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 Triangulum Pinwheel: 02-23 (41), 02-22 (40), 02-24 (38), 02-21 (37), 02-25 (37) — by astronomy; check the weather when the night is within four days.

2027-02-16astronomy score per night — click a bar for that night2027-03-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-02-16 Tue	17	—	unknown	19:30–21:50 (marginal, 2.33 h)	79.1° 16:10	10.22	78%	59.6°
2027-02-17 Wed	19	—	unknown	19:30–21:50 (marginal, 2.33 h)	79.1° 16:05	10.18	87%	73.8°
2027-02-18 Thu	23	—	unknown	19:35–19:55 (good, 0.33 h)	79.1° 16:05	10.13	94%	88.2°
2027-02-19 Fri	29	—	unknown	19:35–21:05 (good, 1.5 h)	79.1° 16:00	10.09	98%	102.7°
2027-02-20 Sat	35	—	unknown	19:35–21:15 (good, 1.67 h)	79.1° 15:55	10.05	100%	117.0°
2027-02-21 Sun	37	—	unknown	19:35–21:15 (good, 1.67 h)	79.1° 15:50	10.01	99%	131.0°
2027-02-22 Mon	40	—	unknown	19:40–21:10 (good, 1.5 h)	79.1° 15:45	9.97	95%	144.3°
2027-02-23 Tue	41	—	unknown	19:40–21:15 (good, 1.58 h)	79.1° 15:45	9.92	89%	156.2°
2027-02-24 Wed	38	—	unknown	19:40–21:10 (good, 1.5 h)	79.1° 15:40	9.88	81%	164.6°
2027-02-25 Thu	37	—	unknown	19:40–21:10 (good, 1.5 h)	79.1° 15:35	9.84	72%	164.0°
2027-02-26 Fri	36	—	unknown	19:40–21:05 (good, 1.42 h)	79.1° 15:30	9.79	62%	155.6°
2027-02-27 Sat	33	—	unknown	19:45–21:00 (good, 1.25 h)	79.1° 15:30	9.75	53%	145.1°
2027-02-28 Sun	31	—	unknown	19:45–20:55 (good, 1.17 h)	79.1° 15:25	9.7	43%	133.9°
2027-03-01 Mon	29	—	unknown	19:45–20:50 (good, 1.08 h)	79.1° 15:20	9.66	34%	122.7°
2027-03-02 Tue	28	—	unknown	19:45–20:50 (good, 1.08 h)	79.1° 15:15	9.61	25%	111.3°
2027-03-03 Wed	26	—	unknown	19:50–20:45 (good, 0.92 h)	79.1° 15:10	9.57	18%	99.9°
2027-03-04 Thu	24	—	unknown	19:50–20:40 (good, 0.83 h)	79.1° 15:10	9.52	11%	88.4°
2027-03-05 Fri	23	—	unknown	19:50–20:35 (good, 0.75 h)	79.1° 15:05	9.47	6%	76.7°
2027-03-06 Sat	21	—	unknown	19:50–20:30 (good, 0.67 h)	79.1° 15:00	9.43	2%	65.0°
2027-03-07 Sun	19	—	unknown	19:55–20:30 (good, 0.58 h)	79.1° 14:55	9.38	0%	53.1°
2027-03-08 Mon	18	—	unknown	19:55–20:25 (good, 0.5 h)	79.1° 14:50	9.33	0%	41.3°
2027-03-09 Tue	16	—	unknown	19:55–20:20 (good, 0.42 h)	79.1° 14:50	9.28	3%	29.8°
2027-03-10 Wed	13	—	unknown	19:55–20:15 (good, 0.33 h)	79.1° 14:45	9.23	7%	19.5°
2027-03-11 Thu	10	—	unknown	20:00–20:05 (good, 0.08 h)	79.1° 14:40	9.19	13%	14.4°
2027-03-12 Fri	8	—	unknown	20:00–20:40 (marginal, 0.67 h)	79.1° 14:35	9.14	21%	19.4°
2027-03-13 Sat	6	—	unknown	20:00–20:35 (marginal, 0.58 h)	79.1° 14:35	9.09	31%	30.2°
2027-03-14 Sun	4	—	unknown	20:00–20:30 (marginal, 0.5 h)	79.1° 14:30	9.04	42%	42.7°
2027-03-15 Mon	3	—	unknown	20:00–20:20 (marginal, 0.33 h)	79.1° 14:25	8.99	53%	55.9°
2027-03-16 Tue	2	—	unknown	20:05–20:15 (marginal, 0.17 h)	79.1° 14:20	8.94	64%	69.5°
2027-03-17 Wed	2	—	unknown	20:05–20:15 (marginal, 0.17 h)	79.1° 14:15	8.89	75%	83.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-02-16&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.