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: 06-05 (2), 06-01 (1), 06-02 (1), 06-03 (1), 06-04 (1) — by astronomy; check the weather when the night is within four days.

2040-05-07astronomy score per night — click a bar for that night2040-06-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-05-07 Mon	0	—	unknown	—	79.2° 11:50	5.98	11%	33.0°
2040-05-08 Tue	0	—	unknown	—	79.2° 11:45	5.93	5%	25.0°
2040-05-09 Wed	0	—	unknown	—	79.2° 11:40	5.87	2%	22.0°
2040-05-10 Thu	0	—	unknown	—	79.2° 11:40	5.82	0%	25.5°
2040-05-11 Fri	0	—	unknown	—	79.2° 11:35	5.76	1%	33.4°
2040-05-12 Sat	0	—	unknown	—	79.2° 11:30	5.71	3%	43.1°
2040-05-13 Sun	0	—	unknown	—	79.2° 11:25	5.65	7%	53.5°
2040-05-14 Mon	0	—	unknown	—	79.2° 11:20	5.6	13%	64.2°
2040-05-15 Tue	0	—	unknown	—	79.2° 11:20	5.55	20%	75.1°
2040-05-16 Wed	0	—	unknown	—	79.2° 11:15	5.49	28%	86.0°
2040-05-17 Thu	0	—	unknown	—	79.2° 11:10	5.44	37%	97.0°
2040-05-18 Fri	0	—	unknown	—	79.2° 11:05	5.39	46%	108.1°
2040-05-19 Sat	0	—	unknown	—	79.2° 11:05	5.34	56%	119.2°
2040-05-20 Sun	0	—	unknown	—	79.2° 11:00	5.29	66%	130.3°
2040-05-21 Mon	0	—	unknown	—	79.2° 10:55	5.24	75%	141.1°
2040-05-22 Tue	0	—	unknown	—	79.2° 10:50	5.19	84%	150.8°
2040-05-23 Wed	0	—	unknown	—	79.2° 10:45	5.15	91%	157.2°
2040-05-24 Thu	0	—	unknown	—	79.2° 10:45	5.1	97%	156.7°
2040-05-25 Fri	0	—	unknown	—	79.2° 10:40	5.05	100%	148.9°
2040-05-26 Sat	0	—	unknown	—	79.2° 10:35	5.01	100%	137.5°
2040-05-27 Sun	0	—	unknown	—	79.2° 10:30	4.97	97%	124.5°
2040-05-28 Mon	0	—	unknown	—	79.2° 10:25	4.93	91%	111.0°
2040-05-29 Tue	0	—	unknown	—	79.2° 10:25	4.89	84%	97.4°
2040-05-30 Wed	0	—	unknown	—	79.2° 10:20	4.85	74%	83.9°
2040-05-31 Thu	0	—	unknown	—	79.2° 10:15	4.81	63%	70.7°
2040-06-01 Fri	1	—	unknown	—	79.2° 10:10	4.77	52%	58.0°
2040-06-02 Sat	1	—	unknown	—	79.2° 10:10	4.74	41%	46.0°
2040-06-03 Sun	1	—	unknown	—	79.2° 10:05	4.71	31%	35.2°
2040-06-04 Mon	1	—	unknown	—	79.2° 10:00	4.67	21%	26.5°
2040-06-05 Tue	2	—	unknown	—	79.2° 09:55	4.64	14%	22.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-05-07&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.