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: 03-16 (93), 03-17 (93), 03-18 (93), 03-19 (93), 03-20 (93) — by astronomy; check the weather when the night is within four days.

2028-03-11astronomy score per night — click a bar for that night2028-04-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-03-11 Sat	25	—	unknown	21:55–05:05 (marginal, 7.17 h)	50.2° 01:30	9.15	99%	9.5°
2028-03-12 Sun	33	—	unknown	21:30–05:05 (marginal, 7.58 h)	50.2° 01:25	9.1	95%	16.7°
2028-03-13 Mon	71	—	unknown	21:35–22:00 (good, 0.42 h)	50.2° 01:25	9.05	88%	29.8°
2028-03-14 Tue	87	—	unknown	21:30–01:10 (good, 3.67 h)	50.2° 01:20	9.0	80%	43.2°
2028-03-15 Wed	92	—	unknown	21:30–03:50 (good, 6.33 h)	50.2° 01:15	8.95	70%	56.5°
2028-03-16 Thu	93	—	unknown	21:25–04:40 (good, 7.25 h)	50.2° 01:10	8.9	60%	69.3°
2028-03-17 Fri	93	—	unknown	21:20–04:45 (good, 7.42 h)	50.2° 01:05	8.85	50%	81.8°
2028-03-18 Sat	93	—	unknown	21:15–04:45 (good, 7.5 h)	50.2° 01:05	8.8	41%	94.0°
2028-03-19 Sun	93	—	unknown	21:15–04:45 (good, 7.5 h)	50.2° 01:00	8.75	31%	105.9°
2028-03-20 Mon	93	—	unknown	21:10–04:45 (good, 7.58 h)	50.2° 00:55	8.7	23%	117.7°
2028-03-21 Tue	93	—	unknown	21:05–04:45 (good, 7.67 h)	50.2° 00:50	8.64	16%	129.3°
2028-03-22 Wed	93	—	unknown	21:00–04:40 (good, 7.67 h)	50.2° 00:50	8.59	9%	140.8°
2028-03-23 Thu	93	—	unknown	20:55–04:35 (good, 7.67 h)	50.2° 00:45	8.54	5%	152.1°
2028-03-24 Fri	93	—	unknown	20:55–04:30 (good, 7.58 h)	50.2° 00:40	8.49	2%	162.8°
2028-03-25 Sat	93	—	unknown	20:50–05:30 (good, 7.67 h)	50.2° 00:35	8.43	0%	170.3°
2028-03-26 Sun	93	—	unknown	21:45–05:25 (good, 7.67 h)	50.2° 01:30	8.38	1%	166.7°
2028-03-27 Mon	93	—	unknown	21:40–05:20 (good, 7.67 h)	50.2° 01:30	8.33	3%	156.4°
2028-03-28 Tue	93	—	unknown	21:40–05:15 (good, 7.58 h)	50.2° 01:25	8.27	7%	144.7°
2028-03-29 Wed	93	—	unknown	21:35–05:10 (good, 7.58 h)	50.2° 01:20	8.22	13%	132.5°
2028-03-30 Thu	93	—	unknown	21:30–05:10 (good, 7.67 h)	50.2° 01:15	8.16	21%	119.9°
2028-03-31 Fri	93	—	unknown	21:30–05:05 (good, 7.58 h)	50.2° 01:10	8.11	30%	107.1°
2028-04-01 Sat	91	—	unknown	21:35–05:00 (good, 7.42 h)	50.2° 01:10	8.05	40%	93.9°
2028-04-02 Sun	87	—	unknown	21:40–04:55 (good, 7.25 h)	50.2° 01:05	8.0	51%	80.5°
2028-04-03 Mon	83	—	unknown	22:45–04:55 (good, 6.17 h)	50.2° 01:00	7.94	63%	66.7°
2028-04-04 Tue	75	—	unknown	01:35–04:20 (good, 2.75 h)	50.2° 00:55	7.89	73%	52.7°
2028-04-05 Wed	46	—	unknown	21:30–05:15 (marginal, 7.75 h)	50.2° 00:55	7.83	83%	38.5°
2028-04-06 Thu	31	—	unknown	22:10–04:55 (marginal, 6.75 h)	50.2° 00:50	7.78	91%	24.5°
2028-04-07 Fri	26	—	unknown	21:35–04:40 (marginal, 7.08 h)	50.2° 00:45	7.72	97%	12.2°
2028-04-08 Sat	24	—	unknown	21:35–04:30 (marginal, 6.92 h)	50.2° 00:40	7.66	100%	11.7°
2028-04-09 Sun	31	—	unknown	21:35–04:20 (marginal, 6.75 h)	50.2° 00:35	7.61	100%	23.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-03-11&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.