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 Seven Sisters: 02-23 (90), 02-21 (89), 02-22 (89), 02-24 (88), 02-25 (86) — by astronomy; check the weather when the night is within four days.

2038-02-13astronomy score per night — click a bar for that night2038-03-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-02-13 Sat	31	—	unknown	19:30–00:00 (marginal, 4.5 h)	72.5° 18:35	10.32	65%	14.8°
2038-02-14 Sun	21	—	unknown	19:30–23:40 (marginal, 4.17 h)	72.5° 18:30	10.28	74%	26.4°
2038-02-15 Mon	19	—	unknown	19:30–23:25 (marginal, 3.92 h)	72.5° 18:25	10.24	83%	39.0°
2038-02-16 Tue	23	—	unknown	19:30–23:25 (marginal, 3.92 h)	72.5° 18:25	10.2	90%	52.4°
2038-02-17 Wed	31	—	unknown	19:30–23:30 (marginal, 4.0 h)	72.5° 18:20	10.16	96%	66.2°
2038-02-18 Thu	42	—	unknown	19:35–20:55 (good, 1.33 h)	72.5° 18:15	10.12	99%	80.5°
2038-02-19 Fri	57	—	unknown	19:35–22:20 (good, 2.75 h)	72.5° 18:10	10.08	100%	95.0°
2038-02-20 Sat	72	—	unknown	19:35–23:00 (good, 3.42 h)	72.5° 18:05	10.04	98%	109.8°
2038-02-21 Sun	89	—	unknown	19:35–23:05 (good, 3.5 h)	72.5° 18:05	10.0	92%	124.5°
2038-02-22 Mon	89	—	unknown	19:40–23:00 (good, 3.33 h)	72.5° 18:00	9.95	85%	139.1°
2038-02-23 Tue	90	—	unknown	19:40–23:00 (good, 3.33 h)	72.5° 17:55	9.91	76%	153.2°
2038-02-24 Wed	88	—	unknown	19:40–23:00 (good, 3.33 h)	72.5° 17:50	9.87	65%	166.2°
2038-02-25 Thu	86	—	unknown	19:40–23:00 (good, 3.33 h)	72.5° 17:45	9.82	54%	171.6°
2038-02-26 Fri	83	—	unknown	19:45–22:55 (good, 3.17 h)	72.5° 17:45	9.78	43%	161.8°
2038-02-27 Sat	82	—	unknown	19:45–22:50 (good, 3.08 h)	72.5° 17:40	9.73	32%	149.3°
2038-02-28 Sun	79	—	unknown	19:45–22:45 (good, 3.0 h)	72.5° 17:35	9.69	23%	136.6°
2038-03-01 Mon	77	—	unknown	19:45–22:40 (good, 2.92 h)	72.5° 17:30	9.64	15%	124.0°
2038-03-02 Tue	74	—	unknown	19:45–22:40 (good, 2.92 h)	72.5° 17:30	9.6	9%	111.5°
2038-03-03 Wed	71	—	unknown	19:50–22:35 (good, 2.75 h)	72.5° 17:25	9.55	4%	99.2°
2038-03-04 Thu	69	—	unknown	19:50–22:30 (good, 2.67 h)	72.5° 17:20	9.5	1%	87.1°
2038-03-05 Fri	67	—	unknown	19:50–22:25 (good, 2.58 h)	72.5° 17:15	9.46	0%	75.1°
2038-03-06 Sat	65	—	unknown	19:50–22:25 (good, 2.58 h)	72.5° 17:10	9.41	1%	63.2°
2038-03-07 Sun	61	—	unknown	19:55–22:20 (good, 2.42 h)	72.5° 17:10	9.36	4%	51.4°
2038-03-08 Mon	56	—	unknown	19:55–22:15 (good, 2.33 h)	72.5° 17:05	9.32	8%	39.8°
2038-03-09 Tue	50	—	unknown	19:55–22:10 (good, 2.25 h)	72.5° 17:00	9.27	14%	28.4°
2038-03-10 Wed	43	—	unknown	19:55–22:00 (good, 2.08 h)	72.5° 16:55	9.22	21%	17.4°
2038-03-11 Thu	35	—	unknown	20:00–21:50 (good, 1.83 h)	72.5° 16:50	9.17	29%	8.6°
2038-03-12 Fri	28	—	unknown	20:00–21:35 (good, 1.58 h)	72.5° 16:50	9.12	38%	11.5°
2038-03-13 Sat	21	—	unknown	20:00–22:20 (marginal, 2.33 h)	72.5° 16:45	9.07	48%	22.1°
2038-03-14 Sun	16	—	unknown	20:00–22:05 (marginal, 2.08 h)	72.5° 16:40	9.02	58%	34.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-02-13&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.