ollypenrice

Indeed! However, I've no idea how one might go about making a widefield image from a single focal length. Is it even possible? lly

Very helpful, George. Thanks. You're in safe hands with Dave Wills, he's a good guy. Olly

You can be absolutely sure that we all send her our best wishes and condolences. Olly

Valid question. Our situation is that we want to squeeze a fifth robotic instrument into a roll-off roof shed designed for four piers. The instrument is just a Samyang 135 lens, so very small, and we can get away with squeezing this setup in if it is free of counterweight arms, etc. The AM5 mount and camera are perfect for the limited space available. At present the Samyang is occupying a main pier and this isn't necessary, it's overkill. Olly

Quality takes time. Nice one! Olly

Tom did the postage and packing. Regarding printing, even when you follow the correct colour protocols you'll want to see a test print or two first before committing to a big one. I now do my own prints, up to super-A3, and find results unpredictable, so I'll do several 10x15 tests first, adjusting the image accordingly. Usually this has to do with the brightnesses at the bright end but blue saturation can often be sky high for some reason, even with a calibrated monitor. Tom went to the printer in person to run through this procedure. A 1.0 x 1.8 metre print costs several hundred euurs so you don't want to lose one! Olly

Perfect. Thanks, Peter. Olly

Well spotted. The difference is just half a point in Ps Colour balance, midtones, away from green towards magenta. That's one point, faded by 50%. Because I wasn't confident about the background reds I reduced their colour saturation early on. Olly

In the end I decided it was in the data, though this may be wrong. It's been through DBE. There is certainly what looks like IFN in the top right. I do think the small star count might be lower in the redder regions, suggesting the presence of obscuring dust. I think when the capture is very deep it's reasonable to expect variation in the background but it's very hard to tell. I can see absolutely no trace of the green glow seen in BrendanC's image in an Equalized version of our data and have to conclude that it must be spurious. Olly

The 255 hour image on AB does show some field Ha which you might pick up. Probably worth a look, though they said it was very faint. Olly

Wow, Rivington must have livened up a bit since I last lived around there! (That would be fifty years ago...) I think the Trough of Bowland would be darker but it's further away. Olly

I was intrigued, this morning, by the feature looking like a tidal tail emerging from NGC5198, the elliptical to the right of M51. First I wanted to check that it wasn't an artifact and a careful look at the data, equalized in Ps, suggested it wasn't. I then found a couple of comparable images, including a good one by Dave Wills of PixelSkies, which also show it. Dave describes it as 'recently discovered,' as do a few other imagers who've captured it. I haven't yet found anything about the discovery but will keep looking. Yet again, the RASA shows us that 'deep is fun.' Olly

A mighty fine piece of work. We use the same lens-camera combo and, like you, find that it works! Olly

What was your image scale with the 12 inch? I'm just wondering if you were oversampled, in which case resampling downwards before processing might be good for the faint stuff. I also wonder if it might be possible to downsample still more, stretch the hell out of the tidal streams, denoiose them and then resample them back up again to blend with a conventionally processed main spiral. Thinking out loud. Olly

A huge loss. The first thing to say is that he was, quite simply, an extraordinarily nice man. He was so 'available' to the amateur community that, like many others, I met him several times and pestered him with questions which he answered with endless patience. What a very, very sad blow. Olly

RASA capture and pre-processing is, as usual, by Paul Kummer. TEC capture and all post processing is my fault! The RASA can't do high res detail with a 400mm FL but in 9 hours it can go seriously deep. This image is mostly RASA with the spiral details in M51 coming from a TEC 140 image at 0.9"PP. The RASA image was up-sampled by 25% and that's how you'll see it if you go to the full res. I think it's remarkable that we can get away with this when chasing faint tidal loops but, of course, they contain no small scale detail. Noise Xterminator is a big player in this trick. Full version is here: https://ollypenrice.smugmug.com/Other/Galaxies/i-HVknc9M/A Olly

With a large mosaic there are new problems to be overcome besides those which present themselves with a single frame image. The big ones are field geometry and field illumination. At the time we made the big Orion mosaic we were stitching in Registar and this does not generate a global template or 'cartographic projection' of the full field geometry. If you just stitch images together from one near the middle, for instance, the distortions will be crazy by the edge of the field. We had to experiment with ways of addressing this. Modern software can help with this, up to a point. We still find enormous mosaics defeat it. Software is also pretty good at seamlessly stitching two panels but, on larger scales, the brightness begins to vary so the background sky will be brighter or darker in different locations. I have worked round this by laboriously creating 'patch' sections to cover irregularities and blending them in by hand and eye. I've also worked in strips, making a strip of images across the top, then adding the neighbouring strip below that, adjusting it by hand along the way and so on down. Star removal software makes mosaics much easier but can introduce problems of its own, notably a visible tile pattern across the image. This needs a cosmetic fix if the imager can come up with one... Astronomy Now published an article in which I ran through my approach to the processing of Yves Van den Broek's Galactic Equator Mega-Mosaic. This project was easier than Orion and took about a working week. https://www.astrobin.com/full/g82xf7/B/ How long people spend on post-processing a single image, I don't know. In my case it will be about four hours then, after walking away from it, a couple more on tiny details or mild adjustments. Olly

I've collaborated with my friend Tom O'Donoghue and sold astro prints we've imaged together, though Tom did all the marketing and website construction. I won't link to his website out of respect for the forum rules, or the spirit of those rules. The image in which I collaborated had 400 hours of capture and probably a month's full time work in processing. It was also runner up in the APOTY competition. I have, though, made a satisfactory living out of astrophotography, but not by selling my images. My images have been the 'advertisements' which publicized my astronomy guest house and imaging workshops and I've also generated income by being asked by magazines to write feature articles on aspects of AP. One thing's for sure: I would not try to sell any image which did not contain something new, something not seen in any existing images. Over the last fifteen years that might leave me with about five images which meet this requirement, so not many! Sometimes I get nice messages from folks who ask if they might buy an image from me and, if the images are only mine (I do a lot of collaborations) I usually just give them away. Olly

I think there are many levels of ownership. The simplest, and weakest, is created when you buy something and it's yours. So two people go out and buy the same expensive racing bicycle and sit with it outside a café at the bottom of Mont Ventoux. One of them went out in the morning, rode up the mountain and down it, then rode over it the other way. The other just rode it from his hotel to the café. I cannot possibly consider their levels of ownership to be equivalent., though a lawyer can. Olly

Or your own remote setup? Olly

First off, it is indeed a beautiful galaxy and you've done it proud. And, secondly, it isn't available to your own observatory and that's a pretty good excuse. (When you say you'd have to get on a plane with your dual rig, I'm sure you're right. They wouldn't let you inside it with that lot! ) Unsatisfying? Hmmm... These days my 'observing,' which is to say my interaction with the night sky, comes largely through image processing. Paul Kummer looks after capture and pre-processing though, naturally, we discuss tactics ahead of that and the kit is partly mine and based at my home. Still, my situation is not entirely unlike yours with these data and yet I find it very satisfying. It's in processing its image that I feel I get to know an object. I try to tease out its secrets, persuade it to reveal things it doesn't usually reveal. This is why I now so much like working with fast systems. We can never resolve at the professional level but we can go deeper. We can also mosaic so as to show the relationship between objects and, sometimes, the way in which they are interconnected. The fast systems give me the buzz of seeing something I haven't seen before. Sometimes it's said that you never really look at something until you try to draw it. Probably true, but I'd add that I never really look at an astrophoto till I try to process it. Olly

Heretic! TeleVue rack and pinions are excellent; smooth, light and capable of holding heavy eyepieces without slipping. (This is a visual focuser, single speed.) I still have one on a 30 year old Pronto and the one on my merely 10 year old Gensis was perfect as well. Everything about the build quality of TeleVues is designed to see the scope outlive its owners. They are fully repairable and adjustable as well. I'm sure Magnus is right in that this is the F8.6. It certainly isn't one of the F5 scopes which are remarkably short, physically. (Edit: I took my F5 'Pearl River' Genesis onto a plane as carry-on.) Olly

Many thanks, Don. Olly

Never having taken solar flats I just watched a good video on how to do it. The extreme defocus method was the one I didn't understand. How can this correct vignetting if the chip is sampling a smaller or larger diameter light cone? The case for using flats is certainly overwhelming, as it is for DS imaging. Olly

A very nice, natural-looking processing job. Olly