3 replies to this topic

[arifindobson]

Dear friends,

I would like to share and hopefully get feedback on my side projects trying to build a simple Photometry Web App for teaching the principles of Image processing.

https://arifin96.my.id/astro/phot.html

The objective of this project is to show from image to measuring the stars/galaxies apparent brightness. Next step would be to build a Spectro simple app and real experiments using LED light to show the sistance and apparent brightness relations.

Currently if you open big images it will slow a bit, trying to figure out how to make it responsive, recomended open in your laptop.

Cheers, happy new Year (soon) 🎊 🕛

[lambermo]

I just gave it a try. Everything seems to be working fine and I see that clicking on a location adds a line below with the measurements.
I expected to be able to zoom in and out on the image but that's not available yet.
Changing the sampling circle is a bit awkward now too, maybe make this dynamic with control or shift zoom ?

Fun project no doubt. I'll check back in on progress.

[robin_astro]

An interesting demo but to measure the apparent brightness of the object, you need to subtract the mean sky background level (normally measured in an anulus around the circle) from the pixel values in the circle and then you need the sum of the counts of all the pixels in the circle, not the average.

 

Cheers

Robin

[robin_astro]

The results should also be independent of the settings of brightness, contrast and gamma which does not appear to be the case. In particular photometric measurements depend on the response being linear ie gamma = 1

 

Cheers

Robin