IC 434

[Stefan B]

Great image, Dietmar. Surely you nailed Alnitak

I did not use the "Shrink" and "Superstructure" modules,

WHY? I couldn't live without these two modules! They rescue my images EVERY time. Just kidding, you can of course use whatever modules you want. But were there particular reasons to omit these modules?

Regards
Stefan

PS. But seriously, Shrink and Super Structure are super important

[decay]

Hehe, Stefan. I just wanted to shock folks here

Seriously, using Shrink was not necessary in my eyes in this case after having used SVDecon. Stars are already pretty small, aren't they?

And I do use Superstructure frequently, but sometimes it tends to produce mottled background structures with my data sets. I discovered, that sometimes Denoise with a high setting for Grain Size gives a smoother overall impression.

Best regards, Dietmar.

[Stefan B]

Hi Dietmar,

alright, fully understood your points. And yes, stars are small of course. But current fashion is even smaller stars or no stars at all I get that so the emphasis is on the DSO. But it's a bit too much for me at the moment. Lots of (dim) stars at least are an indicator of how deep your image is, right?

Regards
Stefan

[decay]

Tony Flanders, frequent CN poster and formerly prominent Sky & Telescope staff member, continually rails against maps purporting to provide Bortle values (https://www.cloudynights.com/topic/8567 ... nfo-ratio/. I don't quite get what all the fuss is about, but I don't have an old-timer's attachment to the idea of visually determining the Bortle value on every different night. But one idea he champions that makes sense to me is thinking in terms of the artificial:natural brightness ratio. Those numbers are also given on the lightpollution.info maps. My home is shown as a ratio of 13.4 vs my club's dark site an hour drive away at 0.45.

Hi Ron,

I don’t know, if you remember your post , but I put this on my (never-ending) todo list to give you a short response. Now it’s time to

I’ve read the thread on CN you linked and I agree with you, that most parts of all these cranky discussions don’t make any deeper sense.

The Bortle scale was introduced to estimate sky quality without technical equipment and it was meant for visual observations, not for AP. Now people try to map this scale to physically measured darkness levels and I can understand that this feels like some kind of abuse with respect to the underlying intension of this scale.

Reading the thread on CN, I tend to agree with user “Redbetter” – brightness is a physical unit that is best mapped onto a logarithmic scale – just like loudness levels, (acoustic) frequencies or the like.

For me, in fact, Tony Flanders gives an impressive performance why _not_ to use a linear scale in this case. But it doesn’t really matter which scale to use, I suppose. After all, they all are all just mappings for this physical unit “brightness” and everyone should use what fits best for him.

What I’m interested in, is to have somehow comparable information of what sky a particular image was taken under in order to compare it with my own images. I would like to know if the quality of my images is OK for my location or if the quality is limited by equipment, insufficient personal skills in acquisition or post-processing or whatever.

And I wonder whether the information we get from the light pollution maps is helpful for this? Your home is shown with a ratio (to use your preferred scale) of 13.4 , my home with 3.6 and Mike’s location probably about 25. So my problems are probably not due to light pollution?!

I will try to measure the sky here with ASTAP, as Mike wrote. That sounds interesting; if I understand correctly, ASTAP does this by comparing the visibility and brightness of stars in the captured image with those found on a star catalogue.

Best regards, Dietmar.

[dx_ron]

I don’t know, if you remember your post ,

Vaguely

What I’m interested in, is to have somehow comparable information of what sky a particular image was taken under in order to compare it with my own images. I would like to know if the quality of my images is OK for my location or if the quality is limited by equipment, insufficient personal skills in acquisition or post-processing or whatever.

I also look to see if an astrobin or CN image includes this (most do not), but I don't really need anything all that precise. Whatever might be meant by "B5", it is likely to be darker than my house and not quite as dark as my club's dark site.

One reasonable argument against the original Bortle scale is that 'B4' covers a very wide range of skies. But Bortle is baked-in as an integral concept in amateur astronomy and no amount of yelling at clouds is going to make it disappear.