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: 04-16 (93), 04-17 (93), 04-18 (93), 04-19 (93), 04-20 (93) — by astronomy; check the weather when the night is within four days.

2034-04-16astronomy score per night — click a bar for that night2034-05-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-04-16 Sun	93	—	unknown	21:45–04:05 (good, 6.33 h)	50.2° 00:10	7.23	5%	172.7°
2034-04-17 Mon	93	—	unknown	21:50–04:00 (good, 6.17 h)	50.2° 00:10	7.17	1%	169.7°
2034-04-18 Tue	93	—	unknown	21:50–03:55 (good, 6.08 h)	50.2° 00:05	7.12	0%	155.1°
2034-04-19 Wed	93	—	unknown	21:50–03:50 (good, 6.0 h)	50.2° 00:00	7.06	2%	140.1°
2034-04-20 Thu	93	—	unknown	21:50–03:50 (good, 6.0 h)	50.2° 23:55	7.0	7%	125.1°
2034-04-21 Fri	93	—	unknown	21:55–03:45 (good, 5.83 h)	50.2° 23:50	6.94	14%	110.3°
2034-04-22 Sat	93	—	unknown	21:55–03:40 (good, 5.75 h)	50.2° 23:50	6.88	23%	95.9°
2034-04-23 Sun	90	—	unknown	21:55–03:35 (good, 5.67 h)	50.2° 23:45	6.83	33%	82.0°
2034-04-24 Mon	86	—	unknown	22:00–03:30 (good, 5.5 h)	50.2° 23:40	6.77	44%	68.4°
2034-04-25 Tue	81	—	unknown	22:00–03:30 (good, 5.5 h)	50.2° 23:35	6.71	55%	55.4°
2034-04-26 Wed	55	—	unknown	00:25–02:55 (good, 2.5 h)	50.2° 23:30	6.65	65%	42.6°
2034-04-27 Thu	37	—	unknown	22:05–03:45 (marginal, 5.67 h)	50.2° 23:30	6.59	74%	30.3°
2034-04-28 Fri	28	—	unknown	22:05–03:35 (marginal, 5.5 h)	50.2° 23:25	6.53	82%	18.2°
2034-04-29 Sat	22	—	unknown	22:05–03:20 (marginal, 5.25 h)	50.2° 23:20	6.48	89%	7.2°
2034-04-30 Sun	18	—	unknown	22:10–03:05 (marginal, 4.92 h)	50.2° 23:15	6.42	94%	7.8°
2034-05-01 Mon	17	—	unknown	22:10–02:50 (marginal, 4.67 h)	50.2° 23:15	6.36	98%	18.8°
2034-05-02 Tue	19	—	unknown	22:10–02:35 (marginal, 4.42 h)	50.2° 23:10	6.3	100%	30.4°
2034-05-03 Wed	28	—	unknown	22:15–02:50 (marginal, 4.58 h)	50.2° 23:05	6.24	100%	42.1°
2034-05-04 Thu	40	—	unknown	22:15–03:00 (marginal, 4.75 h)	50.2° 23:00	6.19	98%	53.9°
2034-05-05 Fri	55	—	unknown	22:15–00:20 (good, 2.08 h)	50.2° 22:55	6.13	95%	65.8°
2034-05-06 Sat	85	—	unknown	22:20–01:45 (good, 3.42 h)	50.2° 22:55	6.07	90%	77.7°
2034-05-07 Sun	93	—	unknown	22:20–02:20 (good, 4.0 h)	50.2° 22:50	6.02	83%	89.8°
2034-05-08 Mon	93	—	unknown	22:20–02:25 (good, 4.08 h)	50.2° 22:45	5.96	75%	102.1°
2034-05-09 Tue	93	—	unknown	22:25–02:25 (good, 4.0 h)	50.2° 22:40	5.9	66%	114.6°
2034-05-10 Wed	93	—	unknown	22:25–02:25 (good, 4.0 h)	50.2° 22:35	5.85	56%	127.4°
2034-05-11 Thu	93	—	unknown	22:25–02:25 (good, 4.0 h)	50.2° 22:35	5.79	45%	140.5°
2034-05-12 Fri	93	—	unknown	22:30–02:20 (good, 3.83 h)	50.2° 22:30	5.74	34%	153.9°
2034-05-13 Sat	92	—	unknown	22:30–02:15 (good, 3.75 h)	50.2° 22:25	5.68	24%	167.5°
2034-05-14 Sun	90	—	unknown	22:30–02:15 (good, 3.75 h)	50.2° 22:20	5.63	15%	174.8°
2034-05-15 Mon	88	—	unknown	22:35–02:10 (good, 3.58 h)	50.2° 22:20	5.57	7%	161.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-04-16&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.