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: 03-15 (5), 03-16 (5), 03-17 (4), 03-18 (3), 03-19 (2) — by astronomy; check the weather when the night is within four days.

2042-03-15astronomy score per night — click a bar for that night2042-04-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-03-15 Sat	5	—	unknown	20:05–20:25 (marginal, 0.33 h)	79.2° 14:25	8.97	40%	116.2°
2042-03-16 Sun	5	—	unknown	19:30–19:55 (marginal, 0.42 h)	79.2° 14:20	8.92	30%	103.6°
2042-03-17 Mon	4	—	unknown	20:05–20:20 (marginal, 0.25 h)	79.2° 14:15	8.87	20%	90.3°
2042-03-18 Tue	3	—	unknown	20:05–20:15 (marginal, 0.17 h)	79.2° 14:15	8.82	11%	76.7°
2042-03-19 Wed	2	—	unknown	19:35–19:40 (marginal, 0.08 h)	79.2° 14:10	8.77	5%	62.7°
2042-03-20 Thu	1	—	unknown	—	79.2° 14:05	8.72	1%	48.8°
2042-03-21 Fri	1	—	unknown	—	79.2° 14:00	8.66	0%	35.4°
2042-03-22 Sat	1	—	unknown	—	79.2° 13:55	8.61	2%	24.1°
2042-03-23 Sun	1	—	unknown	—	79.2° 13:55	8.56	7%	18.7°
2042-03-24 Mon	0	—	unknown	—	79.2° 13:50	8.51	15%	23.4°
2042-03-25 Tue	0	—	unknown	—	79.2° 13:45	8.45	24%	33.7°
2042-03-26 Wed	0	—	unknown	—	79.2° 13:40	8.4	34%	45.5°
2042-03-27 Thu	0	—	unknown	—	79.2° 13:35	8.35	44%	57.7°
2042-03-28 Fri	0	—	unknown	—	79.2° 13:35	8.29	55%	69.7°
2042-03-29 Sat	0	—	unknown	—	79.2° 13:30	8.24	64%	81.6°
2042-03-30 Sun	0	—	unknown	—	79.2° 14:25	8.18	74%	93.2°
2042-03-31 Mon	0	—	unknown	—	79.2° 14:20	8.13	82%	104.7°
2042-04-01 Tue	0	—	unknown	—	79.2° 14:15	8.08	88%	115.9°
2042-04-02 Wed	0	—	unknown	—	79.2° 14:15	8.02	94%	126.9°
2042-04-03 Thu	0	—	unknown	—	79.2° 14:10	7.97	98%	137.5°
2042-04-04 Fri	0	—	unknown	—	79.2° 14:05	7.91	100%	147.6°
2042-04-05 Sat	0	—	unknown	—	79.2° 14:00	7.85	100%	156.1°
2042-04-06 Sun	0	—	unknown	—	79.2° 14:00	7.8	98%	161.0°
2042-04-07 Mon	0	—	unknown	—	79.2° 13:55	7.74	95%	159.4°
2042-04-08 Tue	0	—	unknown	—	79.2° 13:50	7.69	90%	152.2°
2042-04-09 Wed	0	—	unknown	—	79.2° 13:45	7.63	83%	142.4°
2042-04-10 Thu	0	—	unknown	—	79.2° 13:40	7.57	75%	131.4°
2042-04-11 Fri	0	—	unknown	—	79.2° 13:40	7.52	66%	119.7°
2042-04-12 Sat	0	—	unknown	—	79.2° 13:35	7.46	56%	107.5°
2042-04-13 Sun	0	—	unknown	—	79.2° 13:30	7.4	45%	94.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-03-15&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.