m56

[alacant]

Hi everyone

After the galaxy, this occupied the gso until the end of darkness at around 05:15. Quite cute.

Amazing to see Vega so high and Antares so far west... Must be summer.

Thanks for looking. At least we managed a bit of colour for this one. 

700d on gso203 30x3min

Edited May 6, 2021 by alacant
png-jpg

[vlaiv]

Nice one.

Maybe try to wipe the background? This has distinct red cast to it.

Median pixel value are 35 for red, 30 for green and 28 for blue.

Good background should be around 18:18:18 or so?

[scotty38]

I'm sure Vlaiv is correct but nevertheless I love it, nice one....

[bottletopburly]

Looks good to my eyes 👀 alacant 

[alacant]

15 hours ago, scotty38 said:

Vlaiv is correct

There's a first time for everything! But seriously, despite being shown to be misleadingly wrong on any number of occasions, he insists with his armchair muses.

According to the latest, the vast majority of images presented on this forum are bad.

 

 

[vlaiv]

44 minutes ago, alacant said:

There's a first time for everything! But seriously, despite being shown to be misleadingly wrong on any number of occasions, he insists with his armchair muses.

According to the latest, the vast majority of images presented on this forum are bad.

 

 

I was not aware that I was "misleadingly wrong on any number of occasions".

Was I wrong in this case? And if not, why did you change the image to correct the background then ?

49 minutes ago, alacant said:

According to the latest, the vast majority of images presented on this forum are bad.

Could you please clarify when did I say that majority of images presented on this forum are bad?

 

[alacant]

27 minutes ago, vlaiv said:

Was I wrong in this case?

We already told you. There's a first time for everything.

27 minutes ago, vlaiv said:

Could you please clarify

Your definition of good seems to be something to do with 18.

Anyway, we're off to do astro-photgraphy. 18 of course. Try it!

Edited May 6, 2021 by alacant

[ollypenrice]

16 hours ago, vlaiv said:

Nice one.

Maybe try to wipe the background? This has distinct red cast to it.

Median pixel value are 35 for red, 30 for green and 28 for blue.

Good background should be around 18:18:18 or so?

Higher than that for me. (I spent some time trying to persuade Alacant of this, a while back!) 20-20-20 is my personal minimum and I prefer 23-23-23. One of my cameras simply refuses to get that high, though. It also depends on what's in there beside background since the eye responds to contrast. And, again, if there is obscuring dust in an image a higher dust-free background will help accentuate it.

I've been staring at Alacant's background in a state of bafflement since it didn't look too red or to high to me but it's now been edited? Looks good now, to me, in any event.

1 hour ago, alacant said:

There's a first time for everything! But seriously, despite being shown to be misleadingly wrong on any number of occasions, he insists with his armchair muses.

According to the latest, the vast majority of images presented on this forum are bad.

 

 

This is SGL.

Olly

[ollypenrice]

^^ By which I meant, this is SGL, not Cloudy Nights.

Olly

[vlaiv]

1 hour ago, alacant said:

Your definition of good seems to be something to do with 18.

Anyway, we're off to do astro-photgraphy. 18 of course. Try it!

It is not my definition - I was just trying to remember numbers that @ollypenrice said he uses most often for background level. I do consider his images to be good and by extension - you can conclude that it is recommendation for good value - not definition.

I don't have definition of good - I prefer darker backgrounds but not too dark and although I process most of image "by the numbers" - background is something that I do by feel in each image.

[scotty38]

While we're on the subject just how do you actually see what the background is whether it's 18, 20 or whatever?

[vlaiv]

3 minutes ago, scotty38 said:

While we're on the subject just how do you actually see what the background is whether it's 18, 20 or whatever?

I personally saw that background had red cast and downloaded the image and opened it in Gimp.

There you can inspect histogram of each channel and see where histogram peak is. There is also value inspection tool (which you can set to sample average of few pixels to avoid noise).

Another way to do it is to open image in ImageJ and run statistics - there you can get mean and median pixel values (median is better measure of background values as it is less sensitive to high values that come in stars).

[ollypenrice]

8 minutes ago, scotty38 said:

While we're on the subject just how do you actually see what the background is whether it's 18, 20 or whatever?

Open the image in Civilization (Also known as Photoshop) and, from the eyedropper tools, go for Colour Sampler. In the top menu set the sample to 3x3 or 5x5 average and place markers on the background sky. You're allowed four so spread them around. The values per channel appear in the Info box.

Once I've made my LRGB image and know that the colour balance is at parity (RGB all nearly the same) I get rid of the samplers and just use Curves to read the background brightness. Open, Curves, put the cursor on a bit of background, Ctrl click and a point appears on the curve with a number telling you the current background level. I set the final level this way just so as not to have markers cluttering the image, but either will do.

Olly

[scotty38]

Thanks both, I don't have PS but I do have Affinity Photo and PI so will look at applying the methods there...

[ollypenrice]

Just now, scotty38 said:

Thanks both, I don't have PS but I do have Affinity Photo and PI so will look at applying the methods there...

I've come to regard this as an absolutely key early step. The background has to be right before you go any further and it needs watching with hawk-like intensity throughout the processing job! (The background can and should be a tad high to begin with, to be precise, but it must be colour balanced. You can clip it down a point at the end but if you clip it too soon it's gone for good.

Olly

[scotty38]

Thanks again. I am new to this, as well as PI, so all i do right now is either ABE or a meddle with DBE and see what happens.... That may well also be a completely different thing/objective but that's back to my inexperience....

[alacant]

58 minutes ago, ollypenrice said:

if you clip it too soon it's gone for good

Affinity aside, which we've never tried and so don't know, I don't think any of @scotty38's software will allow otherwise.