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 V1057 Cyg: 02-16 (17), 02-15 (15), 01-18 (14), 02-14 (14), 01-26 (13) — by astronomy; check the weather when the night is within four days.

2043-01-18astronomy score per night — click a bar for that night2043-02-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-01-18 Sun	14	—	unknown	19:00–20:25 (marginal, 1.42 h)	87.3° 13:30	11.16	56%	70.9°
2043-01-19 Mon	12	—	unknown	19:00–20:15 (marginal, 1.25 h)	87.3° 13:25	11.14	67%	77.1°
2043-01-20 Tue	11	—	unknown	19:00–20:10 (marginal, 1.17 h)	87.2° 13:25	11.11	78%	83.9°
2043-01-21 Wed	12	—	unknown	19:00–20:10 (marginal, 1.17 h)	87.3° 13:20	11.09	86%	91.0°
2043-01-22 Thu	12	—	unknown	19:05–20:05 (marginal, 1.0 h)	87.3° 13:15	11.06	93%	98.0°
2043-01-23 Fri	12	—	unknown	18:30–20:05 (marginal, 1.58 h)	87.3° 13:10	11.03	98%	104.5°
2043-01-24 Sat	12	—	unknown	18:30–20:00 (marginal, 1.5 h)	87.2° 13:05	11.0	100%	110.3°
2043-01-25 Sun	12	—	unknown	19:05–19:10 (good, 0.08 h)	87.2° 13:05	10.98	99%	115.0°
2043-01-26 Mon	13	—	unknown	19:05–19:10 (good, 0.08 h)	87.3° 13:00	10.95	97%	118.3°
2043-01-27 Tue	13	—	unknown	19:10–19:15 (good, 0.08 h)	87.3° 12:55	10.92	92%	120.0°
2043-01-28 Wed	12	—	unknown	18:35–19:45 (marginal, 1.17 h)	87.3° 12:50	10.89	86%	120.1°
2043-01-29 Thu	10	—	unknown	19:10–19:40 (marginal, 0.5 h)	87.2° 12:45	10.86	79%	118.6°
2043-01-30 Fri	10	—	unknown	19:10–19:40 (marginal, 0.5 h)	87.2° 12:45	10.83	70%	115.9°
2043-01-31 Sat	9	—	unknown	19:15–19:35 (marginal, 0.33 h)	87.3° 12:40	10.79	62%	112.0°
2043-02-01 Sun	8	—	unknown	05:40–06:00 (marginal, 0.33 h)	87.3° 12:35	10.76	52%	107.4°
2043-02-02 Mon	7	—	unknown	05:40–06:00 (marginal, 0.33 h)	87.3° 12:30	10.73	43%	102.0°
2043-02-03 Tue	8	—	unknown	05:35–06:00 (marginal, 0.42 h)	87.2° 12:25	10.69	34%	96.3°
2043-02-04 Wed	8	—	unknown	05:30–05:55 (marginal, 0.42 h)	87.3° 12:25	10.66	25%	90.2°
2043-02-05 Thu	9	—	unknown	05:25–05:55 (marginal, 0.5 h)	87.3° 12:20	10.63	17%	84.0°
2043-02-06 Fri	10	—	unknown	05:20–06:25 (marginal, 1.08 h)	87.3° 12:15	10.59	10%	77.9°
2043-02-07 Sat	10	—	unknown	05:20–06:25 (marginal, 1.08 h)	87.2° 12:10	10.55	5%	72.0°
2043-02-08 Sun	11	—	unknown	05:50–05:55 (good, 0.08 h)	87.2° 12:10	10.52	1%	66.9°
2043-02-09 Mon	11	—	unknown	05:45–05:50 (good, 0.08 h)	87.3° 12:00	10.48	0%	62.8°
2043-02-10 Tue	12	—	unknown	05:40–05:50 (good, 0.17 h)	87.3° 12:00	10.44	2%	60.3°
2043-02-11 Wed	12	—	unknown	05:35–05:50 (good, 0.25 h)	87.2° 11:50	10.41	5%	59.8°
2043-02-12 Thu	13	—	unknown	05:35–05:50 (good, 0.25 h)	87.2° 11:50	10.37	12%	61.2°
2043-02-13 Fri	13	—	unknown	05:30–05:45 (good, 0.25 h)	87.3° 11:45	10.33	20%	64.6°
2043-02-14 Sat	14	—	unknown	05:25–05:45 (good, 0.33 h)	87.3° 11:40	10.29	30%	69.5°
2043-02-15 Sun	15	—	unknown	05:20–05:45 (good, 0.42 h)	87.3° 11:35	10.25	41%	75.5°
2043-02-16 Mon	17	—	unknown	05:15–05:45 (good, 0.5 h)	87.2° 11:30	10.21	53%	82.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-01-18&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.