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 Vega: 02-20 (67), 02-19 (66), 02-18 (65), 02-17 (63), 02-16 (62) — by astronomy; check the weather when the night is within four days.

2026-01-22astronomy score per night — click a bar for that night2026-02-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2026-01-22 Thu	32	0	0	—	87.1° 10:50	11.06	17%	78.1°
2026-01-23 Fri	33	26	9	04:50–05:00 (marginal, 0.17 h)	87.1° 10:45	11.03	26%	83.2°
2026-01-24 Sat	34	0	0	—	87.1° 10:40	11.0	36%	88.7°
2026-01-25 Sun	36	0	0	—	87.1° 10:35	10.97	47%	94.4°
2026-01-26 Mon	37	0	0	—	87.1° 10:30	10.94	58%	99.9°
2026-01-27 Tue	38	21	8	06:00–06:05 (marginal, 0.08 h)	87.1° 10:30	10.91	69%	105.0°
2026-01-28 Wed	39	0	0	—	87.1° 10:25	10.88	80%	109.3°
2026-01-29 Thu	37	0	0	—	87.1° 10:20	10.85	88%	112.4°
2026-01-30 Fri	33	0	0	—	87.1° 10:15	10.82	95%	114.0°
2026-01-31 Sat	33	0	0	—	87.1° 10:15	10.79	99%	114.1°
2026-02-01 Sun	31	0	0	—	87.1° 10:10	10.76	100%	112.5°
2026-02-02 Mon	31	0	0	—	87.1° 10:05	10.72	99%	109.6°
2026-02-03 Tue	30	0	0	—	87.1° 10:00	10.69	95%	105.7°
2026-02-04 Wed	30	0	0	—	87.1° 09:55	10.66	89%	101.1°
2026-02-05 Thu	30	0	0	—	87.1° 09:55	10.62	82%	96.1°
2026-02-06 Fri	31	0	0	—	87.1° 09:50	10.59	74%	91.0°
2026-02-07 Sat	33	0	0	—	87.1° 09:45	10.55	65%	86.0°
2026-02-08 Sun	36	0	0	—	87.1° 09:40	10.51	56%	81.3°
2026-02-09 Mon	39	0	0	—	87.1° 09:35	10.48	46%	76.9°
2026-02-10 Tue	44	0	0	—	87.1° 09:35	10.44	37%	73.0°
2026-02-11 Wed	48	0	0	—	87.1° 09:30	10.4	28%	69.8°
2026-02-12 Thu	53	0	0	—	87.1° 09:25	10.36	20%	67.4°
2026-02-13 Fri	58	32	19	05:00–05:45 (marginal, 0.75 h)	87.1° 09:20	10.32	13%	66.1°
2026-02-14 Sat	60	0	0	—	87.1° 09:20	10.29	7%	65.8°
2026-02-15 Sun	60	88	53	03:30–05:45 (good, 2.25 h)	87.1° 09:15	10.25	3%	66.8°
2026-02-16 Mon	62	0	0	—	87.1° 09:10	10.21	0%	69.0°
2026-02-17 Tue	63	0	0	—	87.1° 09:05	10.17	0%	72.4°
2026-02-18 Wed	65	100	65	03:10–05:40 (good, 2.5 h)	87.1° 09:00	10.12	2%	76.7°
2026-02-19 Thu	66	0	0	—	87.1° 09:00	10.08	7%	81.8°
2026-02-20 Fri	67	0	0	—	87.1° 08:55	10.04	14%	87.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-01-22&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.