Widefield star replacement after StarXterminator - an idea.

[ollypenrice]

When replacing stars in widefield images, we now have the luxury of total control over their size. If we want a powdery coating of tiny stars, we can have it. The problem, though, is that such pinprick stars when seen over brighter nebulosity are invisible, giving the impression that they are not there in reality. This doesn't look right and is inherently misleading.

What I'm exploring, now, is a possible Photoshop solution:

1) Take your fully stretched starless image, convert it to greyscale and greatly increase its contrast. (Eg use the equalize filter and then fade it to taste.) Here's one I made from a Milky Way widefield. Clone out the residual stars ff you like but this was just a test.

2)  Open your 'Stars only' image, partially stretched in my case, make a copy layer, add a layer mask and paste the mask above onto that. Stretch a little more through it. That's it.

What happens is that stars will be further stretched in accordance with the brightness of the background underneath them. Where the mask is black, they will receive no further stretch while, where it is white, they will receive the full extra stretch. While this does not respect the captured brightness of each star, it does reduce the false impression that the brighter regions are starless.

Olly