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: 03-02 (23), 03-01 (21), 02-27 (20), 02-28 (20), 02-26 (19) — by astronomy; check the weather when the night is within four days.

2039-02-01astronomy score per night — click a bar for that night2039-03-02

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-02-01 Tue	1	—	unknown	—	71.1° 11:35	10.76	57%	101.2°
2039-02-02 Wed	1	—	unknown	—	71.1° 11:30	10.73	66%	109.2°
2039-02-03 Thu	2	—	unknown	05:55–06:00 (marginal, 0.08 h)	71.1° 11:25	10.7	75%	116.8°
2039-02-04 Fri	2	—	unknown	06:20–06:30 (marginal, 0.17 h)	71.1° 11:20	10.66	83%	123.6°
2039-02-05 Sat	3	—	unknown	06:15–06:30 (marginal, 0.25 h)	71.1° 11:20	10.63	89%	129.3°
2039-02-06 Sun	3	—	unknown	05:45–05:55 (marginal, 0.17 h)	71.1° 11:15	10.59	95%	133.3°
2039-02-07 Mon	3	—	unknown	05:40–05:55 (marginal, 0.25 h)	71.1° 11:10	10.56	98%	134.8°
2039-02-08 Tue	4	—	unknown	05:40–05:55 (marginal, 0.25 h)	71.1° 11:05	10.52	100%	133.4°
2039-02-09 Wed	4	—	unknown	05:35–05:50 (marginal, 0.25 h)	71.1° 11:00	10.48	99%	129.2°
2039-02-10 Thu	4	—	unknown	05:30–05:50 (marginal, 0.33 h)	71.1° 11:00	10.45	96%	122.8°
2039-02-11 Fri	5	—	unknown	05:25–05:50 (marginal, 0.42 h)	71.1° 10:55	10.41	91%	114.7°
2039-02-12 Sat	5	—	unknown	05:20–05:50 (marginal, 0.5 h)	71.1° 10:50	10.37	83%	105.6°
2039-02-13 Sun	5	—	unknown	05:20–05:45 (marginal, 0.42 h)	71.1° 10:45	10.33	74%	95.9°
2039-02-14 Mon	5	—	unknown	05:15–05:45 (marginal, 0.5 h)	71.1° 10:45	10.29	63%	85.9°
2039-02-15 Tue	6	—	unknown	05:10–05:45 (marginal, 0.58 h)	71.1° 10:40	10.25	52%	76.1°
2039-02-16 Wed	8	—	unknown	05:05–05:45 (marginal, 0.67 h)	71.1° 10:35	10.21	41%	66.8°
2039-02-17 Thu	8	—	unknown	05:00–06:15 (marginal, 1.25 h)	71.1° 10:30	10.17	30%	58.4°
2039-02-18 Fri	10	—	unknown	05:30–05:40 (good, 0.17 h)	71.1° 10:25	10.13	20%	51.5°
2039-02-19 Sat	12	—	unknown	05:20–05:40 (good, 0.33 h)	71.1° 10:25	10.09	12%	46.9°
2039-02-20 Sun	14	—	unknown	05:20–05:40 (good, 0.33 h)	71.1° 10:20	10.05	6%	45.3°
2039-02-21 Mon	14	—	unknown	05:15–05:35 (good, 0.33 h)	71.1° 10:15	10.01	2%	46.8°
2039-02-22 Tue	15	—	unknown	05:10–05:35 (good, 0.42 h)	71.1° 10:10	9.96	0%	51.1°
2039-02-23 Wed	17	—	unknown	05:05–05:35 (good, 0.5 h)	71.1° 10:05	9.92	1%	57.4°
2039-02-24 Thu	18	—	unknown	05:00–05:35 (good, 0.58 h)	71.1° 10:05	9.88	4%	64.9°
2039-02-25 Fri	18	—	unknown	05:00–05:30 (good, 0.5 h)	71.1° 10:00	9.83	8%	73.0°
2039-02-26 Sat	19	—	unknown	04:55–05:30 (good, 0.58 h)	71.1° 09:55	9.79	14%	81.4°
2039-02-27 Sun	20	—	unknown	04:50–05:30 (good, 0.67 h)	71.1° 09:50	9.74	22%	89.9°
2039-02-28 Mon	20	—	unknown	04:45–05:25 (good, 0.67 h)	71.1° 09:50	9.7	30%	98.3°
2039-03-01 Tue	21	—	unknown	04:40–05:25 (good, 0.75 h)	71.1° 09:45	9.65	39%	106.4°
2039-03-02 Wed	23	—	unknown	04:40–05:25 (good, 0.75 h)	71.1° 09:40	9.61	48%	114.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-02-01&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.