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 Andromeda Galaxy: 03-13 (5), 03-14 (5), 03-15 (3), 03-16 (3), 03-17 (1) — by astronomy; check the weather when the night is within four days.

2045-03-13astronomy score per night — click a bar for that night2045-04-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-03-13 Mon	5	—	unknown	20:00–20:20 (marginal, 0.33 h)	89.8° 13:40	9.06	20%	89.0°
2045-03-14 Tue	5	—	unknown	20:00–20:20 (marginal, 0.33 h)	89.7° 13:35	9.01	13%	78.6°
2045-03-15 Wed	3	—	unknown	20:05–20:15 (marginal, 0.17 h)	89.5° 13:30	8.96	7%	68.3°
2045-03-16 Thu	3	—	unknown	20:05–20:10 (marginal, 0.08 h)	89.7° 13:30	8.91	3%	58.2°
2045-03-17 Fri	1	—	unknown	—	89.8° 13:25	8.86	1%	48.4°
2045-03-18 Sat	1	—	unknown	—	89.8° 13:20	8.8	0%	39.6°
2045-03-19 Sun	1	—	unknown	—	89.6° 13:15	8.75	2%	32.6°
2045-03-20 Mon	1	—	unknown	—	89.5° 13:15	8.7	5%	29.1°
2045-03-21 Tue	1	—	unknown	—	89.7° 13:10	8.65	11%	30.6°
2045-03-22 Wed	0	—	unknown	—	89.8° 13:05	8.6	18%	36.7°
2045-03-23 Thu	0	—	unknown	—	89.8° 13:00	8.54	27%	45.7°
2045-03-24 Fri	0	—	unknown	—	89.6° 12:55	8.49	38%	56.4°
2045-03-25 Sat	0	—	unknown	—	89.6° 12:55	8.44	49%	68.0°
2045-03-26 Sun	0	—	unknown	—	89.8° 13:50	8.39	60%	80.2°
2045-03-27 Mon	0	—	unknown	—	89.8° 13:45	8.33	71%	92.7°
2045-03-28 Tue	0	—	unknown	—	89.7° 13:40	8.28	81%	105.2°
2045-03-29 Wed	0	—	unknown	—	89.5° 13:35	8.22	89%	117.6°
2045-03-30 Thu	0	—	unknown	—	89.6° 13:35	8.17	95%	129.4°
2045-03-31 Fri	0	—	unknown	—	89.8° 13:30	8.12	99%	139.9°
2045-04-01 Sat	0	—	unknown	—	89.8° 13:25	8.06	100%	147.8°
2045-04-02 Sun	0	—	unknown	—	89.7° 13:20	8.01	98%	151.0°
2045-04-03 Mon	0	—	unknown	—	89.5° 13:20	7.95	94%	148.6°
2045-04-04 Tue	0	—	unknown	—	89.7° 13:15	7.89	88%	141.8°
2045-04-05 Wed	0	—	unknown	—	89.8° 13:10	7.84	81%	133.0°
2045-04-06 Thu	0	—	unknown	—	89.8° 13:05	7.78	72%	123.1°
2045-04-07 Fri	0	—	unknown	—	89.6° 13:00	7.73	63%	112.9°
2045-04-08 Sat	0	—	unknown	—	89.6° 13:00	7.67	54%	102.6°
2045-04-09 Sun	0	—	unknown	—	89.8° 12:55	7.61	44%	92.3°
2045-04-10 Mon	0	—	unknown	—	89.8° 12:50	7.56	35%	81.9°
2045-04-11 Tue	0	—	unknown	—	89.7° 12:45	7.5	26%	71.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-03-13&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.