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 North America Nebula: 01-21 (18), 01-23 (18), 01-22 (17), 01-24 (17), 02-15 (16) — by astronomy; check the weather when the night is within four days.

2038-01-21astronomy score per night — click a bar for that night2038-02-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-01-21 Thu	18	—	unknown	19:00–19:25 (good, 0.42 h)	87.2° 13:15	11.08	99%	116.6°
2038-01-22 Fri	17	—	unknown	19:05–19:25 (good, 0.33 h)	87.2° 13:15	11.05	96%	118.4°
2038-01-23 Sat	18	—	unknown	19:05–19:30 (good, 0.42 h)	87.2° 13:10	11.03	90%	118.4°
2038-01-24 Sun	17	—	unknown	19:05–19:25 (good, 0.33 h)	87.2° 13:05	11.0	82%	116.4°
2038-01-25 Mon	15	—	unknown	19:05–19:20 (good, 0.25 h)	87.2° 13:00	10.97	72%	112.7°
2038-01-26 Tue	13	—	unknown	19:10–19:20 (good, 0.17 h)	87.2° 13:00	10.94	61%	107.6°
2038-01-27 Wed	13	—	unknown	19:10–19:15 (good, 0.08 h)	87.2° 12:55	10.91	50%	101.7°
2038-01-28 Thu	12	—	unknown	18:35–19:45 (marginal, 1.17 h)	87.2° 12:50	10.88	39%	95.3°
2038-01-29 Fri	11	—	unknown	19:10–19:40 (marginal, 0.5 h)	87.2° 12:45	10.85	28%	88.8°
2038-01-30 Sat	10	—	unknown	19:10–19:35 (marginal, 0.42 h)	87.2° 12:40	10.82	19%	82.3°
2038-01-31 Sun	9	—	unknown	19:15–19:35 (marginal, 0.33 h)	87.2° 12:40	10.79	11%	76.3°
2038-02-01 Mon	9	—	unknown	05:40–06:00 (marginal, 0.33 h)	87.2° 12:35	10.75	6%	71.0°
2038-02-02 Tue	9	—	unknown	05:35–06:00 (marginal, 0.42 h)	87.2° 12:30	10.72	2%	66.7°
2038-02-03 Wed	9	—	unknown	05:30–06:00 (marginal, 0.5 h)	87.2° 12:25	10.69	0%	63.5°
2038-02-04 Thu	9	—	unknown	05:30–05:55 (marginal, 0.42 h)	87.2° 12:20	10.65	0%	61.7°
2038-02-05 Fri	9	—	unknown	05:25–05:55 (marginal, 0.5 h)	87.2° 12:20	10.62	3%	61.4°
2038-02-06 Sat	10	—	unknown	05:20–06:25 (marginal, 1.08 h)	87.2° 12:15	10.58	7%	62.4°
2038-02-07 Sun	10	—	unknown	05:50–05:55 (good, 0.08 h)	87.2° 12:10	10.55	13%	64.8°
2038-02-08 Mon	11	—	unknown	05:50–05:55 (good, 0.08 h)	87.2° 12:05	10.51	20%	68.1°
2038-02-09 Tue	11	—	unknown	05:45–05:50 (good, 0.08 h)	87.2° 12:00	10.47	28%	72.4°
2038-02-10 Wed	12	—	unknown	05:40–05:50 (good, 0.17 h)	87.2° 11:55	10.44	36%	77.3°
2038-02-11 Thu	12	—	unknown	05:35–05:50 (good, 0.25 h)	87.2° 11:50	10.4	46%	82.7°
2038-02-12 Fri	14	—	unknown	05:30–05:50 (good, 0.33 h)	87.2° 11:45	10.36	55%	88.4°
2038-02-13 Sat	13	—	unknown	05:30–05:45 (good, 0.25 h)	87.2° 11:45	10.32	65%	94.4°
2038-02-14 Sun	15	—	unknown	05:25–05:45 (good, 0.33 h)	87.2° 11:40	10.28	74%	100.3°
2038-02-15 Mon	16	—	unknown	05:20–05:45 (good, 0.42 h)	87.2° 11:35	10.24	83%	106.0°
2038-02-16 Tue	16	—	unknown	05:30–05:45 (good, 0.25 h)	87.2° 11:30	10.2	90%	111.1°
2038-02-17 Wed	14	—	unknown	05:25–05:40 (good, 0.25 h)	87.2° 11:25	10.16	96%	115.2°
2038-02-18 Thu	14	—	unknown	05:20–05:40 (good, 0.33 h)	87.2° 11:25	10.12	99%	117.9°
2038-02-19 Fri	15	—	unknown	05:20–05:40 (good, 0.33 h)	87.2° 11:20	10.08	100%	118.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-01-21&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.