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: 01-01 (100), 01-02 (100), 01-03 (100), 01-04 (100), 01-05 (100) — by astronomy; check the weather when the night is within four days.

2041-01-01astronomy score per night — click a bar for that night2041-01-30

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-01-01 Tue	100	—	unknown	18:45–00:45 (good, 6.0 h)	79.2° 19:10	11.45	1%	122.4°
2041-01-02 Wed	100	—	unknown	18:45–00:40 (good, 5.92 h)	79.2° 19:05	11.44	0%	108.7°
2041-01-03 Thu	100	—	unknown	18:45–00:35 (good, 5.83 h)	79.2° 19:00	11.42	2%	94.6°
2041-01-04 Fri	100	—	unknown	18:45–00:30 (good, 5.75 h)	79.2° 19:00	11.41	7%	80.5°
2041-01-05 Sat	100	—	unknown	18:45–00:25 (good, 5.67 h)	79.2° 18:55	11.4	14%	66.7°
2041-01-06 Sun	97	—	unknown	18:50–00:25 (good, 5.58 h)	79.2° 18:50	11.38	24%	53.4°
2041-01-07 Mon	87	—	unknown	18:50–00:20 (good, 5.5 h)	79.2° 18:45	11.37	34%	41.0°
2041-01-08 Tue	73	—	unknown	18:50–23:55 (good, 5.08 h)	79.2° 18:45	11.35	45%	30.2°
2041-01-09 Wed	56	—	unknown	19:20–22:25 (good, 3.08 h)	79.2° 18:40	11.34	56%	22.7°
2041-01-10 Thu	39	—	unknown	18:50–00:25 (marginal, 5.58 h)	79.2° 18:35	11.32	66%	21.5°
2041-01-11 Fri	26	—	unknown	18:55–00:10 (marginal, 5.25 h)	79.2° 18:30	11.3	75%	26.9°
2041-01-12 Sat	23	—	unknown	18:55–23:50 (marginal, 4.92 h)	79.2° 18:25	11.28	83%	35.8°
2041-01-13 Sun	25	—	unknown	18:55–23:40 (marginal, 4.75 h)	79.2° 18:25	11.26	90%	46.2°
2041-01-14 Mon	30	—	unknown	18:55–23:40 (marginal, 4.75 h)	79.2° 18:20	11.24	95%	57.0°
2041-01-15 Tue	40	—	unknown	18:55–23:45 (marginal, 4.83 h)	79.2° 18:15	11.22	98%	68.0°
2041-01-16 Wed	52	—	unknown	18:55–20:55 (good, 2.0 h)	79.2° 18:10	11.2	100%	79.1°
2041-01-17 Thu	66	—	unknown	19:00–22:00 (good, 3.0 h)	79.2° 18:05	11.17	100%	90.2°
2041-01-18 Fri	81	—	unknown	19:00–23:05 (good, 4.08 h)	79.2° 18:05	11.15	97%	101.2°
2041-01-19 Sat	100	—	unknown	19:00–23:15 (good, 4.25 h)	79.2° 18:00	11.12	94%	112.2°
2041-01-20 Sun	100	—	unknown	19:00–23:20 (good, 4.33 h)	79.2° 17:55	11.1	88%	123.1°
2041-01-21 Mon	100	—	unknown	19:05–23:15 (good, 4.17 h)	79.2° 17:50	11.07	82%	133.7°
2041-01-22 Tue	100	—	unknown	19:05–23:15 (good, 4.17 h)	79.2° 17:50	11.05	74%	143.8°
2041-01-23 Wed	100	—	unknown	19:05–23:15 (good, 4.17 h)	79.2° 17:45	11.02	65%	152.6°
2041-01-24 Thu	100	—	unknown	19:05–23:10 (good, 4.08 h)	79.2° 17:40	10.99	55%	158.4°
2041-01-25 Fri	100	—	unknown	19:05–23:10 (good, 4.08 h)	79.2° 17:35	10.96	45%	158.0°
2041-01-26 Sat	100	—	unknown	19:10–23:05 (good, 3.92 h)	79.2° 17:30	10.93	34%	151.1°
2041-01-27 Sun	100	—	unknown	19:10–23:00 (good, 3.83 h)	79.2° 17:30	10.9	24%	140.7°
2041-01-28 Mon	99	—	unknown	19:10–22:55 (good, 3.75 h)	79.2° 17:25	10.87	15%	128.4°
2041-01-29 Tue	97	—	unknown	19:10–22:55 (good, 3.75 h)	79.2° 17:20	10.84	8%	115.1°
2041-01-30 Wed	96	—	unknown	19:10–22:50 (good, 3.67 h)	79.2° 17:15	10.81	3%	101.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-01-01&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.