How do you back up night sky photos on a trip without a laptop?

You can review and back up night sky photos with only a phone: plug an SD or CFexpress card reader into your iPhone, copy the files with the Files app to a portable drive or to the phone, then upload to cloud storage when you reach Wi-Fi. Aim for two copies in two places before you format a card.

A mobile-only backup routine

1. Shoot to the card as usual. Use several smaller cards rather than one huge one.
2. Back at the car or lodging, plug a card reader into the phone (USB-C or Lightning, matching your phone).
3. Open Files › Browse, find the card, and copy the folder to a portable SSD, or import into Photos.
4. Check a few frames at full size, then keep the card untouched.
5. On Wi-Fi, let your cloud service upload the copy from the phone or drive.
6. Format the card in the camera only after you have two good copies.

Gear that makes it work

Item	Why
Card reader for your phone’s port	Gets files off the card without a laptop
Small portable SSD	Holds RAW files the phone has no room for
Card case	Keeps used and empty cards apart
Short cable	Some readers need power from a USB-C phone

Things that trip people up

• RAW files are big. A night of time-lapse or stacking frames can fill a phone quickly; copy to the drive, not to Photos.
• Hotel Wi-Fi is slow. Uploading a full night can take hours; start it before bed.
• Cold to warm. Let the camera and cards warm up in a closed bag before opening, to avoid condensation.
• Labels. Mark used cards (a sticker or flipping them in the case) so you never format the only copy.

Planning the next night

Sky Map (my app) helps you plan, not edit: its AR view shows where constellations sit over the horizon, and Tonight’s Sky Conditions shows cloud cover, humidity and the best time. Its core map works offline at the site.

Related: astrophotography packing list for flying, plan a Milky Way photo night, stargazing trip checklist.