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: 05-01 (76), 05-02 (76), 05-05 (76), 05-03 (75), 05-04 (75) — by astronomy; check the weather when the night is within four days.

2036-04-15astronomy score per night — click a bar for that night2036-05-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-04-15 Tue	26	—	unknown	04:40–05:00 (good, 0.33 h)	71.1° 07:45	7.26	74%	52.8°
2036-04-16 Wed	29	—	unknown	03:40–05:00 (good, 1.33 h)	71.1° 07:40	7.2	66%	46.6°
2036-04-17 Thu	34	—	unknown	02:55–04:55 (good, 2.0 h)	71.1° 07:35	7.14	56%	42.4°
2036-04-18 Fri	45	—	unknown	02:30–04:55 (good, 2.42 h)	71.1° 07:30	7.09	47%	40.7°
2036-04-19 Sat	53	—	unknown	02:25–04:55 (good, 2.5 h)	71.1° 07:30	7.03	37%	41.8°
2036-04-20 Sun	59	—	unknown	02:25–04:50 (good, 2.42 h)	71.1° 07:25	6.97	28%	45.5°
2036-04-21 Mon	65	—	unknown	02:20–04:50 (good, 2.5 h)	71.1° 07:20	6.91	20%	51.4°
2036-04-22 Tue	65	—	unknown	02:15–04:45 (good, 2.5 h)	71.1° 07:15	6.85	13%	58.8°
2036-04-23 Wed	67	—	unknown	02:10–04:45 (good, 2.58 h)	71.1° 07:10	6.8	7%	67.5°
2036-04-24 Thu	68	—	unknown	02:05–04:45 (good, 2.67 h)	71.1° 07:10	6.74	3%	76.9°
2036-04-25 Fri	69	—	unknown	02:05–04:40 (good, 2.58 h)	71.1° 07:05	6.68	0%	86.9°
2036-04-26 Sat	71	—	unknown	02:00–04:40 (good, 2.67 h)	71.1° 07:00	6.62	0%	97.2°
2036-04-27 Sun	71	—	unknown	01:55–04:40 (good, 2.75 h)	71.1° 06:55	6.56	3%	107.5°
2036-04-28 Mon	72	—	unknown	01:50–04:35 (good, 2.75 h)	71.1° 06:55	6.5	8%	117.5°
2036-04-29 Tue	74	—	unknown	01:45–04:35 (good, 2.83 h)	71.1° 06:50	6.45	15%	126.5°
2036-04-30 Wed	74	—	unknown	01:45–04:30 (good, 2.75 h)	71.1° 06:45	6.39	25%	133.7°
2036-05-01 Thu	76	—	unknown	01:40–04:30 (good, 2.83 h)	71.1° 06:40	6.33	35%	138.3°
2036-05-02 Fri	76	—	unknown	01:40–04:30 (good, 2.83 h)	71.1° 06:35	6.27	46%	139.0°
2036-05-03 Sat	75	—	unknown	01:35–04:25 (good, 2.83 h)	71.1° 06:35	6.21	58%	135.9°
2036-05-04 Sun	75	—	unknown	01:35–04:25 (good, 2.83 h)	71.1° 06:30	6.16	69%	129.7°
2036-05-05 Mon	76	—	unknown	01:30–04:25 (good, 2.92 h)	71.1° 06:25	6.1	78%	121.4°
2036-05-06 Tue	64	—	unknown	01:35–04:20 (good, 2.75 h)	71.1° 06:20	6.04	87%	112.1°
2036-05-07 Wed	56	—	unknown	01:40–04:20 (good, 2.67 h)	71.1° 06:15	5.99	93%	102.2°
2036-05-08 Thu	49	—	unknown	02:00–04:20 (good, 2.33 h)	71.1° 06:15	5.93	98%	92.1°
2036-05-09 Fri	41	—	unknown	02:45–04:15 (good, 1.5 h)	71.1° 06:10	5.87	100%	82.1°
2036-05-10 Sat	36	—	unknown	03:30–04:15 (good, 0.75 h)	71.1° 06:05	5.82	99%	72.5°
2036-05-11 Sun	32	—	unknown	04:05–04:15 (good, 0.17 h)	71.1° 06:00	5.76	97%	63.6°
2036-05-12 Mon	30	—	unknown	00:40–04:10 (marginal, 3.5 h)	71.1° 06:00	5.71	93%	55.5°
2036-05-13 Tue	31	—	unknown	00:30–04:10 (marginal, 3.67 h)	71.1° 05:55	5.65	87%	48.7°
2036-05-14 Wed	34	—	unknown	00:25–04:10 (marginal, 3.75 h)	71.1° 05:50	5.6	80%	43.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-04-15&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.