Adlernebel un die Säulen der Schöpfung in SHO

[B4silio]

Die Nebel kehren in den Himmel zurück, und (von Zeit zu Zeit) ist der Himmel klar. So konnte ich einige Bilder von M16 machen.

Leider kann man es von meinem Balkon aus nur 1h30 pro Tag sehen, bevor es hinter die gegenüberliegenden Häuser fällt. Ich werde also noch ein paar Nächte darauf verbringen müssen, weil es immer noch zu viel Rauschen gibt. Aber zumindest könnte ich die Kombinationen der 3 Farbkanäle ausprobieren.

Adlernebel in SHO - 3h 55m

• Hydrogen Alpha: 1h 55m

• Oxygen III: 35 min

• Sulphur II : 1h 25m

[B4silio]

Aktualisierung!

Ich konnte zwei weitere Nächte mit Fotos für insgesamt 11 Stunden hinzufügen.
(Ha : 6h | O3: 2h40 | S2: 2h20)

[oreoluna]

Hallo Basilio.
Ich staune immer wieder, was Du aus Zürich heraus von deinem Balkon zauberst,
RESPEKT!
CS Jozef

[B4silio]

Heheh danke, Josef!

Ich bin ein grosser Fan dessen, was die Integrationsalgorithmen zu leisten vermögen (mein Beitrag ist relativ einfach, fast klickt und wartet, wenn alles gut eingerichtet ist!)

Ich habe eine breitere Version gemacht. Ich habe die Farben etwas überarbeitet, da das Ha im Ganzen eine wichtigere Rolle spielte (im Vergleich zur zoomed-in Version).

3x Panel Mosaik, ~14h (8.3h Ha / 3.3h O3 /3.6 S2)

[B4silio]

Und die letzte Version nach Hinzufügen von 7 Stunden Licht:
21h (12 Ha, 4.5 O3, 4.5 S2)
1.Juni bis 24 Juli (12 Nächte)

[W.Zhou]

Hello Basilio,
Thats amazing!
Its incredibly that you made it on the balcony
BTW i am quite interested in narrow band filter, so it works like normal RGB filter which must calibrate and combine in process?

Weixin

[B4silio]

Hey Weixin,

Thanks for your kind words! Yes, the narrowband filters basically only select a specific response (usually corresponding to the material corresponding to their namesake).
If you're using a mono camera (as I am), you end up with 3 grayscale images to which you assign colors in photoshop or pixinsight, and then you treat it as a normal rgb image.
If you're using a color camera you can actually find tri-band filters, which end up bringing you different colors on the different channels right off the bat (a "one-shot narrowband color" so to say).

One thing to be careful with is star color: the Ha signal is always much stronger than S2 or O3, which means to combine the 3 channels you need to boost S2 and O3 much more, but that means that the red and blue colors are pushed up a lot, and stars all become magenta colored. You need to get rid of the very strong magenta cast during post processing, but both PS and PI have options for that!

Other than that Narrowband makes it possible to take picture from horribly light polluted places and with a full moon, so that's a very significant plus!

Ciao
Basilio

[W.Zhou]

Hi Basilio

Many thanks for the tutorial!
Now i am using a duo band filter on my color camera( O-3 and H-alpha)
As you mentioned, the color of stars is a huge problem when i try to stretch the curve (and also when i try to reduce noises with ATWT or MWT). May I ask if there’s a better way to get rid of that in PI? I tried serval times with mask and SCNR (well this process seems incorrect) but there’s still some strange halos around the star .

Many many thanks!

Weixin

Hey Weixin,

Thanks for your kind words! Yes, the narrowband filters basically only select a specific response (usually corresponding to the material corresponding to their namesake).
If you're using a mono camera (as I am), you end up with 3 grayscale images to which you assign colors in photoshop or pixinsight, and then you treat it as a normal rgb image.
If you're using a color camera you can actually find tri-band filters, which end up bringing you different colors on the different channels right off the bat (a "one-shot narrowband color" so to say).

One thing to be careful with is star color: the Ha signal is always much stronger than S2 or O3, which means to combine the 3 channels you need to boost S2 and O3 much more, but that means that the red and blue colors are pushed up a lot, and stars all become magenta colored. You need to get rid of the very strong magenta cast during post processing, but both PS and PI have options for that!

Other than that Narrowband makes it possible to take picture from horribly light polluted places and with a full moon, so that's a very significant plus!

Ciao
Basilio

[B4silio]

Hi Basilio

Many thanks for the tutorial!
Now i am using a duo band filter on my color camera( O-3 and H-alpha)
As you mentioned, the color of stars is a huge problem when i try to stretch the curve (and also when i try to reduce noises with ATWT or MWT). May I ask if there’s a better way to get rid of that in PI? I tried serval times with mask and SCNR (well this process seems incorrect) but there’s still some strange halos around the star .

Many many thanks!

Weixin

Hey Weixin!
One thing you can do is to split the channels and work on them independently as grayscale images:
1 - Use Channel Management > ChannelExtraction to split Red and Blue (Green you can ignore or treat the same as green)
2 - Take the blue channel image (which will have the largest halos) and do a Star Mask (increase Scale to 7 to make sure big stars are kept)
3 - you need to "grow" the star mask or the darker parts of the halo will not be corrected/reduced; the easiest way to do this is to do a HistogramTransformation and brighten it a bit (or you can try Morphological Dilation but that's probably overkill)
4 - Apply the mask back to the blue image and open the Morphological Operations panel
5 - Set Operator to Morphological Selection, set selection to ~0.25 and 2 or 3 iterations, apply and see if it's not too strong. If it is, either reduce the iterations, or set selection to ~0.35
6 - Use Channel Management > Channel Combination to put back the color channels

For SCNR I guess you did:
1 - Invert the image colors
2 - Use SCNR to remove green
3 - Re-Invert the image
The issue might be that if you are using a due band filter, your halo might not be really magenta, but rather "a lot more cyan than necessary" (basically you're not boosting Sulphur). In this case the method above should help as you're fixing the halo before combining the colors.

Hope this helps!

++
Basilio

[quantonaut]

Ganz grosses Space-Kino

tolle Arbeit Basilio, wenn man sieht wie die Qualität des
Kunstwerks mit Zunahme der Integrationszeit waechst
fühlt man sich auch selber motiviert mehr zeit in dieses nicht immer einfache Hobby zu investieren

kann man mich erinnern als ich meine ersten Aufnahmen von M16 mit F10 gemacht habe, es gibt Momente im Leben die vergisst man einfach nicht

cs,