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Thanks all, will post a link to dataset a bit later. Didn't want to do that if there was nobody prepared to have a go, but as everyone is advising it I will do so. I will also have another go at processing myself. I will also give details on darks, flats, bias etc which were all used. Thanks

Hi, Would there be anyone out there happy to have a go at processing a dataset I have of the Heart Nebula? I'm not particularly great at image processing but I get by, however this one is giving me real trouble! It doesn't matter what I do in Photoshop I cannot seem to get anything resembling a half decent image from the stack. Especially given the integration time (about 5hrs with an astro modded Canon 600D and my 130PDS). I would post a result of my attempts at it, but to be honest I've never got far enough in to the processing to be happy enough to save it. Things go wrong pretty much from the off with initial stretches. I've tried gentle stretches, aggressive ones, colour preserving Arc hyperbolic etc etc and the end result always looks VERY red and background incredibly washed out. Any attempt at colour balance / correction or gradient removal sees a lot of the nebula just vanish. I'm stumped as to what I'm doing wrong. APP gives a bit better result, but VERY noisy and I just get nowhere with startools. So if anyone is up for a challenge then please let me know, I would be genuinely intrigued to see what could be done with it compared to my half baked attempts! Thanks Ed

Thats what I'm planning, but not got round to yet

Thanks @vlaiv, I get what you are saying about the transmission. Looking more closely at the transmission graphs in @vineyard post it looks to me that this does work if the CLS filter is the first one that light hits, as this has wider bandpass ranges than the UHC. The UHC's ranges seem to fall within those of the CLS. But doesn't that mean that the CLS is effectively doing nothing? In my simple head the CLS is filtering out a lot of the surplus light but then its further filtered by the UHC. That is the one controlling what gets to the sensor? I suspect there is something going on here I still don't understand! This is of course also assuming that the graphs are accurate and do not transmit any light out of these bands! If thats not the case and there is a small amount of transmission outside of these bands then all bets are off! Ed

Used magic lantern on my astro modded 600D before I hooked it up to my laptop for control. Worked fine, from memory it was a little fiddly to set it up. So long ago now though that I can't remember the exact steps! Ed

Interesting thread, and to be clear I'm not arguing whether mono is faster or not, I get the theory behind that and I'm still in a quandry as to whether to go mono or not when I finally purchase a dedicated astro cam (mono would be significantly more money though!). I'm just curious as to how stacking filters can work unless they overlap in their bandpass somehow. Even then though, I would have thought its only the overlapping portion that actually makes it to the camera sensor? Watching for the result of Olly's investigation! 🙂 Ed

I'm no expert but does stacking filters work? Surely the filter which the light hits first is preventing the wavelength of the 2nd filter getting through?

That's good to hear, thanks. Would be good to bottom this one out for good as I'm really struggling to choose an alternative which gives as good for, sensitivity etc without spending at least £500 more!

Just come across this thread while researching whether the 294MC Pro is the camera for me. I had long got it on my shopping list but recently saw all the negative comments surfacing about using it with a dual or tri band filter.... something I would be interested in medium term as it seems the only clear nights in the south UK are full moon 😒 So am I right to assume from this that there should be no issue with the 294 and dual or tri band filters if the gain is upped to 200 in order to get on the linear part of its response? (for subs and calibration files) Thanks Ed

ok, thanks all. Will be buying in the UK when I have the funds.... and can make up my mind as to which camera to buy, but thats a different story!

ok, thanks for replies. I do agree but when there is such a substantial saving to be had its worth exploring. Sounds like a UK purchase is still the way to go...

Hi All, Has anyone purchased cameras from ZWO directly? I would normally be very supportive of purchasing from a local shop, or UK based but the savings I could potentially make on buying direct from ZWO are significant. Though I appreciate I could get stung for import duty etc. Hence the question, any real world experience from anyone would be appreciated. Thanks Ed

Alacant, do you have details on the springs needed, strength, length etc? Thanks

As long as it's cloudless as well! Wet here in southern UK tonight. Clear skies forecast tomorrow night though so fingers crossed!

It does come out if the back focus yes, but a 10mm extension ring solves that and moves the recessed part of the baader out of the way of the securing screws on the focus tube. That's one of of the causes of slight tilt with the baader.... So kills 2 birds with one stone. I'm sure there must be a way of working out how much of the primary you would lose by pushing it up the OTA 10mm but I can't figure out the maths on that. I'm also researching whether a screw in fixing on the end of the focus tube is lower profile than the original, if so it would further reduce the focus tube protrusion meaning even less requirement to move the primary up the OTA.

Exactly that yes. It has the added advantage of pushing the recessed part of the baader down the focus tube enough to no longer interfere with the securing screws.

There is an alternative route that doesn't necessarily mean the extra expense of the GPU (over the Baader) or cutting the focuser. You can get low profile DSLR adaptors from the likes of FLO. They add 1mm to the image train rather than the normal 11mm. So you are half way to getting that 20mm needed in order to keep the focuser out of the OTA. This is where I'm at currently and I intend to get the other 10mm by moving the primary mirror up the OTA by 10mm and using silicone sealant to secure it to its mount. Trouble is I can't find details on what screws and springs people have upgraded to in order to move the primary! What I would say is that the GPU seems to be less sensitive to tilt than the Baader from everyones experience on here, but is significantly more money. So there is obviously a choice to be had there! Baader+ roughly £30 on extras to get the focus tube out of the OTA (or of course chop the focus tube), or go with the GPU knowing you won't have the OTA protrusion problem right from the start. I'm sort of stuck with the Baader route as I had already purchased it so its a no brainer to spend a small sum on the mods rather than £250 on the GPU. Ed

Hi Martin, Question regarding this please. I've been holding back on buying a 294mc Pro because I saw all the issues that were coming to light with NB filters etc both on this forum and CN. Though I must confess I've not looked of late. Are you saying that if you use a gain of 200 rather than 120 then all these issues with whacky patterns etc go away with calibration frames? It was really putting me off the 294 as it seemed like the perfect fit for my requirements up to reading about the emerging issues. I know some have gone to the 533 instead but the sensor is so much smaller Thanks Ed

Does anyone have details on what longer collimation screws and springs I would need to buy in order to push the primary mirror up the OTA a bit?

On the topic of the draw tube protruding I'm going down a path that will hopefully allow me to get to a point where I've cured it without having to chop the end off and still use the baader mpc. I'm half way there currently but this is what I've done so far: Purchased one of these: https://www.firstlightoptics.com/adapters/ts_m48_eos_s.html At the time the Flo website said it didn't latch in to the camera like a normal bayonette fitting but I can confirm it does and so is 100% secure. With it only being 1mm optical path you gain 10mm over the standard Eos adaptor. However, you also need a 10mm one of these: https://www.rothervalleyoptics.co.uk/rvo-m48-extension-tubes-various-lengths-available.html This keeps the baader spaced at the critical 57-58mm, but inside the draw tube now rather than via the older 11mm Eos adaptor. It also has the added benefit of pushing the recessed part of the baader mpc down the drawtube, allowing the drawtube fixing (in my case an aftermarket compression ring) to clamp to the 10mm extension tube instead and so prevents the issues associated with the baader tilting when clamped. This has halved my drawtube projection in to the OTA and works perfectly. The remaining 10mm I need to lose will be done by fitting longer main mirror screws and springs. Haven't done that as yet as I don't know what items to source! It's cost me £40 so far which for me is money well spent to not have to chop the drawtube and continue to use the baader. Hth Ed

Can someone tell me what removing the x4 rubber grommets on the focusser achieves? I've had a quick skim through the last few pages of this thread but not seen any explanation. Thanks

I was about to ask exactly the same question about how to confirm the seeing conditions on any given night. I use NINA, which shows a FWHM graph for stars in each image - I thought that was focus related, but is it effectively the seeing conditions for that image? Thanks Ed

Needs to be just enough to keep the temperature just above the dew point but no more, you don't want to create warm air thermals!

I've had all sorts of trouble with my astro modded 600d and banding, though straight horizontal banding so not quite the same as yours. I went through a LOT of trouble shooting to get to the bottom of it including the following: Different USB cable, running both the camera and laptop from their batteries rather than mains adaptors, saving images to the camera SD card instead of downloading 'on the fly', rerouting USB cables, different ISO values, different exposure lengths, and different stacking software. Most of the above made no significant difference at all, but swapping from DSS to APP to stack, using ISO800 and exposure lengths of 4 mins have reduced it significantly. A really aggressive stretch will still show some issues but it is greatly reduced. Shooting the Orion nebula the other night I did some 30s and some 10s exposures for the core and the banding was way more evident in those, so its definitely something to do with needing to get above the read noise etc of the camera. According to this article the best ISO for the EOS600D is ISO800 http://dslr-astrophotography.com/iso-dslr-astrophotography/ I hope some of this helps! Your banding does look different so it may not be this, but worth knowing just in case. Ed

Thank you, yes I did, always seem to need an LP filter despite my location 'only' being Bottle 5. I get some horrid gradients and colour cast otherwise. I use the Astronomic CLS clip in for my EOS600D.