To diffract or not, that is the question ....

[steppenwolf]

There has been some comment both here and elsewhere ( ) about the use of artificial diffraction spikes on star images and although I have no doubt the board has tocuhed on the subject before, I would be interested in people's opinions on the following two images, especially in the light of new software produced by processing guru Noel Carboni.:-

No diffraction spikes

With diffraction spikes

[Psychobilly]

kttp:// whats that then....

Diffracrion spike you either love em or hate them sometimes they can be a paig in the butt....

I do like Nadeems subtle use of them in his unguided cluster images....

Peter...

[steppenwolf]

I believe that's called a typo but as the images don't appear to be there even without the typo, it is currently a moot point

[Psychobilly]

At the end of the day I suppose its a matter of personal choice .. although others may think otherwise...

Are you imaging and processing for art, science or enjoyment... I remember a similar discussion on one of the less Progressive Astro Imaging Groups....

Billy....

[steppenwolf]

....... and now with images too - Jeez, I hate computers .....

[shaunster]

I prefer with

It just looks more pleasing to my eye, allthough its very easy to overdo.

[ashworthacca]

Don't usually like to see them but of the 2 images I like the one with the diffraction spikes:)

[malp]

I much prefer the image without them Steve, I think they distract. One diff spike can look good on a bright star only

[barkis]

Did response to your NGC7000 Image prompt you to run a poll Steve? Ah!, I see it was. The pics have appeared.

Personally, and purely from an aesthetic point of view, I like them, but only as a garnish for want of a better explanation. A large Nebula containing lots of fore, or background bright stars, may not look right, and experienced imagers certainly would not include them I'm sure.

The general public, or a large percentage would probably vote to have them, simply on the basis they expect stars to have them.

Ron.

[Psychobilly]

Ah piccies... and just a few broken place holders... computers hey...

The ones on the stars over the Ha nebulosity look about right the ones over the dark stuff look a bit overdone... but that just my opinion once they start merging and meshing it looks "messy" to me...

Noels Starspikes Pro gives so much flexibilty compared to the version thats in his astro actions...

Nadeem seems to get it about right...

Which do you prefer?

I have noticed even Roundycat is slipping the odd few in from time to time these days...

Billy...

[jgs001]

I'm not really for or against them... Some people like them and if they want to add them... then that's fine. Personally, I don't feel a need to add them...

[steppenwolf]

and experienced imagers certainly would not include them I'm sure.

This is the interesting point for me, I'd certainly regard Greg Parker as an experienced imager and he slips them in from time to time!

Which do you prefer?

I have noticed even Roundycat is slipping the odd few in from time to time these days...

I've noticed Dennis use them too. What do I think? I think they definitely have a place and I will still occasionally use them but I think they failed on this particular image and I am displaying the non-spike version on my website!

[brianb]

If your imaging system has natural diffraction spikes, fine, leave them alone. If it doesn't, don't add artificial ones, they never look quite right. Just my humble opinion.

[Shibby]

I like the way they look, but imho it feels wrong adding artificial ones.

[Deneb]

I thinks it all down to personal preference really, even when adding spikes to an image of clusters, sometimes they don't look right, there's only a few nebula pics I could insert spikes into. But then again I find if you want a particular image to stand out a bit, they do add some nice colour saturation to the stars.

@Steve - Im with Billy with this was one, the stars featured in the ha areas look quite well blended in.

Nadeem.

[ncjunk]

I just flat don't like them as i prefer a natural round looking stars (which taking into account my guiding is a bit rich!). This seems to me to be the same as the fact i don't like marmite or spiders, other people like all these things and i am fine with that. Just dont ever ask me to put artificial spikes in.

[adamsp123]

TBH they work on some images much better than others, in this case my immediate reaction was to much prefer the one without spikes

[MikeD]

All my images have diff spikes but they are always from spider veins on a newt or wire added to the front of a refractor.

I don't have a problem with artificial spikes just don't think I would ever use them when its so easy to get real ones.

Mike.

[Earl]

Ask me when I can make images worthwhile considering doing it..... might be a while

[RikM]

A few of my images have natural diffraction spikes on the brighter stars, but I use a Newt so I guess they come from the vanes.

For aesthetics I like spikes. Artificial spikes, used judiciously, can be a real plus for a picture. They shouldn't be over done though.

Rik

[peter shah]

they must look natural.....i sometimes use them to enhance my real ones, i have also used them to repair spikes that get lost when adding data that has rotated ie if i have taken the camera off for what ever reason or if ive imaged over several nights and i get rotation in the frames and the frames dont match exactly, artificial ones can sharpen them back up...

these are real

astropix.co.uk

astropix.co.uk

these have been enhanced or repaired

astropix.co.uk

astropix.co.uk

http://www.astropix.co.uk/ps/pages/NGC7000.htm

so as long as they arent over done they have a place in image processing.....im not sure if i would use them if i imaged with a refractor

[Tim]

My answer would be, it depends. For the same reasons as Peter gives, but also on the target of choice.

M45 for instance can look superb with the main stars accentuated, but in nebulae shots as above, then they can detract a little. Real diffraction spikes give a certain coloured effect, with I think the new spikes tool imitates a lot better.

So maybe take each image on its merits and add a spiky star or two if appropriate......

[gary1968]

I actually love spikes, they add a certain 'something'. i dont usually like artificial spikes though but they work well for me in the image above, or is it that they have been well applied..... I am a newt fan and think that the spikes created by the traditional newt cant be beaten.

Anyhoo, it is a cracking image and as I said, the spikes work well.....

Gary

[fatwoul]

I don't know if a newbie is allowed to comment, but I think spikes are fine if they are "real" - that is to say caused by secondary mirror mounts or whatever.

Aesthetically, "Fake" spikes remind me too much of those cokin star filters that I thought were really fantastic when I was 15. I now have dozens of old negatives that are embarrassingly cheesy as a result. Had I not used that silly filter, I'd have some images that I could still use.

(That's not to say that I think someone's work here is cheesy or embarrassing - far from it; I am intimidated on a daily basis by the standard of images on SGL - but I think the effect just takes me back to some questionable creative decisions of my youth that I'd rather forget.)

Anyway, I chose a Mak Newt rather than a conventional Newt for several reasons, one of which was to avoid spikes. At the time I felt it would be better to capture the images as "purely" as possible to begin with, and add things in later if I felt necessary.

On reflection, I don't think I will ever add spikes to an image.

On reflection! Cos I have a newtonian? A REFLECTOR?? Oh nevermind...

[roundycat]

Seems I am with the majority on the poll. I have just finished a narrow band Cygnus wall and I did a mark two with some spikes courtesy of Star Spikes Pro. I didn't post it.

Having no experience with a natural spike producer I have no idea when they are prominent and when not. Clearly the bigger stars get spiked by a spider much more easily and the small ones hardly at all. Or is that wrong? Do the smaller stars get spiked by a spider just as easily but they don't get resolved in the finished picture after aligning, combining and re-sizing and all the other things that destroy resolution?

I have seen some artificial spikes by Noel and when they are applied to the bigger stars they look pretty. Turn up the intensity to produce a lot more spikes and they look terrible because they overwhelm the picture. The biggest problem we face with them in the UK is the crappy sky. When your stars come with fuzz and halos around them in spite of your best efforts adding a spike that is sharper than the stars looks just wrong. De-focusing the artificial spike makes it too fat and it looks even worse.

To me the big problem is getting the spike to match the star and then not having it overwhelm the nebula. Clusters and, possibly, galaxies might offer the best use for them.

Dennis

ps; the overall image scale has a bearing on it too.