IC1396 (Elephant's Trunk)

I usually shoot three-minute exposures, though five minutes is possible, but the final stacked result ends up about the same. However, losing a frame—whether it’s three minutes or five—makes a big difference. There’s some strange issue with the stars—they all have large halos, even the faint ones. I didn’t want to create a synthetic star field; if the stars didn’t turn out well, it means I need to redo it. I’ve now also added an IR-cut filter into the reducer adapter—hopefully that helps.

There are three causes of halos: poor-quality filters, atmospheric haze, and fogged or dirty optics.

I've used this filter before without any issues, and the optics are clean. However, I can't say for sure about haze—that might be the cause.

:) Just realized now that I bought the camera from you.