Your going to hate me for this...

[Quatermass]

I'm with Gina on this one I'm afraid. I don't like diffraction spikes on stars. I have empathy with Gina's argument that you're creating a visual defect that only exists in some images because of the construction of the telescope, but my main objection is that I just find them distracting. Perhaps because I started off with refractors and even now most of my scopes don't create diffraction spikes they just don't look quite "real" to me.

James

I think its the opposite with me James because I started off with the skywatcher 200p which produces loads of diffraction spikes on my images it weird for me to see just little round blobs. I like both really, and when I get my evostar ed80 focal reducer will be posting both with and with out to see how they look. The above example is extreme as I was testing out the software smaller spikes and fewer would be the norm for me later. Its a bit like lens flare in images it not a natural part of the scene but it looks cool. Its nice to have the choice now.

[Quatermass]

Oh so twinkly

Only if you have spiders in your eyes

[Atlas]

I for one, love spikey star images.

[Quatermass]

A crusty old air force sergeant vote for spiky stars lol my dad was a crusty old airforce sergeant, worked as an aircraft mechanic for the US airforce at Bentwaters in Woodbridge. His name was Herbert J Casto

[iwatkins]

Hope you get it to work Ian I really like it and it has a ton of features to play with.

Wierdness. Just fired up my imaging PC again and all is fine. Maybe it was because I had just done a CS update and hadn't rebooted.

Actually, I quite like it and fast too. I'll have a play now and see what it can do.

Cheers

Ian

[Quatermass]

Wierdness. Just fired up my imaging PC again and all is fine. Maybe it was because I had just done a CS update and hadn't rebooted.

Actually, I quite like it and fast too. I'll have a play now and see what it can do.

Cheers

Ian

Glad you got it working Ian..

Here is the needle galaxy I posted earlier with stars added and with out to compare. I like both of them really but the stars one I like a little bit more.

Now I like the picture with stars but I also like the one with out stars.. now which is better.. there's only one way to find out..

FIGHT!

[iwatkins]

QM

I've been having a play.

Personally think it really adds some sparkle to plain old star fields but if overdone can overpower a shot with delicate nebula as the main target. I guess its the same old story, use to enhance but not to overpower an image.

Will play with it a bit more before deciding whether to buy it...

So, some tests shots below:

Cheers

Ian

[Quatermass]

AH yes I like, works really well on m42 and Seven sisters I think, its a fun bit of software to have a play around with as well. You can also try just switching to the stars only and that helps to get them looking nicer before applying them.

[eddy]

I like the difraction spikes, but feel it gives the image a somewhat "CGI" feel to it, almost fake.

I was talking to my Dad the other day, and he thought that the Eagle nebula was CGI (the hubble images) and was shocked when i told him they were the images/photos that hubble took, then i proceeded to show him Amateur efforts and explained it was taken from someones "garden" he was even more gob-smacked.

My 5 yr old brother is REALLY into space at the moment, so next time its clear ill be shipping my gear up there for a night under the stars with him

With regard the photos, they look really good, but find them almost "cartoony" if you will

[Quatermass]

I agree that it does change your image from a pure image to a more artificial look to a degree but then again its all down to personal taste. I am a cartoonist so that's another reason why it appeals.

Heres one of my old cartoons from Smash hits mag back in the 80s it later went on to star Zitty Ben still do a few but more into my astrophotography these days.

[Charon]

Great image.

[David JM]

To process or not to process, that is the question.

The spikey stars may be more visually appealing to some and not others [i'm in the 'only the bigger stars camp] and colouring by H-a, O-III and the rest is used a lot to enhance detail.

I try not to process anything too much if I can help it, and I usually convert my images into "naked eye" orientation as my Mak Cas does a left-right reverse.

For a 'this is how it looks' I would probably leave the stars as blobs, for a 'this is pretty' then a few diff spikes are probably OK if it were explained they were added.

In making images like this are we meeting the non-astro expectations of images? A lot of diff spike images are artifacts of the 'scopes used to get them so are the public expecting them on all images?

Oh, and it's "you're"... [appropriate smiley here]

[terrym2002uk]

Psst... Noels actions does this for under half the price but it doesnt add the nice halos that you seem to have.

It would look better if restricted to the fatter stars as well.

Psst... Startools can also do things like that too. Welcome | StarTools

[terrym2002uk]

Glad you got it working Ian..

Here is the needle galaxy I posted earlier with stars added and with out to compare. I like both of them really but the stars one I like a little bit more.

Now I like the picture with stars but I also like the one with out stars.. now which is better.. there's only one way to find out..

FIGHT!

Thats funny, but dont they both have star's in ?

[richbyers]

that picture on some sort of slideshow + hendrix psychedelic music = great times....oh i like it very much

[Quatermass]

Thats funny, but dont they both have star's in ?

The top one was put through star pro 2 and has them slightly more enhanced.

Being a sci fi fan I like my images to look a bit more in that direction. The great thing about this software is you have total control over the stars you enhance.

[Quatermass]

Psst... Startools can also do things like that too. Welcome | StarTools

Star tools looks very interesting but dont think it will beat photoshop just yet.

[jager945]

Synthesizing believable diffraction spikes is not as straightforward as it seems. The naive way would be to simply 'paint' on nice looking replacement star. The result of this method is, as we can see, usually not very convincing.

A more physically correct approach requires each individual star be reduced to a point light, measuring magnitude and temperature by means of photometry, after which the starlight is scattered according to a point spread function that is unique to your telescope. Each and every component in the OTA that obstructs or affects the starlight, down to individual protruding screws, mirror clips, flocking, mirror material, etc. affects how the starlight looks and behaves.

Contrary to what you might think, each and every pixel in your image is affected by the starlight as well as starlight outside the immediate imaging plane. That's why you can still see Alnitak's spikes, for example, without the actual star even being recorded.

Once you have modeled your virtual telescope (along with aperture and focal length), you can start calculating how stars would have looked through such a scope, given the angular size of the image you have recorded.

It is also important to take into account focus and seeing conditions, which would have had an impact on how much of detail is visible in the individual stars' diffraction patterns.

Additionally, star color of the stars needs to be forced to into adhering to a black body radiation curve in order to be able to simulate dispersion properly.

The final result will be an approximation at best, but should yield a more convincing, physically correct result. Of course, this doesn't take into account any stretching you have performed on the point source light prior to handing it to a star re-synthesis routine.

I took the liberty of reprocessing your image - hope that's okay. The attached image contains re-synthesized star light. The effect is subtle (as it should be) but distinctly noticeable when viewed up close/zoomed in.

I'd also have to disagree with those who say that (proper) diffraction pattern synthesis is not useful. It is included in StarTools not for aesthetic purposes, but for the purpose of reconstructing stars that were either affected by lens aberrations/corrections (warping their spikes), or for accentuating faint nebulosity in widefields, where star distribution often correlates with gas distribution.

EDIT: Further to the above description, it is also imperative that *all* stars/point lights get the same treatment. Otherwise the diffraction will look 'wrong'.

EDIT: I should also say I guessed a 8" F6 Newtonian with an image at 150 ArcSecs. Other equipment/parameters would look totally different...

EDIT: Doh. Just read you used an ED80. Re-synthesised the image accordingly.

Cheers,

Ivo

[Quatermass]

Thats very interesting and alot of the corrections to images we work on avoid that kind of consideration. Mybe its because we dont understand the complex nature of light or the way light from distant objects behaves. I dont regard my images to be accurate to such a degree often the changes made are down to what appeals rather then accuracy. You need to strike a ballance between both factors for your own imaging styles. However knowing and learning more about the way starlight works is very interesting thank you.

Sent from my GT-S5670 using Tapatalk

[jager945]

You need to strike a ballance between both factors for your own imaging styles.

Too true - of course there is no 'right' way of processing an image. We do what we feel conveys our intentions best. It's all about knowing about the (informed!) choices you can make to get there.

[Quatermass]

Imaging has allways been subjective to the personal interpretation of the individual but I think your right that we also need to know about what we are imaging in terms of its qualitys and behaviour.

I am not of a scientific mind really with my approach to imaging but that is not to say that I dont want to know more about the subjects I image.

For instance when we start wanting to produce images using filters it becomes more important to understand why we are using them and how light is going to effect what we are doing.

Because of my dyslexia I really struggled at school with technical historical and scientific stuff my brain works best with images and so much that I was taught is theory void of imagery, and it was a real burden to translate it over to my way of understanding stuff.

And understanding theory is often devoid of visual interpretation when explaining it which leaves me struggling with my brain trying to translate the theory to visual as this is the way my brain operates.

When translated to visual interpretation I can then move forward quickly but dyslexia has its advantages and disadvantages ie I am am very creative and able to see things faster then others at times but it flaws me when I have to deal with non visual descriptive data.

When that happens I find myself doubling up on my task of understanding it by having to turn it into visual information.

Does that make any sense:confused:

[Quatermass]

Sorry I know this has nothing to do with this discussion but my wife just asked me to come down stairs why I asked.. just come down she said..

When I came in the living room our 6 chickens were standing there looking at me!

The dog had come in and left the back door open and the chickens decided to come and have a look around so funny...

[LukeSkywatcher]

I'm a fan of diffraction spikes. They add a certain something to images if done right. On bright stars they look great. I'm not convinced about across the whole starfield, but i can live with it.

Well done. Nice image

[ollypenrice]

Vandal!!!

He heh, no, if you like them you like them.

I'm going to talk to Ralph The Optical Genius next month about whether it would be possible to replace the spider on a Takahshi Epsilon with an optical window and remove those G-awful ruddy spikes! Without them I'd have an Epsilon like a shot. (Well, I'd have to steal some money first...)

Olly

[Quatermass]

I will be doing both spikey and round in the future, spiky with my newt and round with my refractor. That way I can have both, and if I still prefer spikes I can add them with star spike pro 2. It's nice to have a choice, but I think I will always prefer spikey stars.Then again I once wore flared jeans and thought they were cool, until I became a punk rocker then drain pipes were my jean of choice, we change like the seasons.