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), 02-23 (17), 02-22 (15), 02-21 (14), 02-20 (12) — by astronomy; check the weather when the night is within four days.

2028-01-26astronomy score per night — click a bar for that night2028-02-24

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-01-26 Wed	0	—	unknown	—	71.1° 12:00	10.96	0%	41.5°
2028-01-27 Thu	0	—	unknown	—	71.1° 11:55	10.93	2%	42.0°
2028-01-28 Fri	1	—	unknown	—	71.1° 11:50	10.9	5%	45.2°
2028-01-29 Sat	1	—	unknown	—	71.1° 11:45	10.87	10%	50.4°
2028-01-30 Sun	1	—	unknown	—	71.1° 11:40	10.84	16%	57.2°
2028-01-31 Mon	1	—	unknown	—	71.1° 11:40	10.81	23%	65.0°
2028-02-01 Tue	1	—	unknown	—	71.1° 11:35	10.77	32%	73.6°
2028-02-02 Wed	1	—	unknown	—	71.1° 11:30	10.74	41%	82.6°
2028-02-03 Thu	2	—	unknown	06:25–06:30 (marginal, 0.08 h)	71.1° 11:25	10.71	51%	92.1°
2028-02-04 Fri	2	—	unknown	06:20–06:30 (marginal, 0.17 h)	71.1° 11:25	10.67	62%	101.8°
2028-02-05 Sat	3	—	unknown	06:20–06:30 (marginal, 0.17 h)	71.1° 11:20	10.64	72%	111.5°
2028-02-06 Sun	3	—	unknown	06:15–06:30 (marginal, 0.25 h)	71.1° 11:15	10.6	81%	120.9°
2028-02-07 Mon	4	—	unknown	05:40–05:55 (marginal, 0.25 h)	71.1° 11:10	10.57	90%	129.3°
2028-02-08 Tue	4	—	unknown	05:40–05:55 (marginal, 0.25 h)	71.1° 11:05	10.53	96%	135.7°
2028-02-09 Wed	4	—	unknown	05:35–05:50 (marginal, 0.25 h)	71.1° 11:05	10.49	99%	138.6°
2028-02-10 Thu	4	—	unknown	05:30–05:50 (marginal, 0.33 h)	71.1° 11:00	10.46	100%	137.0°
2028-02-11 Fri	5	—	unknown	05:25–05:50 (marginal, 0.42 h)	71.1° 10:55	10.42	97%	131.4°
2028-02-12 Sat	5	—	unknown	05:25–05:50 (marginal, 0.42 h)	71.1° 10:50	10.38	92%	123.1°
2028-02-13 Sun	6	—	unknown	05:20–05:50 (marginal, 0.5 h)	71.1° 10:45	10.34	84%	113.5°
2028-02-14 Mon	6	—	unknown	05:15–05:45 (marginal, 0.5 h)	71.1° 10:45	10.3	75%	103.2°
2028-02-15 Tue	6	—	unknown	05:10–05:45 (marginal, 0.58 h)	71.1° 10:40	10.27	65%	92.9°
2028-02-16 Wed	7	—	unknown	05:05–05:45 (marginal, 0.67 h)	71.1° 10:35	10.23	54%	82.9°
2028-02-17 Thu	8	—	unknown	05:05–06:15 (marginal, 1.17 h)	71.1° 10:30	10.18	44%	73.3°
2028-02-18 Fri	9	—	unknown	05:35–05:40 (good, 0.08 h)	71.1° 10:30	10.14	34%	64.4°
2028-02-19 Sat	10	—	unknown	05:30–05:40 (good, 0.17 h)	71.1° 10:25	10.1	25%	56.4°
2028-02-20 Sun	12	—	unknown	05:25–05:40 (good, 0.25 h)	71.1° 10:20	10.06	17%	49.7°
2028-02-21 Mon	14	—	unknown	05:15–05:35 (good, 0.33 h)	71.1° 10:15	10.02	10%	44.6°
2028-02-22 Tue	15	—	unknown	05:10–05:35 (good, 0.42 h)	71.1° 10:10	9.98	6%	41.8°
2028-02-23 Wed	17	—	unknown	05:05–05:35 (good, 0.5 h)	71.1° 10:10	9.93	2%	41.6°
2028-02-24 Thu	18	—	unknown	05:05–05:35 (good, 0.5 h)	71.1° 10:05	9.89	0%	44.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-01-26&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.