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

2038-03-17astronomy score per night — click a bar for that night2038-04-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-03-17 Wed	2	—	unknown	20:05–20:20 (marginal, 0.25 h)	79.2° 14:15	8.87	86%	99.2°
2038-03-18 Thu	2	—	unknown	20:05–20:15 (marginal, 0.17 h)	79.2° 14:10	8.82	93%	112.3°
2038-03-19 Fri	1	—	unknown	—	79.2° 14:10	8.77	98%	125.4°
2038-03-20 Sat	1	—	unknown	—	79.2° 14:05	8.72	100%	137.9°
2038-03-21 Sun	1	—	unknown	—	79.2° 14:00	8.67	99%	148.8°
2038-03-22 Mon	1	—	unknown	—	79.2° 13:55	8.61	95%	155.3°
2038-03-23 Tue	1	—	unknown	—	79.2° 13:55	8.56	88%	154.0°
2038-03-24 Wed	0	—	unknown	—	79.2° 13:50	8.51	79%	146.1°
2038-03-25 Thu	0	—	unknown	—	79.2° 13:45	8.46	69%	135.4°
2038-03-26 Fri	0	—	unknown	—	79.2° 13:40	8.4	59%	123.7°
2038-03-27 Sat	0	—	unknown	—	79.2° 13:35	8.35	48%	111.9°
2038-03-28 Sun	0	—	unknown	—	79.2° 14:35	8.3	38%	100.1°
2038-03-29 Mon	0	—	unknown	—	79.2° 14:30	8.24	28%	88.5°
2038-03-30 Tue	0	—	unknown	—	79.2° 14:25	8.19	20%	77.2°
2038-03-31 Wed	0	—	unknown	—	79.2° 14:20	8.13	12%	66.2°
2038-04-01 Thu	0	—	unknown	—	79.2° 14:15	8.08	7%	55.6°
2038-04-02 Fri	0	—	unknown	—	79.2° 14:15	8.02	3%	45.4°
2038-04-03 Sat	0	—	unknown	—	79.2° 14:10	7.97	1%	36.2°
2038-04-04 Sun	0	—	unknown	—	79.2° 14:05	7.91	0%	28.7°
2038-04-05 Mon	0	—	unknown	—	79.2° 14:00	7.86	2%	24.5°
2038-04-06 Tue	0	—	unknown	—	79.2° 14:00	7.8	5%	25.2°
2038-04-07 Wed	0	—	unknown	—	79.2° 13:55	7.74	9%	30.6°
2038-04-08 Thu	0	—	unknown	—	79.2° 13:50	7.69	16%	38.8°
2038-04-09 Fri	0	—	unknown	—	79.2° 13:45	7.63	23%	48.6°
2038-04-10 Sat	0	—	unknown	—	79.2° 13:40	7.57	32%	59.2°
2038-04-11 Sun	0	—	unknown	—	79.2° 13:40	7.52	42%	70.4°
2038-04-12 Mon	0	—	unknown	—	79.2° 13:35	7.46	52%	82.1°
2038-04-13 Tue	0	—	unknown	—	79.2° 13:30	7.4	62%	94.3°
2038-04-14 Wed	0	—	unknown	—	79.2° 13:25	7.35	73%	106.8°
2038-04-15 Thu	0	—	unknown	—	79.2° 13:20	7.29	82%	119.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-03-17&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.