Siderea on iPhone and iPad

The Siderea app for iPhone and iPad shows your finished results, for example at the telescope or on the couch. It does no stacking and no editing; the projects stay on your Mac.

Set up

1. Sign in to the same Apple Account on the Mac and on the iPhone or iPad, with iCloud Drive switched on.
2. On the Mac, open Siderea → Settings… and check that Mirror results to iCloud Drive is on (it is by default).
3. Stack a project. When the stack is done, Siderea copies it to iCloud Drive → Siderea on the Mac.
4. Open the app on the iPhone or iPad. The project appears in the list as soon as iCloud has synced it.

What is mirrored

For every finished stack of a project, in the folder iCloud Drive/Siderea/<project>/:

File	Content
<name>.fits	The result itself, 32-bit float. The app downloads it only when you open the image.
<name>.jpg	A preview with the long edge at 2048 pixels, stretched like the Mac shows it (the Share export preset). The list and the grid use it.
<name>.report.html	The frame report of the stack.
project.json	Name, object, date, total exposure and the list of results.

The image you have open and active in Siderea is mirrored as well, as the entry Current image (or the image's name): a few seconds after every editing step, undo or redo, and when you make another image active, it is replaced by a JPEG of the image as the window shows it. The app checks for changes every few seconds while it is open, so you see the current state on the iPhone or iPad without doing anything; iCloud itself needs a moment to deliver the file, from a few seconds up to a minute. Only the committed steps count, not the live preview while you drag a slider. It is one file per project, current.jpg, and it stays after you close the image, as the last state. A project that is not open as a folder (an image opened on its own) is not mirrored.

Images you export from Siderea into the project's export folder are mirrored too, but only as a JPEG preview named export-<name>.jpg (a JPEG export is copied as it is): so an edited image reaches the iPhone after you export it, not while you edit it. The viewer shows them in the project like a stack, without Load Full Resolution. Other files in the export folder, such as frame report PDFs, are not copied.

Frames, calibration masters and the cache are not copied. Deleting a result in Siderea removes its files from the folder at the next sync. Files you put into the folder yourself are left alone.

Mirroring happens after every stack, after every export and after deleting a result. You can switch it off for all projects in Siderea → Settings… → iPhone and iPad, or for one project with Mirror results to iCloud Drive in the Stack step. A project that has never been mirrored does not appear in the app.

Looking at an image

• Projects: every mirrored project with a preview, object name, date and total exposure.
• Project: the results as a grid. Tap one to open it.
• Image: pinch to zoom, drag to move, double-tap for 1:1. The preview shows right away; the full FITS file loads in the background, with progress while iCloud downloads it.
• Auto-Stretch: switches between the auto-stretch (like the Mac) and the linear data.
• Histogram: shows or hides the histogram.
• Info: exposure, frames, filter, gain, temperature and, if the image was plate solved, the field of view and pixel scale.
• Frame Report: opens the frame report of the stack.
• Share: sends the preview JPEG.
• Load Full Resolution: downloads the full FITS file and shows it in place of the preview. While you zoom in, the app shows the part you look at in full resolution.

Layouts

On an iPhone the app goes from the list to the project to the image. On an iPad it shows the projects next to the content. The iPhone Duo folded behaves like an iPhone; unfolded it behaves like an iPad, with the info beside the image. Folding or unfolding keeps the same image, the zoom and the visible detail.