ollypenrice

I think it's pretty damned close. I still think the blues would stand more saturation and, in Photoshop, I would use Selective Colour to lower the cyans in red. This is a demon tweak for anything Ha. Olly

As others have said, this is a great start. You picked a popular but very difficult target, the only one on which I've found multiple exposure lengths to be unavoidable. Combining them is quite a complex process but can be done. If you don't have any short exposures you can use a very soft stretch to replicate them. How blown is your core in the linear image? It cannot be 'de-blown' but there is no reason for the brightest parts to get any brighter. This is a good photoshop tutorial. https://www.astropix.com/html/processing/laymask.html This is the method I always use on M42 to produce something like this: https://www.astrobin.com/321869/B/?nc=&nce= Exposure time in One Shot Colour and Mono? There's no free lunch. An OSC captures red on a quarter of its pixels, green on half its pixels and blue on a quarter of its pixels. It might be better to replace the term 'one shot colour' with the rather cumbersome, 'quarter of a shot red, half a shot green, quarter of a shot blue.' When a mono shoots through a colour filter it shoots that colour onto all pixels. There's not much overall difference in that respect. On faint targets, though, a mono can shoot luminance on all pixels and this picks up faint signal very fast. You don't actually need as much colour as luminance so mono starts to pull away. It's also much faster in narrowband. In theory there is a slight resolution advantage in mono but, in reality, you will be very unlikely to be able to see it. Olly

As a proof of concept it's a total success, no? Olly

There are too many variables for a clean answer. How reflective are the curtains? How reflective is the window glass? How reflective are the surfaces newly illuminated outside and how much of that reflection is directed back into the room? If someone holds mirrors up outside the window, the room will surely get lighter. If the curtains are made of glitter and the window looks onto a mat black wall, it will get darker. It would only need a photographic light meter to get a good idea of the reality. Most cameras have them built in... Olly

Interesting. I'll have another look at my own raw Glob data if I can still find it. Olly

Very good. M78 is an absolute devil of a thing to image in my view. I seem to remember Steve Richards saying the same. The one bit I'd be inclined to work on would be the large, bright blue patch of nebulosity. I bet you could get more structure out of it if you held the brightness down, and more colour as well. Anyway, this is a good result on a tough target. Olly

Perfect - and you can't often say that about images of globulars. That really is tight, bright and controlled. Olly

Lots to enjoy in that one, Dave. The processing has a soft but precise touch. Olly

Very nicely done. I think you may be surprised by how little of the nebula will fit on your four panels! It gets bigger and bigger the deeper you go... Just giving you fair warning!! lly

Given the ease with which the moon and planets can be found, I can't see much benefit from the GoTo. On the doubles, yes, it might be a help. I'm sure you'd be disappointed on DSOs, however. Olly

To back up Dave, above, AstroArt can also correct identified-column defects. You just need to know what column it is on the x axis, plug this in on the third page of 'Preprocessing' and stack as usual. The defects will vanish. I used my CCDs like this for many years so being on the way out is a slow process. What I have never seen, though, is a column defect which varied between filters. If it's caused by dither, you're using a big dither for a CCD. Just identify where the line lies on the x axis and see if it's the same. I think it will be. Olly

Tremendous. I think you've established a connection between the Breaking Wave and the PacMan, something Tom and I failed to do in our original Breaking Wave. I think I'll go back to the linear data if I still have it and process using the modern tools. Olly

I'm afraid I'm tempted to say 'Neither,' but let's begin with your criteria. You've gone for 4 inch aperture and this does make sense for visual observing. Deciding on an aperture, as a first step, though, makes no sense at all for imaging. An experienced imager would think like this: 1) What can my mount support a) in terms of weight and b) in terms of tracking accuracy. Longer focal lengths image at finer image scales and need more accurate tracking. A very good EQ5 can, under autoguiding, run with a tracking error of about 0.5 arcseconds. You might find it's more like 0.8 or 0.9 arcsecs, though. Whatever it is, you need to multiply that by 2 to find your finest useful image scale. So a guide error of 0.5 arcsecs allows an image scale of 1 arcsec per pixel. An error of 0.8" can image at 1.6 arcsecs per pixel, etc. As a beginner I'd want to be imaging at nothing finer than 2 arcsecs per pixel. Try any scope-camera combination in this calculator to see what it gives. https://www.12dstring.me.uk/fovcalc.php 2) What field of view do I want? Shorter focal length = wider field of view. The calculator above will show you what you'll get in a variety of combinations. 3) How fast do I want the system to be? F ratio is a useful indicator if you're careful or if the camera is already chosen. You can also speed a system up by binning your pixels to make them effectively larger. The requirement to do visual and imaging with one rig is a bit of a problem since the requirements are not the same. Keeping a Dob for visual and going for an imaging-priorty Apo gets round the issue. If I were starting out in imaging I'd probably go for this: https://www.firstlightoptics.com/william-optics/william-optics-redcat-51-v1-5-apo-f49.html. Flat field, sharp stars across a large chip, tolerant image scale, fairly fast and good colour correction. Olly

I'll have you know that my PC is not covered against being soused in spat out coffee! I'm already searching for ways in which I can delight my friends with this phrase... lly

This unfamiliarity is the charm, though I wonder if it's to everyone's taste. I once had a guest who was not too pleased with the Heart Nebula he captured here with the dual Tak106. It had way more outlying signal than he was expecting or was used to and I think he wanted a more familiar view. My feeling is the reverse: I love to find what I haven't seen before. Olly

Plenty of resolution in that one. Olly

I don't have many issues with colour, other than blue sometimes being too saturated. The adjustments I need are to brightness and dynamic range. I very often need to subdue the brightest parts of the image and sometimes need to lift the dark stuff up a bit. My monitors are about 12 years old and I use a Datacolour Spider. The problem with this is that I can't increase the screen brightness as much as the spider demands and a friend to whom I lent it said the same. I suppose I should just shell out for a pukka monitor, really, but I'd welcome your input. Olly

Stunning in view of the circumstances. This rig is going to sing. Seen at full size I think it's a little over-sharpened but what the heck? Olly

It's a long way for me, now, but I used to love it. Olly

Are you talking about the Short Tube 102? Olly

Since this is part of what I do professionally, I had a good excuse for A3. At least, a good enough excuse to get past my feeble conscience! I use the same. I calibrate the screen using a spider. I do print from Photoshop using ProphotoRGB colourspace. Do I calibrate the printer? Now there's a question! Since my best answer is, 'I don't know,' I suspect that the real answer is 'No.' All advice welcome... Olly

I firmly believe this, but it's easier for me because my colours are more or less right from the stack and rarely need more than ABE or DBE and a bit of SCNR green. I wonder what the uncalibrated image would look like with a big dose of SCNR green because, apart from the blues looking green, the colour looks good. Olly

For me, a £500 budget for a refractor to look through would be second hand without a doubt. I'd want 4 inches minimum and a semi-apo spec. Olly

Nice to see all of it! Olly

That's a really interesting one with similar irregularities on the right hand side. Olly