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: 11-14 (7), 11-15 (7), 11-11 (6), 11-12 (6), 11-13 (6) — by astronomy; check the weather when the night is within four days.

2027-10-17astronomy score per night — click a bar for that night2027-11-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-10-17 Sun	0	—	unknown	—	50.2° 12:10	9.9	94%	132.1°
2027-10-18 Mon	0	—	unknown	—	50.2° 12:05	9.94	88%	118.8°
2027-10-19 Tue	0	—	unknown	—	50.2° 12:00	9.98	80%	105.4°
2027-10-20 Wed	0	—	unknown	—	50.2° 11:55	10.02	70%	91.8°
2027-10-21 Thu	0	—	unknown	—	50.2° 11:50	10.07	59%	78.0°
2027-10-22 Fri	0	—	unknown	—	50.2° 11:45	10.11	48%	64.1°
2027-10-23 Sat	0	—	unknown	—	50.2° 11:40	10.15	36%	50.2°
2027-10-24 Sun	0	—	unknown	—	50.2° 11:40	10.19	26%	36.4°
2027-10-25 Mon	0	—	unknown	—	50.2° 11:35	10.23	16%	22.9°
2027-10-26 Tue	0	—	unknown	—	50.2° 11:30	10.27	9%	11.3°
2027-10-27 Wed	0	—	unknown	—	50.2° 11:25	10.31	4%	11.6°
2027-10-28 Thu	0	—	unknown	—	50.2° 11:20	10.34	1%	23.1°
2027-10-29 Fri	0	—	unknown	—	50.2° 11:20	10.38	0%	36.2°
2027-10-30 Sat	0	—	unknown	—	50.2° 10:15	10.42	2%	49.3°
2027-10-31 Sun	0	—	unknown	—	50.2° 10:10	10.46	6%	62.2°
2027-11-01 Mon	0	—	unknown	—	50.2° 10:05	10.49	12%	74.8°
2027-11-02 Tue	0	—	unknown	—	50.2° 10:00	10.53	20%	87.1°
2027-11-03 Wed	1	—	unknown	—	50.2° 10:00	10.57	28%	99.2°
2027-11-04 Thu	1	—	unknown	—	50.2° 09:55	10.6	37%	111.1°
2027-11-05 Fri	1	—	unknown	—	50.2° 09:50	10.64	46%	122.8°
2027-11-06 Sat	1	—	unknown	—	50.2° 09:45	10.67	56%	134.3°
2027-11-07 Sun	2	—	unknown	05:25–05:30 (marginal, 0.08 h)	50.2° 09:40	10.7	65%	145.8°
2027-11-08 Mon	3	—	unknown	05:50–06:00 (marginal, 0.17 h)	50.2° 09:40	10.74	74%	157.1°
2027-11-09 Tue	4	—	unknown	05:50–06:05 (marginal, 0.25 h)	50.2° 09:35	10.77	82%	167.3°
2027-11-10 Wed	4	—	unknown	05:15–05:30 (marginal, 0.25 h)	50.2° 09:30	10.8	89%	170.2°
2027-11-11 Thu	6	—	unknown	05:10–05:35 (marginal, 0.42 h)	50.2° 09:25	10.83	94%	161.3°
2027-11-12 Fri	6	—	unknown	05:10–05:35 (marginal, 0.42 h)	50.2° 09:25	10.86	98%	149.3°
2027-11-13 Sat	6	—	unknown	05:05–05:35 (marginal, 0.5 h)	50.2° 09:20	10.89	100%	136.4°
2027-11-14 Sun	7	—	unknown	05:00–05:35 (marginal, 0.58 h)	50.2° 09:15	10.92	99%	123.0°
2027-11-15 Mon	7	—	unknown	04:55–05:35 (marginal, 0.67 h)	50.2° 09:10	10.95	96%	109.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-10-17&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.