Sunset Hunter
Measure the sky
From Dina Huapi, lakeshore · 41.0682°S 71.1570°W
I'm building a forecast of how good each sunset in Bariloche will be, and it learns from what really happens. Take a photo from here: your phone measures how much colour there is and where in the sky, and sends me just those numbers.
- 1.Open the camera and let it use the compass and your location.
- 2.Point towards the sun with the mountains in the bottom third of the frame: the guides show you where. The sun doesn't need to be in it.
- 3.Tap Measure. If you can, repeat every 5 or 10 minutes: the best colour often comes after the sun is gone.
How is your photo scored?
Your phone looks only at the sky pixels, above the real outline of the mountains, and knows how far from the sun each one is. The score has two parts, and the higher one wins.
The floor: the band30
The strip of sky just above the mountains, on the sun's side. If the colour gradient shows there, the sunset is already fair (30), even without a single cloud. No colour there, and it's poor.
The show: from fair upwards, the more the sky lights up. Three numbers, the same ones you see after measuring:
Warm colour50%
How much of the sky is red, orange, pink or magenta. Colour far from the sun counts for more, because it's rarer.
Intensity30%
How vivid and varied the colours are. Flat grey gives almost nothing, and it only counts when there's warm colour: a clear blue sky is vivid too.
Reaches20%
How many degrees from the sun the colour reaches. The best ones light up the sky from end to end. A few stray pixels aren't enough.
You can point anywhere in the sky, since every pixel knows where it is. But the band only shows if the photo takes in the sun's side, so aim at least one shot that way.
Four example skies
These skies are drawn by code, from Playa Centro towards where the sun just set, over the real outline of the mountains and at the size your phone measures. The score comes from the same maths that runs on your phone.
Flat overcast
0
- Band
- 0%
- Warm colour
- 0%
- Intensity
- 3
- Reaches
- 0°
No colour in the band or anywhere else: poor.
Clear
30
- Band
- 57%
- Warm colour
- 1%
- Intensity
- 64
- Reaches
- 8°
The gradient along the mountains is enough for fair, but there are no clouds to light up.
Clouds lit near the sun
63
- Band
- 100%
- Warm colour
- 29%
- Intensity
- 81
- Reaches
- 40°
The mid-level clouds catch colour on the sun's side; further away they stay grey.
The whole sky on fire
90
- Band
- 100%
- Warm colour
- 82%
- Intensity
- 103
- Reaches
- 46°
Reds and pinks from end to end: the sunset Sunset Hunter is out looking for.
The maths is provisional: I keep the raw numbers, so I'll keep tuning it with what people measure and what I write down.
The photo never leaves your phone. Your location only confirms you're at the lookout, and I never publish it.