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: 04-12 (56), 04-14 (56), 04-11 (55), 04-13 (55), 04-09 (54) — by astronomy; check the weather when the night is within four days.

2038-03-18astronomy score per night — click a bar for that night2038-04-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-03-18 Thu	29	—	unknown	03:45–04:55 (good, 1.17 h)	71.1° 08:35	8.82	93%	131.2°
2038-03-19 Fri	29	—	unknown	03:40–04:55 (good, 1.25 h)	71.1° 08:30	8.77	98%	124.1°
2038-03-20 Sat	27	—	unknown	03:40–04:50 (good, 1.17 h)	71.1° 08:30	8.72	100%	115.1°
2038-03-21 Sun	24	—	unknown	03:45–04:50 (good, 1.08 h)	71.1° 08:25	8.67	99%	104.8°
2038-03-22 Mon	22	—	unknown	03:55–04:50 (good, 0.92 h)	71.1° 08:20	8.61	95%	94.1°
2038-03-23 Tue	20	—	unknown	04:15–04:45 (good, 0.5 h)	71.1° 08:15	8.56	88%	83.3°
2038-03-24 Wed	20	—	unknown	04:20–04:45 (good, 0.42 h)	71.1° 08:10	8.51	79%	73.0°
2038-03-25 Thu	21	—	unknown	04:00–04:45 (good, 0.75 h)	71.1° 08:10	8.46	69%	63.5°
2038-03-26 Fri	23	—	unknown	03:30–04:40 (good, 1.17 h)	71.1° 08:05	8.4	59%	55.4°
2038-03-27 Sat	27	—	unknown	04:15–05:40 (good, 1.42 h)	71.1° 09:00	8.35	48%	49.1°
2038-03-28 Sun	31	—	unknown	03:55–05:35 (good, 1.67 h)	71.1° 08:55	8.3	38%	45.1°
2038-03-29 Mon	39	—	unknown	03:50–05:35 (good, 1.75 h)	71.1° 08:50	8.24	28%	44.0°
2038-03-30 Tue	44	—	unknown	03:45–05:35 (good, 1.83 h)	71.1° 08:50	8.19	20%	45.6°
2038-03-31 Wed	45	—	unknown	03:45–05:30 (good, 1.75 h)	71.1° 08:45	8.13	12%	49.6°
2038-04-01 Thu	47	—	unknown	03:40–05:30 (good, 1.83 h)	71.1° 08:40	8.08	7%	55.3°
2038-04-02 Fri	46	—	unknown	03:35–05:25 (good, 1.83 h)	71.1° 08:35	8.02	3%	62.3°
2038-04-03 Sat	48	—	unknown	03:30–05:25 (good, 1.92 h)	71.1° 08:35	7.97	1%	70.0°
2038-04-04 Sun	50	—	unknown	03:30–05:25 (good, 1.92 h)	71.1° 08:30	7.91	0%	78.1°
2038-04-05 Mon	50	—	unknown	03:25–05:20 (good, 1.92 h)	71.1° 08:25	7.86	2%	86.6°
2038-04-06 Tue	51	—	unknown	03:20–05:20 (good, 2.0 h)	71.1° 08:20	7.8	5%	95.1°
2038-04-07 Wed	52	—	unknown	03:15–05:20 (good, 2.08 h)	71.1° 08:15	7.74	9%	103.5°
2038-04-08 Thu	52	—	unknown	03:10–05:15 (good, 2.08 h)	71.1° 08:15	7.69	16%	111.7°
2038-04-09 Fri	54	—	unknown	03:10–05:15 (good, 2.08 h)	71.1° 08:10	7.63	23%	119.4°
2038-04-10 Sat	54	—	unknown	03:05–05:10 (good, 2.08 h)	71.1° 08:05	7.57	32%	126.2°
2038-04-11 Sun	55	—	unknown	03:00–05:10 (good, 2.17 h)	71.1° 08:00	7.52	42%	131.8°
2038-04-12 Mon	56	—	unknown	03:00–05:10 (good, 2.17 h)	71.1° 07:55	7.46	52%	135.2°
2038-04-13 Tue	55	—	unknown	02:55–05:05 (good, 2.17 h)	71.1° 07:55	7.4	62%	135.7°
2038-04-14 Wed	56	—	unknown	02:55–05:05 (good, 2.17 h)	71.1° 07:50	7.35	73%	133.0°
2038-04-15 Thu	51	—	unknown	02:55–05:00 (good, 2.08 h)	71.1° 07:45	7.29	82%	127.4°
2038-04-16 Fri	49	—	unknown	02:50–05:00 (good, 2.17 h)	71.1° 07:40	7.23	90%	119.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-03-18&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.