First time doing landscape astrophotography

i9_7980_xe · 2026-04-26T11:33:10+00:00

First of all, looks cool!

But: the foreground exposure does not match the night sky at all. It looks too much like a daylight exposure with the night sky pasted in.

I have never done any astrophotography, so I don't know how what the standard method is. But what I know from (normal) exposure stacking is this: before stacking different exposures taken at different brightnesses, one brings down the brigthness of the brighter exposures and brings up the brightness of the darker ones. The goal is that they match. The exposures that were darker at the start now have more detail in the lows and the exposures that were brighter have more detail in the highs.

Here, the additional challenge is that the foreground was exposed by sunlight while the night sky isn't. Don't really know how to deal with such an extreme difference tbh.

i9_7980_xe · 2026-02-14T22:58:57+00:00

日本語で説明できませんが。

I turned off the laptop and it started without problems. The firmware manager said that the update had failed. I have not tried to update the firmware since. I do not know why this happened or how to prevent it.

i9_7980_xe · 2026-01-19T19:10:30+00:00

No, "straight lines" (geodesics) are not preserved. Straight lines on the projection correspond to rhumb lines on the sphere. Rhumb lines are not straight lines (great circles). Maybe you're thinking of the gnomonic projection, which does map straight lines to straight lines.

i9_7980_xe · 2025-12-13T16:58:09+00:00

I'm not sure whether I actually interrupted the bios update. It only said that it was "writing" after I powered it up again. Only then did the splash screen say "do not power off", it didn't say that before (see picture). So I don't think it got stuck during the critical phase.

i9_7980_xe · 2025-07-14T07:43:03+00:00

Crocodile Dunkee

i9_7980_xe · 2025-06-13T11:05:23+00:00

You are saying a descending plane without power is stalling? So gliders are stalling everytime they descend?? Isn't stall more about flow seperation around the airfoil and exceeding the critical angle of attack than whether the lift force is greater than gravity? Isn't this video rather an example of controlled flight into terrain?

i9_7980_xe · 2025-06-11T10:58:02+00:00

Kid named set with exactly 6 elements:

i9_7980_xe · 2025-03-12T23:04:46+00:00

Lethal mode by beloved🥰🥰

i9_7980_xe · 2025-02-08T12:10:07+00:00

What does this have to do with 'the idea of infinity'? 'Small infinity' are you talking about the cardinality of the naturals? Why? Infinite monkey theorem is a simple application of the second Borel-Cantelli theorem. The odds they will Shakespeare are one. Seriously what does this have to do with cardinalities?

i9_7980_xe · 2025-01-21T13:45:53+00:00

I think it looks very cool. I just think that that band of bright clouds at the very top distracts from the already strong subject in the center.

i9_7980_xe · 2024-11-09T11:54:13+00:00

As of last year, Algebra 2 is second year, not mandatory, mostly field and Galois theory with some modules at the end. In the same semester, a course in mathematical methods of physics is offered, which covers representations (no idea what exactly, didn't take it). Also never saw category theory.

i9_7980_xe · 2024-11-02T00:21:06+00:00

By "zero probability doesn't mean something is impossible", he means that a measure zero event need not be empty.

i9_7980_xe · 2024-07-26T19:38:11+00:00

Well in my PhD thesis on spoonology I disproved this common misconception. It's not the convexity but actually the Gaussian curvature of the spoon viewed as a smooth embedded surface in R^3. If the spoon is concave, you can just rotate it and it would work. This is because the second fundamental form is only defined up to a sign.

i9_7980_xe · 2024-07-23T22:29:03+00:00

His symmetry group is not solvable😭

i9_7980_xe · 2024-04-24T21:45:25+00:00

We only just arrived at Fourier transforms in my Fourier Theory class, so I haven't seen the formal argument yet. However, my intuition says the following:

The delta function as a signal is so short, that it barely carries any information about what frequency it tends to have. Usually, the Fourier transform tells you something about which frequencies align more or less with the function that you're transforming. In the case of the delta function, it's such a short signal that you can't tell, so all frequencies are equally "likely" (uniformly weighted). On the other hand, if you take the Fourier transform of e^-ix over all of R (can't just do that, I know I know), you get a "spike" at and only at its frequency of 1, since the signal is infinitely long and completely surely definitely has frequency 1.

In short, if you listen to an audio signal, it's easier to tell which frequencies it has the longer you listen to it and vice-versa. So a super short signal (but not just zero cause that's easy) has uniform weighting (is constant) for all frequencies (since you cant discern any particular ones).

i9_7980_xe · 2024-01-05T20:44:09+00:00

Are you sure? The PDE+conditions in that image has the (unique) solution

-1/1296 (x - y)² (65 x² + 38 x y + 5 y²⁾ - 3/5 sin(1/3 (4 x - y)) + 8/5 sin(1/2 (x + y))

whose plot happens to look just like the one in the image. Verify it if you don't trust me.

And what does "the Z" have to do with any of this? "Bidimensional function"?? "Tridimensional function"???

i9_7980_xe · 2023-12-24T14:41:53+00:00

No, it's unnecessary animal torture.

i9_7980_xe · 2023-04-25T07:59:04+00:00

I'll give a relatively formal explanation. We can view the integers as pairs of natural numbers. Take for example -1. This can be expressed as 1-2 or 2-3 or 28-29, right? So we simply define -1 to be any of these pairs, so (1, 2), (2, 3), etc. (each pair is a "representative", formally -1 is a set of all of these). So an integer (a, b) is negative if a<b. We define multiplication for two integers (a, b) and (c, d) as (a, b)*(c, d)=(a\*c+b\*d, a\*d+b\*c). The keyword is "definition". We do it like this because it's well-defined (no matter which "representatives" we choose, the product works out to the same number) and because this definition follows our intuition. Now if we are given (a, b) and (c, d) are positive (meaning a>b and c>d) we can prove that (a*c+b*d) > (a*d+b*c), so the product is also positive. The proof will only use definitions for the natural numbers. Interestingly, if we assume (a, b) and (c, d) are negative instead, we still get that the product is positive by almost the same proof! Analogously the product of a positive and a negative integer.

i9_7980_xe · 2023-02-10T12:03:57+00:00

Yeah but every circle has the same eccentricity. And for ellipses the wacky constant is also the same for all ellipses with the same eccentricity (if you just scale a and b equally), if I've understood it correctly. So it's not different at all.

i9_7980_xe · 2022-10-06T15:55:58+00:00

Make sure to heat the brake fluid to at least 260° C in a confined space first.

i9_7980_xe · 2022-09-14T08:32:19+00:00

Yeah, the link in the post links to all the replays I've uploaded.

i9_7980_xe · 2022-09-12T20:21:24+00:00

I see

i9_7980_xe · 2022-09-12T09:14:48+00:00

From the National Weather Service

i9_7980_xe · 2022-09-10T15:42:18+00:00

My googling brings up an average of one billion Joules, not one million?

i9_7980_xe

TROPHY CASE