Show arcseconds/pixel in ocular plugin (further to Bug 1656825])

[Volker H.]

Further to Bug 1656825:

For a given sensor the published horizontal and vertical pixel sizes, resolutions und sensor dimensions often leave room for interpretation.

For example Cannon published for it's EOS600D sensor:
Chip size: 22,3 x 14,9
Resolution: 5184 x 3456
Pixel size: 4,3 x 4,3
Resolution times pixel size does not accurately match the chip size.

Proposal:
Calculate exact chip sizes from resolutions and pixel sizes.
Calculate FOV and arcsec/pixel from exact chip sizes.
Present results in Stellarium rounded to 1 digit after comma (more are meaningless).

This assures that square pixels have equal h-scales and v-scales.

[gzotti (georg-zotti)]

Counterproposal: Indicate pixel size calculated from Chip size (these are standardized like APS-C) and resolution, round displayed pixel size to 0.1µm. (So Pixel size is not editable.)

BTW, not always are pixels square!

[Volker H. (hvolker)]

I am aware that pixels are not always square. Square pixels were taken as an example to make the differences in the computed scales obvious.
As pointed out sensor data can be interpreted in various ways. I still believe that published pixel size data should be the best starting point for calculations. But I can easily live with the counterproposal as long as the results are rounded to 0,1 µm.

[Alexander Wolf (alexwolf)]

The bug report was moved to https://github.com/Stellarium/stellarium/issues/432