Fegato

Already said I think, but I would look at the L-eNhance as an extra tool in the box. Given that you have fairly dark skies, you don't "need" it for many targets. It mostly depends what you are trying to achieve in your final image. I have used the L-eNhance, and I have the IDAS NBZ dual narrowband filter too, as it works slightly better at fast speeds (I have a RASA). However, as I've gained experience and learnt about what I'm doing, I've realised that in Bortle 3 I am blessed with the potential to just shoot all my images in broadband if I want to, and this includes favourite narrowband targets (star removal during processing is a key part of this too). You just get a very different take - dust and subtle colour shifts versus the bright colours and different palettes often used in narrowband imaging.

For the last couple of weeks I have had the luxury of multiple consecutive clear nights with no moon here in SW Wales. The rig was wheeled out on Friday 12th, and only brought inside on Wednesday 24th due to a trip away, albeit the moon was starting to encroach by then. I chose this target for a three panel mosaic, as it was just about high enough in the sky for my N / NE sightlines - I found that I could get the flying bat and the seahorse nicely into one image. This is what you get with a broadband Sh2-129 - no squid! But there are alternative joys to be found - dust and reflection nebulosity in particular. RASA 11 v2 on CEM120, ASI2400MC Pro, 3h 45m of 30s exposures over 3 panels. More detail at https://astrob.in/xq0tqd/B/

OK, my final offer is the Moon, Venus, and a fast moving bat, almost perfectly aligned!

a quick snap (with my Fuji XT20) before the sun has gone down - Venus just about visible if you look hard!

high hazy cloud here... should be clearing soon hopefully. Can just see the moon, but no Venus yet

Nice one! Stars are manic in this area, but must admit I'm doing the DBE star removal thing with every image now, just makes it so much easier to see what you're doing.

I think the core can blow out due to the stretching, as you're often trying to bring out all the dust and dark stuff in this area. So I've tackled it with masks (range masks in particular), having used my "standard" exposure length for broadband (30s in my case). If it feels too bright even after that, you can try HDRMultiscaleTransform - I've sometimes had success with this. Or you could even use full HDR processing if the core really is blown out by 300s and you have the multiple exposure times. It's a tricky one, as the more you stretch the dust, the more you have to bring up the core anyway in order to keep it looking "natural", there's a limit to how much you can sensibly mask. Here's my latest attempt at this - https://astrob.in/fw81wa/0/ - I've really brought the dust out, so the core is quite bright

Might have posted this pixel rejection image before, but here's my worst - shorter timescale (about 1 hour), wider field (approx 3 x 2). Stretched a lot.... image was Sh2-150 in Cepheus, but not very good - perhaps the pixel rejection was so excessive it ruined the SNR.

Maybe you know this bit already, but in addition to the exposure tolerance, you can use the Grouping Keywords (on the right) alongside similarly named sub-directories to flexibly pre-process different groups of subs. So you might calibrate separately (due e.g. different flats or exposures), and then stack together. Or calibrate and stack separately (e.g. mosaic panels). And with the subs and flats in the appropriate sub-directories you can load all in one go using the Directory button (bottom left). re: adding subs later - no problem, but to get the benefit you need to run ImageIntegration on the whole stack again (obviously don't have to re-calibrate the old subs, but you might not be able to do this flexibly in WBPP)

Nice one! I have a RASA 11 too and shoot in Bortle 3. I don't shoot longer exposures than 30 seconds, and that's still quite heavy on saturated pixels. You may find your stars are a little easier to control if you reduce your exposure time, and certainly easier to get some colour in to? However, difficult to stop the flaring artifacts given the wires across the corrector plate, however well you organise them, and however short the exposures. Not sure what your StarXTerminator issue is, but FYI StarXTerminator is also designed to work with a stretched image. I use it 2 ways, linear and non-linear: 1. With a linear image, unscreen stars box unchecked, I will often remove stars in order to make DBE easier to apply (note - need to apply DBE with normalise checked). I then add back in straight away ($T+stars) before colour calibration etc. Adam Block has a youtube video showing how this can be really useful when starfield is quite heavy making DBE difficult. 2. After a light stretch (to whatever star intensity I think I'm after), I remove with unscreen stars box checked, and add back in right at the end of processing - iif((stars <=0.01), stars, 0.001); ~(~$T * ~stars). RC explains the unscreen issue here - https://pixinsight.com/forum/index.php?threads/unscreening-and-re-screening-recombining-stars-with-starless-images.18602/

Yes I had a small vignette with the ASI294MC Pro with mine too, but always pretty even as yours. Agree about the stars - if they're not too bad, then implies collimation should be close. And I forgot about the filter draw - but that would have to be wonky to produce that end result presumably? re: the Starizona recommendation to start fully pushed in, that always seemed a bit silly to me, as you can then only move in one direction (albeit it does ensure you're totally flat I guess). I used John Hayes recommendations as here - https://www.cloudynights.com/articles/cat/articles/the-amazing-hyperstar-a-guide-to-optimize-perf-r3013

If that's vignetting, it's strange how extremely off centre the sensor is to the light path, given the way the Hyperstar attaches. Sorry if obvious questions but did you reset the Hyperstar so it the adjustment screws were all at the same level (e.g. using small shims)? And is everything totally tightly attached? Beyond that, yes collimation is the first step

Ha ha! Yes it is quite a bright - I had a go at it last month. I had some advantage though - dark skies, no moon, a very fast scope, and more to the point, no 3nm filter! https://astrob.in/6n78xm/0/

I use NINA, the latest release version. There are some specific settings for the Meridian Flip which provide lots of flexibility and allow you to set things up so that minimum time is wasted and/or you take advantage of your mount's ability to run beyond the meridian. However, you need to get these set up correctly for your mount settings in order to make sure that it doesn't get stuck - you can have the settings such that the mount stops before NINA performs the flip. Once the settings are correct, I've not had a problem with it - works every time. I can't say NINA is better, as I've never used anything else (apart from Sharpcap, which I still use for some things). However, I will say that I really like it - loads of capabilities and continually improving. In particular: Framing Assistant is excellent used with the colour HIPS sky survey; the new Advanced Sequencer provides a very flexible tool for setting up long imaging sessions (with my RASA I will run all night on multiple targets); auto focus is great, and with Hocus Focus plug-in there is an Aberration Tool which has been a Godsend for me in sorting out tilt.

Well done, that is a beautiful Pleiades!

Thanks Dave! My skies are just about Bortle 3. It's darkest to the North, and I have low light plumes to SE and SW, but yes, due South is pretty decent. There's a low wooded hill that prevents me going too much lower than this, but that probably helps a bit too - not a single artificial light to be seen.

thanks Olly!

We've had a number of clear and moonless nights in the last week, and I had my eyes on the Blue Horsehead Nebula. It's very low here - max just over 18 degrees altitude - but you can get almost 90 minutes imaging it in astronomical darkness at this time of year, so I thought I'd give it a go. I needed a 2 panel mosaic to get the framing right. On the first night I shot panel 1 and it looked promising, and I thought I maybe had just about enough data, so set up panel 2 the following night. Scratched my head the next morning as the frame looked very similar to the previous night - ah, I'd put panel 1 into the sequencer again! (doh!). A third clear night allowed me to have a go at panel 2, but clouds came in during the early hours and ruined it. A fourth session really suffered from the wind - it wasn't really a night for imaging, although I got about 40% just about usable subs. Fortunately a fifth night got me a completed panel 2. Really lucky to get that many chances, doesn't happen here very often! Anyway, here it is. I've tried to keep the processing reasonably subtle, and despite the name, I've been purposefully light on saturating the blues. Acquisition details - RASA 11 v2 on CEM120, ASI2400MC Pro, no filters, 190 x 30" (1h 35'), 250 x 20" (1h 23')

Yes, but the speed of the scope (focal ratio essentially) has a big impact. My RASA 11 is F/2.2. This has roughly a 5x exposure "advantage" over F/5 for example and 10x over F/7. Obviously camera, target, sky conditions, and filters all come into play as well. Certainly narrowband will generally need longer exposures - I'm usually around 60s -180s when using a dual narrowband filter, depending on conditions.

It partly depends on your set up and how long your subs are, but you really want as many as you can use, as it's all about reducing SNR, and the more subs the better. I certainly wouldn't take the approach of only picking the "best" ones. I find I reject less and less. I use Pixinsight, and the pixel rejection algorithms allied to the improved weighting capabilities mean that it can pretty much sort it out for itself. I do like to blink through all the subs to see what I've got, and I will reject ones with very clear cloud impact or trailing stars, but I've largely stopped bothering about FWHM and eccentricity - I just let the software sort that out based on the weightings. I have a RASA and it's a bit of an extreme instrument, so 30s is a max exposure for me in broadband. I'll normally be looking for at least 120 subs to stack, but can get good results with less that that. But I'll rarely count something as finished with less than 60 or so. As well as the need to get the best SNR, the pixel rejection algorithms just work better with lots of subs.

Spotted this - does sound like you need to convert your TIFF files to FITS... https://groups.io/g/DeepSkyStacker/topic/tiff_files_come_out_as_gray/80969992?p=

NB for the future, now you've got the 2600, I would save in FITS format in NINA rather than TIFF so you get all the Astro header data included.

That's what you would expect out of NINA - 16 bit greyscale. The debayer should turn it to RGB. If you make a sub available I can look at it in Pixinsight and debayer if you want?

I don't use DSS, but I'm a bit confused as to why you got a greyscale image? L-enHance is a dual narrowband filter and should give you a colour image if you use OSC and process it as colour. It's also got quite wide bands, particularly on the blue/green, and should give you a decent M101, enhancing the Ha quite nicely (albeit, longer exposures required). All I can think is - did you run debayer on the subs? It will be greyscale until you do this...

Thanks! I did have all sorts of trouble with it - I think bright galaxies and faint IFN is a particular challenge!