ollypenrice

I ask you, what kind of person with that kind of wallet only has one two-inch eyepiece? lly

In intensity but not in delicacy, I think. Olly

False click. Sorry.

I think that a tweak with the highlights filter in Ps Highlights and Shadows at a late stage in the stretching would be all you'd need - or a curve which flattened a little earlier. Indeed, spotting it is the thing. Regular checks zoomed in to 100% are essential. Personally, I don't process for pixel-peepers so I check at 100%, not more. Another key technique is to apply noise reduction only where it's necessary, in the faintest signal. One more thing, too. For some time I have been halting my Levels stretches once the background sky is up to my desired brightness. After that, I pin the background and stretch only above it. I see no reason to drag the background towards the noise floor. Olly

PS, I lost touch with Sid after I left Scunthorpe-Under-Railbridge but, while I was back up North, I bumped into him in my Aunt's kitchen. He'd become a real fridge magnate. Olly. I am grateful to another SGL member for messaging me with this pun. For reasons incomprehensible to me, she was reluctant to take the credit for it...

Any image can be stretched beyond its useful data content and its noise floor. If we do this we cannot blame anyone but ourselves. The use of a fast system makes it harder, not easier, to stretch too far but every data set has its limits and we should respect them. Looking at Lee's image at the scale presented, I see no evidence at all that it has been pushed too far, but that's me and my perception. (If I were to offer a comment it might be to be a bit more careful about the white point, which may be clipped slightly. However, the faint regions are the best I've ever seen.) I have to say that StarX and NoiseX may well be the holy grail of imaging from my point of view. The separation of an image into zones requiring different processing has always been the key to creating a good picture and the separation of stars from background is the most potent-ever expression of this. It's not just that softly stretched stars can be put back into a hard-stretched image: the imager can see what they are doing while working on the uncluttered nebulosity. Although I've used StarX on some photon-hoover datasets, most of my time with it has been spent revising older images from slower systems. StarX is also of particularlu high value to widefield imagers because it overcomes the key weakness of small aperture optics: they give larger stars. Nice as they often were, camera lens images were given away by their large stars. Not any more, though. I've been drawn into the Samyang 135 fold precisely because of this. Olly

This won't be relevant to your problem but darks are likely to do more harm than good with a DSLR. Olly

Shapes can resemble each other without being fractal. Certainly a candidate. I think that, as Jim says, the local physical forces (and particle abundances) will be comparable. Olly

I'm seeing convincing traces of hydrogen here for the first time and I have enough data on this target to sink a ship. Brilliant. Absolutely brilliant. Can't wait to get started. Olly

Oh, I thought it was on show at Sid Selfridge's shop, just down the road from where I lived in Scunthorpe-Under-Railbridge. I should've known because Sid used to sell fridges, mainly... lly

If I were going to spend 11 grand on a visual observing setup, it wouldn't be that one! As well as disliking the price, I take exception to Selfridge's inability to use capital letters properly. How very parvenu of them, my dears. lly

Inspired by Fegato's excellent recent image of this target, I went back to two sets of data I have on it and combined them. The first was refractor-CCD-HaLRGB captured with Gnomus and Mrs Gnomus some time ago, the second a recent CMOS-OSC-RASA 8 set with Paul Kummer. Having StarXterminator was a huge bonus when stretching the faint dust. Olly

I must admit that I'd go further, but it's a purely personal thing. Olly

I really like it, too. Great processing to end up with small stars and a smooth transition into the notoriously difficult and bright core. Olly

Good! Olly

Stunning result, all the more so for the integration time in narrowband. Olly

Nice. I might be inclined to let the black point up a bit. Olly

I strongly suspect you could wring more colour out if it. Nice and sharp with perfect framing. Olly

Lots going on there... Olly

That's a good result. I can never see any significant difference in quality between finished TIFFs and JPEGs so I wonder why you do. It may be to do with the colour spaces in your workflow. I process mostly in Photoshop set to the Prophoto RGB colour space. This has the broadest colour gamut available. When I'm done, I go to Edit - Convert to Profile (not Assign Profile)- and convert to the internet standard, sRGB. However, I resample my JPEGs down to smaller image sizes as I convert to JPEG. A bit of experimenting might help to sort out your issue but I'm not up on the technicalities. Olly

What are you trying to do? The F ratio is altered internally within the lens by closing or opening its iris. If the camera and the lens are digitally connected, the camera can be used to change the opening of the iris. If not, the iris must be adjusted manually on the lens. However, many astrophotographers prefer not to stop down the aperture (increase the F ratio) by using the internal iris of the lens. They prefer to reduce the aperture of the lens by using a circular mask on the front, often a step-down filter ring, or several rings threaded into each other. The advantage is that this reduces the aperture with a circular obstruction which won't create spikes or artifacts around stars. The internal iris stops down with a set of blades approximating to circle. This is fine for daytime photography but not good for stars, which are better if the stopping down is done with a circular reduction. Olly

I suspect that the importance of back focus will be far greater for deep sky imaging on a large chip than for planetary on a small one. Olly

Superb. I wonder if any of this could be picked up by a very fast broadband rig in RGB. One of the drawbacks of HaLRGB imaging is that it lets us prioritize the hydrogen so easily using an Ha filter. We can get a deep hydrogen image that way without spending so long on the broadband, thereby causing us to miss the deepest broadband signal. I like broadband-only images for precisely this reason. The Ha is downplayed relative to the surrounding dust and emerges from it more naturally. Olly.

Great image. I've done this in HaLRGB with the Tak FSQ and CCD. Yours is a much finer image. The great thing about the RASA-CMOS combination is the delicacy and finesse of the dust it can capture, which is particularly good here. Olly

My opinion is that, in using a camera with a chip smaller than full frame, you are wasting a lot of what cost so much to build the scope. That large illuminated field is probably the scope's biggest single asset. I used mine with full frame and relished that vast field of view. A kind of One Shot Mosaic! As for pixel size, with a focal length of just over 500mm, you don't have to worry about oversampling. Small pixels are good news. I agree that the 2600 is a great sensor (we now have two here) but, in an FSQ106, I'd want full frame - especially after what I'd paid for the possibility! Olly