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: 04-29 (74), 04-30 (74), 04-28 (72), 04-26 (71), 04-27 (71) — by astronomy; check the weather when the night is within four days.

2036-04-01astronomy score per night — click a bar for that night2036-04-30

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-04-01 Tue	48	—	unknown	03:35–05:30 (good, 1.92 h)	71.1° 08:40	8.05	27%	120.1°
2036-04-02 Wed	47	—	unknown	03:35–05:25 (good, 1.83 h)	71.1° 08:35	8.0	38%	128.6°
2036-04-03 Thu	49	—	unknown	03:30–05:25 (good, 1.92 h)	71.1° 08:30	7.94	49%	135.3°
2036-04-04 Fri	48	—	unknown	03:30–05:20 (good, 1.83 h)	71.1° 08:25	7.88	61%	139.0°
2036-04-05 Sat	49	—	unknown	03:25–05:20 (good, 1.92 h)	71.1° 08:25	7.83	72%	138.9°
2036-04-06 Sun	49	—	unknown	03:25–05:20 (good, 1.92 h)	71.1° 08:20	7.77	81%	134.8°
2036-04-07 Mon	44	—	unknown	03:25–05:15 (good, 1.83 h)	71.1° 08:15	7.72	89%	127.8°
2036-04-08 Tue	43	—	unknown	03:20–05:15 (good, 1.92 h)	71.1° 08:10	7.66	95%	118.9°
2036-04-09 Wed	38	—	unknown	03:25–05:15 (good, 1.83 h)	71.1° 08:05	7.6	99%	109.1°
2036-04-10 Thu	33	—	unknown	03:30–05:10 (good, 1.67 h)	71.1° 08:05	7.55	100%	98.9°
2036-04-11 Fri	29	—	unknown	04:05–05:10 (good, 1.08 h)	71.1° 08:00	7.49	98%	88.6°
2036-04-12 Sat	26	—	unknown	04:35–05:05 (good, 0.5 h)	71.1° 07:55	7.43	95%	78.6°
2036-04-13 Sun	24	—	unknown	04:55–05:05 (good, 0.17 h)	71.1° 07:50	7.38	89%	69.2°
2036-04-14 Mon	25	—	unknown	05:00–05:05 (good, 0.08 h)	71.1° 07:50	7.32	82%	60.5°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-04-01&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.