Low-Cost, High-Gain: A Smart Electronic Eyepiece For Capturing The Cosmos

DIY electronic eyepiece viewfinder for telescope

We’ve all seen spectacular pictures of space, and it’s easy to assume that’s how it looks to the naked eye through a nice telescope. But in most cases, that’s simply not true. Space is rather dark, so to make out dim objects, you’ll need to amplify the available light. This can be done with a larger telescope, but that’s an expensive route. Alternatively, you can observe objects for longer periods. This second approach is what [Jordan Blanchard] chose, creating a budget electronic eyepiece for his telescope.

This eyepiece is housed in a 3D printed enclosure designed to fit a standard 1.25″ telescope focuser. The sleek, ergonomic enclosure resembles a night vision device, with a 0.39″ screen for real-time observation of what the camera captures through the telescope. The screen isn’t the only way to view — a USB-C video capture module lets you connect a phone or computer to save images as if you were peering through the viewfinder.

The star of this project is the IMX307 camera module, which supports sense-up mode for 1.2-second exposures and increased gain to capture dim objects without post-processing. This sensor, commonly used in low-light security cameras and dash cams, excels at revealing faint celestial details. All combined, this project cost under 200 Euros, an absolute steal in the often pricey world of astronomy.

Don’t have a telescope? Don’t worry, you can build one of those as well.

18 thoughts on “Low-Cost, High-Gain: A Smart Electronic Eyepiece For Capturing The Cosmos

  1. We live in amazing times that such hardware is so readily available and inexpensive.

    It was not so long ago that civilian possession of equipment of this capability was either science fiction, or would invite the curiosity of three-letter agencies.

    Though, at the rate we’re going, we might be revisiting that situation soon.

  2. I hate to be the guy in the room to say this. But we’ve been doing this for about 30 years now. There’s an entire unsung amateur astronomy community. Making your own crap long before GitHub.. check out cloudynights.com if you want to get a feel for the community.

    Cruel_world

    1. True, Cruel, we have been doing this for a while, and longer than 30 years. A friend of mine made a DIY digital sensor star image through a telescope in 1985. I was a late bloomer and didn’t get around to it until 1989 with a crummy used Fairchild 100×100 CCD that still cost more than a good SLR. Noisy, low-sensitivity webcams followed, then better dedicated cameras with progressively better quantum efficiency and lower dark noise, but they were not cheap — I still have an Apogee camera that has a quantum efficiency exceeding 90% and can integrate for more than an hour, but it cost as much as a decent car and is now obsolete.

      And we still didn’t have OK electronic viewfinders until recently. Some folks used camcorder viewfinders, but they didn’t match the (decent) sensor readout rates, so you might as well do the whole thing at the computer anyway.

      Now you can get a high quality (for 2010) sensor and a good EVF for (comparatively) chump change. That’s the amazing part.

      But now, sadly, there are no more dark skies in a lot of places. It’s nice to see increasing interest in dark sky preserves, where a camera/viewer like this will, er, shine.

    2. Yes, I know well, I was doing the same between modifying the USB webcam for the planetary and then for the deep sky. Even retrieve a image intensification tube in an old night vision binocular to precisely make an eyepiece more suitable for the deep sky. But it was a long time ago. Today I bother myself more with that, I have a camera dedicated to astronomy behind my C11 and that is quite enough for me.
      But I also host astronomy night open to the public several times a year, generally focused on the planetary because the deep sky is too complicated and quite disappointing for the unexperienced eye.
      Since then, I’ve had a Seestar S50 to accompany the observation, to easily make deep skies, it’s great, but it still lacked the nostalgia to look into the eyepiece and see in real time.
      That’s why I decided to make this electronic eyepiece. Buying an off-the-shelf one at nearly €2000 was really not on the program; I’m already doing the astronomy night voluntarily, so I don’t have the budget for that.
      So I tried to make one with passable quality. I knew that there were analog video cameras where you could slightly modify the exposure to have just what it takes to see something. The hardest part was precisely finding a CCTV camera with that cheaply; it took me ordering 3 camera modules to finally come across the right one

  3. This kind of project/article is the perfect candidate for a before/after set of pictures. As someone that’s starting to look into getting a telescope, knowing just how benefit there is to something like this (and especially compared to its cost) would be very helpful.

      1. Interesting. I was unfamiliar with AHD (analog HD) or TVI or CVI (competing systems for sending digital HD video over coax, kind of like SDI). It seems like the security camera market developed its own solutions to allow for upgrading the video quality cameras and recorders while keeping the same cable infrastructure in place.

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