My first attempt at a 5 minute exposure on the Pleiades gave me a big green blob

I was using my old DSLR, a Canon T3i, with a basic 50mm lens from my balcony in Austin. I set the ISO to 800 and left the shutter open for 300 seconds, hoping to catch more of that faint dust. Instead of stars, the whole center of the frame was just a bright, fuzzy green glow. I think my sensor overheated and created a lot of amp glow, which I didn't even know was a thing with exposures that long. Has anyone else had this happen with an older camera, and is there a way to fix it in processing, or do I just need to stick to much shorter shots?

3 comments

3 Comments

danielb431mo ago

Yeah, that green blob is a classic. My old T2i would do the same thing past about two minutes, just cook itself. Dark frames are the move, like the other guy said, but honestly I gave up and just started stacking a bunch of 30-second shots. Way less noise, no weird glow, and if a plane flies through one frame you just toss it.

danielhenderson1mo agoMost Upvoted

Wait, your T2i would actually overheat from taking long exposures? I thought those old Canons were built like tanks. I've only ever seen that green glow from pushing the sensor way too hard in the heat. Did it happen even on a cold night, or was it just a summer thing? That sounds like a major design flaw they really should have fixed.

hayden4661mo ago

My buddy had the same green blob issue with his old Nikon. He started taking dark frames and subtracting them, which helped a ton. Maybe give that a shot?