ollypenrice

The image is essentially great, to my eye, but that dusky magenta for the Ha doesn't sit well for me. Did you use a heavy dose of SCNR green? That would slew the hue towards magenta. However, I think it will be more to do with how you blended the Ha. I keep it very simple and add Ha to red in Blend Mode Lighten. I prefer not to add it to luminance but, if I do, it is only at a very low opacity - 10% max. It can also be useful to boost Ha signal at any time in Ps by going to Selective Colour, Reds, and dropping the cyans in red. Edit: I don't think your RGB is blotchy but it does show a mild trace of the tile pattern which sometimes arises from StarXterminator. Sometimes I don't get this at all and sometimes it's awful and takes a lot of fixing. Olly

Great framing idea! Olly

A belated processing note: when replacing the stars and keeping them small, I found that those in front of the bright nebula didn't show at all, giving the impression that the nebula sat in a stellar void. With the stars still as a top layer I used the Ps Colour Select tool to select the bright nebulosity and gave the top layer a gentle further stretch within the selection to bring them into view. In small format this doesn't show much but, when zoomed in, it looks more natural. Olly

If you hadn't mentioned the moon, who'd have known? Nothing wrong with those. Olly

Diffraction spikes are an artifact but, if you must have them, they can be created by cluttering your aperture with string or by using Noel's Actions in post processing. But why? Grrr! To be honest, modern post processing possibilities make star control so simple that it strikes me as being more sensible to concentrate on a system which gets the best object signal. I'm using a RASA 8 and a Samyang 135 at the moment. Native stars are not great in either, but does it matter? Star Xterminator gives me almost total control over them. How does StarX work with Newt spikes? I don't know, but if it doesn't work with them I would would ditch the Newt straight away because star removal-replacement has revolutionized imaging. Olly

Ah, that word, the 'stand...' I know it's a trivial business of words but nobody in astrophotograhy ever uses the word 'stand' to describe a 'mount.' That's because it doesn't stand, it tracks, and it is by far the most important part of the rig. First Light Optics, the sponsors of this forum, will sort you out with the bits you need and will see you proud in future developments. My kit priority order has never changed. It is mount-camera-optics. Yes, optics last. Olly

I'm afraid I don't know. I've never seen one of these. Lucas Mesu is an excellent engineer, however. Olly

I've polar aligned the original Mesus several times and a guest brings one here every year. However, these are not on the angled pier, which has a limited latitude range, I presume. Which one are you using? Alignment is, in my view very easy. The Alt-Az adjustments bolt are beautifully made in stainless steel and are hefty and free from flex. Our guest just uses the Mesu polar scope, which is actually the Losmandy optical tube on a Mesu bracket which simply bolts on and off. He says it works fine and is all he uses. No need for drift refinement. I've never had any issues with balance. I have no clutches but it doesn't seem to matter. Just balancing by feel has always worked fine. My oldest Mesu has the proud boast that it has never, ever, lost a sub to guiding error and that's in commercial use over a ten year period. Olly

You'd like to image 'galaxies and nebulae' but, most of the time, these require different telescopes or lenses. Most galaxies and small and most of the well-known and brighter nebulae are large. There are exceptions but I don't regard a nebula telescope as being the same as a galaxy telescope. Ratlet makes the key point above. For a given camera, a shorter focal length lowers resolution, making tracking precision less critical. There is no point in putting a high resolution (long focal length) setup on a mount which is not tracking to a high standard. The resolution will be lost to the tracking error. I agree that a camera lens is your best bet. Primes work better than zooms, as a rule, but check the astro performance of any lens you consider because stars are odd things where lenses are concerned. Some give good stars, some don't. It doesn't simply go with price. The most important thing is getting your tracking as accurate as possible. A Box Brownie held still will easily beat a Hasslelbad that is wobbling around.

My new workflow using StarX is the most consistent I've ever followed. In the past I'd do things differently at each stage, depending on how the image was progressing. For the first time since I started I can say that I do actually have a predictable workflow now. Processing really is easier than it has ever been, though Paul's meticulous pre-processing has a lot to do with that. Olly

This was one of the best parts of processing the data. On earlier versions I've always worried about whether the orange colours around the Garnet Star were just bloat from the star's light. In this version I can feel confident that the gasses themselves do have this colour. Olly

Imaged with Paul Kummer who did capture, stacking and mosaic construction. I post processed. RASA 8, ASI2600 OSC, EQ6, based here in SE France. I've image IC1396 several times but never like this, with the super-fast system and the X-suite to liberate the nebula from the starfield. Very exciting! In the top right is the start of the Flying Bat nebula. It's a big image, best seen here: https://ollypenrice.smugmug.com/Other/Emission-Nebulae/i-5ZjzWhw/A Olly

This is great. The region cries out for a piece of work like this and you've done it proud. Olly

I think I knew what to expect when I opened the thread! M27 has, I think, been put to bed for at least a decade... Beautiful. No green? Olly

That is a truly magnificent framing. Olly

There is no ionized hydrogen in the Pleiades field so the modding of your camera should not, in principle, affect your result one way or the other. It will be good on emission nebulae though. This target will give you something even in a short integration time because the main stars are bright. After that, it will give and give and give and give as you do more integration. The extended faint nebulosity rewards patience! Olly

It's not clear what we are looking at, here. The green-magenta top image is the subtraction map for background extraction? What we need to see are the original image screen stretched, the background extraction map and the image screen stretched after the map has been subtracted. JPEGs will do fine for a first look. Olly

I can't afford one Hospice de Beaune, let alone one too many (whatever that might be.) lly

We are not just talking about optical physics in discussing an imaging rig, we are also discussing the interaction between the optics and the camera and the data with the processing software and, as Andrew said, the role of other variables like the atmosphere. I don't assert that what I observe derives from the optics. I don't know where it comes from - it is just what I observe... Olly

OK, I've probably zapped that feature in processing but, then again, I can see features in ours not seen in the others. The question marked feature is there in ours but softer - as you'd expect from broadband. Of those posted, I think ours has the most information. This may be down to different ways of looking, of course. Olly

The MN190 deserves a makeover with quality hardware around the optics. 1000mm FL and F5 is right on the money for galaxies and nebulae. The joy of widefield and a fast system, though, is that you can do something new or rarely seen. Whatever you do on M51 will have been done better by the professionals. That doesn't stop it from being satisfying but getting a new perspective on a region is an incomparable buzz for me. Olly

I knew it! I had a glass of Hospice de Beaune the other day and saw the waiter half drop the bottle on his way to our table. I couldn't put my finger on what was wrong with the bouquet but now I realize that it was a nasty dose of viscous shear! (It had separated the berry notes from the truffle.) Olly

Here's a close crop at full size from a work in progress. The stars are lousy but, in my view, Trunk details are good. I can fix the stars very easily, however, and get them good enough for my own taste. They are still not the best but I can live with them... I'm not concerned by how much of this arises from my processing workflow because it's the workflow I use and it does what I want it to do. What you see above is the working reality of using RASA data. The non-stellar parts of the image neither had nor needed any intervention. RASA stars do need attention, though. They also needed it when I was using an earlier workflow. Another example,. Before: After In this case the difference is slight, seen as a crop, but an extended starfield looks much better with the adjustment. When using good refractors the stars needed far less attention and I've had to come up with efficient solutions for adjusting RASA stars. Olly

Perhaps we should be talking about camera-telescope systems. I will take a moment to send you a crop from a RASA 8 image, given a basic stretch, which includes both stars and detailed nebulosity. It will not be at all difficult for me to find such a crop which shows poor stars and good nebulosity. It won't be tonight: I'm old and tired out!! lly

No, I do not believe this. I cannot believe it. I spend many hours per week working from linear data and every minute of those hours tells me it is incorrect. Olly