Cathedral, Mountain, Moon | Hacker News Reader

Cathedral, Mountain, Moon

apod.nasa.gov

150 points_Microft18 comments

My favorite genre of astrophotography involving perfect alignment are photos of ISS transits over the Sun or Moon, e.g. [1], [2]. There is even a website which caluclates such transits [3]. Destin from "Smarter Every Day" made a video [4] about ISS transiting the Sun during an eclipse with all the details of preparations and setup.

1. https://petapixel.com/2023/06/13/photographer-captures-iss-c...

2. https://mashable.com/article/space-station-moon-transit-phot...

3. https://transit-finder.com/

4. https://youtu.be/lepQoU4oek4?feature=shared

They must have had incredible patience to wait millions of years until that mountain finally lined up with that cathedral.

They don’t explain how they took this photo, but I’m assuming they used the lens compression technique. In simple terms, the photographer takes a photo very far away from the foreground using a really long lens. This makes the background appear bigger, relative to the foreground.

You have to have something around 600mm (or even something longer) to magnify the moon that much.

EXIF reports 500mm with an EOS R5, which is a full frame machine. So it's cropped generously.

That is actually not correct. The focal length has no effect on this.

It does, to the extent that you can’t normally take a 50mm shot and crop it to the same framing because of resolution limits - you’ll end up with a blurry 128x96px image. Maybe a fuji GFX could do it, but here the long range is what allows this particular image and perspective to be produced.

Completely opposite. Longer the lens, more the compression. To be able to get moon at that size with that resolution, you need “half a telescope”. Try shooting the moon with a 135mm lens, you’ll get a coin on the sky.

Yes. That's because as you move away from the foreground object, the ratio of distances to foreground and background decreases. In the limit, this ratio approaches one, and you get an orthographic projection, where the projected size of objects (after zooming in) is independent of their distance from the camera.

Worth nothing it's less to do with the lens and more about distance to the subject. If you took a wider angle shot and cropped it, it would look the same (albeit lower resolution).

Yes, this is fairly counterintuitive but true. The focal length has nothing to do with it (other than letting you see the subject from farther away).

Can I just say I love how 1995 the HTML for APOD is?

And they could update the look quite a bit without bloat or extra JS.

The mountain in the background looks a lot different than I expected and is actually the highest peak in this part of the Alps:

https://en.m.wikipedia.org/wiki/Monte_Viso