StarTools

A common target, but new to me. Never properly achievable until I started using the full spectrum camera, but even then, too big to fit in my FOV. The 610mm of the new Newt, however, can sort of just fit it in. Or at least a good chunk of it.

This is initial, interim data, for the February challenge on CN, all taken with the L-eNhance filter. I racked up all of 2 hours integration from my first night, spending a lot of time getting situated first. The second night I fought winds and bad seeing, but ultimately got 2 hours out of that also that I decided to add in. Except for the truly awful subs which were discarded.

I may or may not rack up more L-eNhance time. The month is half over, and at the moment the moon is rather close to target. When that clears I want to start adding some data that will be first light with my new SII filter.

Rig is a 6" Orion f/4 Newtonian, MPCC Mk III, f/s Nikon D5300, on a belt modded HEQ5 Pro. Acquisition through BYN. Subs were 240s at ISO200. Flats taken for each session using a new exposure method, and a master ISO200 bias was used. All fed into DSS and stacked per ST guidelines.

In initial processing, my OIII channels were showing a strong left-sided gradient, and for Wipe to handle it I felt I was having too much of the Ha channel impacted. Or so it looked like. As I was playing around with it anyway for potential stacking purposes, I opened my DSS file in Siril and used the RGB split to quickly write out 3 new FITS. I composed the R into ST as mono and, after cropping the edges, ran an independent lighter Wipe. I then composed the G and B as (2xG)B, (GB)(GB), mono, in order to match crop and then run a stronger Wipe to clean up that gradient. Finally those results were composed as bicolor into R-Ha and G-OIII, and not as OSC/DSLR as the 2xG was already taken into account.

Then just processed through (including Wipe again, but with the settings now pretty much all zeroed out), and it seemed to allow for better detail and a lot cleaner data to work with.

This version is in the H(H+O)O gold/blue. Am looking forward though to seeing how much sulfur I can capture and what kind of SHO image can be created out of it. Or at least SHOHb, since it's only an L-eNhance not an L-eXtreme.

Nice! A very respectable Rosette.
There are surprisingly few S-II-with-a-DSLR images out there, so I'd be really keen to see how you go with this. I guess duo/tri-band filters are a fairly new development still, and people like yourself are still pioneering composites.

Thanks, Ivo.

Yeah I guess it's passable. Could use more time than 4 hours of course. But it's my best Rosette.

Not sure I want to be a pioneer. I might lead people astray!

I did not think of my DSLR as a hindrance though, and perhaps it could be. The only other imager I know so far who has added a SII to his L-eNhance was doing it on an ASI071.

We shall see. It's out there acquiring first sulfur right now. Sure is a whole lot of moon parked next to the Rosette though.

Well, first Sulfur was a bust. But I didn't come away empty-handed. I learned that direct moonlight into the Newt will bounce around in there and make its way to the camera. No baffling in these things.

The next day I built a shield of sorts that can be attached to the end of the scope when needed. Still in beta, and I had a couple hiccups, but overall it did the job fair enough. Guiding was good, after having tried the NINA TPPA again, except for a shaky period when my moon shield appears to have come a little loose. That will be fixed. In the end, I racked up just short of 4 hours of SII.

After extraction to mono and registration with the prior L-eNhance data, I still had to use a strong "pre-Wipe" on the data, same as I applied to the extracted GB before. I blame overall moonglow in the sky. Even though the direct moonlight was blocked, it was still only 29° away from the Rosette.

Combining the three into a real SHO was a lot of fun though, especially once I got to Color. So many options.

First time I have done this with my data, so it's flawed of course. I may look into culling some of the worst subs from both filter runs, and then maybe play around with weighting. Or not. Not sure yet. It's possible I just need less of a global stretch in order to not pull so much noise out of the background, and then perhaps enhance/brighten the main target in other ways.

Regarding the L-eNhance, I'm wondering if the Hb inclusion really harms the SHO nature of things in any major way. It's just hydrogen, except a state higher of emission than the Ha, probably variable by temperature in some low to moderate percentage of H overall. But since the hydrogen structure should thus match up, would not the only "defect" be a slight, though not uniform, tinting of my Ha? In an HOO I suppose that would be a purpling of the red, and in SHO I suppose a blueing of the green.

I also really need to figure out the nuts and bolts of the Color module NB matrix mappings, now that I can really do it in tricolor. Does anyone know if that's explained anywhere? I've read the module descriptions and notes, of course. Basically the math of it though, and what it means for what the channels are doing.

But here it is, my first DSLR L-eNhance + 6.5nm SII SHO, first go-through. I imagine it will show that I don't know what I'm doing just yet. Tried to stay somewhat classic by choosing a blend that has a nice green tint still, along with iconic magenta stars. Need them to be even more magenta though next time.

That has come out really, really well! Very close to what I was hoping/expecting, and comparing well with other SHO Rosettes. Well done - this is a fantastic example of a real SHO image, exclusively done with a "modest" DSLR. Excellent work!

admin wrote: ↑Wed Feb 16, 2022 6:36 am
That has come out really, really well! Very close to what I was hoping/expecting, and comparing well with other SHO Rosettes. Well done - this is a fantastic example of a real SHO image, exclusively done with a "modest" DSLR. Excellent work!

Thanks, Ivo!

It's just a start. Alpha version, in a way. And while this target probably is well-infused with SII, I am looking forward to more of this. I've done a handful of SHO images with shared and tutorial data, but there's just something extra about it being your own data, that makes you want to explore it that much more.

I will hit you up in order to get my head right about understanding how the color matrix works, though! Questions are buzzing through my head.

But oh boy, I was itching to get through all those "boring" things like HDR and SVD, and was not disappointed when I got to Color and hit the SHO button. Really cool to see that extra hue show up and augment the H and O. I need to start working on how the structures reveal. Bicolor balancing I have some experience with, but this seems a little different ballgame.

Hi Mike!

Very cool stuff! Really impressive result for the conditions with DSLR and bright moon. I wouldn't have even tried with the moon next to the target. And if I would have, the result would be much worse.

SII definetly adds something to the object. Makes me think if I should buy one of those filters, too? Which one did you use by the way?

Anyway, thanks for sharing!

Best regards
Stefan

Thanks, Stefan!

Yes it's really adding a lot of fun to this. I ordered the Optolong 6.5nm 2" SII. The nights were clear and I couldn't resist getting out there with it, despite the moon's proximity. So I'm sure I paid the price a little for that. A little more separation from the moon probably would have helped.

I worked up a second version last night that could be closer to my final for this dataset. No changes to the stacks, but I processed through at a higher resolution (50% bin instead of 40%), about 3000x2000, and worked the AutoDev, Contrast, and HDR a bit differently. In color I chose a different mapping and bias levels. I this this version reveals some structure better, and without the left side being plagued as much with remnant gradient I didn't need to crop that off.


I also then took that final into FilmDev, and reduced the Blue Luminance Contribution to 50%. I think I like that better aesthetically, as it tames down the baby blue of the central region a bit. Of course it is affecting the total channel everywhere. Reducing it even lower produces a really interesting take on it, quite eerie. However, I am wondering if the process is legit or flawed. Even beyond whether I should be fiddling with weighting like that, the fact that it was post-tracking/processing means that when those ST modules were doing their thing, they contemplated and used a different luminance combination. Could doing this change after the fact produce artifacts or flaws? I wonder if I would be better served to alter the relative Synth L weighting at the outset, in Compose, and how that result would then pan out. I suppose I will have to try!


Does the slightly subdued blue (I could reduce it more too) seem better at revealing overall detail, especially as to the other colors?

EDIT: I should note just to be clear about the process and what it was affecting -- the blue channel here already represented only OIII, having been the pre-combined (2xG)(B) from earlier steps leading up to my final SHO compose. At least that's what I assume, as I'm not sure I have the Color module/matrix mapping understood correctly just yet.

Mike,
That’s a great effort there from a 6” newt and DSLR
Yes newts are light buckets and cause all sorts of issues near a growing moon
You’ve certainly extracted some nice color blends from your data
Well done !!
Martin

Thanks Martin!

Yeah both the Newt and the SII have turned out to be enjoyable purchases for my sophomore year of AP. Still a lot of kinks to work out, but pretty reasonable early results.

I think my next step here will be to process each of the filters as mono, so I can then flip (or I guess blink, as so many people seem to like to say) between them and compare the different acquisitions.

ST being ST and often auto-sensing based on what it is seeing, I don't think I can necessarily replicate each filter channel identically, such as to come up with what each filter contributed to a final color picture as above, but I might be able to get close enough for curiosity purposes.