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 (2), 03-20 (1), 03-21 (1) — by astronomy; check the weather when the night is within four days.

2027-03-17astronomy score per night — click a bar for that night2027-04-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-03-17 Wed	2	—	unknown	20:05–20:15 (marginal, 0.17 h)	79.1° 14:15	8.89	75%	83.3°
2027-03-18 Thu	2	—	unknown	20:05–20:15 (marginal, 0.17 h)	79.1° 14:15	8.84	84%	97.3°
2027-03-19 Fri	2	—	unknown	20:05–20:10 (marginal, 0.08 h)	79.1° 14:10	8.79	92%	111.3°
2027-03-20 Sat	1	—	unknown	—	79.1° 14:05	8.73	97%	125.2°
2027-03-21 Sun	1	—	unknown	—	79.1° 14:00	8.68	100%	138.6°
2027-03-22 Mon	1	—	unknown	—	79.1° 13:55	8.63	100%	151.3°
2027-03-23 Tue	1	—	unknown	—	79.1° 13:55	8.58	97%	161.7°
2027-03-24 Wed	0	—	unknown	—	79.1° 13:50	8.53	92%	165.4°
2027-03-25 Thu	0	—	unknown	—	79.1° 13:45	8.47	86%	159.3°
2027-03-26 Fri	0	—	unknown	—	79.1° 13:40	8.42	78%	149.0°
2027-03-27 Sat	0	—	unknown	—	79.1° 13:40	8.37	70%	137.8°
2027-03-28 Sun	0	—	unknown	—	79.1° 14:35	8.31	60%	126.4°
2027-03-29 Mon	0	—	unknown	—	79.1° 14:30	8.26	51%	115.0°
2027-03-30 Tue	0	—	unknown	—	79.1° 14:25	8.2	42%	103.6°
2027-03-31 Wed	0	—	unknown	—	79.1° 14:20	8.15	32%	92.1°
2027-04-01 Thu	0	—	unknown	—	79.1° 14:20	8.1	24%	80.6°
2027-04-02 Fri	0	—	unknown	—	79.1° 14:15	8.04	16%	68.9°
2027-04-03 Sat	0	—	unknown	—	79.1° 14:10	7.99	10%	57.1°
2027-04-04 Sun	0	—	unknown	—	79.1° 14:05	7.93	5%	45.3°
2027-04-05 Mon	0	—	unknown	—	79.1° 14:00	7.87	1%	33.5°
2027-04-06 Tue	0	—	unknown	—	79.1° 14:00	7.82	0%	22.5°
2027-04-07 Wed	0	—	unknown	—	79.1° 13:55	7.76	1%	15.0°
2027-04-08 Thu	0	—	unknown	—	79.1° 13:50	7.71	5%	17.3°
2027-04-09 Fri	0	—	unknown	—	79.1° 13:45	7.65	10%	27.3°
2027-04-10 Sat	0	—	unknown	—	79.1° 13:45	7.59	18%	39.7°
2027-04-11 Sun	0	—	unknown	—	79.1° 13:40	7.54	28%	52.9°
2027-04-12 Mon	0	—	unknown	—	79.1° 13:35	7.48	38%	66.4°
2027-04-13 Tue	0	—	unknown	—	79.1° 13:30	7.42	50%	80.0°
2027-04-14 Wed	0	—	unknown	—	79.1° 13:25	7.36	61%	93.7°
2027-04-15 Thu	0	—	unknown	—	79.1° 13:25	7.31	72%	107.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-03-17&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.