First law of astrophotography

[vlaiv]

I'm feeling cheeky tonight

Here it goes:

"If you can't take your stack, do basic white point / gamma 2.2 / black point stretch and get nice looking image - you are doing it wrong"

aaaaand discuss!

 

[Elp]

Quantify nice.

[saac]

Go fast or go home.

Jim 

[Paul M]

Doing anything right just feels wrong to me!

Y'all end up in a furrow...  🤣

[vlaiv]

1 hour ago, Elp said:

Quantify nice.

Well, now that you put it that way and we need to discuss aesthetics then it all goes down the drain

My point by this "first law" was that one should really hone capture / gathering step as well as data reduction part - calibration and stacking, rather than ever increasingly rely on sophisticated algorithms to produce nice looking image.

If your data looks nice - meaning no need for sharpening / noise reduction / star removal / ai assisted routines / star rounding or reduction or whatever, if you do basic 3 step stretch, and by nice - I mean without any artifacts and showing at least some level of target / nebulosity (whatever was captured) with relatively tight round stars and not too much noise, then it will easy to touch up to make it a great image without excessive use of tools.

Here is an example. This is by no means great image - but look at it for a moment - and this is really just 3 step stretch - set white point as low as possible without starting to clip signal, do 2.2-2.4 gamma stretch and move black point up as needed:

It is mono only image, and is there anything obviously wrong with it, or does it look ok / nice (not great, not showing all there is to be show - just plain nice).

 

[ONIKKINEN]

And I'd be inclined to agree, although not exactly by how you said you do it.

It will be fairly obvious if the image is nice or not just by looking at the stacked image in autostretch screen transfer mode in Siril. Which is pretty close to what you meant with the blackpoint/gamma thing actually since it does just a simple stretch and no other behind the scenes trickery. Sharpening and all the AI voodoo is just icing on the cake, but if the cake is made of clay, obviously the AI tricks wont turn it into sacher cake.

[ollypenrice]

You can paint a self portrait by dipping your hand in mud and pressing it against the cave wall.

No need for all this, then:

lly

 

 

 

[StarryEyed]

If your image needs to be nice before you can appreciate it then your a photographer.

If you can appreciate your image because of what it shows you then your an astronomer.

If you can't appreciate anything about your image your about to give up or spend more money.

[Swoop1]

1st Law of Astrophotography- if you have a full head of lustrously natural hair- don't start.

[Elp]

This is likely the first thing you need to learn post processing yes. As @ONIKKINEN said in Siril you can determine pretty much straight away whether the data will be good or not via it's multiple preview modes after it's been stacked. I find galaxy imaging in particular doesn't need much work and you can usually get away with levels stretching but end up tweaking colour/saturation, then start messing with sharpness then start going loopy. Nebulae take more steps to look "nice".

Edited September 19, 2023 by Elp

[AstroMuni]

1 hour ago, Swoop1 said:

1st Law of Astrophotography- if you have a full head of lustrously natural hair- don't start.

Applies only to gents 😉

[ollypenrice]

OK, let's try it:

Of lesser importance, it is a horrible image.

Of greater importance, I gained no pleasure whatever from producing it!!  It offered all the intellectual interest of stretching an elastic band. If that was all that astrophotography had to offer I wouldn't do it.

Olly

 

 

Edited September 19, 2023 by ollypenrice
False click

[knobby]

15 minutes ago, ollypenrice said:

OK, let's try it:

Of lesser importance, it is a horrible image.

Of greater importance, I gained no pleasure whatever from producing it!!  It offered all the intellectual interest of stretching an elastic band. If that was all that astrophotography had to offer I wouldn't do it.

Olly

 

 

Can anyone else see the Queen of hearts blowing a smoke ring at the top left of image 🙂

 

[vlaiv]

41 minutes ago, ollypenrice said:

Of lesser importance, it is a horrible image.

Why?

[ollypenrice]

18 minutes ago, vlaiv said:

Why?

- Big crude stars as produced by small amateur optics.

- Vast amounts of information contained in the data not rendered visible.  (Faint nebulosity from emission and reflection.)

Olly

Edit. I think this has more to say and is much nicer to look at.

Edited September 19, 2023 by ollypenrice

[andrew s]

There are no laws in art only opinions.

Diffraction spikes rule ok. 😊

Regards Andrew 

Edited September 19, 2023 by andrew s

[vlaiv]

57 minutes ago, ollypenrice said:

- Big crude stars as produced by small amateur optics.

- Vast amounts of information contained in the data not rendered visible.  (Faint nebulosity from emission and reflection.)

I think that this both makes a point and shows how we misunderstood each other.

To reiterate "the law":  "If you can't take your stack, do basic white point / gamma 2.2 / black point stretch and get nice looking image - you are doing it wrong"

Since you don't like big crude stars from small amateur optics - "you are doing it wrong" - take big amateur optics

And second thing - I did not say that image can't be made nicer, better looking, more attractive with extensive processing - my point was exactly as expressed, if you do very basic stretch and you have no obvious objections to the image - then you are doing it right.

Sure you can pull out more with stronger stretch, but that is not the point of above "law". Point of above "law" was to point to obvious flaw in data gathering / processing step. In this particular case you don't like the star shapes which does indicate that optics you were using is not without flaws.

I don't know what was used, but given that you are into fast optics / going deep at the moment - I suspect one of the two: Samyang 135mm F/2 or RASA8. Both of these systems are not diffraction limited, so no wonder you don't like the stars if it was taken with one of them.

Now again, I'm not saying that you should not use such systems if you want to accomplish something in particular - but I do think that above still applies. Just basic stretch will reveal issues that would otherwise be masked by "special processing".

[Elp]

2 hours ago, ollypenrice said:

it is a horrible image

I think it looks fine, of course you can continue on with the processing.

Part of the fun for me is simply capturing something which is so far away and seemingly impossible to see visually. 

[ollypenrice]

Oh, I agree. A basic stretch will reveal defects, and the fewer the better. 

My enthusiasm for the RASA 8 and the Samyang 135 are predicated on the availablity of star-control software. Certainly in the case of the Samyang, I wouldn't consider it at all without StarX or Starnett. (I use StarX.) The RASA is much more attractive with this software but would be tempting without it.

We'd all like perfect optics, mount and camera. When we have to settle for less, it seems wise to reflect on which hardware shortcomings we can fix in processing and which hardware virtues we can best exploit. I find the RASA and Samyang data both fixable and exploitable thanks to post processing.

1 hour ago, andrew s said:

There are no laws in art only opinions.

Diffraction spikes rule ok. 😊

Regards Andrew 

In wafting, sing-song voice, 'I can't hear you, I can't hear you!'  However, you are welcome to add diff spikes to any of my images. May I suggest carving them into your screen with a pointed stick???

lly

[Elp]

3 minutes ago, Elp said:

Part of the fun for me is simply capturing something which is so far away and seemingly impossible to see visually. 

Something like this, it's no where near a perfect sub, heck it's not even processed but one 2 minute sub straight out of my astro modded Canon 600D via the Z61, I will always remember taking this image:

[Astroscot2]

2 hours ago, knobby said:

Can anyone else see the Queen of hearts blowing a smoke ring at the top left of image 🙂

 

I always see her on wide M16 images, glad its not only just me 😉

[AstroMuni]

1 hour ago, ollypenrice said:

Edit. I think this has more to say and is much nicer to look at.

I think this is now talking more about aesthetics & subjective matters rather than what could be applied to a 'rule', is it not?

I like your image as it showcases the sheer number of stars & nebulosity.

Edited September 19, 2023 by AstroMuni

[alacant]

15 hours ago, vlaiv said:

Here is an example.

Surely we can't possibly comment until we've seen the now customary starless version!

[ollypenrice]

23 minutes ago, alacant said:

Surely we can't possibly comment until we've seen the now customary starless version!

No starless versions from me! I've never posted one.

Olly

[andrew s]

59 minutes ago, ollypenrice said:

In wafting, sing-song voice, 'I can't hear you, I can't hear you!'  However, you are welcome to add diff spikes to any of my images. May I suggest carving them into your screen with a pointed stick???

Now look what you made me do!

thanks Andrew