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: 09-12 (100), 09-13 (100), 09-14 (100), 09-15 (100), 09-16 (100) — by astronomy; check the weather when the night is within four days.

2033-09-05astronomy score per night — click a bar for that night2033-10-04

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-09-05 Mon	47	—	unknown	21:25–03:55 (marginal, 6.5 h)	71.1° 22:20	7.85	86%	37.9°
2033-09-06 Tue	37	—	unknown	21:25–03:35 (marginal, 6.17 h)	71.1° 22:20	7.9	93%	38.1°
2033-09-07 Wed	35	—	unknown	21:25–03:20 (marginal, 5.92 h)	71.1° 22:15	7.96	98%	42.7°
2033-09-08 Thu	41	—	unknown	21:20–03:15 (marginal, 5.92 h)	71.1° 22:10	8.01	100%	50.8°
2033-09-09 Fri	53	—	unknown	21:20–22:05 (good, 0.75 h)	71.1° 22:05	8.07	99%	60.9°
2033-09-10 Sat	71	—	unknown	21:15–00:15 (good, 3.0 h)	71.1° 22:05	8.12	95%	72.3°
2033-09-11 Sun	81	—	unknown	21:15–01:35 (good, 4.33 h)	71.1° 22:00	8.18	88%	84.0°
2033-09-12 Mon	100	—	unknown	21:15–02:35 (good, 5.33 h)	71.1° 21:55	8.23	80%	95.7°
2033-09-13 Tue	100	—	unknown	21:10–02:45 (good, 5.58 h)	71.1° 21:50	8.28	70%	106.9°
2033-09-14 Wed	100	—	unknown	21:10–02:45 (good, 5.58 h)	71.1° 21:45	8.34	59%	117.5°
2033-09-15 Thu	100	—	unknown	21:05–02:45 (good, 5.67 h)	71.1° 21:45	8.39	48%	126.9°
2033-09-16 Fri	100	—	unknown	21:05–02:40 (good, 5.58 h)	71.1° 21:40	8.44	37%	134.7°
2033-09-17 Sat	100	—	unknown	21:05–02:40 (good, 5.58 h)	71.1° 21:35	8.49	28%	140.1°
2033-09-18 Sun	100	—	unknown	21:00–02:40 (good, 5.67 h)	71.1° 21:30	8.54	19%	142.5°
2033-09-19 Mon	100	—	unknown	21:00–02:35 (good, 5.58 h)	71.1° 21:25	8.6	12%	141.5°
2033-09-20 Tue	100	—	unknown	21:00–02:30 (good, 5.5 h)	71.1° 21:25	8.65	6%	137.3°
2033-09-21 Wed	100	—	unknown	20:55–02:25 (good, 5.5 h)	71.1° 21:20	8.7	2%	131.0°
2033-09-22 Thu	100	—	unknown	20:55–02:20 (good, 5.42 h)	71.1° 21:15	8.75	0%	123.3°
2033-09-23 Fri	100	—	unknown	20:50–02:20 (good, 5.5 h)	71.1° 21:10	8.8	0%	114.8°
2033-09-24 Sat	100	—	unknown	20:50–02:15 (good, 5.42 h)	71.1° 21:10	8.85	2%	105.7°
2033-09-25 Sun	100	—	unknown	20:50–02:10 (good, 5.33 h)	71.1° 21:05	8.9	5%	96.5°
2033-09-26 Mon	100	—	unknown	20:45–02:05 (good, 5.33 h)	71.1° 21:00	8.95	10%	87.1°
2033-09-27 Tue	100	—	unknown	20:45–02:00 (good, 5.25 h)	71.1° 20:55	9.0	16%	77.7°
2033-09-28 Wed	100	—	unknown	20:45–02:00 (good, 5.25 h)	71.1° 20:50	9.05	24%	68.4°
2033-09-29 Thu	100	—	unknown	20:40–01:55 (good, 5.25 h)	71.1° 20:50	9.1	32%	59.4°
2033-09-30 Fri	95	—	unknown	20:40–01:50 (good, 5.17 h)	71.1° 20:45	9.15	42%	51.1°
2033-10-01 Sat	88	—	unknown	20:35–01:45 (good, 5.17 h)	71.1° 20:40	9.19	52%	43.9°
2033-10-02 Sun	75	—	unknown	20:35–01:40 (good, 5.08 h)	71.1° 20:35	9.24	63%	38.9°
2033-10-03 Mon	47	—	unknown	20:35–02:05 (marginal, 5.5 h)	71.1° 20:30	9.29	73%	37.4°
2033-10-04 Tue	38	—	unknown	20:30–01:50 (marginal, 5.33 h)	71.1° 20:30	9.34	83%	40.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-09-05&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.