Just realized I've been framing my Milky Way shots all wrong

Spent two years stacking 15 second exposures thinking I needed them that short to avoid star trails. Then I watched a video from a guy in Tucson who uses 30 second exposures on the same star tracker I own. Checked my math and yeah I was leaving half the light on the table. Anybody else figure out they were using way too short exposures for their setup?

2 comments

2 Comments

brookethomas1mo ago

Haven't done Milky Way yet but don't you have to factor in your camera's sensor size too? My crop sensor needs shorter exposures than a full frame to avoid trails. Checked with a calculator and I was actually overexposing my shots by like 10 seconds.

jordan_webb491mo ago

Actually the sensor size thing matters more for the focal length math than exposure time. The rule of 500 or 600 works regardless of sensor because it's based on your actual focal length and how much sky you're covering. A crop sensor just means you're zoomed in more so star movement is more obvious. What really threw me off was light pollution. I spent months following those calculator numbers only to realize my suburban backyard had way more sky glow than I thought. Stacking shorter exposures helped me get cleaner data without the trails and without overexposing the background. Try taking like 15 second subs at f/2.8 and stacking 20 of them instead of one long exposure. That fixed my overexposure issues completely.