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In March this year I made this posting viewtopic.php?t=5180 with 22 hours of data of M81. And the result was good. But in the past months I gathered some more processing knowledge, there was an update of StarNet (star removal software) and a new program was introduced to reduce noise, NoiseXTerminator.

So I decided to re-do M81 all over again.
And this is the dramatic (in the good way) result, it's like I used a completely other set of data.
There is WAY more detail in it, the dust lanes more defined, the weaker outer parts of M81 also visible, Holmberg IX (the faint blob on the left) is also better visible with even some detail in it, and so on.
And the colors are also "better", I used https://www.nasa.gov/feature/goddard/2017/messier-81 as reference.

Below is the scaled down version, but here is the full resolution: https://i.ibb.co/cTdJYgC/M81v2.jpg.
And for a total comparison, this is the March version: https://i.ibb.co/869926X/M81.jpg

Added also a detail comparison, here it shows very well that the March processing (left) has way less detail than the recent processing (right).

Menno



Left: March processing, right current processing

Menno

A good image - you know things are going well if Holmberg is captured. I compared the 2 images - it might be worth posting a side-by-side comparison?

I go back and re-process older data (particularly during the summer months) - it is surprising what improvements are to be had from experience.

Dave

Thanks Dave!
Added a detail comparison, thanks for the idea

And yes, surprise is the right word. I recall being a kind of frustrated in March when even with 22 hours of data, some details only could be seen in the raw, noisy images. And now I'm able to show.

Menno

Hi Menno,
Great work on re-processing of the image which gives it
an almost 3D perspective. With having just started out in
astro imaging I"m picking up quite a few pointers when it
comes to threads like this.
Cheers
George

Hi Menno,

I thought that the old image was appealing artistically with the particular colour palette and unstretched smooth appearance but the latter is certainly better scientifically in the detail that it shows.
Tim

Thanks George and Tim

George: yes, processing older data can give some nice surprises when your knowledge and software has grown/changed. If I had known that when Is started, I would have kept all my data. But I only started saving it, making back ups, around a year ago.

Tim: yes, I know what you mean. As a matter of fact I have a 50/50 blend of the 2 images now as my desktop background

Menno

Menno

I have an external USB3 4Tb drive. When I come in from a session, the laptop data is copied to the 4Tb. I then copy data to an internal SSD drive for processing. I currently hold around 3Tb on the external drive (back to 2017) and always process a copy of the captured data.

Dave

Hi Dave

Yes, I have somewhat the same. I have an external 2Tb drive now where I copy my subs and master flats- and darkflats calibration files. At first I did all the calibration files but the space went down very fast

Menno