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 Great Orion Nebula: 03-13 (43), 03-12 (42), 03-14 (41), 03-15 (39), 03-16 (38) — by astronomy; check the weather when the night is within four days.

2028-03-06astronomy score per night — click a bar for that night2028-04-04

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-03-06 Mon	11	—	unknown	19:55–22:10 (marginal, 2.25 h)	42.9° 19:00	9.39	77%	39.2°
2028-03-07 Tue	11	—	unknown	19:55–22:00 (marginal, 2.08 h)	42.9° 18:55	9.34	86%	48.5°
2028-03-08 Wed	14	—	unknown	19:55–22:05 (marginal, 2.17 h)	42.9° 18:50	9.29	93%	59.8°
2028-03-09 Thu	18	—	unknown	19:55–22:15 (marginal, 2.33 h)	42.9° 18:45	9.25	98%	72.2°
2028-03-10 Fri	24	—	unknown	19:55–20:30 (good, 0.58 h)	42.9° 18:40	9.2	100%	85.0°
2028-03-11 Sat	31	—	unknown	20:00–21:30 (good, 1.5 h)	42.9° 18:40	9.15	99%	97.8°
2028-03-12 Sun	42	—	unknown	20:00–21:40 (good, 1.67 h)	42.9° 18:35	9.1	95%	110.3°
2028-03-13 Mon	43	—	unknown	20:00–21:50 (good, 1.83 h)	42.9° 18:30	9.05	88%	122.0°
2028-03-14 Tue	41	—	unknown	20:00–21:45 (good, 1.75 h)	42.9° 18:25	9.0	80%	132.5°
2028-03-15 Wed	39	—	unknown	20:05–21:40 (good, 1.58 h)	42.9° 18:25	8.95	70%	141.1°
2028-03-16 Thu	38	—	unknown	20:05–21:40 (good, 1.58 h)	42.9° 18:20	8.9	60%	146.7°
2028-03-17 Fri	36	—	unknown	20:05–21:35 (good, 1.5 h)	42.9° 18:15	8.85	50%	148.2°
2028-03-18 Sat	34	—	unknown	20:05–21:30 (good, 1.42 h)	42.9° 18:10	8.8	41%	145.5°
2028-03-19 Sun	32	—	unknown	20:10–21:25 (good, 1.25 h)	42.9° 18:05	8.75	31%	139.6°
2028-03-20 Mon	31	—	unknown	20:10–21:20 (good, 1.17 h)	42.9° 18:05	8.7	23%	131.9°
2028-03-21 Tue	29	—	unknown	20:10–21:20 (good, 1.17 h)	42.9° 18:00	8.64	16%	123.0°
2028-03-22 Wed	28	—	unknown	20:10–21:15 (good, 1.08 h)	42.9° 17:55	8.59	9%	113.5°
2028-03-23 Thu	26	—	unknown	20:15–21:10 (good, 0.92 h)	42.9° 17:50	8.54	5%	103.7°
2028-03-24 Fri	24	—	unknown	20:15–21:05 (good, 0.83 h)	42.9° 17:45	8.49	2%	93.7°
2028-03-25 Sat	23	—	unknown	20:15–21:00 (good, 0.75 h)	42.9° 17:45	8.43	0%	83.5°
2028-03-26 Sun	22	—	unknown	21:15–22:00 (good, 0.75 h)	42.9° 18:40	8.38	1%	73.2°
2028-03-27 Mon	19	—	unknown	21:20–21:55 (good, 0.58 h)	42.9° 18:35	8.33	3%	63.1°
2028-03-28 Tue	16	—	unknown	21:20–21:50 (good, 0.5 h)	42.9° 18:30	8.27	7%	53.4°
2028-03-29 Wed	14	—	unknown	21:20–21:40 (good, 0.33 h)	42.9° 18:25	8.22	13%	44.4°
2028-03-30 Thu	10	—	unknown	21:25–21:30 (good, 0.08 h)	42.9° 18:25	8.16	21%	36.9°
2028-03-31 Fri	8	—	unknown	21:25–22:10 (marginal, 0.75 h)	42.9° 18:20	8.11	30%	32.3°
2028-04-01 Sat	5	—	unknown	21:25–22:05 (marginal, 0.67 h)	42.9° 18:15	8.05	40%	32.1°
2028-04-02 Sun	4	—	unknown	21:25–21:50 (marginal, 0.42 h)	42.9° 18:10	8.0	51%	36.8°
2028-04-03 Mon	2	—	unknown	21:30–21:40 (marginal, 0.17 h)	42.9° 18:10	7.94	63%	45.0°
2028-04-04 Tue	2	—	unknown	21:30–21:35 (marginal, 0.08 h)	42.9° 18:05	7.89	73%	55.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-03-06&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.