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: 05-18 (83), 05-19 (79), 05-20 (77), 05-21 (71), 05-22 (62) — by astronomy; check the weather when the night is within four days.

2034-05-18astronomy score per night — click a bar for that night2034-06-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-05-18 Thu	83	—	unknown	22:35–02:00 (good, 3.42 h)	50.2° 22:05	5.42	1%	116.8°
2034-05-19 Fri	79	—	unknown	22:40–01:55 (good, 3.25 h)	50.2° 22:00	5.37	5%	101.9°
2034-05-20 Sat	77	—	unknown	22:40–01:50 (good, 3.17 h)	50.2° 22:00	5.32	11%	87.3°
2034-05-21 Sun	71	—	unknown	22:40–01:45 (good, 3.08 h)	50.2° 21:55	5.27	20%	73.2°
2034-05-22 Mon	62	—	unknown	22:45–01:40 (good, 2.92 h)	50.2° 21:50	5.22	29%	59.5°
2034-05-23 Tue	49	—	unknown	22:45–01:40 (good, 2.92 h)	50.2° 21:45	5.17	39%	46.4°
2034-05-24 Wed	36	—	unknown	22:45–01:10 (good, 2.42 h)	50.2° 21:40	5.13	49%	33.6°
2034-05-25 Thu	28	—	unknown	22:50–02:00 (marginal, 3.17 h)	50.2° 21:40	5.08	59%	21.3°
2034-05-26 Fri	21	—	unknown	22:50–01:45 (marginal, 2.92 h)	50.2° 21:35	5.04	69%	9.7°
2034-05-27 Sat	16	—	unknown	22:50–01:35 (marginal, 2.75 h)	50.2° 21:30	4.99	77%	5.5°
2034-05-28 Sun	13	—	unknown	22:50–01:20 (marginal, 2.5 h)	50.2° 21:25	4.95	85%	15.8°
2034-05-29 Mon	11	—	unknown	22:55–01:05 (marginal, 2.17 h)	50.2° 21:25	4.91	91%	27.4°
2034-05-30 Tue	12	—	unknown	22:55–01:05 (marginal, 2.17 h)	50.2° 21:20	4.87	95%	39.1°
2034-05-31 Wed	15	—	unknown	22:55–01:10 (marginal, 2.25 h)	50.2° 21:15	4.83	98%	50.9°
2034-06-01 Thu	19	—	unknown	23:00–01:15 (marginal, 2.25 h)	50.2° 21:10	4.79	100%	62.8°
2034-06-02 Fri	24	—	unknown	23:00–23:15 (good, 0.25 h)	50.2° 21:05	4.76	99%	74.8°
2034-06-03 Sat	30	—	unknown	23:00–00:20 (good, 1.33 h)	50.2° 21:05	4.72	97%	86.9°
2034-06-04 Sun	35	—	unknown	23:00–00:30 (good, 1.5 h)	50.2° 21:00	4.69	93%	99.2°
2034-06-05 Mon	43	—	unknown	23:00–00:35 (good, 1.58 h)	50.2° 20:55	4.66	87%	111.7°
2034-06-06 Tue	43	—	unknown	23:05–00:35 (good, 1.5 h)	50.2° 20:50	4.63	79%	124.4°
2034-06-07 Wed	41	—	unknown	23:05–00:40 (good, 1.58 h)	50.2° 20:45	4.61	70%	137.3°
2034-06-08 Thu	41	—	unknown	23:05–00:35 (good, 1.5 h)	50.2° 20:45	4.58	60%	150.4°
2034-06-09 Fri	39	—	unknown	23:05–00:30 (good, 1.42 h)	50.2° 20:40	4.56	49%	163.7°
2034-06-10 Sat	38	—	unknown	23:05–00:25 (good, 1.33 h)	50.2° 20:35	4.53	38%	175.4°
2034-06-11 Sun	35	—	unknown	23:10–00:25 (good, 1.25 h)	50.2° 20:30	4.51	27%	167.0°
2034-06-12 Mon	34	—	unknown	23:10–00:20 (good, 1.17 h)	50.2° 20:25	4.5	17%	152.8°
2034-06-13 Tue	33	—	unknown	23:10–00:15 (good, 1.08 h)	50.2° 20:25	4.48	9%	138.1°
2034-06-14 Wed	31	—	unknown	23:10–00:10 (good, 1.0 h)	50.2° 20:20	4.47	4%	123.2°
2034-06-15 Thu	29	—	unknown	23:10–00:10 (good, 1.0 h)	50.2° 20:15	4.45	1%	108.3°
2034-06-16 Fri	28	—	unknown	23:10–00:05 (good, 0.92 h)	50.2° 20:10	4.44	0%	93.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-05-18&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.