Navi and her ghost - in progress

[dx_ron]

The Ghost of Cassiopeiae has been on my 'want list' for quite some time. The two challenges are Navi, at ~mag 2 and that I wanted a full-spectrum image rather than just narrowband. I went ahead and started with the AT130EDT at 910mm and arbitrarily chose 30-second subs. I only have just over 2 hours, so I figured now is a good time to take a look to see if this is how I want to keep going.

Gamma_Cas_OSC-only_130minutes.jpg (490.54 KiB) Viewed 18205 times

So yeah, good old Navi rather dominates. The star is also the story of the nebula. As I understand it, the gas/dust cloud is physically close to the star and is being shaped by the intense radiation (Navi is a famously strong x-ray source), so I don't want to just nerf it into oblivion.

What would you do? Try to subtly tame the halo? It's way too big for StarTool's star tools to do any more than carve out an unnatural hole out of the middle, I expect. Take extreme measures to tame the star? I actually like the delicate "refractor diffraction spikes" surrounding the star, but I doubt they could survive any efforts to dim the overall glow.

[fmeireso]

Ron,

I would leave Navi just the way it is. There is no real halo like surrounding, or concentric circles like i see often in my pictures. Ok it has a strong glow but frankly i don't find it obstrusive. My Navi looks less good, it is blue and also big and also a faint halolike blue center...

https://www.astrobin.com/full/x40hjt/0/

The ghost is another story. I never like the color that came out of Startools, too pinkish and babylike so i went for a ghostly grey/white look...
It is a really difficult target. I think you did rather well, espescially for only 2 hours. I had over 15 and that with a mono cam and it still was not enough. I never understood it...i will redo it , but not anytime soon...

[dx_ron]

Thanks Freddie. Your ghost looks quite spectral! Yes, 'halo' is maybe not the right word, as that has become so tightly linked to reflections off of glass (especially filters) and I don't think that is the case here. There's a lot of Ha in addition to the dust, so you start seeing the characteristic pink - like it or not I have a bit of a start on duoband data, as I will want to see eventually what NBaccents does.

[dx_ron]

Some progress. Still just the 2-ish hours of OSC, but I have added 6-ish hours of duoband - mostly with my new L-Ultimate filter but 1+ hour with the AlpT. For now I'm just lumping the two together, despite their slightly different passbands (5nm vs 3nm).

Narrowband only:

Gamma-Cas_duoband_67x300s_1600.jpg (495.13 KiB) Viewed 17793 times

And HaRGB using NBAccents:

Gamma-Cas_OSC_262x30s+67x300s_v2.jpg (495.55 KiB) Viewed 17793 times

I got tired of masking individual stars withing the nebulosity to desaturate the duoband coloring. But if I ever decide to use the NB-only version I will layer in RGB stars anyway. I should probably tone down the stars in the HaRGB version, as it's a tad garish. I did have to do substantial undo repair work on the stars after adding in the Ha.

[Mike in Rancho]

This one is really hard to evaluate.

I looked over a fair number of examples on astrobin, and I'm still not sure what should be real.

At first glance, it seems the NB Accent is too cooked. Particularly the left edge and upper right corner. But I think the Ha structure on the right side could be legit (though not sure of the wheel cogs around Navi?). On the left side, where I've seen somebody stretch that out more, it's more brown dust.

Tough balance of course. Backing off the left may lose the neat stuff to the upper right. But I might go less strong on the NB Accent, maybe not pure red, so just enough for good enhancement, and then set that off if you can with the reflection regions. Those tend to be blue-gray, but I get the feeling it's not OIII? So if that's more in the true broadband blue region, not sure how you could protect that against the Ha blend-in, and stay non-artsy, anyway.

If some of it did get into the OIII duo, then you could just note duoband in the Compose slot and see about balancing both bands in the NB Accent.

[dx_ron]

Yeah - the NBaccents version is way overcooked. Will be re-doing that, probably just by turning down the main % slider rather than choosing Balmer. I don't understand that huge difference in the total amount of "Ha" between the Balmer (very mild) vs Pure red (very strong) - but it's always there.

The blueish is definitely reflection - you can see it clearly in the OSC-only version. I did not try to add any Oiii in the NB compositing.

[dx_ron]

Back with less cooking.

First, I tried Balmer accents, but bumped the strength up to ~160%. It's not half bad, really. I didn't follow up with undoing damage and NR, so I'll have to repeat it if it's the presentation I decide on. But, if you go look back at the OSC-only, this is really subtle.

Balmer_160%.jpg (499.88 KiB) Viewed 17416 times

The back to red, but with strength toned way down to 56% followed by a masked undo and NR. In making the mask I used a lot of "similar color" (then inverted) so I could undo the nb accent everywhere except the Ha regions. That had the side benefit of protecting the stars embedded with the Ha, though there was a lot of manual fiddling. It would be nice to have a bandwidth control for 'similar'.

red_56%_undo+nr_1600_500.jpg (483.5 KiB) Viewed 17416 times

The *really* important question is - which way is right-side up? I think I prefer it rotated 180° from the versions here (I like the original post orientation better)

[Mike in Rancho]

On the most important questions, yes flip it!

Navi, which looks quite good I think, at the top, and the ghostie things in their "correct" ghostly orientations.

These two are improved, but I'm not sure which I like better. I'm leaning towards the Balmer, mostly because the transitions are smoother and the reflection regions stand out more. But in the pure red with reversal, the star field looks cleaner, and there's some additional Ha structure. Hmmm.

Has me wondering if there's still more middle ground somewhere.

I've done large scale NB Accent reversals as well, mostly galaxy shots though, where all you really want is the galactic Ha knots, and the streaks if talking Bodes and Cigar. On those I try things like brightness masking or "brighter than", and then touch up/remove stars using inverts.

Agree that some custom user controls could make Mask more useful, though that always runs the risk of permitting more painting. But by color and by brightness are often unusable really, without being able to dial in the parameters to the dataset.