Increasing star size to produce 'realistic' image

[old_eyes]

Below is a picture of the Coathanger I took on my June trip to Olly at Les Granges. 4 x 5 mins subs RGB with his Takahashi and Atik 4000. The conditions were variable and a thin veil of cloud came over during the blue exposures. However, I carried on anyway and processed it because it was my first image under my own steam.

The thing I noticed is that the cloud increased the apparent size and impact of the main stars. One of the things that I have noticed in high quality images of asterisms and constellations is that the main stars can get lost against the richer field stars that get pulled up by the camera. So the image does not really look like what you see visually. It is 'true' in the sense that even bright stars are small on the detector, but it is not so aesthetically pleasing.

Is there a way in post-processing that you can subtly 'bloat' the brighter stars to get the identifiable visual image and still pull all the fainter stars and objects into view?

old_eyes

[steppenwolf]

Yes there is a method - here is how I do it:-

To enhance the appearance of some images and in particular, wide field

constellation images, it can be quite effective to enlarge the key stars in an

image.

Start by selecting the stars that you want to make 'glow' by using the

elliptical marquee tool. Hold down the 'shift' key and draw a circular marquee

around each star. Keep the 'shift' key held down throughout and continue

selecting all the stars that you want to work on. When you have selected all

the stars, copy them to the clipboard and then paste them back on top of the

original image.

Next, the top layer must be blurred so select Filter - Blur - Gaussian Blur

and choose a suitable pixel radius that gives the result that you want.

Finally, to give a more realistic appearance, change the layer blend from

'Normal' to 'Screen'. You can now adjust the intensity of this effect by

adjusting the 'opacity' of the top layer and when you are happy with the result,

flatten the images by selecting Layer - Flatten Image.

Here is an example:-

[old_eyes]

Thanks Steve. Very clear. I shall certainly give that a go once the clouds clear and I actually get a chance for some widefields .

old_eyes

[kris h]

Very nice image i haven't seen a image of the coathanger before

[old_eyes]

Very nice image i haven't seen a image of the coathanger before

It is in Vulpecula. On a straight line from Altair to Vega below Albireo. Also known as Brocchi's Cluster and Collinder 399. Makes a great binocular or widefield telescope object. Some asterisms have very fanciful names, but this actually looks like its name.

old_eyes

[steppenwolf]

It's certainly a lovely image and the different star colours making up the asterism would respond well to this technique. I took an image of this object a couple of years ago under misty skies and that too accentuated the star colours a bit as shown below.

[old_eyes]

Beautiful Steve! The diffraction spikes add nicely!

Maybe I shouldn't worry if there is a touch of haze in the air.

old_eyes