This app was mentioned in 8 comments, with an average of 71.00 upvotes
I know there are a few mobile apps that can give you similar results. One for Android called StarTrails that will blend a series of captures, usually for creating star trail photos, but would work for other captures. Might try that out. I'm sure there are similar apps for iPhone.
StarTrail Photos Generator looks like what you want, though I can't vouch for it.
Also Motion Camera looks like it might work, but again, I've never tried it.
What's wrong with this?
https://play.google.com/store/apps/details?id=pkg.androidsbuddy.startrailphotosgen
Seems pretty meh, but found this.
https://play.google.com/store/apps/details?id=pkg.androidsbuddy.startrailphotosgen
This is one that most refer to whenever this question is brought up. I've never used it myself.
Camera FV-5 supposedly has the capability. Though it is paid.
I used this one. It's an android app, but I'm sure there's some for iPhones as well.
Someone mentioned this in another thread this is posted in.
https://play.google.com/store/apps/details?id=pkg.androidsbuddy.startrailphotosgen