DaveS

Unfortunately discussion about why "we" didn't follow up Apollo would break the forum rule about politics.

Terraforming Mars So tongue in cheek I wonder she can speak!

My main instrument is on a pier in an obsy, my secondary is on a pier under a TG cover on a raised platform. I've not seen shifts in any dust bunnies between sessions. Even when I was setting up each session I never broke down the imaging train unless I was making major changes, in which case, yes new Flats and Dark Flats were needed.

I think a realistic, at least at first, base will need to be dug well underground, perhaps in lava tubes if any can be found. The difference between a colonisation and exploration trip is crucial. I would not expect colonists to be expecting to return on the next "flight" but explorers might.

When I said "Long term plans" I was implying expansion into a colony. A colony needs to be self-sustaining, which means reproduction unless you're planning on sending a stream of people on one-way trips. Hoe 1/3rd (Or thereabouts) gravity will affect pregnancy and childbirth is currently unknown, but had better *be* known if a colony has a long-term future.

And any Mars base with any long term ideas had better include a maternity unit in their medical centre.

Vasimr.

A one-way trip isn't a suicide mission if you're setting up a colony, with people expecting to live out their (Long, hopefully) lives there. I doubt the Pilgrim Fathers (What about the mothers? Much more important) on the Mayflower were expecting (Or even wanted) to return to England. Your assumption that billionaires want their employees to commit suicide is dangerously close to political.

For an in-depth not-too-technical look at rocket pollution check out This Article and Video

First of all cancel all non-essential air travel (Most *is* non essential) and stop making cement. These outweigh any current or near term foreseen space travel by many orders of magnitude.

Doesn't even have to be that exotic, we're not talking fusion, antimatter, let alone warp drives. The Nuclear Salt Water Rocket will do very nicely thank you.

These sort of arguments always depress me, as take them back far enough and Acanthostega would never have bothered crawling out onto land.

I have a calibration library of Dark, Flat, Dark Flat, and Bias frames, with Flats and Dark Flats for each filter, and for bin 1 and bin 2 that I reuse for images. May only redo them every 6 months to a year. Certainly don't do new Flats every session, waste of time and storage space. On my ODK there's no need to refocus between filters, and on the TS apo I have a set of filter offsets so that the software can nudge the focus for each filter. Takes no more time than to rotate the wheel.

Many thanks Wim. Yes, I can follow this though AA has some differences. I may try stretching in Affinity as it has a mid-point slider which AA doesn't. I've been trying various different routes through the processing, all the way from the original subs. Trying both DSS and AA for stacking (With and without Bias, think without is better, maybe). Then a simple Linear Gradient Reduction (Which doesn't mind alignment edges) for the masters. Then either Trichromy before any stretching or stretching before Trichromy. At the moment I'm finding the Digital Development Process in AA useful as it applies a log stretch. During this I keep an eye on the histogram to avoid Black and White Clipping. For the Luminance I've also been applying a touch of Unsharp Mask though this has a tendency to white clip. And so on, and so forth. Because AA doesn't like combining different sized frames I wait until after LRGB combination before cropping and Adaptive Gradient Reduction, then colour curves and maybe another Histogram Stretch. AA doesn't have an Arcsinh stretch unfortunately, else I'd be using it and saving myself a lot of trouble. Beginning to think I'm going all round the houses to get to where I should be able to more straightforwardly. Time to look again at PI? Possibly, though I ran out my trial version and had to uninstall it when my old boot drive became full. Have a new boot drive so have room now. I also found it unintuitive compared with AA.

Remember that the biggest source of LP is the Devil's Lightbulb, AKA the Moon. Under moonlight H-alpha might be the only viable option, in which case mono wins. And given how many clear nights seem to coincide with a full moon... As an aside, I checked the focus with my ODK and Chroma filters, finding no measurable shift. Checked both with a Bahtinov Mask and the autofocus routine in ASA Sequence. The Bahtinov figures were identical, and with the autofocus, the variation between filters was less than the variation between runs.

Sorry, I was referring to my images, where I have a solid dot in the centre that just doesn't want to play nice. I really must take more care over my phrasing, the core in your version looks better than all of mine, though the latest version of AstroArt is very capable. I really don't want to get involved with PI, the last time I tried it I nearly had my brains trickling out of my ears. Going to pause again and have a think about how to proceed.

Looking again at your process the core region of NGC 7331 shows much better detail than mine, plus the warmer colours are more pronounced, minse are a bit washed out and tending to blue. I'm thinking you used PI? I am still seeing an annoying dot in the centre which leads me to think it's saturated somewhere.

I think DD mounts use a three phase motor with each phase being independently controlled. High resolution Renishaw encoders aren't cheap either. The fact that only a couple of high-end manufacturers make them should be a clue, as if they were simple I reckon more companies would make them. I have two such mounts, and yes they are brilliant but cost an arm and both legs!

Ah, was replying just before going to bed. What I was meaning was software binning the data I already have. I will hardware bin any new data.

Thanks Wim, that's a much better result than I got. I think I'm inclined to agree with you regarding the sampling, my sky can't support 0.61"/px unfortunately. I may try software binning and see how it goes. I think this data set was from stacking in DSS using Bias as well as the usual Darks, Flats, and Dark Flats. This might have upset the calibration (DSS complains if you don't include Bias). I have a later set from stacking in AstroArt 8 which I'll upload tomorrow. Following @Laurin Dave's query about the focus I ran a check with a Bahtinov Mask but could see no shift in the diffraction figure between L, R, G, or B. Maybe higher order aberrations are in play here. I may have to check the mirror spacing but that's a real pain to do.

Thanks, yes I think this is (Just about) the best so far. Really need to hone my processing skills then I won't be going round in circles so much, guess I'm still learning. This image had rather a lot of magenta in the background and spiral arms, but the latest AstroArt has an "Attenuate single colour" function in the colours menu that I've been experimenting with. Seems to be quite useful.

I dunno but I think this might be the best of my iterations. This base file name is "Fifth LRGB". There are variations of "Sixth (Or should that be "Sith") LRGB, but think this might just be better. This is from a stack in AstroArt 8, the sixth is from a stack in DSS. But I'm about ready to call a halt to going round in circles. Maybe if I manage to collect more data I'll be able to progress. I don't have any H-alpha but don't know how much effect it will have at this scale.

Holding off for the moment. I've come to the realisation that I don't use this rig enough to justify spending much on it. Maybe in the new year I will. I still like the Borg 55 mm f/3.9 but can't even begin to justify spending that kind of money.

I think only my tablet PC can run Win 11. All the rest are either too old or don't have a high enough spec of processor. TBH my office PC that I do my imaging work on is now 10 years old so could do with replacing as the imaging PC. I recently had to replace the graphics card as the old one died.

Thrashing around with this image. This is where I've got so far. The file name says "Fourth LRGB" but it's the second or third iteration I've done today. The others weren't worth saving. Still having trouble retaining detail in the core of NGC 7331 and getting good colour. All my efforts have a bright burned-out dot in the centre, suspect saturating the CCD.