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 Seven Sisters: 03-13 (46), 03-14 (39), 03-15 (30), 03-16 (23), 03-27 (21) — by astronomy; check the weather when the night is within four days.

2043-03-13astronomy score per night — click a bar for that night2043-04-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-03-13 Fri	46	—	unknown	20:00–21:55 (good, 1.92 h)	72.6° 16:45	9.08	9%	31.5°
2043-03-14 Sat	39	—	unknown	20:00–21:45 (good, 1.75 h)	72.5° 16:40	9.03	17%	16.8°
2043-03-15 Sun	30	—	unknown	20:05–21:35 (good, 1.5 h)	72.5° 16:40	8.98	27%	2.3°
2043-03-16 Mon	23	—	unknown	20:05–21:20 (good, 1.25 h)	72.6° 16:35	8.93	38%	12.0°
2043-03-17 Tue	17	—	unknown	20:05–22:00 (marginal, 1.92 h)	72.6° 16:30	8.88	49%	26.0°
2043-03-18 Wed	13	—	unknown	20:05–21:50 (marginal, 1.75 h)	72.6° 16:25	8.83	60%	39.7°
2043-03-19 Thu	11	—	unknown	20:10–21:45 (marginal, 1.58 h)	72.5° 16:20	8.78	70%	53.1°
2043-03-20 Fri	12	—	unknown	20:10–21:40 (marginal, 1.5 h)	72.5° 16:20	8.73	79%	66.3°
2043-03-21 Sat	13	—	unknown	20:10–21:40 (marginal, 1.5 h)	72.6° 16:15	8.68	87%	79.2°
2043-03-22 Sun	15	—	unknown	20:10–20:15 (good, 0.08 h)	72.6° 16:10	8.62	93%	91.9°
2043-03-23 Mon	18	—	unknown	20:15–20:55 (good, 0.67 h)	72.6° 16:05	8.57	97%	104.4°
2043-03-24 Tue	20	—	unknown	20:15–21:00 (good, 0.75 h)	72.5° 16:00	8.52	100%	116.8°
2043-03-25 Wed	20	—	unknown	20:15–21:00 (good, 0.75 h)	72.5° 16:00	8.47	100%	129.0°
2043-03-26 Thu	20	—	unknown	20:15–20:55 (good, 0.67 h)	72.6° 15:55	8.41	98%	141.1°
2043-03-27 Fri	21	—	unknown	20:20–20:55 (good, 0.58 h)	72.6° 15:50	8.36	95%	153.0°
2043-03-28 Sat	20	—	unknown	20:20–20:55 (good, 0.58 h)	72.5° 15:45	8.31	90%	164.9°
2043-03-29 Sun	19	—	unknown	21:20–21:55 (good, 0.58 h)	72.5° 16:45	8.25	84%	176.7°
2043-03-30 Mon	17	—	unknown	21:20–21:50 (good, 0.5 h)	72.6° 16:40	8.2	76%	171.5°
2043-03-31 Tue	14	—	unknown	21:25–21:45 (good, 0.33 h)	72.6° 16:35	8.14	68%	159.5°
2043-04-01 Wed	13	—	unknown	21:25–21:40 (good, 0.25 h)	72.6° 16:30	8.09	58%	147.5°
2043-04-02 Thu	11	—	unknown	21:25–21:40 (good, 0.25 h)	72.5° 16:25	8.03	49%	135.2°
2043-04-03 Fri	10	—	unknown	21:25–21:35 (good, 0.17 h)	72.5° 16:25	7.98	38%	122.6°
2043-04-04 Sat	7	—	unknown	20:55–21:55 (marginal, 1.0 h)	72.6° 16:20	7.92	29%	109.6°
2043-04-05 Sun	7	—	unknown	21:30–21:55 (marginal, 0.42 h)	72.6° 16:15	7.87	19%	96.1°
2043-04-06 Mon	6	—	unknown	21:30–21:50 (marginal, 0.33 h)	72.6° 16:10	7.81	11%	82.1°
2043-04-07 Tue	4	—	unknown	20:55–21:20 (marginal, 0.42 h)	72.5° 16:05	7.76	5%	67.8°
2043-04-08 Wed	3	—	unknown	21:00–21:15 (marginal, 0.25 h)	72.5° 16:05	7.7	1%	53.0°
2043-04-09 Thu	3	—	unknown	21:00–21:10 (marginal, 0.17 h)	72.6° 16:00	7.64	0%	37.9°
2043-04-10 Fri	2	—	unknown	21:00–21:05 (marginal, 0.08 h)	72.6° 15:55	7.59	2%	22.8°
2043-04-11 Sat	1	—	unknown	—	72.5° 15:50	7.53	7%	7.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-03-13&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.