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Hachiōji

35.656° N   139.324° E  ·  127 M
41 /100
PEAK
Marginal, but there is a 2 hours gap from 01:00.
BEST WINDOW 01:00–03:00 · ASTRO DARK 01:00–04:00 · MOON 0%
Transparency
0.26
Seeing
0.97
Cloud
40%
Moon
0%

Fair tonight

Hour by hour, local to Hachiōji. Colour encodes the score and nothing else; every other measurement is luminance.

Sky state
Lighter = daylight and twilight  ·  unshaded = astronomical dark
Score
01
02
03
04
05
36
41
2
13
0
BEST WINDOW
Low cloud
39%
38%
95%
31%
66%
Mid cloud
13%
3%
10%
8%
48%
High cloud
0%
2%
32%
73%
48%
Transparency
0.20
0.21
0.26
0.26
0.26
Seeing
0.96
0.97
0.93
0.93
0.96
Moon clear
down
down
down
down
down
Inspect

Cloud tracks show clear sky — a longer bar is better. The figure inside each track is the raw measurement.

Why this hour scored what it did
01 Fair · 36/100
Starting from
100
Cloud
−46
Transparency
−17
Seeing
−0
Moonlight
−0
Darkness
−0
Score
36
CLOUD 46% LOW 39% MID 13% HIGH 0% SUN -36.6° MOON -35.7° / 0% WIND 2 TEMP 21°
Excellent 75+ Good 55+ Fair 35+ Poor 15+ Not worth it Seeing is estimated from surface wind — see how we score.

What are you doing tonight?

The same forecast, weighted for the target. Planetary work barely cares about moonlight; long exposures die on high cloud a visual observer would never notice.

SET UP 00:30 · OBSERVE 01:00–03:00 · 2H · MEAN 39

Darkness and moonlight dominate. Faint fuzzies need a genuinely dark sky more than they need steady air.

010305
CLOUD RETURNS 03:00
SET UP 00:30 · OBSERVE 01:00–03:00 · 2H · MEAN 48

Seeing is everything and moonlight is irrelevant. Bright targets punch through twilight, so darkness barely counts.

010305
CLOUD RETURNS 03:00MOONLIGHT IGNORED FOR THIS TARGET
SET UP 01:30 · OBSERVE 02:00–03:00 · 1H · MEAN 38

Tolerates soft seeing, but high cloud wrecks a wide frame and moonlight raises the background everywhere.

010305
CLOUD RETURNS 03:00
NO USABLE WINDOW FOR THIS TARGET TONIGHT

Needs conditions to hold still for hours. Sustained transparency matters more than any single good hour.

010305
CONDITIONS STAY BELOW THE USABLE THRESHOLD
SET UP 00:30 · OBSERVE 01:00–03:00 · 2H · MEAN 38

Naked eye, whole sky. Total cloud and moonlight are the only things that count.

010305
CLOUD RETURNS 03:00
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The next week of nights

Tonight · 12 Aug
41
Fair
MOON 0%
01:00–03:00
Tomorrow · 13 Aug
10
Clouded out
MOON 1%
Friday · 14 Aug
11
Clouded out
MOON 5%
Saturday · 15 Aug
24
Poor
MOON 8%
Sunday · 16 Aug
29
Poor
MOON 19%
Monday · 17 Aug
29
Poor
MOON 28%
Tuesday · 18 Aug
45
Fair
MOON 37%
21:00–22:00
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Nearby locations

About this forecast

Conditions for Hachiōji, Japan are computed from the MET Norway forecast model for these exact coordinates, combined with sun and moon positions we calculate directly. The score weighs cloud cover by layer, atmospheric transparency, estimated seeing, moonlight and how dark the sky actually gets. Read the full method →