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Exes and Ohs (7kyu): Codewars (TDD in JavaScript)
Hi! It’s Friday. So let’s chill and do something easy today. If this is your first time here and you want to learn Frontend and JavaScript, start right now by subscribing, and don’t forget to turn on the subtitles. [Music playing] Let’s solve today codewars’ kata titled “Exes and Ohs.” Check to see if a string has the same amount of ‘x’s and ‘o’s. The method must return a boolean and be case insensitive.
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La Informática: Promotora de un mundo mas sostenible
CAMELOPARDALIS, THE PROGRAM, YOUR PROGRAM Realized by: Javier Puras, David Romé and Ignacio Jorquera Today, in Camelopardalis we have attended a seminar where experts will explain to us about Production and sustainable development In few moments, we will stay with them, and those experts will explain us about the most innovative technologies of this moment ¡Pay attention! Here you will be shown how to avoid execc production thanks to the Cloud.
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IS THE 500 RULE for astrophotography completely WRONG?!?
Hi everyone this is Nico Carver. My website is at nebulaphotos.com and today we’re gonna find out does the rule 500 work or is it completely wrong? First off what is the rule of 500? well it’s a rule of thumb for determining the maximum exposure time in seconds of an untracked photo before the Earth’s rotation causes your stars to trail. So that’s a lot to take in let’s unpack that everything we’re talking about in this video is assuming you just have your camera set up on a fixed tripod we don’t have a astrophotography mount or a tracking device like a star tracker it’s just the tripod and the camera and then we take a photo of the night sky typically we’d want to do this with a shutter release or an intervalometer or the timer function on your camera cuz you don’t want to accidentally get some motion blur by hitting that shutter so use one of those devices the easiest one if you don’t have anything is just set your camera up to be on a on a timer so like a two second or three second time or after you hit the shutter and that’s it so what we’re talking about is fixed tripod no no mount or tracking device how long can we expose for untracked and sometimes when we have this kind of setup we may want to see what we call star trails as that can be an interesting type of photo like this one I took in Glacier National Park in Montana this is just a single long exposure but if you want to do Milkyway photography or wide field deep sky astir photography we typically want the stars to be little pinpoints of light little round dots not trail arcs not lines not egg-shaped we want them to be round but there is a dilemma because while we want to get round stars we also want to expose for as long as possible the reason is so we can get enough to make the photo dynamic because we want to actually be able to see the Milky Way or see the Northern Lights or whatever or the nebula or whatever it is that we’re really trying to bring out in that photo other than the stars as an example I can take a very short picture so here’s an example of a 1⁄100 of a second picture of the night sky and you don’t see much of anything it’s business lead arc we might see a couple little star cores and those stars are actually round in this photo because it’s a very short exposure but we just don’t have enough signal to see anything interesting other than those very little bright star wars so the question is again how do we calculate the maximum exposure time with no star trailing well the rule of 500 is the most famous answer to this question and it’s a very simple math equation which makes it compelling let’s say you’re using a lens and printed on the side of the lens is the focal length so this is the Canon 50 millimeter also called the Canon nifty 50 it is a inexpensive lens if you don’t have much money but you want to get started in Astro photography this might be a good choice because it’s not very expensive and 50 millimeter is also a nice one to use because it’s very easy to divide by 50 so let’s go ahead and plug in the numbers here and we actually only have to plug in one number 500 divided by 50 millimeters gives us 10 and that’s it the rule claims you can expose for 10 seconds before your stars will be visibly trailed and before I talk about does this work which we will get to I mean I’d actually do the tests and we’ll see I want to talk a little bit about the history as far as I know I’m not sure I’ve done some research and I’m not sure exactly where this rule came for I am a librarian I have access to a lot of older books on astrophotography and in all of these books I could not find the rule of 500 or any rule as simple as this one many of these books did have rules for trying to come up with exposure time untracked but none of them had something like this internet research tells me that this came from the film era and it used to be the rule of 600 so you read that we divide 600 by the focal length and it was only meant for printing photos enlarged up to 8 by 10 inches about this big so anything over that this rule acknowledged that you might be able to see star trails but if you were using film and you were printing you know fairly medium sized print not too big than it was supposed to work but then at some point people caught on to this rule and it became mantra it became the rule - that - no and it was repeated in countless articles videos forums all over the internet and that sort of surprises me because with digital cameras this rule doesn’t actually seem to work but let’s go back does it work I would argue that it all depends on your expectations what it doesn’t do is it does not reliably result in pinpoint round stars with any of the modern digital sensors that I tried it with at any focal length so if your expects poq tation is to see no star trails then no this does not work doesn’t work though for very wide field pictures for instance you know shooting the Milky Way with a 14 millimeter lens with a nice landscape in front then sharing that on Instagram or even printing it out you know about this big sure it does work for that I I think you can get a very nice photograph following the rule of 500 and you can even win contests with the rule 500 I know this for a fact because before I got really into deep sky Astro photography with telescopes and mounts and all that I was using the rule of 500 back in 2014 and I won opt is best night sky award for this shot of the aurora borealis or the Northern Lights but if we zoom in here you can see the stars are clearly trail their lines not round points so is the rule completely wrong as I asked in my title again I’d say it depends on what you expect from the rule if you just want a basic rule of thumb for your nightscape where the focus is really the whole scene and the emphasis is more on the landscape and other aspects like in this photo there Aurora then I think the rule of 500 is not bad at least as a starting point I’d always recommend though experimenting a bit you might find that a rule with especially with modern digital sensors a rule of 400 might work a little bit better rule 400 would be more conservative and it would result in a shorter exposure time for instance if we go back to this 50 millimeter lens and we solve the equation that would give us a exposure time of 8 seconds rather than 10 so so far I’ve been started to thinking about like you know single shots that kind of thing but but what about us who really want to do untracked Astro photography and we want to be sure we have round stars pinpoint stars even when zoomed in to a hundred percent on a computer monitor is there a rule for us and I can say yes but the downside is it has to be a bit more complicated because the rule of 500 or 400 or whatever it is only accounts for one thing focal length it doesn’t account for a number of factors that could have an impact on whether or not you get star trails in your photograph and the most important being pixel pitch I can tell you for a fact that the size of the pixel pitch in your sensor does make an impact okay I made a little crude illustration here if you imagine one sensor has large six micron pixels this is fairly common size for a full-frame sensor there are six microns across and six microns tall so this in this grid this is four pixels now imagine a sensor a more common modern sensor which would have three micron pixels so for the four pixels here that we have in the six micron pixel array we have 16 3 micron pixels you’ll notice all these pixels are square that’s the most common thing in modern sensors almost any modern sensor will have square pixels so that makes a little easier to draw something out like this what you’ll find is that with the sensor that has the smaller pixels if we use the same focal length you’re going to get start railing much quicker on this finer pixel pitch than you would on the with the camera with the larger pixels and this is because we’ve dramatically changed the image scale let me try to explain this here with an example this example is not going to be perfectly sound but hopefully you at least get the idea here let’s imagine that a star falls right here on both sensors if we do a short enough exposure that star will look round on both sensors in the the camera with the smaller pixels it’s just going to fall onto that pixel right there and it will make a fairly round pinpoint exposure I mean pinpoint star if if it falls on that pixel in the six micron one then it would fill that whole pixel right and you’d still have a nice pinpoint star but then let’s imagine we do a longer exposure and this star starts to spread across two pixels as the Earth rotates okay what do you have then you have star trailing so you have a line instead of a point well on the camera sensor with the bigger pixels it’s still falling within that bigger pixel so you still have a pinpoint of light now this is a simplified example I’m not getting into all the sensor characteristics but hopefully it made some sense why pixel pitch does matter okay another factor that the rule of 500 ignores it’s not quite as important as pixel pitch is the declination of the object you’re shooting so an easy way to think of this is the closer your object is to one of the celestial poles either the North celestial pole or the South celestial Pole the longer you can expose for without star trails and this is quite obvious when you look at a photo like the one I showed earlier that’s just a single long exposure and the North celestial pole is roughly centered and you can see that close to the celestial Pole the trails are shorter and the further that we move away from the pole they get longer so I was looking around for a rule that would take into account some of these factors that I mentioned and I came across someone who had already created a really nice formula his name is Frederick Michaud of the societe astronomique du Havre.
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Windows 10 LTSC. The Fastest Operating System? 🚀🖥️
Hello everybody! In today’s video, we will discuss Windows 10 LTSC edition. We will explore its peculiarities, functionality, how to download it and use it in your preferred language. This edition is good for low-end PCS, as it is stripped of all unnecessary features. The LTSC edition was developed in 2019 to replace the previous version, LTSB. LTSC is another Enterprise edition with some functions disabled and an extended period of support.
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Blue City Theme Youtube,Twitter & Avatar Revamp/Rebrand │PSD Template
BLUE CITY THEME Hey, what up it QzyCav here & in today video I going be give you a Blue City Theme Youtube, Twitter & Avatar Revamp/Rebrand │PSD Template Avatar: QzyCav Banner: QzyCav Header: The download link for the template with the font file will be in the video description. Thanks for watching & leave a like. .
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Hemp Decortication in 60 seconds
Hi I am Jerry from Nottingham Farms, and we are located outside of King of Prussia PA in Oaks but what we have is our D8 Decorticator. What this does it takes the industrial hemp stalk as you see it here it takes the stalk from the field and it makes two products We take the stalk and feed it up the feeder and as it decorticates it goes through the drum roller and comes out with two products.
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GNOME 3.38: How i Build & Use Development Versions of GNOME (Mutter demo)
So, how I’m using the latest GNOME? I get this question a lot, so here’s a quick demo of my workflow! The first thing is I’m using Fedora Rawhide. Rawhide provides development versions of GNOME and.. Wait! Rawhide actually only delivers point releases. For example, it will ship GNOME 3.37.1 and then 3.37.2, but nothing between. That means I need to build from master, and that’s what this video is all about!
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Introduction to gRPC
On today’s Visual Studio Toolbox, Sourabh is going to show us how to build a gRPC service from scratch. [MUSIC] >> Hi, welcome to Visual Studio Toolbox. I’m your host, Robert Green and joining me today is Sourabh Shirhatti. Welcome to the show. >> Thanks, Rob. I’m happy to be here. >> We’re going to talk about gRPC. >> That’s right. >> You’re on On.NET talking about it.
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Asus Prime b350+ Bios update
Hello and welcome! Continuation of building Homelab Second part of building homelab Updating BIOS and make Bios settings for kvm pod installation Try to give soon second kvm pod installation on this same case Asus provide bios updates on there support site Go to Support and select Driver & Utility Here are Bios & Firmwares available I select lasted version of bios so it’s more stable Download it and extract zip file Copy cap - file to usb stick Next update itself Go to BIOS by pressing DEL - key or F2 Then nagivate to Advanced mode or press F7 -key Nagivate to Tool - tab Select ASUS EZ Flash 3 Utility Select via Storage Devices Also Bios can downloaded via internet on ASUS EZ Flash 3 Utility Now select proper storage device and select cap file And press enter on cap file Then wait….
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TDT4205 Compiler Construction lecture 19-1: Data flow analysis overview
Welcome to our first video lecture on compiler construction. Today we’ll continue to look at an overview of how dataflow analysis actually work and how these fit together with the general framework we’ve introduced in the last lecture. In upcoming lectures we’ll take a closer look at different dataflow analysis that make use of our framework here. Today we’re taking a closer look at classical bit vector dataflow analyses.