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: 07-10 (2), 07-11 (2), 07-12 (2), 07-13 (2), 07-14 (2) — by astronomy; check the weather when the night is within four days.

2034-07-10astronomy score per night — click a bar for that night2034-08-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-07-10 Mon	2	—	unknown	22:15–22:30 (marginal, 0.25 h)	50.2° 18:35	4.8	29%	142.7°
2034-07-11 Tue	2	—	unknown	22:15–22:25 (marginal, 0.17 h)	50.2° 18:35	4.84	19%	128.3°
2034-07-12 Wed	2	—	unknown	22:15–22:20 (marginal, 0.08 h)	50.2° 18:30	4.88	11%	113.8°
2034-07-13 Thu	2	—	unknown	—	50.2° 18:25	4.92	5%	99.3°
2034-07-14 Fri	2	—	unknown	22:10–22:15 (marginal, 0.08 h)	50.2° 18:20	4.96	1%	84.8°
2034-07-15 Sat	1	—	unknown	—	50.2° 18:20	5.0	0%	70.6°
2034-07-16 Sun	1	—	unknown	—	50.2° 18:15	5.04	2%	56.6°
2034-07-17 Mon	1	—	unknown	—	50.2° 18:10	5.09	6%	43.0°
2034-07-18 Tue	1	—	unknown	—	50.2° 18:05	5.13	12%	29.8°
2034-07-19 Wed	1	—	unknown	—	50.2° 18:00	5.18	19%	17.2°
2034-07-20 Thu	1	—	unknown	—	50.2° 18:00	5.23	28%	5.7°
2034-07-21 Fri	0	—	unknown	—	50.2° 17:55	5.28	37%	8.9°
2034-07-22 Sat	0	—	unknown	—	50.2° 17:50	5.33	47%	20.4°
2034-07-23 Sun	0	—	unknown	—	50.2° 17:45	5.38	56%	32.2°
2034-07-24 Mon	0	—	unknown	—	50.2° 17:40	5.43	65%	44.0°
2034-07-25 Tue	0	—	unknown	—	50.2° 17:40	5.48	74%	55.8°
2034-07-26 Wed	0	—	unknown	—	50.2° 17:35	5.53	82%	67.7°
2034-07-27 Thu	0	—	unknown	—	50.2° 17:30	5.58	89%	79.9°
2034-07-28 Fri	0	—	unknown	—	50.2° 17:25	5.63	94%	92.2°
2034-07-29 Sat	0	—	unknown	—	50.2° 17:25	5.69	98%	104.8°
2034-07-30 Sun	0	—	unknown	—	50.2° 17:20	5.74	100%	117.6°
2034-07-31 Mon	0	—	unknown	—	50.2° 17:15	5.8	99%	130.7°
2034-08-01 Tue	0	—	unknown	—	50.2° 17:10	5.85	97%	144.1°
2034-08-02 Wed	0	—	unknown	—	50.2° 17:05	5.91	92%	157.6°
2034-08-03 Thu	0	—	unknown	—	50.2° 17:05	5.96	85%	170.9°
2034-08-04 Fri	0	—	unknown	—	50.2° 17:00	6.02	76%	173.3°
2034-08-05 Sat	0	—	unknown	—	50.2° 16:55	6.07	65%	160.0°
2034-08-06 Sun	0	—	unknown	—	50.2° 16:50	6.13	54%	146.1°
2034-08-07 Mon	0	—	unknown	—	50.2° 16:45	6.19	42%	131.9°
2034-08-08 Tue	0	—	unknown	—	50.2° 16:45	6.24	31%	117.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-07-10&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.