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 3C 273: 07-17 (1) — by astronomy; check the weather when the night is within four days.

2029-07-17astronomy score per night — click a bar for that night2029-08-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-07-17 Tue	1	—	unknown	—	50.2° 18:10	5.1	42%	14.8°
2029-07-18 Wed	0	—	unknown	—	50.2° 18:05	5.14	54%	26.9°
2029-07-19 Thu	0	—	unknown	—	50.2° 18:00	5.19	65%	40.4°
2029-07-20 Fri	0	—	unknown	—	50.2° 17:55	5.24	76%	54.1°
2029-07-21 Sat	0	—	unknown	—	50.2° 17:55	5.29	85%	67.8°
2029-07-22 Sun	0	—	unknown	—	50.2° 17:50	5.34	92%	81.5°
2029-07-23 Mon	0	—	unknown	—	50.2° 17:45	5.39	97%	95.1°
2029-07-24 Tue	0	—	unknown	—	50.2° 17:40	5.44	100%	108.4°
2029-07-25 Wed	0	—	unknown	—	50.2° 17:35	5.49	100%	121.5°
2029-07-26 Thu	0	—	unknown	—	50.2° 17:35	5.54	98%	134.1°
2029-07-27 Fri	0	—	unknown	—	50.2° 17:30	5.59	94%	146.4°
2029-07-28 Sat	0	—	unknown	—	50.2° 17:25	5.65	88%	157.9°
2029-07-29 Sun	0	—	unknown	—	50.2° 17:20	5.7	81%	167.5°
2029-07-30 Mon	0	—	unknown	—	50.2° 17:20	5.75	73%	169.1°
2029-07-31 Tue	0	—	unknown	—	50.2° 17:15	5.81	64%	161.0°
2029-08-01 Wed	0	—	unknown	—	50.2° 17:10	5.86	55%	150.3°
2029-08-02 Thu	0	—	unknown	—	50.2° 17:05	5.92	46%	139.0°
2029-08-03 Fri	0	—	unknown	—	50.2° 17:00	5.97	36%	127.3°
2029-08-04 Sat	0	—	unknown	—	50.2° 17:00	6.03	27%	115.4°
2029-08-05 Sun	0	—	unknown	—	50.2° 16:55	6.09	19%	103.2°
2029-08-06 Mon	0	—	unknown	—	50.2° 16:50	6.14	11%	90.6°
2029-08-07 Tue	0	—	unknown	—	50.2° 16:45	6.2	6%	77.6°
2029-08-08 Wed	0	—	unknown	—	50.2° 16:40	6.26	2%	64.3°
2029-08-09 Thu	0	—	unknown	—	50.2° 16:40	6.31	0%	50.8°
2029-08-10 Fri	0	—	unknown	—	50.2° 16:35	6.37	1%	37.1°
2029-08-11 Sat	0	—	unknown	—	50.2° 16:30	6.43	5%	23.6°
2029-08-12 Sun	0	—	unknown	—	50.2° 16:25	6.49	11%	12.2°
2029-08-13 Mon	0	—	unknown	—	50.2° 16:25	6.54	19%	12.3°
2029-08-14 Tue	0	—	unknown	—	50.2° 16:20	6.6	29%	23.8°
2029-08-15 Wed	0	—	unknown	—	50.2° 16:15	6.66	40%	37.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-07-17&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.