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 3C 273: 03-11 (93), 03-12 (93), 03-13 (93), 03-25 (93), 03-26 (93) — by astronomy; check the weather when the night is within four days.

2038-03-11astronomy score per night — click a bar for that night2038-04-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-03-11 Thu	93	—	unknown	21:50–05:10 (good, 7.33 h)	50.1° 01:35	9.17	29%	129.4°
2038-03-12 Fri	93	—	unknown	21:45–05:05 (good, 7.33 h)	50.1° 01:30	9.12	38%	117.4°
2038-03-13 Sat	93	—	unknown	21:50–05:05 (good, 7.25 h)	50.1° 01:25	9.07	48%	105.1°
2038-03-14 Sun	92	—	unknown	21:55–05:05 (good, 7.17 h)	50.1° 01:20	9.02	58%	92.4°
2038-03-15 Mon	87	—	unknown	22:25–05:00 (good, 6.58 h)	50.1° 01:15	8.97	68%	79.4°
2038-03-16 Tue	82	—	unknown	00:25–05:00 (good, 4.58 h)	50.1° 01:15	8.92	78%	65.9°
2038-03-17 Wed	55	—	unknown	21:30–05:00 (marginal, 7.5 h)	50.1° 01:10	8.87	86%	52.0°
2038-03-18 Thu	33	—	unknown	23:05–04:55 (marginal, 5.83 h)	50.1° 01:05	8.82	93%	37.5°
2038-03-19 Fri	22	—	unknown	01:55–04:55 (marginal, 3.0 h)	50.1° 01:00	8.77	98%	22.7°
2038-03-20 Sat	19	—	unknown	02:55–04:35 (marginal, 1.67 h)	50.1° 01:00	8.72	100%	7.6°
2038-03-21 Sun	22	—	unknown	21:15–00:45 (marginal, 3.5 h)	50.1° 00:55	8.67	99%	7.6°
2038-03-22 Mon	33	—	unknown	20:50–04:25 (marginal, 7.58 h)	50.1° 00:50	8.61	95%	22.8°
2038-03-23 Tue	82	—	unknown	21:00–21:50 (good, 0.83 h)	50.1° 00:45	8.56	88%	37.8°
2038-03-24 Wed	89	—	unknown	20:55–01:40 (good, 4.75 h)	50.1° 00:40	8.51	79%	52.4°
2038-03-25 Thu	93	—	unknown	20:50–03:45 (good, 6.92 h)	50.1° 00:40	8.46	69%	66.7°
2038-03-26 Fri	93	—	unknown	20:45–04:10 (good, 7.42 h)	50.1° 00:35	8.4	59%	80.5°
2038-03-27 Sat	93	—	unknown	20:45–05:10 (good, 7.42 h)	50.1° 00:30	8.35	48%	93.9°
2038-03-28 Sun	93	—	unknown	21:40–05:15 (good, 7.58 h)	50.1° 01:25	8.3	38%	106.9°
2038-03-29 Mon	93	—	unknown	21:35–05:10 (good, 7.58 h)	50.1° 01:20	8.24	28%	119.5°
2038-03-30 Tue	93	—	unknown	21:30–05:10 (good, 7.67 h)	50.1° 01:20	8.19	20%	132.0°
2038-03-31 Wed	93	—	unknown	21:30–05:05 (good, 7.58 h)	50.1° 01:15	8.13	12%	144.2°
2038-04-01 Thu	93	—	unknown	21:25–05:00 (good, 7.58 h)	50.1° 01:10	8.08	7%	156.2°
2038-04-02 Fri	93	—	unknown	21:25–05:00 (good, 7.58 h)	50.1° 01:05	8.02	3%	168.2°
2038-04-03 Sat	93	—	unknown	21:25–04:55 (good, 7.5 h)	50.1° 01:05	7.97	1%	179.8°
2038-04-04 Sun	93	—	unknown	21:30–04:50 (good, 7.33 h)	50.1° 01:00	7.91	0%	168.1°
2038-04-05 Mon	93	—	unknown	21:30–04:45 (good, 7.25 h)	50.1° 00:55	7.86	2%	156.3°
2038-04-06 Tue	93	—	unknown	21:30–04:45 (good, 7.25 h)	50.1° 00:50	7.8	5%	144.5°
2038-04-07 Wed	93	—	unknown	21:35–04:40 (good, 7.08 h)	50.1° 00:45	7.74	9%	132.6°
2038-04-08 Thu	93	—	unknown	21:35–04:35 (good, 7.0 h)	50.1° 00:45	7.69	16%	120.6°
2038-04-09 Fri	93	—	unknown	21:35–04:30 (good, 6.92 h)	50.1° 00:40	7.63	23%	108.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-03-11&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.