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: 05-21 (98), 05-22 (98), 05-20 (96), 05-17 (94), 05-18 (94) — by astronomy; check the weather when the night is within four days.

2034-04-23astronomy score per night — click a bar for that night2034-05-22

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-04-23 Sun	66	—	unknown	02:15–04:45 (good, 2.5 h)	71.1° 07:15	6.83	33%	137.1°
2034-04-24 Mon	68	—	unknown	02:10–04:45 (good, 2.58 h)	71.1° 07:10	6.77	44%	141.4°
2034-04-25 Tue	67	—	unknown	02:10–04:40 (good, 2.5 h)	71.1° 07:05	6.71	55%	141.9°
2034-04-26 Wed	67	—	unknown	02:05–04:40 (good, 2.58 h)	71.1° 07:00	6.65	65%	138.8°
2034-04-27 Thu	68	—	unknown	02:05–04:40 (good, 2.58 h)	71.1° 07:00	6.59	74%	133.1°
2034-04-28 Fri	67	—	unknown	02:00–04:35 (good, 2.58 h)	71.1° 06:55	6.53	82%	125.7°
2034-04-29 Sat	61	—	unknown	02:00–04:35 (good, 2.58 h)	71.1° 06:50	6.48	89%	117.3°
2034-04-30 Sun	55	—	unknown	02:05–04:35 (good, 2.5 h)	71.1° 06:45	6.42	94%	108.4°
2034-05-01 Mon	48	—	unknown	02:05–04:30 (good, 2.42 h)	71.1° 06:45	6.36	98%	99.2°
2034-05-02 Tue	42	—	unknown	02:35–04:30 (good, 1.92 h)	71.1° 06:40	6.3	100%	89.9°
2034-05-03 Wed	37	—	unknown	03:15–04:30 (good, 1.25 h)	71.1° 06:35	6.24	100%	80.6°
2034-05-04 Thu	32	—	unknown	03:55–04:25 (good, 0.5 h)	71.1° 06:30	6.19	98%	71.4°
2034-05-05 Fri	29	—	unknown	01:10–04:25 (marginal, 3.25 h)	71.1° 06:25	6.13	95%	62.6°
2034-05-06 Sat	28	—	unknown	01:05–04:20 (marginal, 3.25 h)	71.1° 06:25	6.07	90%	54.3°
2034-05-07 Sun	29	—	unknown	00:55–04:20 (marginal, 3.42 h)	71.1° 06:20	6.02	83%	47.0°
2034-05-08 Mon	33	—	unknown	04:15–04:20 (good, 0.08 h)	71.1° 06:15	5.96	75%	41.4°
2034-05-09 Tue	42	—	unknown	01:40–04:15 (good, 2.58 h)	71.1° 06:10	5.9	66%	38.3°
2034-05-10 Wed	59	—	unknown	01:05–04:15 (good, 3.17 h)	71.1° 06:05	5.85	56%	38.6°
2034-05-11 Thu	69	—	unknown	01:00–04:15 (good, 3.25 h)	71.1° 06:05	5.79	45%	42.5°
2034-05-12 Fri	78	—	unknown	01:00–04:10 (good, 3.17 h)	71.1° 06:00	5.74	34%	49.4°
2034-05-13 Sat	86	—	unknown	00:55–04:10 (good, 3.25 h)	71.1° 05:55	5.68	24%	58.5°
2034-05-14 Sun	90	—	unknown	00:50–04:10 (good, 3.33 h)	71.1° 05:50	5.63	15%	69.0°
2034-05-15 Mon	90	—	unknown	00:45–04:05 (good, 3.33 h)	71.1° 05:50	5.57	7%	80.4°
2034-05-16 Tue	92	—	unknown	00:40–04:05 (good, 3.42 h)	71.1° 05:45	5.52	2%	92.2°
2034-05-17 Wed	94	—	unknown	00:40–04:05 (good, 3.42 h)	71.1° 05:40	5.47	0%	104.1°
2034-05-18 Thu	94	—	unknown	00:35–04:00 (good, 3.42 h)	71.1° 05:35	5.42	1%	115.6°
2034-05-19 Fri	94	—	unknown	00:30–04:00 (good, 3.5 h)	71.1° 05:30	5.37	5%	125.9°
2034-05-20 Sat	96	—	unknown	00:25–04:00 (good, 3.58 h)	71.1° 05:30	5.32	11%	134.4°
2034-05-21 Sun	98	—	unknown	00:25–04:00 (good, 3.58 h)	71.1° 05:25	5.27	20%	140.1°
2034-05-22 Mon	98	—	unknown	00:20–03:55 (good, 3.58 h)	71.1° 05:20	5.22	29%	141.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-04-23&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.