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: 02-26 (25), 02-25 (24), 02-23 (23), 02-24 (23), 02-20 (21) — by astronomy; check the weather when the night is within four days.

2026-01-28astronomy score per night — click a bar for that night2026-02-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2026-01-28 Wed	7	0	0	—	87.3° 12:50	10.88	80%	88.9°
2026-01-29 Thu	7	0	0	—	87.3° 12:45	10.85	88%	96.7°
2026-01-30 Fri	6	0	0	—	87.3° 12:40	10.82	95%	104.3°
2026-01-31 Sat	6	0	0	—	87.3° 12:40	10.79	99%	111.1°
2026-02-01 Sun	7	0	0	—	87.3° 12:35	10.76	100%	116.7°
2026-02-02 Mon	7	0	0	—	87.3° 12:30	10.72	99%	120.7°
2026-02-03 Tue	7	19	1	—	87.3° 12:25	10.69	95%	122.7°
2026-02-04 Wed	7	0	0	—	87.3° 12:20	10.66	89%	122.7°
2026-02-05 Thu	8	0	0	—	87.3° 12:20	10.62	82%	120.9°
2026-02-06 Fri	8	0	0	—	87.3° 12:15	10.59	74%	117.5°
2026-02-07 Sat	9	14	1	—	87.3° 12:10	10.55	65%	112.9°
2026-02-08 Sun	9	11	1	—	87.3° 12:05	10.51	56%	107.6°
2026-02-09 Mon	9	0	0	—	87.3° 12:00	10.48	46%	101.7°
2026-02-10 Tue	10	0	0	—	87.3° 11:55	10.44	37%	95.4°
2026-02-11 Wed	11	0	0	—	87.3° 11:50	10.4	28%	89.0°
2026-02-12 Thu	13	0	0	—	87.3° 11:45	10.36	20%	82.5°
2026-02-13 Fri	13	59	8	05:20–05:45 (marginal, 0.42 h)	87.3° 11:45	10.32	13%	76.2°
2026-02-14 Sat	15	0	0	—	87.3° 11:40	10.29	7%	70.3°
2026-02-15 Sun	16	88	14	05:35–05:45 (good, 0.17 h)	87.3° 11:35	10.25	3%	65.0°
2026-02-16 Mon	17	0	0	—	87.3° 11:30	10.21	0%	60.7°
2026-02-17 Tue	17	0	0	—	87.3° 11:25	10.17	0%	57.9°
2026-02-18 Wed	18	100	18	05:10–05:40 (good, 0.5 h)	87.3° 11:25	10.12	2%	57.0°
2026-02-19 Thu	20	0	0	—	87.3° 11:20	10.08	7%	58.1°
2026-02-20 Fri	21	0	0	—	87.3° 11:15	10.04	14%	61.3°
2026-02-21 Sat	21	0	0	—	87.3° 11:10	10.0	22%	66.1°
2026-02-22 Sun	21	2	0	—	87.3° 11:10	9.96	32%	72.3°
2026-02-23 Mon	23	25	6	05:00–05:35 (marginal, 0.58 h)	87.3° 11:05	9.91	43%	79.3°
2026-02-24 Tue	23	7	2	—	87.3° 11:00	9.87	55%	86.9°
2026-02-25 Wed	24	0	0	—	87.3° 10:55	9.83	66%	94.6°
2026-02-26 Thu	25	58	15	04:30–05:30 (marginal, 1.0 h)	87.3° 10:50	9.78	76%	102.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-01-28&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.