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 HD 189733: 03-14 (32), 03-15 (32), 03-16 (32), 03-13 (31), 03-28 (31) — by astronomy; check the weather when the night is within four days.

2038-02-27astronomy score per night — click a bar for that night2038-03-28

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-02-27 Sat	16	—	unknown	05:00–05:30 (good, 0.5 h)	71.1° 09:50	9.73	32%	53.4°
2038-02-28 Sun	17	—	unknown	04:55–05:25 (good, 0.5 h)	71.1° 09:45	9.69	23%	47.7°
2038-03-01 Mon	21	—	unknown	04:40–05:25 (good, 0.75 h)	71.1° 09:45	9.64	15%	44.4°
2038-03-02 Tue	23	—	unknown	04:35–05:25 (good, 0.83 h)	71.1° 09:40	9.6	9%	43.9°
2038-03-03 Wed	23	—	unknown	04:35–05:20 (good, 0.75 h)	71.1° 09:35	9.55	4%	46.2°
2038-03-04 Thu	24	—	unknown	04:30–05:20 (good, 0.83 h)	71.1° 09:30	9.5	1%	50.8°
2038-03-05 Fri	25	—	unknown	04:25–05:20 (good, 0.92 h)	71.1° 09:25	9.46	0%	57.0°
2038-03-06 Sat	25	—	unknown	04:20–05:15 (good, 0.92 h)	71.1° 09:25	9.41	1%	64.2°
2038-03-07 Sun	26	—	unknown	04:20–05:15 (good, 0.92 h)	71.1° 09:20	9.36	4%	72.1°
2038-03-08 Mon	28	—	unknown	04:15–05:15 (good, 1.0 h)	71.1° 09:15	9.32	8%	80.4°
2038-03-09 Tue	27	—	unknown	04:10–05:10 (good, 1.0 h)	71.1° 09:10	9.27	14%	88.9°
2038-03-10 Wed	28	—	unknown	04:05–05:10 (good, 1.08 h)	71.1° 09:05	9.22	21%	97.4°
2038-03-11 Thu	30	—	unknown	04:00–05:10 (good, 1.17 h)	71.1° 09:05	9.17	29%	105.8°
2038-03-12 Fri	30	—	unknown	04:00–05:05 (good, 1.08 h)	71.1° 09:00	9.12	38%	114.0°
2038-03-13 Sat	31	—	unknown	03:55–05:05 (good, 1.17 h)	71.1° 08:55	9.07	48%	121.6°
2038-03-14 Sun	32	—	unknown	03:50–05:05 (good, 1.25 h)	71.1° 08:50	9.02	58%	128.3°
2038-03-15 Mon	32	—	unknown	03:45–05:00 (good, 1.25 h)	71.1° 08:50	8.97	68%	133.4°
2038-03-16 Tue	32	—	unknown	03:50–05:00 (good, 1.17 h)	71.1° 08:45	8.92	78%	136.0°
2038-03-17 Wed	30	—	unknown	03:45–05:00 (good, 1.25 h)	71.1° 08:40	8.87	86%	135.3°
2038-03-18 Thu	29	—	unknown	03:45–04:55 (good, 1.17 h)	71.1° 08:35	8.82	93%	131.2°
2038-03-19 Fri	29	—	unknown	03:40–04:55 (good, 1.25 h)	71.1° 08:30	8.77	98%	124.1°
2038-03-20 Sat	27	—	unknown	03:40–04:50 (good, 1.17 h)	71.1° 08:30	8.72	100%	115.1°
2038-03-21 Sun	24	—	unknown	03:45–04:50 (good, 1.08 h)	71.1° 08:25	8.67	99%	104.8°
2038-03-22 Mon	22	—	unknown	03:55–04:50 (good, 0.92 h)	71.1° 08:20	8.61	95%	94.1°
2038-03-23 Tue	20	—	unknown	04:15–04:45 (good, 0.5 h)	71.1° 08:15	8.56	88%	83.3°
2038-03-24 Wed	20	—	unknown	04:20–04:45 (good, 0.42 h)	71.1° 08:10	8.51	79%	73.0°
2038-03-25 Thu	21	—	unknown	04:00–04:45 (good, 0.75 h)	71.1° 08:10	8.46	69%	63.5°
2038-03-26 Fri	23	—	unknown	03:30–04:40 (good, 1.17 h)	71.1° 08:05	8.4	59%	55.4°
2038-03-27 Sat	27	—	unknown	04:15–05:40 (good, 1.42 h)	71.1° 09:00	8.35	48%	49.1°
2038-03-28 Sun	31	—	unknown	03:55–05:35 (good, 1.67 h)	71.1° 08:55	8.3	38%	45.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-02-27&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.