Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for Triangulum Pinwheel: 12-24 (100), 12-25 (100), 12-26 (100), 12-27 (100), 12-28 (100) — by astronomy; check the weather when the night is within four days.

2037-12-21astronomy score per night — click a bar for that night2038-01-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-12-21 Mon	44	—	unknown	18:35–01:05 (marginal, 6.5 h)	79.2° 19:55	11.51	100%	53.2°
2037-12-22 Tue	61	—	unknown	18:35–19:45 (good, 1.17 h)	79.2° 19:50	11.51	100%	64.7°
2037-12-23 Wed	75	—	unknown	18:40–22:20 (good, 3.67 h)	79.2° 19:45	11.5	98%	76.9°
2037-12-24 Thu	100	—	unknown	18:40–23:50 (good, 5.17 h)	79.2° 19:45	11.5	94%	89.3°
2037-12-25 Fri	100	—	unknown	18:40–00:45 (good, 6.08 h)	79.2° 19:40	11.5	87%	101.9°
2037-12-26 Sat	100	—	unknown	18:40–00:55 (good, 6.25 h)	79.2° 19:35	11.49	78%	114.5°
2037-12-27 Sun	100	—	unknown	18:40–00:55 (good, 6.25 h)	79.2° 19:30	11.49	68%	126.8°
2037-12-28 Mon	100	—	unknown	18:40–00:55 (good, 6.25 h)	79.2° 19:25	11.48	57%	138.4°
2037-12-29 Tue	100	—	unknown	18:40–00:55 (good, 6.25 h)	79.2° 19:25	11.48	46%	148.4°
2037-12-30 Wed	100	—	unknown	18:40–00:50 (good, 6.17 h)	79.2° 19:20	11.47	35%	154.7°
2037-12-31 Thu	100	—	unknown	18:45–00:50 (good, 6.08 h)	79.2° 19:15	11.46	24%	154.4°
2038-01-01 Fri	100	—	unknown	18:45–00:45 (good, 6.0 h)	79.2° 19:10	11.45	15%	147.8°
2038-01-02 Sat	100	—	unknown	18:45–00:40 (good, 5.92 h)	79.2° 19:05	11.44	8%	137.7°
2038-01-03 Sun	100	—	unknown	18:45–00:35 (good, 5.83 h)	79.2° 19:05	11.43	3%	126.3°
2038-01-04 Mon	100	—	unknown	18:45–00:30 (good, 5.75 h)	79.2° 19:00	11.41	0%	114.4°
2038-01-05 Tue	100	—	unknown	18:45–00:30 (good, 5.75 h)	79.2° 18:55	11.4	0%	102.4°
2038-01-06 Wed	100	—	unknown	18:50–00:25 (good, 5.58 h)	79.2° 18:50	11.39	2%	90.5°
2038-01-07 Thu	100	—	unknown	18:50–00:20 (good, 5.5 h)	79.2° 18:50	11.37	6%	78.9°
2038-01-08 Fri	100	—	unknown	18:50–00:15 (good, 5.42 h)	79.2° 18:45	11.36	12%	67.6°
2038-01-09 Sat	99	—	unknown	18:50–00:10 (good, 5.33 h)	79.2° 18:40	11.34	18%	56.8°
2038-01-10 Sun	91	—	unknown	18:50–00:10 (good, 5.33 h)	79.2° 18:35	11.32	26%	46.6°
2038-01-11 Mon	83	—	unknown	18:50–00:05 (good, 5.25 h)	79.2° 18:30	11.3	35%	37.3°
2038-01-12 Tue	72	—	unknown	18:55–23:40 (good, 4.75 h)	79.2° 18:30	11.28	44%	29.7°
2038-01-13 Wed	55	—	unknown	18:55–22:25 (good, 3.5 h)	79.2° 18:25	11.27	54%	25.1°
2038-01-14 Thu	40	—	unknown	18:55–00:15 (marginal, 5.33 h)	79.2° 18:20	11.24	63%	25.3°
2038-01-15 Fri	29	—	unknown	18:55–23:55 (marginal, 5.0 h)	79.2° 18:15	11.22	72%	30.4°
2038-01-16 Sat	26	—	unknown	18:55–23:45 (marginal, 4.83 h)	79.2° 18:10	11.2	81%	38.8°
2038-01-17 Sun	27	—	unknown	19:00–23:35 (marginal, 4.58 h)	79.2° 18:10	11.18	88%	49.0°
2038-01-18 Mon	32	—	unknown	19:00–23:30 (marginal, 4.5 h)	79.2° 18:05	11.15	94%	60.2°
2038-01-19 Tue	41	—	unknown	19:00–19:35 (good, 0.58 h)	79.2° 18:00	11.13	98%	72.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-12-21&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.