Send us a night of FITS files

What happens to your files

What changes

Your observing site (the latitude and longitude in each file's header) is replaced, on your computer before anything uploads, by the center of the map cell it falls in: one of about 12.6 million equal cells that cover the Earth, each about 6 km across (a HEALPix order-10 cell, the same rule the SkyCruncher app uses when you share). Every file from the same place gets the same cell center, so the site we receive says which cell you observe from, not where in it, and many uploads cannot be averaged back to your exact spot. Site elevation is rounded to the nearest 100 m. Header values we know are worked out from your site (the target's altitude and azimuth, airmass, sidereal time and hour angle) are recalculated for the cell's center or removed, and a FITS file whose site we cannot read is not sent.

What is kept

Everything else: the image data, observation times, exposure, gain, camera and telescope details, target coordinates (RA/Dec), and comments that do not repeat your site. We need these for the measurements.

Where files go

Private SkyCruncher storage. They are used for analysis only and are not published or shared. What does become public is a dot on the sky map: the target, its position on the sky, the number of frames and the hours of exposure, without your name, telescope or site (Privacy). What the analysis keeps from each frame: the Frame Receipt Format.

Kept on your computer

This browser remembers the drive or folder you connected and a fingerprint of each file it has sent (a hash of its name, size and date, not the name itself), so the same files are not sent twice. This page stores nothing about your site: the cell needs no memory. (An older version of this page, and the Clean your files page, kept a site offset in this browser; clearing this site's data in your browser removes it.) None of that is uploaded.

Deleting them

Email data@skycruncher.io with the batch ID shown after your upload, and we will delete the whole batch.

Notes and logs

Notes, capture logs (NINA, ASCOM, Alpaca) and gear lists or equipment profiles (.txt, .md, .log, .json, .xml, .profile, .csv, up to 10 MB each) are scrubbed on your computer first: any site coordinates we recognize become their cell center, as in your FITS files, and a file still holding a GPS position we recognize near the site of a FITS file in the same upload is skipped. Pointing values a mount writes in a log (its altitude, azimuth, sidereal time or hour angle) are kept as they are; with the time, they can show where you were to within tens of meters, so remove those lines from a log first if that matters to you. User names and home-folder paths are removed. You see every change before you upload. A file we cannot read is skipped, never sent as it is.

What is skipped

Previews, JPGs, videos and everything else in the folder. Besides the text files above, only .fit, .fits, .fts and .fz files are sent.

XISF and camera raw files

XISF and camera raw files (.xisf, .cr2, .cr3, .nef, .arw, .raf, .dng) are converted to FITS in your browser; the original file is never sent, and its location is replaced by its cell center like any other.

File names

File and folder names are sent. We change parts that look like coordinates or match your site, but we can't catch every way of writing one, so please don't put coordinates in names.

Zip and tar files

.zip, .tar, .tar.gz and .fits.gz files are opened on your computer. Each file inside is handled like a file you dropped, and the archive itself is never sent. .7z and .rar files can't be opened here yet; unpack them first.