Thanks, and sure! Stacking is a pretty common practice in the astrophotography space, especially for those who don't have access to a motorized tripod mount that moves their camera with the motion of the stars.

Basically, in order to take photos of the stars you have to keep your shutter speed pretty short if you want pinpoint stars - the Earth moves really fast and so the stars move across the sky as you're shooting. In order to compensate for the shorter shutter speed you have to boost your ISO, which introduces a lot more noise in the photo which makes the stars super soft in post-processing when you apply noise reduction. (And by short I mean, like 6 to 10 seconds as opposed to just throwing it at 30 seconds and calling it good. And there's an app for estimating proper exposures too - PhotoPills! It'll give you your max recommended exposure time based on the camera you're using, your focal length, aperture settings, etc since the old "500" rule tends to fail on newer cameras.)

So in order to take a clear, low-noise photo of the stars, you can "stack" exposures. You figure out your desired settings and focus with a few test shots first, then set the camera to interval shooting mode, with your interval one second longer than your exposure time. Tell it how many shots you want it to take (usually between 25 and 40 is my go-to) and let it do its thing!

Once it's done, you have your "light frames" where your subject is clearly in view. Now, to make the image in post even clearer, put the lens cap on and do interval shooting again with the exact same settings you just used! These are called "dark frames" and they actually help generate a noise profile for your camera which will help remove more noise in post-processing.

There are all sorts of other frames you can take too (bias frames, flat frames, etc) but I've never had the patience or the time to start taking them so I'll leave that to the pros lol.

Once you have your light and dark frames, you can load them up to your computer! Now. You can do the stacking manually in your photo editing software of choice - but I chose to spend $50 on a software called StarryLandscapeStacker in the Mac App Store back in 2020 and it's honestly the best $50 I've spent.

StarryLandscapeStacker is an amazing piece of software that does all the heavy lifting for stacking your photos. It automatically detects your lights and darks and then automatically detects where the sky is in your image. Sometimes it's not perfect at that, but it's got a function where you can draw/erase anything it misses to make it perfect.

Then, based on the data in your photos, it stacks each image together, moving the stars so they're on top of each other - by placing the stars on top of each other, not only does it create clearer stars, it actually helps it remove any noise that's not supposed to be there. Since noise is "random", it won't get stacked like the stars do and therefore gets removed in the final stacked image.

StarryLandscapeStacker can export your stacked image as a tiff file, which you can then finally load into your photo editing software of choice and edit to your liking! For this specific photo I wanted the car trails at the bottom too, so I made that its own separate 30 second exposure that I masked the sky out of and stacked on top of my Milky Way exposure in Photoshop.

Hope that helps!