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: 03-27 (43), 03-29 (43), 03-30 (43), 03-28 (42), 03-25 (41) — by astronomy; check the weather when the night is within four days.

2042-03-09astronomy score per night — click a bar for that night2042-04-07

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-03-09 Sun	17	—	unknown	04:30–05:10 (good, 0.67 h)	71.1° 09:10	9.27	92%	101.3°
2042-03-10 Mon	17	—	unknown	04:30–05:10 (good, 0.67 h)	71.1° 09:05	9.22	86%	93.3°
2042-03-11 Tue	18	—	unknown	04:25–05:10 (good, 0.75 h)	71.1° 09:05	9.17	78%	85.2°
2042-03-12 Wed	18	—	unknown	04:20–05:05 (good, 0.75 h)	71.1° 09:00	9.12	70%	77.1°
2042-03-13 Thu	19	—	unknown	04:15–05:05 (good, 0.83 h)	71.1° 08:55	9.07	60%	69.2°
2042-03-14 Fri	21	—	unknown	04:05–05:05 (good, 1.0 h)	71.1° 08:50	9.02	50%	61.7°
2042-03-15 Sat	24	—	unknown	04:00–05:00 (good, 1.0 h)	71.1° 08:50	8.97	40%	55.2°
2042-03-16 Sun	29	—	unknown	03:40–05:00 (good, 1.33 h)	71.1° 08:45	8.92	30%	50.1°
2042-03-17 Mon	33	—	unknown	03:40–04:55 (good, 1.25 h)	71.1° 08:40	8.87	20%	47.5°
2042-03-18 Tue	35	—	unknown	03:35–04:55 (good, 1.33 h)	71.1° 08:35	8.82	11%	48.0°
2042-03-19 Wed	36	—	unknown	03:30–04:55 (good, 1.42 h)	71.1° 08:30	8.77	5%	51.7°
2042-03-20 Thu	36	—	unknown	03:25–04:50 (good, 1.42 h)	71.1° 08:30	8.72	1%	58.3°
2042-03-21 Fri	37	—	unknown	03:25–04:50 (good, 1.42 h)	71.1° 08:25	8.66	0%	66.8°
2042-03-22 Sat	39	—	unknown	03:20–04:50 (good, 1.5 h)	71.1° 08:20	8.61	2%	76.4°
2042-03-23 Sun	38	—	unknown	03:15–04:45 (good, 1.5 h)	71.1° 08:15	8.56	7%	86.5°
2042-03-24 Mon	40	—	unknown	03:10–04:45 (good, 1.58 h)	71.1° 08:10	8.51	15%	96.4°
2042-03-25 Tue	41	—	unknown	03:05–04:45 (good, 1.67 h)	71.1° 08:10	8.45	24%	105.8°
2042-03-26 Wed	41	—	unknown	03:05–04:40 (good, 1.58 h)	71.1° 08:05	8.4	34%	114.4°
2042-03-27 Thu	43	—	unknown	03:00–04:40 (good, 1.67 h)	71.1° 08:00	8.35	44%	121.7°
2042-03-28 Fri	42	—	unknown	02:55–04:35 (good, 1.67 h)	71.1° 07:55	8.29	55%	127.4°
2042-03-29 Sat	43	—	unknown	02:55–05:35 (good, 1.67 h)	71.1° 08:55	8.24	64%	131.2°
2042-03-30 Sun	43	—	unknown	03:55–05:35 (good, 1.67 h)	71.1° 08:50	8.18	74%	132.7°
2042-03-31 Mon	40	—	unknown	03:50–05:30 (good, 1.67 h)	71.1° 08:45	8.13	82%	131.8°
2042-04-01 Tue	40	—	unknown	03:50–05:30 (good, 1.67 h)	71.1° 08:40	8.08	88%	128.7°
2042-04-02 Wed	38	—	unknown	03:45–05:25 (good, 1.67 h)	71.1° 08:35	8.02	94%	124.0°
2042-04-03 Thu	38	—	unknown	03:45–05:25 (good, 1.67 h)	71.1° 08:35	7.97	98%	117.9°
2042-04-04 Fri	36	—	unknown	03:45–05:25 (good, 1.67 h)	71.1° 08:30	7.91	100%	111.0°
2042-04-05 Sat	32	—	unknown	03:45–05:20 (good, 1.58 h)	71.1° 08:25	7.85	100%	103.4°
2042-04-06 Sun	30	—	unknown	03:45–05:20 (good, 1.58 h)	71.1° 08:20	7.8	98%	95.5°
2042-04-07 Mon	28	—	unknown	04:05–05:15 (good, 1.17 h)	71.1° 08:15	7.74	95%	87.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-03-09&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.