A load of Saturn & Jove imagery..!

[Kokatha man]

Hi folks - I've dropped in & made a few comments about other people's threads from time to time but don't think I've posted any of our own images for 2017 here...or at least not for some time.

To rectify that I'm dropping a large number here for anyone interested...with commiserations for the people who have already seen them, or find this many in one hit really OTT..!

Not really sure which images I'm posting here, but without worrying too much about the chronological order  they give a fair representation of what we've been capturing this year...

The piks (&/or animations) might need clicking on to work...

[Kokatha man]

...my only concern is that there appears to be some significant stretching of the images after loading onto SGL - ie, the appear significantly brighter than they really are, which gives them a slightly washed-out appearance which is a pity... ;(

[Knight of Clear Skies]

That's a stunning set, thanks for posting.

[bob-c]

just wow,brilliant.

                         bob.

 

[Tommohawk]

Another fabulous set of images - thanks for sharing!

Hope you dont mind a couple of questions:

Is your ASI290 cooled? Also, did you ever compare it to the colour 290? I seem to remember you quite liked the 224 colour, although that is a slightly different animal.

The reason I ask is that I'm thinking of going for a 290 colour, but havent seen much in the way of reviews compared to the 224 colour.

Thanks

 

[Pete Presland]

Fabulous set of images, those Saturn images are truly superb!

[cuivenion]

8 hours ago, Kokatha man said:

...my only concern is that there appears to be some significant stretching of the images after loading onto SGL - ie, the appear significantly brighter than they really are, which gives them a slightly washed-out appearance which is a pity... ;(

Stunning images! Try using JPEG files instead of PNG, I've found that that solved the problem, at least from my end. If you want people to see the uncompressed images you can attach TIFF files to the post as well.

[Stub Mandrel]

1 hour ago, cuivenion said:

Stunning images! Try using JPEG files instead of PNG, I've found that that solved the problem, at least from my end. If you want people to see the uncompressed images you can attach TIFF files to the post as well.

JPEG seems to make it worse for me :-(

[Aussie Dave]

10 hours ago, Kokatha man said:

...my only concern is that there appears to be some significant stretching of the images after loading onto SGL - ie, the appear significantly brighter than they really are, which gives them a slightly washed-out appearance which is a pity... ;(

Someone has been busy. Excellent Kokatha man, all of them. A lot of work has gone in to all that.

In regards to the brightening of the images I've also noticed this. It's the dark background of SGF, there's no stretching involved. Your image photo editor probably has a light background so test an image editor with a black background. My final edit tweak is done in an image editor that has a black background to balance it all out before uploading here. It's the same with facebook too when you go to full screen, that's a black background as well. Optical illusion and our eye's playing tricks on us or something like that

There's probably a technical term for it. I call it the dark background voodoo curse

[Stub Mandrel]

59 minutes ago, Aussie Dave said:

Someone has been busy. Excellent Kokatha man, all of them. A lot of work has gone in to all that.

In regards to the brightening of the images I've also noticed this. It's the dark background of SGF, there's no stretching involved. Your image photo editor probably has a light background so test an image editor with a black background. My final edit tweak is done in an image editor that has a black background to balance it all out before uploading here. It's the same with facebook too when you go to full screen, that's a black background as well. Optical illusion and our eye's playing tricks on us or something like that

There's probably a technical term for it. I call it the dark background voodoo curse

I'm not convinced.

I noticed that images open in Photoshop (grey background) appeared to have lower gamma than images in Astra Image (black background) which fits your theory. This is an identical image file with no editing.

BUT

I took a screen grab in both programs and compared the two images, the Astra version was definitely lighter and noisier. The chap who wrote Astra couldn't explain this.

To be honest, it drives me crazy and I wonder if PS deliberately uses a low gamma setting to make images look better! I understand i-products use strangely low gamma settings.

[laudropb]

Great set of images.

[si@nite]

Outstanding work as always Darryl!

[RichLD]

Superb!

[Kokatha man]

Thanks for the comments folks!

No problems re the "stretch" fellas...it did puzzle me at the time because I hadn't noticed it before: it was entirely my eyes after being at the screen for far too long yesterday...well, my eyes & the brain- fatigue that had me entertaining such loopy thoughts..!  - although the darker background of SGL could be thrown in as a temporary influence, exacerbating by confusion/idiocy...

Folks who know me would appreciate my attention to processing...this was merely a moment of idiocy at the end of a very long day...that & working out which images to post amongst all the captures!

Nothing to do with anything else like file-types etc btw.

[Kokatha man]

ps: It isn't a cooled camera Tommohawk...I can't see any advantage there for planetary tbh...& in the colour camera stakes I think it would still be very hard to go past the ASI224MC for noise & sensitivity!

Btw, the string of Saturns one below the other (which doesn't show full-sized, "possibly"  because of some SGL dimensional constraints) are examples from the last 7 years displaying Saturn's changing ring tilt/inclination.....

 

 

Visit our website (always a year or 2 behind due to my laziness!)   http://momilika.net/ 

[Aussie Dave]

11 hours ago, Stub Mandrel said:

I'm not convinced.

I noticed that images open in Photoshop (grey background) appeared to have lower gamma than images in Astra Image (black background) which fits your theory. This is an identical image file with no editing.

BUT

I took a screen grab in both programs and compared the two images, the Astra version was definitely lighter and noisier. The chap who wrote Astra couldn't explain this.

To be honest, it drives me crazy and I wonder if PS deliberately uses a low gamma setting to make images look better! I understand i-products use strangely low gamma settings.

G'day Neil. I'm not doubting that images opened in different image editors will look different but the issue here is the stretched look of images uploaded to a dark or black background website compared to a white or very light coloured website background, in this case especially planetary images.

This has caught me out many times as well. I have to re-edit images just for a few websites with the black or near black background.

The only way to test this would be to take a screen shot of an image you've uploaded to a dark background website and take a screenshot of the same image uploaded to a white background website, then cut both images out (just the planet), paste then both in to a new image and compare both side by side in an image editor. It's all to do with how your eyes and brain interprets contrasts. I guarantee both images will look exactly the same.

Something else to consider that I've found is when I edit images during the day and upload them they look fine, then at night they looked stretched and vise versa, if I edit and upload at night they look fine and the next day they look washed out, wishy washy colours and lost contrast or is that the other way around lol . It all just seems to be a balancing act. Dark background voodoo curse

I have problems reading white text on a dark or black background websites, after about 30 minutes or so of reading it stuffs my eyes up.

[Edit] Strange, after writing this above I downloaded one of Kokatha man's Saturn images and check it in my two image editors both black and light backgrounds and it does seem stretched and a bit on the contrasty side (daytime here).

I'm not knocking your work Kokatha man as great as they all are, much better than what I could ever achieve.

I could be wrong and often am but I think the only way to get an explanation to this would be to ask a webmaster guru.

 

[Stub Mandrel]

I'm worried about taking this thread off-topic, but some experiments to go here:

 

[Kokatha man]

...without being rude, I'd prefer folks to start another thread if they feel the topic mentioned merits further discussion...that way you can post images relevant to your interests! 

As I said above, it was a non-issue & my (original) comments were quite erroneous...there certainly was NOT any image-stretching, nor does software alter aspects such as gamma randomly etc as was suggested: I think I've sufficient expertise to make such comments & I do regret suggesting there was any stretching - looking today it was easy for me to see that I was affected by tiredness etc...

There are a few aspects of SGL I have not mastered, such as editing a post which I tried to do much earlier & which would have prevented this topic ever being brought up here...but now that it has, anyone who feels there is some merit in said topic (not me!) should feel free to discuss it in a specific thread...  

There are of course specific "post-processing" softwares around that do automatically stretch the levels/histograms...but I want to make it perfectly clear that this has not/does not happen on SGL for me!

[Stub Mandrel]

1 minute ago, Kokatha man said:

...without being rude, I'd prefer folks to start another thread if they feel the topic mentioned merits further discussion...that way you can post images relevant to your interests! 

Already done!

[Tommohawk]

11 hours ago, Kokatha man said:

ps: It isn't a cooled camera Tommohawk...I can't see any advantage there for planetary tbh...& in the colour camera stakes I think it would still be very hard to go past the ASI224MC for noise & sensitivity!

 

OK thats great, thanks. The reason I ask re cooling is that although planetary work, unlike DSOs, is typically quite short, there may be occasions when doing longer sessions is required.

For example, when experimenting with settings I have done multiple runs of 3 minutes with breaks of just a few seconds to change the settings. This minimises the effect of variations in seeing. Or perhaps if the seeing is a bit variable, I might to multiple 3-4 minute sessions to try and capture the best. Knowing that you are pretty fastidious about this  (as your results demonstrate!) I wondered it this would be a consideration. I guess not, by the sound of it. Maybe the noise is just so minimal that it doesnt cause problems even with rising sensor temperature?

Thanks

 

[Kokatha man]

...it's the type of noise that is important Tommo: for planetary imaging it is the "read" noise in each frame taken over a very short exposure as opposed to "dark current" where cooling does provide relief!

It is not a forte of mine but this CN link might be worthwhile, amongst others.   https://www.cloudynights.com/topic/484656-photon-noise-dark-noise-read-noise…-confused/  

It is the read noise of the ASI224MC that is the salient aspect of my original comments btw...but despite my impoverished appreciation of many of the finer points of sensors & noise etc, I think I can pretty confidently declare that the situations you describe don't impact re this "general" understanding I have...we would normally capture continuously for 3 or more hours in both hot & cold situations & you can watch the camera temperature graph & logs in FireCapture over these sessions: I can't say that I ever notice anything corresponding to "hot" or "cold" camera sensor readings apropos greater or lesser noise - in either single frames as viewed in AS!2 for example, nor in the stacked images...

My rough means of arriving at a "fit" between theory & practice anyway...  for me!

[Tommohawk]

1 hour ago, Kokatha man said:

...we would normally capture continuously for 3 or more hours in both hot & cold situations & you can watch the camera temperature graph & logs in FireCapture over these sessions: I can't say that I ever notice anything corresponding to "hot" or "cold" camera sensor readings apropos greater or lesser noise - in either single frames as viewed in AS!2 for example, nor in the stacked images...

My rough means of arriving at a "fit" between theory & practice anyway...  for me!

OK that's good enough for me! Thanks for the link BTW - very informative.

[Tyson M]

Always a pleasure seeing your work Daryl 

 

Stunning set!

[Kokatha man]

No worries Tom - & thanks Tyson!

ps: here's a link to "Cambridge in Colour" - yep, it actually spells colour correctly  - an Oz site but very good for all sorts of technical info & tutes etc...this link is to search general topics for something I posted on CN today, with a lot of technical info on sensors etc that are worth reading: you (or anyone else) might like to try typing in "camera noise" to advance your awareness of these matters further.

http://www.cambridgeincolour.com/search.htm 

 

Visit my website (I might even update it one day soon! ) http://momilika.net/

 

[michael.h.f.wilkinson]

Superb set of images. I must say I observe the same kind of colour stretching you describe when posting on SGL. It is almost as if the gamma setting is altered (browser issue?)