quite rare during the winter of 2024-2025. Although there may have been more clear nights compared to the previous season, variable cloudiness often persisted even during these clear nights, or the continuous cloudless periods were too short for effective exoplanet light curve measurements.

The THO research team managed to make transit observations for the first time at the beginning of September 2024, and then again only at the end of December. While weather was not always the sole factor, frequent rains, cloudiness, and unpredictable weather changes posed significant challenges. Despite these difficult observation and measurement conditions, the observation routine and results remained reasonably good. The figures below illustrate some of the measurements performed at THO.

In the fall of 2024, the traditional Czech TRESCA ETD database site underwent a major redesign and is now called VarAstro (var.astro.cz). During the observation season, the beta test version of the VarAstro site was still in use. Nevertheless, the THO research team continued to submit observations there for further use. Previously, the site was a completely open environment where observations could be submitted "on the fly." Of course, the measurement results of the uploaded files had to be reasonable, so no erroneous data could be submitted. Currently, to submit measurement results, access to the site requires registration and administrator approval. Although the usability of the site has some challenges and new features to learn, it remains quite functional.

All observations presented here were made with the Celestron 14” SC telescope and SBIG ST-8XME CCD camera using a photometric R filter on the viewing platform.

TOI-1845.01b

September 6–7, 2024, 18:19–00:01 (UTC)
Dimming 19.9 mmag, recorded value 20.1 mmag. Transit duration 136.1 min, recorded duration 156.3 min. Host star brightness 13.6 mag. The target has been observed only seven times in total on VarAstro. A 120-second exposure was used for imaging.

TOI-6316.01b

September 6–7, 2024, 18:19–00:01 (UTC)
Dimming 22.6 mmag, recorded value 13.1 mmag. Transit duration 231.9 min, recorded duration 215.6 min. Host star brightness 13.2 mag. The target has been observed only three times in total on VarAstro. A 120-second exposure was used for imaging.

TOI-2578.01b

September 9, 2023, 14:54–20:23 (UTC)
Dimming 8.5 mmag, recorded value 11.0 mmag. Transit duration 201 min, recorded duration 157 min. Host star brightness 11.4 mag. This target has also been observed only three times in total on VarAstro. A 60-second exposure was used for imaging.

TOI-1259.01b

December 29, 2024, 00:36–05:13 (UTC)
Dimming 30.8 mmag, recorded value 28.7 mmag. Transit duration 142 min, recorded duration 148 min. Host star brightness 12.1 mag. The target has been observed a lot, a total of 31 times on VarAstro. A 60-second exposure was used for imaging.

HAT-P-36b

December 30–31, 2024, 21:02–01:11 (UTC)
Dimming 21.3 mmag, recorded value 20.4 mmag. Transit duration 111 min, recorded duration 133 min. Host star brightness 12.2 mag. The target has been observed a lot, nearly 300 times in total on VarAstro. A 100-second exposure was used for imaging.