This is a first post to introduce a free app I'm working on called AstroShader and to look for support with beta-testing and discuss ideas for improvements (...and bug fixes).
Download link (free) here
What is AstroShader?
My aim is to make an end-to-end astrophotography app for iOS. Beyond this to also make the application mobile first, e.g. make it easier to take longer captures and stack images on mobile without using a laptop/desktop, and then also some tools to edit them as high quality images.
To achieve this the image capture process is a little different to standard AP workflow. The images are aligned and stacked live during the capture process so only a single image is generated, as 16bit tiff. The downside here is not having the subs data, however it means you can go from setup to final image very quickly.
AstroShader is aimed at anyone but more beginners looking to start imaging or people out travelling/trekking where you can't take loads of kit. Also giving iPhone users some more options, as there are some great images coming out of the newer Pixels, Samsungs and Xiaomis these days.
How to use it:
1) With a tripod or attach to telescope, or lean your iPhone on something.
2) Find focus, easier with shorter exposure time 0.1-0.2s.
3) Set exposure time; ~4s for wide-field with main camera, longer for tracked AP with telescope, shorter for untracked.
4) Set ISO and WB. Other settings; choose camera, timer and alignment function (helps where there is ++ light pollution).
5) Set number of exposures to take.
6) Tap capture, the images are automatically aligned during capture. When complete the image is saved as a tiff and the edit tools open up.
7) The open image button on the bottom left of the main screen can be used to open and edit previously captured images.
How it works:
- The native iPhone exposure range is extended beyond it's max (if needed) by stacking raw sensor data without alignment.
- Per exposure the image is debayered and then aligned and stacked with the next image.
- The above approach is only possible due to modern iPhone GPU processing capabilities and is done to save disc space, each tiff is ~95Mb. e.g. per imaging run of say 150 images would otherwise take up 14Gb if saved and stacked from disc. Downside is you lose the subs data, I guess it's just a different "mobile" approach to AP.
- The data is saved as a 16bit tiff by default, this may not work with the photos app. But in AstroShader you can open 16bit images to edit.
- With the edit tools I tried to offer more than the photos app, so added curves, improved black point and a sharpness stacking tool (with radius and intensity controls). You can also choose png, tiff of heif save format.
- Focus... iPhone do this in a weird way so there isn't a predefined infinity point. You have to find focus manually, but I do save this for the next shot.
- Roughly 1 in 50 attempts to capture and image there's a crash on older devices. I think it's a video memory issue.
- On older devices using all the edit filters at once causes the OS to boot the app from memory.
- (Not a real issue but a TBA) iOS doesn't play nicely with 16it tiffs so the thumbnail preview is messed up and iOS Photos app will convert to a jpeg for editing. When sharing tiffs or pngs from iPhone always use the top "Options" > "All Photos Data" option, or iOS sends a jpeg.
- Another iOS TBA, when you edit images in the iOS Photos app you do not edit the original. Photos saves a jpeg version of the edited image inside a folder with the original. So if you open an image edited in Photos in AstroShader (or another similar app) you won't see any changes from Photos as they aren't reflected in the original full res image.
- Foreground extraction (trees, mountains, etc).
- Planetary imaging workflow.
- ...However looking for other suggestions from real people here too.
Any feedback would be greatly appreciated, whether bugs, UX improvements or major feature requests.