Take 2 Tarantula - now with over 5 hours data

[Robert_T]

First image is with over 5 hours of data taken over three nights and second is from just the one night 1hr 30m version I posted a few days ago for comparison.

Mostly 180s exposures, ASI533mc pro using Askar 400 (72mm f5.6) and most critically the new L extreme filter from Optolong as this is in Bortle 7 skyglow dome of Brisbane city with Moon also well present.

The extra data helps a lot I think. Similar processing but with less noise was able to retain more fine detail.

I may add more to this but suspect it's probably diminishing returns from here.

Comments, advice, critique always welcome.

[Zuts]

You have definately brought out more details, it's looking great. From here though you would need an extra 10 hours to reduce the noise by half.

[ChrisV]

Looking very nice indeed Robert. You have the l-extreme working nicely

I have two suggestions.
Maybe less filtering - looks very soft in feinter parts of the nebula. A bit of noise is a good thing!
And the central bright region is a bit over stretched - looks saturated?
How to do this depends on what processing software you are using

[Nikolas]

It' all about the processing to bring out all that data, have you tried 5 minute exposures? Also what processing software are you using? Are you separating the Ha and O3 channels? There is so much more data to pull out.
This was with the L-extreme and 3.5 hours data (http://www.iceinspace.com.au/forum/attachment_browse.php?a=267971) but at 5 minute subs and Astropixel processor and Photoshop to bring out the Ha channels. There is so much more you can do with this but a great start.

[assbutt94]

Looks great! Have you tried stretching the darker areas a bit more?

[multiweb]

Very nice. I like the stretch on#1. Well done. :thumbsup::thumbsup::thumbsup:

[PKay]

You have some good data there Rob, I'm jealous!

I could play with that for days.

Well done.

[Robert_T]

thanks Zuts, well I've made a start gathering another 2hours last night ... a few more nights and I may have that 10 hours ;-)

[Robert_T]

thanks Chris. Agree. I suspect it's more a case here though that I've applied more selectively masked sharpening in the more detailed and illuminated areas. Something I haven't played with as yet is selective mask stretching, but will be something I work on.

[Robert_T]

thanks assbutt94, I did do some stretching where I first preserved the brighter parts as a paste in place layer, but otherwise haven't selectively targeted stretching to fainter areas - how do you do that?

[Robert_T]

thanks also Marc and Peter for the kind comments.

[Robert_T]

Hey Nik, that's some fantastic detail you have linked there. What scope was that taken with? I have a lot to learn on breaking out the various channel. I use Photoshop for processing and have yet to play much with channel processing. Not sure if it is able to separate Ha and O3 as the dedicated astro processing software, but will be seeing what I can do channel wide in PS first. Also started 5min exposures gathering another 2hours last night, thanks:thumbsup:

[Nikolas]

Thanks Robert
My scope is the TSoptics 130 refractor which mates perfectly with the 294mc camera.
When you do master the channel separation you will really see the differences.

[tempbark]

Very cool images Robert! I have almost the same imaging train (Askar FRA 400 + ASI533MC, minus the L-extreme which I am planning to acquire)! :lol:




Hi Nikolas, when you say channel separation. Are you referring to editing each RGB channel separately? (i.e. different curves adjustments, etc)

[Nikolas]

Yes and no
It's rather complicated to explain but you stack the channels separately with specific software (I use Astropixel processor) Ha and O3 then combine them using RGB combine, I use the HOO algorithm. Ha being red channel and 03 both green and blue channels.
the final image is then stretched etc in photoshop in my case, some prefer pixinsight. I also then stretch and play around with the Ha image and layer than on top of the rgb image as a luminance layer and play around further. It takes time but yields fantastic results.
This video may assist https://www.youtube.com/watch?v=8lki-TfkrlQ&t


and these
https://www.youtube.com/results?search_query=narrowband+ast ropixel+processor

[assbutt94]

You could probably try using curves in whatever image program you use, a bit like the image I've attached. The first point around the black section of the histogram acts as an "anchor", the second stretches the shadows a bit, and the third also acting as an anchor to stop the midrange and top end stretching since the core of the nebula is plenty bright. By using those two anchor points you can prevent the very dark areas (including some noise) and mid-top range of brightness (the core and stars) from stretching, and might be able to bring out some more of that faint surrounding nebulosity.

It's all a matter of personal taste though really, and you have a great image.

[tempbark]

Thank you Nikolas!

[Sunfish]

Fantastic image and well processed. A good example of what the channel separation can do in APP.

[Robert_T]

added some more data and reprocessed. trying to bring out a little fainter detail.

[Nikolas]

It's coming along nicely, some great detail is emerging

[xelasnave]

It is a wonderful image Robert...what I find with more and more exposures is you can get super critical as to what you end up stacking and that in itself I think translates into more is better.
One thing..don't let trying to get more detail, which often turns out to have us looking for hidden nebulosity, cause you to lose focus on the detail in the main object..if we can call it that..given the quality you have achieved I suspect you can get even better detail for the spider..you could see if a " burn" will help but perhaps work up an image concentrating on the spider part which you finally merge in ..like you would do with the core of M42.
However the image you have now is top shelf ...and contrary to others comments to go longer if I were to add anything it probably would be getting shorter exposures off the spider..shorter to me means crisper..and seeing if you can sharpen the spider detail.
Alex

[Robert_T]

thanks Alex, that's great advice. I have some experience with HDR imaging and could use that here to merge. cheers robert