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: 04-24 (68), 04-27 (68), 04-25 (67), 04-26 (67), 04-28 (67) — by astronomy; check the weather when the night is within four days.

2034-04-11astronomy score per night — click a bar for that night2034-05-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-04-11 Tue	32	—	unknown	03:20–05:10 (good, 1.83 h)	71.1° 08:00	7.52	50%	40.1°
2034-04-12 Wed	42	—	unknown	02:55–05:10 (good, 2.25 h)	71.1° 07:55	7.46	40%	37.9°
2034-04-13 Thu	49	—	unknown	02:50–05:05 (good, 2.25 h)	71.1° 07:55	7.4	30%	39.3°
2034-04-14 Fri	55	—	unknown	02:50–05:05 (good, 2.25 h)	71.1° 07:50	7.35	20%	44.5°
2034-04-15 Sat	59	—	unknown	02:45–05:00 (good, 2.25 h)	71.1° 07:45	7.29	12%	52.6°
2034-04-16 Sun	59	—	unknown	02:40–05:00 (good, 2.33 h)	71.1° 07:40	7.23	5%	62.6°
2034-04-17 Mon	61	—	unknown	02:35–05:00 (good, 2.42 h)	71.1° 07:40	7.17	1%	73.8°
2034-04-18 Tue	62	—	unknown	02:35–04:55 (good, 2.33 h)	71.1° 07:35	7.12	0%	85.7°
2034-04-19 Wed	63	—	unknown	02:30–04:55 (good, 2.42 h)	71.1° 07:30	7.06	2%	97.7°
2034-04-20 Thu	63	—	unknown	02:25–04:50 (good, 2.42 h)	71.1° 07:25	7.0	7%	109.4°
2034-04-21 Fri	65	—	unknown	02:20–04:50 (good, 2.5 h)	71.1° 07:20	6.94	14%	120.3°
2034-04-22 Sat	66	—	unknown	02:15–04:50 (good, 2.58 h)	71.1° 07:20	6.88	23%	129.8°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-04-11&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.