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: 02-24 (18), 02-25 (18), 02-26 (18), 02-23 (16), 02-22 (15) — by astronomy; check the weather when the night is within four days.

2048-01-28astronomy score per night — click a bar for that night2048-02-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2048-01-28 Tue	1	—	unknown	—	71.2° 11:50	10.89	96%	133.2°
2048-01-29 Wed	1	—	unknown	—	71.2° 11:45	10.86	99%	138.3°
2048-01-30 Thu	1	—	unknown	—	71.1° 11:45	10.83	100%	140.7°
2048-01-31 Fri	1	—	unknown	—	71.2° 11:40	10.8	99%	139.6°
2048-02-01 Sat	1	—	unknown	—	71.2° 11:35	10.77	96%	135.1°
2048-02-02 Sun	1	—	unknown	—	71.2° 11:30	10.74	90%	128.0°
2048-02-03 Mon	1	—	unknown	—	71.1° 11:25	10.7	83%	119.2°
2048-02-04 Tue	1	—	unknown	—	71.1° 11:25	10.67	74%	109.3°
2048-02-05 Wed	2	—	unknown	05:50–05:55 (marginal, 0.08 h)	71.2° 11:20	10.63	63%	98.8°
2048-02-06 Thu	2	—	unknown	05:45–05:55 (marginal, 0.17 h)	71.2° 11:15	10.6	52%	87.9°
2048-02-07 Fri	3	—	unknown	05:45–05:55 (marginal, 0.17 h)	71.2° 11:10	10.56	41%	77.0°
2048-02-08 Sat	3	—	unknown	05:40–05:55 (marginal, 0.25 h)	71.1° 11:05	10.53	30%	66.5°
2048-02-09 Sun	4	—	unknown	05:35–05:50 (marginal, 0.25 h)	71.2° 11:05	10.49	20%	56.6°
2048-02-10 Mon	5	—	unknown	05:30–05:50 (marginal, 0.33 h)	71.2° 11:00	10.45	12%	48.1°
2048-02-11 Tue	6	—	unknown	05:25–05:50 (marginal, 0.42 h)	71.2° 10:55	10.41	5%	42.0°
2048-02-12 Wed	7	—	unknown	05:25–06:20 (marginal, 0.92 h)	71.2° 10:50	10.38	2%	39.3°
2048-02-13 Thu	8	—	unknown	05:45–05:50 (good, 0.08 h)	71.1° 10:50	10.34	0%	40.6°
2048-02-14 Fri	8	—	unknown	05:40–05:45 (good, 0.08 h)	71.2° 10:45	10.3	1%	45.5°
2048-02-15 Sat	9	—	unknown	05:40–05:45 (good, 0.08 h)	71.2° 10:40	10.26	4%	52.6°
2048-02-16 Sun	10	—	unknown	05:35–05:45 (good, 0.17 h)	71.2° 10:35	10.22	10%	61.0°
2048-02-17 Mon	11	—	unknown	05:30–05:45 (good, 0.25 h)	71.1° 10:30	10.18	16%	70.0°
2048-02-18 Tue	11	—	unknown	05:25–05:40 (good, 0.25 h)	71.1° 10:30	10.14	24%	79.3°
2048-02-19 Wed	12	—	unknown	05:25–05:40 (good, 0.25 h)	71.2° 10:25	10.1	33%	88.6°
2048-02-20 Thu	14	—	unknown	05:20–05:40 (good, 0.33 h)	71.2° 10:20	10.05	42%	97.8°
2048-02-21 Fri	14	—	unknown	05:15–05:35 (good, 0.33 h)	71.2° 10:15	10.01	51%	106.9°
2048-02-22 Sat	15	—	unknown	05:10–05:35 (good, 0.42 h)	71.1° 10:10	9.97	61%	115.6°
2048-02-23 Sun	16	—	unknown	05:05–05:35 (good, 0.5 h)	71.2° 10:10	9.93	70%	123.7°
2048-02-24 Mon	18	—	unknown	05:05–05:35 (good, 0.5 h)	71.2° 10:05	9.88	78%	131.0°
2048-02-25 Tue	18	—	unknown	05:00–05:30 (good, 0.5 h)	71.2° 10:00	9.84	86%	136.9°
2048-02-26 Wed	18	—	unknown	05:00–05:30 (good, 0.5 h)	71.2° 09:55	9.8	92%	140.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2048-01-28&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.