vineyard

Enough Ha on this I think - next step to add the colour (OSC again)

2h40 on the Eastern Veil with a 6nmHA & 294MCPro. Its WIP, so this is just messing around with PI (ghs script) & GIMP. Cheers

Ingenious. I'm toying with the idea of using these cake boards to make the retaining rings: https://www.amazon.co.uk/Culpitt-Round-Cards-Silver-Boards/dp/B09RKM257Q/ just need to figure out the holding cylindrical cardboard contraption. Excellent idea of the hobby boxes to store them carefully in.

Noticed that yesterday evening - well played.

A sad loss & a beautiful eulogy. V good of them to share those photos too, to convey a sense of the person behind the art.

If the Astronomik curves are correct, the CLS is cutting off the long-pass. The Astronomik UHC seems to be somewhat akin to a long-pass filter above 630nm so the CLS would cut that off at about 700nm. (The Baader UHC curve seems to have a shut off in it unlike the Astronomik UHC, at least going by Semrock curves: https://searchlight.semrock.com/?sid=a08a1af9-84ee-49d2-959d-153d7e7c0eb8#)

Thanks @vlaiv - nuanced explanations such as yours is part of why SGL is so rich to learn via. From my clumsily phrased perspective, I was just really surprised at the difference in the two images. For my crude mental model, in the OSC+double stack, all the 4 Bayer arrayed pixels are being used for 4.5-5h yet so much of the structure still doesn't come close to emerging - whereas in the OSC+NB (which to my mind means akin to a mono camera with 1/4 of the pixels, albeit with interpolation between the pixels which a pure mono wouldn't need to do) one night gave so much richer data. Maybe "NB is faster" is a better formulation for what has surprised me. I hear you on the set-up & flats - people's mileage will vary but for me <2h in one night vs 4 nights to get 4-5h is much more convenient, especially with that much difference in data. (I'll admit I'm lazy and if I haven't messed with the setup & no big changes have happened wrt dust bunnies, I just use the same flats for a few nights - I suppose slight focus changes night-to-night should mean I should take new flats). Cheers!

I think it would depend on which filters you stack @edarter & @tomato. If I had 2 proper NB filters, I wouldn't stack them b/c they'll be working on different parts of the spectrum as you say. I can't remember where I first read of this double-stacking but I think it was in some obscure CN thread. Based on the logic described therein, I double-stacked an Astronomik UHC & CLSCCD filter. I've pasted their respective band-passes below - I think b/c they work on v similar parts of the spectrum (as you surmised @ollypenrice) but w slightly tighter passes in the UHC, the combined effect is a bit closer to a dual-band like L-Enhance (still not as tight as that & nowhere near as tight as an L-Extreme). The interesting thing is that in solar, double-stacking HA etalons does tighten the bandpass but perhaps that's because of a different physics being used wrt the filtration mechanism? Thanks too for that image @The Lazy Astronomer - v v helpful. I'll try and do a Pixelmath comarison later, but at quick glance I think there's more finer detail in that than even w the OSC+NB, which would be another validation of mono?

While I save for a fuller frame camera, the eternal debate of mono vs OSC (+dual band filters) wages on in my head. And a point often made is that mono is actually faster not slower. I think I just saw an example of this. Two images below - the colour is about 4.5-5h of OSC over 4 nights last autumn (w dual-stacked filters to synthesise a dual-band) on NGC 6888. The red one is only 1h48from last night via a 6nm HA filter and the same camera 294MCPro on the same target. The difference in data gathered is shocking. Clearly a tighter NB filter will be helping (vs synthetic dual-band), but this is as a semi-mono w c 60% less capture time than the OSC - so I'd imagine a proper mono would have captured even more data? And btw this is on full moon night at a time of year when astro dark doesn't exist (even if the moon wasn't out). Mono really is faster!

That's dedication - bravo!

That is...just stunning. Wow.

Yes I'd noticed that those shapes only seemed to be on the bottom edge not the top, hence my curiosity. Interesting re it being an altitude-related stacking artefact. I'm afraid I don't understand the subtleties of stacking algorithms anywhere near remotely but intuitively yes I can see how higher refraction lower down while the image registers based on stars higher up could do that. It's almost like there's a need for adaptive registration for stacking purposes. Looking fwd to seeing the fuller project. And cracking vistas from the obs.

That's stunning. Is there any justification left for mono when OSC delivers that? Couldn't help pixel peeping (it's that good an image!) and is there some v v slight tilt (there seem to be some trails towards the bottom edge)? (That's not a criticism btw - I'd be over the moon w an image like that - more curiosity)

Huh, its not priced on the FLO website yet. Crikey - I'd better get in there. Did they give a lead time? You're right on the SGPros.

Do you mean prime focus (I think afocal involves an EP)? Great images of the most recent 2 galaxies too. You're definitely motivating me to take the 7"+NV on a galaxy hunt What f-ratio are those galaxy observations running at? (If its a Celestron 8" with NV at prime focus then that suggests f/10?) Thanks!