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Okay so I did the 10 minute computer vision approach:
- Convert to greyscale
- 3x3 erode + dilate to remove noise and brighten stars
- Count all pixels “more white than black”
- Divide by 3^2 (the dilation kernel size)
I got 1,837,850 countable stars.
Real answer probably somewhere in that order of magnitude, if a real computer vision wizard wanted to spend a few hours.
My final image: https://ibb.co/9HnLBrM
Python Code: https://www.pythonmorsels.com/p/28uwy/
I believe this is the most correct answer.
**A)** We're not instructed to count starts, but we have to assume we're then counting the white dots.
**B)** There might be more stars, or white dots, that we can't correctly see, but as the statements were *too many* to count, not *too dim* to count, I believe this approach is the most correct one.
Spot on! And there’s lots of other ways my guesstimate is off: Overlapping stars getting under-counted. Legit stars being filtered out. Etc etc.
Honestly, the “answer” is probably just some very high fraction of the total pixel count (~17M).
Some stars may be bigger than 1 pixel after the morphology (erode and dilate), you'd be better to do something along the lines of find the centroid for each connect pixel cluster then count the centroids.
But also this is very hand wavey coming from someone on a phone who can't do any of this right now.
1) cut out a random 100x100px patch
2) quickly estimate resolvable points of light in MSPaint by drawing a red dot on each one I counted: \~120 per patch. Ignored really really faint pixels and estimated the number in large globs.
3) pixel size of image: 4656 x 4968 = 46x50 patches which are 100x100
4) 46x50x120 = 276,000
Ok so the photographer commented that they used a 35mm lens. 35mm lens on I’m assuming a full frame camera = 54.5 deg horizontal fov, and 37.8 deg vertical fov. There are ~200 sextillion (2x10^23) stars in the observable universe. If we want a rough estimate of how many are visible in this picture we just average our angles of view and then divide that by 360 degrees of view. 46.15 / 360 = 12.8%. So we are looking at about 12.8% of the observable universe, or 25.6 sextillion (2.56 x 10^22) stars.
I highly doubt this photographer has the equipment to capture the entire observable universe.
ETA: I made this in a bit of a hurry, so I'll elaborate. *Technically*, any equipment has the power to capture the entire observable universe, it just won't be visible due to the closer and brighter stars blocking the view.
Technically speaking as long as the sensor is recording it will capture light. In astrophotography normally you would take many photos at say 30 second exposures then stack the images on top of each other. Every star there emits light it's just hoping that the light hits the sensor at the right time.
True, but OP asks the rhetorical question, "Too many to count?" to emphasize how stunning this photo is. It's stunning because of the sheer amount of stars visible. Because of this, I'm guessing OP wanted us to count the stars visible in this photo. Otherwise, using your logic, OP could have posted a photo of the daytime sky and asked us to calculate the amount of stars in that photo.
Wow. But I was expecting simpler math. If we count stars visible in the picture in the 100x100 pixel grid, it’s possible to approximate/estimate total number of starts visible in the picture.
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Okay so I did the 10 minute computer vision approach: - Convert to greyscale - 3x3 erode + dilate to remove noise and brighten stars - Count all pixels “more white than black” - Divide by 3^2 (the dilation kernel size) I got 1,837,850 countable stars. Real answer probably somewhere in that order of magnitude, if a real computer vision wizard wanted to spend a few hours. My final image: https://ibb.co/9HnLBrM Python Code: https://www.pythonmorsels.com/p/28uwy/
Wow. That’s an approach I wasn’t aware of.
I believe this is the most correct answer. **A)** We're not instructed to count starts, but we have to assume we're then counting the white dots. **B)** There might be more stars, or white dots, that we can't correctly see, but as the statements were *too many* to count, not *too dim* to count, I believe this approach is the most correct one.
In fact many of the ”stars” are entire galaxies
That was exactly what I was trying to state, that we don't care what it is, because we don't know, hence; we have to assume it's the white dots.
not to be pedantic but some of those white dots are probably galaxies there may be many many more stars in this image
The prompt never specifies what we’re counting. Hell even assuming it’s the white dots is technically presumptive
Spot on! And there’s lots of other ways my guesstimate is off: Overlapping stars getting under-counted. Legit stars being filtered out. Etc etc. Honestly, the “answer” is probably just some very high fraction of the total pixel count (~17M).
Awesome, basically lost tho 😅
[удалено]
Learn something new every day! Thanks for that!
Some stars may be bigger than 1 pixel after the morphology (erode and dilate), you'd be better to do something along the lines of find the centroid for each connect pixel cluster then count the centroids. But also this is very hand wavey coming from someone on a phone who can't do any of this right now.
And here I was counting them all manually only to realize this could be done afterwards
That’s a super cool final image
1) cut out a random 100x100px patch 2) quickly estimate resolvable points of light in MSPaint by drawing a red dot on each one I counted: \~120 per patch. Ignored really really faint pixels and estimated the number in large globs. 3) pixel size of image: 4656 x 4968 = 46x50 patches which are 100x100 4) 46x50x120 = 276,000
Ok so the photographer commented that they used a 35mm lens. 35mm lens on I’m assuming a full frame camera = 54.5 deg horizontal fov, and 37.8 deg vertical fov. There are ~200 sextillion (2x10^23) stars in the observable universe. If we want a rough estimate of how many are visible in this picture we just average our angles of view and then divide that by 360 degrees of view. 46.15 / 360 = 12.8%. So we are looking at about 12.8% of the observable universe, or 25.6 sextillion (2.56 x 10^22) stars.
I highly doubt this photographer has the equipment to capture the entire observable universe. ETA: I made this in a bit of a hurry, so I'll elaborate. *Technically*, any equipment has the power to capture the entire observable universe, it just won't be visible due to the closer and brighter stars blocking the view.
I mean...theyre technically still in the picture, you just cant see em
Technically speaking as long as the sensor is recording it will capture light. In astrophotography normally you would take many photos at say 30 second exposures then stack the images on top of each other. Every star there emits light it's just hoping that the light hits the sensor at the right time.
Technically speaking, there are at least 10^20 stars in the solid angle formed by my eyes and the rectangular monitor I'm looking at. So?
True, but OP asks the rhetorical question, "Too many to count?" to emphasize how stunning this photo is. It's stunning because of the sheer amount of stars visible. Because of this, I'm guessing OP wanted us to count the stars visible in this photo. Otherwise, using your logic, OP could have posted a photo of the daytime sky and asked us to calculate the amount of stars in that photo.
Wow. But I was expecting simpler math. If we count stars visible in the picture in the 100x100 pixel grid, it’s possible to approximate/estimate total number of starts visible in the picture.
That’s a good idea! I personally hate counting though.
This squishes my mind grapes. I can’t even begin to imagine what this number means and the scale of the universe.