![]() We have the power, we can bend the light! There is no spoon! In this short tutorial I’ll show you how to create this phenomena in your images if you are using a refractor telescope or a normal lens. So yes - we are capturing an image of the bending of light. There’s nothing like messing with photons in the middle of the night to get your juices flowing! Shown to the left in this exposure of the bright star Antares, diffraction spikes are artifacts that show themselves on brighter stars in our images when the beams of light entering the objective end (the business end) of your lens run into an obstacle and are interfered with and bent, causing the light to spread out. That’s a discussion for an entirely different day! What are diffraction spikes? Antares, with diffraction spikes However, there comes a point where too much data manipulation can make the final image less scientifically accurate, and I get a little blurry eyed when it comes to that. At the core of it is scientifically accurate data, assuming it’s acquired properly. That being said, there is a very wide grey area of artistic license in the astrophotography world. Star spikes are something that several astrophotography software packages give you an option to add in after the fact, and while they certainly look nice, to me they are too fake (because they are), too perfect…not real. I’ll push, pull, and enhance what I shoot, but if the pixel isn’t there, I’m not comfortable adding it in. “In mid-infrared light, diffraction spikes also appear around stars, but they are fainter and smaller.”įor now Webb’s “spiky stars” in its NIRCam images are slightly distracting, but just like the higher resolution, more detailed images it produces, it’s something we’ll all quickly get used to seeing.There is a very wide grey area of artistic license in the astrophotography worldI’m not a crazy purist, but I don’t like adding anything to my images that isn’t in the data in the first place. Why? “In near-infrared light, stars have more prominent diffraction spikes because they are so bright at these wavelengths,” said the Space Telescope Science Institute. You can see that only the NIRCam image has really bright “spiky” stars. The right-hand image was taken with Webb’s Near-Infrared Camera (NIRCam) instrument while the left-hand image used the Mid-Infrared Instrument (MIRI) image. Look at the images above of the Southern Ring Nebula. NASA, ESA, CSA, STScI, and The E Why stars in Webb’s images won’t always look spiky at left, and mid-infrared light, at right, from NASA’s Webb Telescope. This side-by-side comparison shows observations of the Southern Ring Nebula in near-infrared light. As it does it creates a diffraction spike perpendicular to each strut, which together form six more diffraction spikes. Diffraction spikes from the strutsĪs the light gathered by those 18 hexagonal segments is reflected onto the secondary mirror sitting in front of it, it hits the struts that support it. So the hexagonal shape of the primary mirror segments was always going to mean that all stars in Webb’s images would have six diffraction spikes. ![]() That’s because light travels as a wave, and when it comes up against a boundary, it's redirected and sent off in a different direction. The hexagonal shape of the 18 mirrors that make up the primary mirror were always going to cause six-sided spiky stars. Webb’s physical construction causes two sets of spikes that purposefully overlap. Webb’s two sets of ‘diffraction spikes’ Diffraction spikes from the primary mirror That’s crucial for understanding the spikes. The two lower structs are angled specifically so they’re 150º from the top strut. See those three struts in front of the primary mirror, above? They support the secondary mirror-where the light from those 18 mirrors that comprise the primary mirror is focused. The James Webb Space Telescope (JWST or Webb), has a primary mirror made from 18 hexagonal segments.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |