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: 01-13 (100), 01-14 (100), 01-15 (100), 01-16 (100), 01-17 (100) — by astronomy; check the weather when the night is within four days.

2037-01-13astronomy score per night — click a bar for that night2037-02-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-01-13 Tue	100	—	unknown	18:55–23:55 (good, 5.0 h)	79.1° 18:25	11.26	6%	123.0°
2037-01-14 Wed	100	—	unknown	18:55–23:50 (good, 4.92 h)	79.2° 18:20	11.24	2%	112.0°
2037-01-15 Thu	100	—	unknown	18:55–23:50 (good, 4.92 h)	79.2° 18:15	11.22	0%	101.0°
2037-01-16 Fri	100	—	unknown	18:55–23:45 (good, 4.83 h)	79.2° 18:10	11.2	0%	90.0°
2037-01-17 Sat	100	—	unknown	19:00–23:40 (good, 4.67 h)	79.1° 18:05	11.17	2%	79.1°
2037-01-18 Sun	100	—	unknown	19:00–23:35 (good, 4.58 h)	79.2° 18:05	11.15	6%	68.4°
2037-01-19 Mon	100	—	unknown	19:00–23:30 (good, 4.5 h)	79.2° 18:00	11.12	11%	58.0°
2037-01-20 Tue	93	—	unknown	19:00–23:30 (good, 4.5 h)	79.2° 17:55	11.1	17%	47.9°
2037-01-21 Wed	87	—	unknown	19:05–23:25 (good, 4.33 h)	79.2° 17:50	11.07	25%	38.6°
2037-01-22 Thu	74	—	unknown	19:05–23:05 (good, 4.0 h)	79.1° 17:50	11.05	34%	30.6°
2037-01-23 Fri	58	—	unknown	19:05–22:55 (good, 3.83 h)	79.2° 17:45	11.02	43%	25.4°
2037-01-24 Sat	43	—	unknown	19:05–20:50 (good, 1.75 h)	79.2° 17:40	10.99	53%	25.3°
2037-01-25 Sun	31	—	unknown	19:05–23:25 (marginal, 4.33 h)	79.2° 17:35	10.96	63%	30.6°
2037-01-26 Mon	26	—	unknown	19:10–23:10 (marginal, 4.0 h)	79.1° 17:30	10.93	73%	39.5°
2037-01-27 Tue	25	—	unknown	19:10–23:00 (marginal, 3.83 h)	79.1° 17:30	10.9	82%	50.4°
2037-01-28 Wed	28	—	unknown	19:10–23:00 (marginal, 3.83 h)	79.2° 17:25	10.87	90%	62.7°
2037-01-29 Thu	36	—	unknown	19:10–19:50 (good, 0.67 h)	79.2° 17:20	10.84	96%	75.7°
2037-01-30 Fri	47	—	unknown	19:10–21:05 (good, 1.92 h)	79.2° 17:15	10.81	99%	89.3°
2037-01-31 Sat	60	—	unknown	19:15–22:15 (good, 3.0 h)	79.1° 17:10	10.78	100%	103.1°
2037-02-01 Sun	73	—	unknown	19:15–22:25 (good, 3.17 h)	79.2° 17:10	10.75	97%	116.7°
2037-02-02 Mon	83	—	unknown	19:15–22:25 (good, 3.17 h)	79.2° 17:05	10.71	92%	129.8°
2037-02-03 Tue	84	—	unknown	19:15–22:25 (good, 3.17 h)	79.2° 17:00	10.68	84%	141.6°
2037-02-04 Wed	84	—	unknown	19:20–22:30 (good, 3.17 h)	79.2° 16:55	10.64	74%	150.9°
2037-02-05 Thu	81	—	unknown	19:20–22:25 (good, 3.08 h)	79.1° 16:55	10.61	64%	155.3°
2037-02-06 Fri	78	—	unknown	19:20–22:20 (good, 3.0 h)	79.2° 16:50	10.57	53%	152.9°
2037-02-07 Sat	76	—	unknown	19:20–22:15 (good, 2.92 h)	79.2° 16:45	10.54	43%	145.5°
2037-02-08 Sun	74	—	unknown	19:20–22:15 (good, 2.92 h)	79.2° 16:40	10.5	33%	135.9°
2037-02-09 Mon	71	—	unknown	19:25–22:10 (good, 2.75 h)	79.1° 16:35	10.46	24%	125.4°
2037-02-10 Tue	69	—	unknown	19:25–22:05 (good, 2.67 h)	79.1° 16:35	10.43	16%	114.6°
2037-02-11 Wed	66	—	unknown	19:25–22:00 (good, 2.58 h)	79.2° 16:30	10.39	9%	103.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-01-13&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.