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: 02-22 (22), 02-20 (21), 02-21 (20), 02-19 (19), 01-24 (17) — by astronomy; check the weather when the night is within four days.

2039-01-24astronomy score per night — click a bar for that night2039-02-22

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-01-24 Mon	17	—	unknown	19:05–19:25 (good, 0.33 h)	87.3° 13:05	11.01	0%	65.3°
2039-01-25 Tue	16	—	unknown	19:05–19:25 (good, 0.33 h)	87.3° 13:05	10.98	2%	62.9°
2039-01-26 Wed	14	—	unknown	19:05–19:15 (good, 0.17 h)	87.3° 13:00	10.95	7%	62.2°
2039-01-27 Thu	12	—	unknown	18:35–19:50 (marginal, 1.25 h)	87.3° 12:55	10.92	13%	63.1°
2039-01-28 Fri	11	—	unknown	19:10–19:45 (marginal, 0.58 h)	87.3° 12:50	10.89	20%	65.4°
2039-01-29 Sat	9	—	unknown	19:10–19:40 (marginal, 0.5 h)	87.3° 12:45	10.86	29%	68.7°
2039-01-30 Sun	8	—	unknown	19:10–19:40 (marginal, 0.5 h)	87.3° 12:45	10.83	38%	73.0°
2039-01-31 Mon	8	—	unknown	19:15–19:35 (marginal, 0.33 h)	87.3° 12:40	10.79	48%	77.8°
2039-02-01 Tue	8	—	unknown	05:40–06:00 (marginal, 0.33 h)	87.3° 12:35	10.76	57%	83.0°
2039-02-02 Wed	8	—	unknown	05:40–06:00 (marginal, 0.33 h)	87.3° 12:30	10.73	66%	88.4°
2039-02-03 Thu	8	—	unknown	05:35–06:00 (marginal, 0.42 h)	87.2° 12:25	10.7	75%	94.0°
2039-02-04 Fri	8	—	unknown	05:30–05:55 (marginal, 0.42 h)	87.3° 12:25	10.66	83%	99.5°
2039-02-05 Sat	9	—	unknown	05:25–05:55 (marginal, 0.5 h)	87.3° 12:20	10.63	89%	104.7°
2039-02-06 Sun	7	—	unknown	05:20–05:55 (marginal, 0.58 h)	87.3° 12:15	10.59	95%	109.4°
2039-02-07 Mon	7	—	unknown	05:20–05:55 (marginal, 0.58 h)	87.3° 12:10	10.56	98%	113.4°
2039-02-08 Tue	8	—	unknown	05:15–05:55 (marginal, 0.67 h)	87.3° 12:10	10.52	100%	116.3°
2039-02-09 Wed	8	—	unknown	05:10–05:50 (marginal, 0.67 h)	87.3° 12:00	10.48	99%	117.7°
2039-02-10 Thu	9	—	unknown	05:05–05:50 (marginal, 0.75 h)	87.3° 12:00	10.45	96%	117.5°
2039-02-11 Fri	9	—	unknown	05:00–05:50 (marginal, 0.83 h)	87.3° 11:50	10.41	91%	115.6°
2039-02-12 Sat	10	—	unknown	05:00–06:20 (marginal, 1.33 h)	87.3° 11:50	10.37	83%	112.1°
2039-02-13 Sun	9	—	unknown	04:55–06:20 (marginal, 1.42 h)	87.3° 11:45	10.33	74%	107.3°
2039-02-14 Mon	11	—	unknown	05:40–05:45 (good, 0.08 h)	87.3° 11:40	10.29	63%	101.6°
2039-02-15 Tue	12	—	unknown	05:35–05:45 (good, 0.17 h)	87.3° 11:35	10.25	52%	95.3°
2039-02-16 Wed	13	—	unknown	05:30–05:45 (good, 0.25 h)	87.2° 11:30	10.21	41%	88.7°
2039-02-17 Thu	14	—	unknown	05:20–05:40 (good, 0.33 h)	87.3° 11:30	10.17	30%	82.2°
2039-02-18 Fri	16	—	unknown	05:15–05:40 (good, 0.42 h)	87.3° 11:25	10.13	20%	76.2°
2039-02-19 Sat	19	—	unknown	05:05–05:40 (good, 0.58 h)	87.3° 11:20	10.09	12%	70.8°
2039-02-20 Sun	21	—	unknown	05:00–05:40 (good, 0.67 h)	87.3° 11:15	10.05	6%	66.5°
2039-02-21 Mon	20	—	unknown	05:00–05:35 (good, 0.58 h)	87.3° 11:15	10.01	2%	63.6°
2039-02-22 Tue	22	—	unknown	04:55–05:35 (good, 0.67 h)	87.3° 11:10	9.96	0%	62.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-01-24&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.