Hi everyone, I hope you're doing well!
I'm planning on shooting an HDR image of the Cat's Eye Nebula. I got a lot of time on the core last year using just the UV/IR cut glass on my 2600mc and 15s exposures. However, I recently purchased an EAF, which seems to get me sharper images, so I'll be restarting this target.
Now onto my question: I'm planning on shooting my longer exposures with my ALP-T filter at 120s, but am contemplating between shooting the shorter 15s exposures with the same ALP-T filter, or with the UV/IR again. Should I shoot with the same filter for both my shorter and longer exposure images? I image from pretty bright Bortle 7-8ish skies, which can cause the backgrounds between images with and without filters to be VERY different. Particularly images without a filter can be tricky to get the background perfectly smooth. I can see this potentially causing problems when merging the images to create my final HDR image. Am I wrong in this assumption or should I shoot both images with the same filter?