Yeah this is generally how low light and HDR camera modes work - by taking multiple photos and then using a technique called "Stacking" to average out noise and improve signal (useful light).
You can also just take 20-30 second exposures if your phone has a "pro" camera mode, then do the rest of the stacking with other tools. The astro mode simply does everything for you, but you get less control over the processing.
The free version of Lightroom on iOS.
Bumped up the contrast, boosted the shadows, adjusted the colors and added some noise reduction and sharpening.