Mask stays hidden

[evripidis]

Is it somehow possible to use a mask (like the documentation says) but not be visible on the website?

The mask should be applied to be able to run all the calculations for the modules, but the user will have to decide with an ON/OFF option, to stay hidden from the end user.

If we have a perfect circle for mask is ok. But if we have a mask which we are trying to cover up trees etc. it is not so appealing.

[EricClaeys]

@evripidis,
Is there a particular module you are thinking about that would use a hidden mask?

I believe the meteor detection module does that, and our to-do list includes adding a mask for auto-exposure.

[evripidis]

I thought it while I was troubleshooting the startrails, but maybe I got it wrong.

If we want to calculate the Brightness Threshold more precise, we need to have opt in a mask correct? So it would be always visible.

[EricClaeys]

If we wanted a more accurate reading of the brightness of the exposed part of an image, i.e., not the black borders that are on many allsky images, a mask could temporarily be applied while calculating the brightness. That mask would not show up in the final image.

The RPi capture program does this to determine what auto-exposure to use - it uses a circular mask that's 1/3 the width of the image. The ZWO capture program is similar.

One of our to-do items is to allow users to specify the mask to use. We could probably also modify the startrails command to use the same mask. This would (I believe) cause the startrails command to produce an average brightness that is the average of all the images' mean values.

Having said that, I'm not sure a more accurate average brightness is needed, other than to be able to compare it to the Target Mean value. The black border of an image is always black (ignoring any internal reflection that fall on the border), so the black area is decreasing the startrails average brightness by a set amount, e.g., 0.05.

Right now, the Brightness Threshold is just a number that's not related to anything. I do see some value in being able to compare it to the Target Mean. For example, it makes sense to me to think "I don't want want any images in my startrails that are brighter than my nighttime Target Mean value".

What are your thoughts?