Felias

It looks greenish on my screen, not yellow. I have tried using Siril's photometric calibration, and it seems to get better, though it's rather reddish. But I only had your already calibrated jpeg to start with, so I didn't expect it to work perfectly. Maybe you could try with your stacked tiff/fits file, and remove the green noise if it doesn't completely go after the calibration.

Thanks for sharing. I'll go for galaxies the next night out (whenever that happens) with my Z61, so I thought I'd practise my new workflow with your image. I did the colour calibration and gradient elimination in Siril, then stretched it in Photoshop. It's true that there was a lot of noise, but working carefully with successive asinh stretches I managed to prevent it from dominating the background. A pass with the PS raw filter got rid of the remaining red pixels, though perhaps it's now too dark a background...

Since it was too windy when I took my photo of Orion a few weeks ago (see my post in the deep sky forum), I put the telescope back in its case and decided to at least take some wide field photos to make a panorama for my pupils. It was a good chance of showing the Winter Hexagon, so there it is. I have also attached the labelled version I made for teaching, though the brighter stars are quite visible if your screen is not too dimmed. Canon 77D Samyang 16 mm f/2.0 15-photo mosaic, 30 seconds, ISO 400, f/2.0

It's been ages since I last posted, but I did not go out imaging in the whole winter (a combination of bad weather and a chest condition that went on for too long). Finally, I managed to drive out to the fields on a couple of nights recently, and take my very first pictures of Orion and the Rosette nebulae. Advice and comments welcome. Orion, 137x25 second subs, ISO 800, Canon 77D WO Z61 on a Star Adventurer Stacked in DSS and processed in Photoshop (after photometric colour calibration in Siril). It was clear, but quite windy, and I had nowhere to shield the telescope. So I ended up discarding most of my images, and among the 137 I left I discarded a further 30% when stacking, so the final image is barely 40 min worth of lights. I guess I'll have to try again next year! Rosette, 136x1 min subs, ISO 1600. Canon 77D WO Z61 on a Star Adventurer Stacked in Siril (plus colour calibration) and processed in Photoshop. It wasn't windy the second night, but there was quite some fog! I couldn't do much about bloated stars, and also it was the first time I tried to track for 1 min with the Star Adventurer at 400 mm. It wasn't perfect, and the stars are elongated due to some slight traiiling. The Rosette started at about 30 degrees above the horizon, and I followed it until the Orion Belt was under the hills, so it was always low and the light pollution gradients were massive (Ashford being the worst offender) and coming from different directions as the nebula went down. I took the data nonetheless, and processed them the best I could. Even though the pictures need improving, these massive HII regions never fail to impress. I was sad to learn that Angélica Gorodischer passed away in February. She was a science fiction writer with a unique style, and this quote from "Los sargazos" (1973) describes the phenomena taking place in those gas bubbles carved by OB stars in a rather poetic manner. As far as I'm aware, that story has never been translated into English, so I'm copying below both my polished version of Google translate (which was quite good, to my surprise) and the original: "Then he wanted to recite the statement of the Langevin paradox, Archimedes’ principle, the alphabet, a spelling rule, the Pagoda of the Monastery of the Benevolent Grace, and he was forced to abandon all his thoughts of man and spin slowly beyond, the blood almost motionless, to the rhythm of flight of the fierce galaxies, to the scale of condensation of the gas clouds, facing the magnetic columns, the tunnels carved out of nothingness by white suns, surrounded by silent explosions, a world in gestation at the tip of each one of his fingers, sinkholes, the space of space, at his feet, where there is no longer room for madness." "Entonces quiso recitar el enunciado de la paradoja de Langevin, el principio de Arquímedes, el alfabeto, una regla de ortografía, La Pagoda del Monasterio de la Gracia Benévola, y se vio obligado a abandonar todos sus pensamientos de hombre y a girar lentamente, la sangre casi inmóvil, más allá, al ritmo de fuga de las feroces galaxias, a la escala de condensación de las nubes de gases, de cara a las columnas magnéticas, a los túneles trabajados en la nada por los soles blancos, rodeado por explosiones silenciosas, mundo en gestación en la punta de cada uno de sus dedos, socavones, el espacio del espacio, a sus pies, donde ya no hay lugar para la locura. "

Had a go myself (been cloudy here for weeks), and I found @ONIKKINEN's advice spot on. It's about the white balance before increasing saturation/vibrance. For comparison, this is the best I get when using the auto white balance in PS, And this is what I get by choosing the dark and light references in the curves tool myself:

Staking into a pool only brings this picture to my mind, I'm afraid...

Well, after all, as Yun Tianming was told, "In my opinion, aesthetics matters the most when you’re buying a star. It’s much better to possess a faraway star that you can see than a nearby star that you can’t. It’s much better to own a bare star that you can see than a star with planets that you can’t. In the end, all we can do is look at it." That's all you can do with a NFT too (apart from speculating)! 🤔

Literally, the brain surgeon sketch!

Oh, that Orion shot (nice one, BTW), was it taken from Semnoz then? I was there the half term, but looking at the mountains, not the sky. I took a photo of the lake from the bend before Les Rochers Blancs: Stunning site, even under the clouds!

My wife, who's a doctor, says she has never met any ophthalmologist who has undergone laser eye surgery, that they all rather would wear glasses. 😅 Although she may be joking/exaggerating, neither of us has ever considered the option, even though we could use it. That's why I prefer imaging to observing! 😇

Ann Leckie -"Ancillary Justice". 😅

Ohh, brings back memories... We searched for "double stars" (was it in Altavista?) when we first had access to the internet in uni, during a lesson, and the results were... peculiar, to say the least. The good old internet, before the dark times, before the empi... before they thought of adding filters! 😅

Thanks!

I agree that clouds can give character to a photo, but they only work if it's a single shot. A stack when it's cloudy is messy, and creates artifacts, I almost gave up on the last picture I posted above.

Thank you! I quite like the clouds in the second picture, but they sort of ruin the last one. They were practically invisible to the naked eye that second night, so I didn't find out until I processed the photos back home.

I thought I'd share some photos I took over the half term. The Milky Way over Lac Annecy, in Haute-Savoie. The bright dots in the bottom left are Jupiter and Saturn, and you can see the Summer Triangle too. The photo is a mosaic of eight pictures stitched together, each taken with my 16 mm Samyang f/2 lens, exposure 25 seconds, ISO 800. I used Hugin to blend the photos into a single panorama; it gave me a few headaches since I had never constructed one before. It was quite cloudy, but one can't be too picky on holiday, not to mention that after a tough climb to the promontory known as Roc de Chère with all the equipment, I wasn't going to give up! I did some trial pictures before starting the panorama, and although it's only half the FOV I intended (4 photos), it was less cloudy around the Milky Way, so I thought it was worth processing. You can only see Saturn, and barely the lake, but here it is: I took some pictures while waiting for darkness, so just to show you what the place was like, here's the sunset after stitching 11 photos (still the Samyang 16 mm). The tiny peninsula in the centre is the subject of a famous painting by Cezanne, by the way : And another panorama with my Canon 50 mm pancake lens: I also captured Jupiter, Saturn and Venus at sunset: And a 50 mm zoom of Venus (very hazy, it was basically behind the clouds): On a different night, I pointed my camera towards the other end of the Miky Way, just across the street from the apartment I was renting in Talloires. It was cloudy again, and there was plenty of light pollution coming from the ermitage de Saint-Germain-sur-Talloires; a nightmare to process. Yet Andromeda and the double cluster are easily seen, and if you squint you can find M33 on the bottom right. A stack of 100 lights, f/2, 10 seconds, ISO 800; plus flats, darks and bias. Foreground blended from a single shot, 30 s, ISO 800. Not my best effort, but I had lots of fun taking these pictures! Watching the sunset over the Alps, alone in the forest, was a special treat. 🤩

First one for me. The second has a bit of a green tinge, although that could be due to a difference in calibration between your computer screen and mine. Also, the nebulosity has better local contrast in the first one.

"For a complex subject, consider neurology, or catalysts, but don't mention ballistics" Robert Heinlein, from "Orphans of the sky". He could have mentioned weather forecasting for that matter!

And some basic star reduction to see better how much nebulosity there is. I must admit that there is more than I could pull with Siril...

Thank you, that was very useful! I applied a mask to the foreground in layers, after HDR, and got rid of the rings in the stars. There's still some in the satellite galaxies, but it's definitely improving. I'll try with other data, but at this rate I can see myself using Startools in the future... Yes, I can spend hours processing. I love pulling the light from the stacked images! 😇

Thank you! Your image has the same problem I encountered: if I want the core to remain bright, the stars get a sharp centre with some halos that ruin the image for me. That's why I had to use the 'reveal core' option, which leaves the stars untouched but looks less realistic (I think the core should be bright, as in your picture, considering the large star density in the region). Is there a way around this? Also, the 'contrast' module can't be used correctly as long as the smudge cannot be masked, it adds an annoying gradient.

Thanks! It looks very green on my screen, though I know my laptop has issues with the colour calibration. And the blacks look clipped, I'd say. I've done a second attempt this afternoon, it is better, but I'm very frustrated that I can't use a mask in modules such as contrast and HDR. I could always enhance in PS, but then I'd lose the denosing made in Startools. I didn't bother cleaning the dark smudge in the corner, for a screen capture, so here it is:

result.fit Thank you! Yes, there is perhaps too much noise removal in the Startools version, but since I was doing just a screen capture I didn't bother refining that part. I think it was the "life" tool that applied the denosing automatically. Not sure now. Yes, I know about selective colour, I did exactly that with the reds in PS. So that means yours is a second iteration of the same process! 😉 I'll try the luminance layer, I didn't think about that, thanks. As for Starnet, I don't like the way the starless version looks, so I just use it to build a good star mask in PS. Then I use the 'minimum' filter, trying not to push it too much (I do like a good star field). I've also tried to use the starless layer to do a 'content aware' fill in PS, it produces good results sometimes. I'll try your suggestion. I attach the stacked file, thank you. I played with different RoI, but it wasn't great (is there a way to select one diagonally?). There is a big black smudge in the upper right corner (dirt on the lens) that didn't help, but found that a carefully chosen mask kept along the process did wonders. I'd love to see what someone experienced in Startools can do with the data! 🙏 result.fit result.fit

Yes, I've got the last version, and my laptot is a Lenovo Legion, i7 and 32 GB of RAM. Windows 10, though, so that may be the issue. Anyway, I've just tested Startools with my data for M31, which I had readily available, and I'm finding difficulties again. This is my previous Siril/PS processing: And this is what I did in Startools (a screen capture, so low res): I was quite frustrated when I tried to use HDR to bring detail, I couldn't use the star mask and they became bloated with a sharp centre, absolutely awful. I had to settle for the adjustment to enhance the core of the galaxy, but it came out too soft and dark, I prefer the core to be brighter as in the first picture. Then the colours were difficult to adjust, and there was a lot of guessing involved, whereas the photometric calibration is Siril is quite straightforward. And in the end, Startools didn't recover much more nebulosity than Siril did, it seems, so it's not a trade off I'm sure that works for me. Obviously, I can't tell just by this processing alone, I'll keep practising and see if I can improve...

I see, thanks. I'd love to do the stacking in Siril, but as I said it's too time-consuming and I'm afraid it may damage the laptop, it just gets too hot for more than half a day. I'll try DSS and Startools again, and see if this time around I can improve my previous attempt!