Cut the wire in half to create two pieces that are about 6cm longer than the diameter of your telescope objective.Wrap the cardboard strip around the objective end of your telescope, and use tape to secure a collar around it.Cut a cardboard into a strip 3cm wide and ~3cm longer than the outer circumference of your telescope’s objective end.It should be about 2.5 times the diameter of your telescope/lens objective in length. I’d recommend the A or D string from a guitar. A thin piece of wire, approx 1 or 2mm thick.And, if you’ve got a deductive train of thought, you likely already know how after reading the above section about what diffraction spikes are. Regardless, keep reading to find out if you’re right! What you need It was an area around a bright star in Cygnus, Sadr, with not a lot of nebulosity but quite a few bright stars that I thought needed a little window dressing. I did it for two reasons - I thought it was pretty, but, I also knew I was going to be imaging a target that was…a little boring. You might want to create diffraction spikes on your stars because you think it’s pretty, and that’s okay. If you’re not, and would like to play around with it …read on. Now, if you’re imaging with a telescope that uses a secondary mirror held in place by a spider (a metal cross piece), you already get them, like this. 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. 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.
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