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: 02-17 (100), 02-18 (100), 02-19 (100), 02-20 (97), 02-21 (96) — by astronomy; check the weather when the night is within four days.

2028-02-17astronomy score per night — click a bar for that night2028-03-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-02-17 Thu	100	—	unknown	19:30–23:30 (good, 4.0 h)	72.5° 18:20	10.18	44%	173.8°
2028-02-18 Fri	100	—	unknown	19:35–23:25 (good, 3.83 h)	72.5° 18:15	10.14	34%	161.2°
2028-02-19 Sat	100	—	unknown	19:35–23:25 (good, 3.83 h)	72.5° 18:15	10.1	25%	148.9°
2028-02-20 Sun	97	—	unknown	19:35–23:20 (good, 3.75 h)	72.5° 18:10	10.06	17%	136.7°
2028-02-21 Mon	96	—	unknown	19:35–23:15 (good, 3.67 h)	72.5° 18:05	10.02	10%	124.7°
2028-02-22 Tue	94	—	unknown	19:35–23:10 (good, 3.58 h)	72.5° 18:00	9.98	6%	112.8°
2028-02-23 Wed	91	—	unknown	19:40–23:10 (good, 3.5 h)	72.5° 17:55	9.93	2%	101.0°
2028-02-24 Thu	89	—	unknown	19:40–23:05 (good, 3.42 h)	72.5° 17:55	9.89	0%	89.2°
2028-02-25 Fri	87	—	unknown	19:40–23:00 (good, 3.33 h)	72.5° 17:50	9.85	0%	77.3°
2028-02-26 Sat	86	—	unknown	19:40–22:55 (good, 3.25 h)	72.5° 17:45	9.8	2%	65.5°
2028-02-27 Sun	80	—	unknown	19:45–22:50 (good, 3.08 h)	72.5° 17:40	9.76	6%	53.5°
2028-02-28 Mon	74	—	unknown	19:45–22:50 (good, 3.08 h)	72.5° 17:35	9.71	11%	41.5°
2028-02-29 Tue	64	—	unknown	19:45–22:45 (good, 3.0 h)	72.5° 17:35	9.67	18%	29.3°
2028-03-01 Wed	53	—	unknown	19:45–22:30 (good, 2.75 h)	72.5° 17:30	9.62	26%	16.9°
2028-03-02 Thu	42	—	unknown	19:50–22:15 (good, 2.42 h)	72.5° 17:25	9.58	35%	4.2°
2028-03-03 Fri	32	—	unknown	19:50–21:10 (good, 1.33 h)	72.5° 17:20	9.53	45%	8.7°
2028-03-04 Sat	22	—	unknown	19:50–22:45 (marginal, 2.92 h)	72.5° 17:15	9.48	56%	22.0°
2028-03-05 Sun	17	—	unknown	19:50–22:30 (marginal, 2.67 h)	72.5° 17:15	9.44	67%	35.7°
2028-03-06 Mon	16	—	unknown	19:55–22:25 (marginal, 2.5 h)	72.5° 17:10	9.39	77%	49.9°
2028-03-07 Tue	18	—	unknown	19:55–22:25 (marginal, 2.5 h)	72.5° 17:05	9.34	86%	64.5°
2028-03-08 Wed	23	—	unknown	19:20–22:25 (marginal, 3.08 h)	72.5° 17:00	9.29	93%	79.4°
2028-03-09 Thu	30	—	unknown	19:55–21:10 (good, 1.25 h)	72.5° 17:00	9.25	98%	94.6°
2028-03-10 Fri	37	—	unknown	19:55–21:45 (good, 1.83 h)	72.5° 16:55	9.2	100%	109.8°
2028-03-11 Sat	42	—	unknown	20:00–21:50 (good, 1.83 h)	72.5° 16:50	9.15	99%	124.9°
2028-03-12 Sun	47	—	unknown	20:00–21:50 (good, 1.83 h)	72.5° 16:45	9.1	95%	139.8°
2028-03-13 Mon	47	—	unknown	20:00–21:55 (good, 1.92 h)	72.5° 16:40	9.05	88%	154.3°
2028-03-14 Tue	45	—	unknown	20:00–21:50 (good, 1.83 h)	72.5° 16:40	9.0	80%	168.3°
2028-03-15 Wed	42	—	unknown	20:05–21:45 (good, 1.67 h)	72.5° 16:35	8.95	70%	178.1°
2028-03-16 Thu	41	—	unknown	20:05–21:40 (good, 1.58 h)	72.5° 16:30	8.9	60%	165.0°
2028-03-17 Fri	39	—	unknown	20:05–21:35 (good, 1.5 h)	72.5° 16:25	8.85	50%	152.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-02-17&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.