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

2040-03-17astronomy score per night — click a bar for that night2040-04-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-03-17 Sat	2	—	unknown	20:05–20:15 (marginal, 0.17 h)	79.2° 14:15	8.84	24%	30.8°
2040-03-18 Sun	2	—	unknown	20:05–20:10 (marginal, 0.08 h)	79.2° 14:10	8.79	33%	40.0°
2040-03-19 Mon	1	—	unknown	—	79.2° 14:05	8.74	42%	50.2°
2040-03-20 Tue	1	—	unknown	—	79.2° 14:05	8.69	52%	60.7°
2040-03-21 Wed	0	—	unknown	—	79.2° 14:00	8.64	61%	71.5°
2040-03-22 Thu	0	—	unknown	—	79.2° 13:55	8.59	70%	82.5°
2040-03-23 Fri	0	—	unknown	—	79.2° 13:50	8.53	78%	93.6°
2040-03-24 Sat	0	—	unknown	—	79.2° 13:45	8.48	86%	104.9°
2040-03-25 Sun	0	—	unknown	—	79.2° 14:45	8.43	92%	116.3°
2040-03-26 Mon	0	—	unknown	—	79.2° 14:40	8.37	97%	127.7°
2040-03-27 Tue	0	—	unknown	—	79.2° 14:35	8.32	99%	138.8°
2040-03-28 Wed	0	—	unknown	—	79.2° 14:30	8.27	100%	149.0°
2040-03-29 Thu	0	—	unknown	—	79.2° 14:25	8.21	98%	156.4°
2040-03-30 Fri	0	—	unknown	—	79.2° 14:25	8.16	94%	157.5°
2040-03-31 Sat	0	—	unknown	—	79.2° 14:20	8.1	87%	151.3°
2040-04-01 Sun	0	—	unknown	—	79.2° 14:15	8.05	79%	141.0°
2040-04-02 Mon	0	—	unknown	—	79.2° 14:10	7.99	68%	129.1°
2040-04-03 Tue	0	—	unknown	—	79.2° 14:10	7.94	57%	116.4°
2040-04-04 Wed	0	—	unknown	—	79.2° 14:05	7.88	46%	103.4°
2040-04-05 Thu	0	—	unknown	—	79.2° 14:00	7.83	35%	90.4°
2040-04-06 Fri	0	—	unknown	—	79.2° 13:55	7.77	24%	77.4°
2040-04-07 Sat	0	—	unknown	—	79.2° 13:50	7.72	16%	64.5°
2040-04-08 Sun	0	—	unknown	—	79.2° 13:50	7.66	8%	52.1°
2040-04-09 Mon	0	—	unknown	—	79.2° 13:45	7.6	3%	40.4°
2040-04-10 Tue	0	—	unknown	—	79.2° 13:40	7.55	1%	30.3°
2040-04-11 Wed	0	—	unknown	—	79.2° 13:35	7.49	0%	23.4°
2040-04-12 Thu	0	—	unknown	—	79.2° 13:30	7.43	2%	22.4°
2040-04-13 Fri	0	—	unknown	—	79.2° 13:30	7.37	6%	27.8°
2040-04-14 Sat	0	—	unknown	—	79.2° 13:25	7.32	11%	36.4°
2040-04-15 Sun	0	—	unknown	—	79.2° 13:20	7.26	18%	46.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-03-17&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.