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), 03-11 (30) — by astronomy; check the weather when the night is within four days.

2038-02-17astronomy score per night — click a bar for that night2038-03-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-02-17 Wed	9	—	unknown	05:35–05:40 (good, 0.08 h)	71.1° 10:30	10.16	96%	136.2°
2038-02-18 Thu	10	—	unknown	05:35–05:40 (good, 0.08 h)	71.1° 10:25	10.12	99%	133.9°
2038-02-19 Fri	10	—	unknown	05:30–05:40 (good, 0.17 h)	71.1° 10:20	10.08	100%	128.3°
2038-02-20 Sat	11	—	unknown	05:30–05:40 (good, 0.17 h)	71.1° 10:20	10.04	98%	120.2°
2038-02-21 Sun	10	—	unknown	05:30–05:35 (good, 0.08 h)	71.1° 10:15	10.0	92%	110.6°
2038-02-22 Mon	10	—	unknown	05:30–05:35 (good, 0.08 h)	71.1° 10:10	9.95	85%	100.3°
2038-02-23 Tue	10	—	unknown	05:30–05:35 (good, 0.08 h)	71.1° 10:05	9.91	76%	89.8°
2038-02-24 Wed	10	—	unknown	05:25–05:30 (good, 0.08 h)	71.1° 10:00	9.87	65%	79.5°
2038-02-25 Thu	12	—	unknown	05:20–05:30 (good, 0.17 h)	71.1° 10:00	9.82	54%	69.7°
2038-02-26 Fri	13	—	unknown	05:10–05:30 (good, 0.33 h)	71.1° 09:55	9.78	43%	60.9°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-02-17&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.