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 Triangulum Pinwheel: 03-17 (3), 03-18 (3), 03-19 (2), 03-20 (1), 03-21 (1) — by astronomy; check the weather when the night is within four days.

2041-03-17astronomy score per night — click a bar for that night2041-04-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-03-17 Sun	3	—	unknown	20:05–20:15 (marginal, 0.17 h)	79.2° 14:15	8.86	100%	138.9°
2041-03-18 Mon	3	—	unknown	20:05–20:15 (marginal, 0.17 h)	79.2° 14:10	8.81	99%	148.7°
2041-03-19 Tue	2	—	unknown	19:35–19:40 (marginal, 0.08 h)	79.2° 14:10	8.75	96%	156.5°
2041-03-20 Wed	1	—	unknown	—	79.2° 14:05	8.7	91%	159.6°
2041-03-21 Thu	1	—	unknown	—	79.2° 14:00	8.65	84%	155.7°
2041-03-22 Fri	1	—	unknown	—	79.2° 13:55	8.6	76%	147.0°
2041-03-23 Sat	1	—	unknown	—	79.2° 13:50	8.55	66%	136.1°
2041-03-24 Sun	0	—	unknown	—	79.2° 13:50	8.49	56%	124.1°
2041-03-25 Mon	0	—	unknown	—	79.2° 13:45	8.44	44%	111.4°
2041-03-26 Tue	0	—	unknown	—	79.2° 13:40	8.39	33%	98.3°
2041-03-27 Wed	0	—	unknown	—	79.2° 13:35	8.33	23%	84.8°
2041-03-28 Thu	0	—	unknown	—	79.2° 13:30	8.28	14%	71.1°
2041-03-29 Fri	0	—	unknown	—	79.2° 13:30	8.23	7%	57.4°
2041-03-30 Sat	0	—	unknown	—	79.2° 13:25	8.17	2%	44.2°
2041-03-31 Sun	0	—	unknown	—	79.2° 14:20	8.12	0%	32.1°
2041-04-01 Mon	0	—	unknown	—	79.2° 14:15	8.06	1%	23.0°
2041-04-02 Tue	0	—	unknown	—	79.2° 14:15	8.01	5%	20.6°
2041-04-03 Wed	0	—	unknown	—	79.2° 14:10	7.95	10%	26.4°
2041-04-04 Thu	0	—	unknown	—	79.2° 14:05	7.9	18%	36.1°
2041-04-05 Fri	0	—	unknown	—	79.2° 14:00	7.84	26%	47.1°
2041-04-06 Sat	0	—	unknown	—	79.2° 13:55	7.78	36%	58.4°
2041-04-07 Sun	0	—	unknown	—	79.2° 13:55	7.73	46%	69.7°
2041-04-08 Mon	0	—	unknown	—	79.2° 13:50	7.67	55%	80.9°
2041-04-09 Tue	0	—	unknown	—	79.2° 13:45	7.62	64%	92.0°
2041-04-10 Wed	0	—	unknown	—	79.2° 13:40	7.56	73%	103.1°
2041-04-11 Thu	0	—	unknown	—	79.2° 13:35	7.5	81%	114.1°
2041-04-12 Fri	0	—	unknown	—	79.2° 13:35	7.44	88%	125.0°
2041-04-13 Sat	0	—	unknown	—	79.2° 13:30	7.39	94%	135.7°
2041-04-14 Sun	0	—	unknown	—	79.2° 13:25	7.33	98%	145.9°
2041-04-15 Mon	0	—	unknown	—	79.2° 13:20	7.27	100%	154.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-03-17&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.