m51

[alacant]

Hi everyone

This is 1 hour and  4 hours. Was it worth the extra three I wonder or is my it'll do type justification misleading me?!

Thanks for looking.

700d @ ISO800

[rotatux]

Difference is far from obvious to me... Depth looks the same, as well as colors. But they are not the same scale so there may be much more details in the second one.

Both good shots given the respective exposures, maybe too large a framing (reduce 25-30% ?), but be proud of them :)

[vlaiv]

Second one obviously better and certainly what one would expect from more exposure.

I agree that both images should be processed the same. In fact, if you really want to do good comparison - try making a split screen scenario.

Take both images - preferably stacked with the same method, bin/scale to same resolution, align them the same (register one to another) and equalize them, and then, in the end, compose one image by taking left part from one image and right part from the other image - while still in linear stage - and process resulting image. This will provide excellent way of seeing the difference between the two.

[david_taurus83]

First one is noisy, second one isn't.

 

So yes, well worth the extra few hours!

Edited February 25, 2020 by david_taurus83

[carastro]

I am finding it difficult to tell as the images are different scale.

Carole 

[celestron8g8]

Very nice capture , love the WFOV ! You have several bonuses in the field also !

[ollypenrice]

3 hours ago, vlaiv said:

Second one obviously better and certainly what one would expect from more exposure.

I agree that both images should be processed the same. In fact, if you really want to do good comparison - try making a split screen scenario.

Take both images - preferably stacked with the same method, bin/scale to same resolution, align them the same (register one to another) and equalize them, and then, in the end, compose one image by taking left part from one image and right part from the other image - while still in linear stage - and process resulting image. This will provide excellent way of seeing the difference between the two.

There is no point in taking a 1 hour and a 4 hour image and applying the processing of the 1 hour image to the 4 hour. The whole point of the 4 hour (or, ideally, the 20 hour!) image is that it will stand much harder processing. However, it would be instructive to apply the harder processing to the shorter image because all its shortcomings would show.

For me the second image is clearly better, particularly in terms of colour intensity. I also think it has a lot more colour to give. It would probably stand more sharpening and local contrast enhancement as well and a harder stretch of just the outer halo. You have to catch more data but you also have to exploit it.

Olly

[alacant]

2 hours ago, carastro said:

different scale

Hi and thanks for taking a look. I made sure they were the same size. Are you seeing something different?

No need to resize or manipulate them. Just a gut reaction side by side is fine.

Cheers

Edited February 25, 2020 by alacant

[vlaiv]

1 minute ago, alacant said:

No need to resize them. Just a gut reaction side by side is fine. 

Not much point in saying that to a certified pixel peeper like myself   - my instant reaction is right click / open in a new window / zoom to full size - even typing it seems long in comparison to motions now firmly set in muscle memory

[alacant]

1 minute ago, vlaiv said:

peeper

@vlaiv: Of course, we'll make an exception for you!

[vlaiv]

1 hour ago, ollypenrice said:

However, it would be instructive to apply the harder processing to the shorter image because all its shortcomings would show.

That sort of thing I had in mind.

Btw, above procedure is applicable to regular session if one wants to see a difference between for example 2h vs 0.5h or similar - you just stack fewer number of subs in one stack.

[ollypenrice]

1 hour ago, vlaiv said:

That sort of thing I had in mind.

Btw, above procedure is applicable to regular session if one wants to see a difference between for example 2h vs 0.5h or similar - you just stack fewer number of subs in one stack.

Certainly true. Once my dear friend Tom O'Donoghue has found how much data is finally enough, by test-processing it, he....... doubles it and calls it a day! 

🤣lly

[tomato]

18 minutes ago, ollypenrice said:

Certainly true. Once my dear friend Tom O'Donoghue has found how much data is finally enough, by test-processing it, he....... doubles it and calls it a day! 

🤣lly

From my motorsport days relating to cubic capacity, supercharger boost etc etc, “if some is good, more is better and too much is just right”.

[des anderson]

A real classic, both are really good. BUT,there`s always a BUT....The 2nd just pip`s the first one a little more detail in the smaller galaxy. Des