Budgie1

That's a bit more than I was expecting. Like @scotty38, I have the ASI294MC Pro and that does vary from -10° to -9° when shooting darks in the house, and I don't tend to worry about the 1° change. Looking at my darks library when I shot at -15°, there was no variation between the Dark Subs. But 3-4° is a bit more of a variation, so if the freezer pack is helping then that may be the way to go. If the power & USB cables are long enough, what about putting it in the fridge to shoot the longer frames?

How much is the sensor temperature varying by?

The 2" Askar is only £20 more than the 1.25" L-eXtreme, so price wise the Askar wins and if you're looking for the 2" version then FLO has one on offer at the moment. Like I said above, I haven't had chance to do a direct comparison between the two filters. They seem to be about equal on the amount of Ha they pick up but the Askar seems to get more OIII, but that could be down to a change in my processing or that I'm using more data.

I dither every two images and haven't had any problems with either APT or PHD2 ignoring the command.

I don't know about the LPro Max vs L-Pro, fortunately I'm in a Bortle 2 area, so only use a UV/IR cut filter. I have, however, used the L-eXtreme for near full Moon nights with the ASI294MC and it works quite well. As long as you're not that close to the Moon it does allow you to take 2-3 minute exposures with little effect from Moon glow. The filter is also very good on Moonless nights for emission nebula like the Flaming Star, Jellyfish & Heart. I used to use the 1.25" version of the L-eXtreme but have now got a filter draw and swapped to the 2" Askar Duo-Band filter, which also works very well. I haven't done a target comparison between the Askar & L-eXtreme, but it's worth considering. This is 3 hours of the Rosette with same camera, scope & mount you have, only using the Askar filter:

Dew Control have a choice of connector, RCA, cigar plug, 2.1mm or 2.5mm. I've not tried their dew heaters, but it would save adding more kit.

Nothing in the post yet up here.

I asked about the camera and filter because the effect looked similar to what I've seen with my ASI294MC Pro when using the L-eXtreme filter. As your camera is the Da version, I assume it's only had the front filter removed, so has retained the UV/IR cut filter? I'm just wondering if the addition of the L2 filter may be causing something, have you tried taking the flats with the L2 filter removed, just to rule that out?

Which make & model of camera do you have and are you using any filters with it? It may also be handy to know what the camera settings are, in case that has any relevance.

I love spending other people's money! 🤣 No light leaks but have a read of THIS POST I made when I first got the Filter Drawer and make sure you get the right holder. Since making that post I bought another spare filter holder (with lips ) so I don't have any issues. I have the 1.25" version of the L-eXtreme which I started using with my ASI294 MC and that is good. The Askar Duo-Band (like the L2) I got during a FLO sale and it was the 2" version, which is why I went for it. I've used it a few time now and it works well, although I haven't done a direct comparison on a target which I've imaged with the L-eXtreme. I would say that, if you can't quite stretch to the L-eXtreme, the Askar is a good alternative. Here's the last two images I've done with the Askar filter:

I also started with the 1.25" filter inside the 11mm spacer but I now use the ZWO Filter Drawer which replaces the 21mm spacer and this allows me to use 2" filters. It also means I can change from the UV/IR cut filter to my Askar Duo-Band without removing the camera from the scope. The Filter Drawer is placed in front of the 11mm spacer on the front of the camera, so the filter is the last thing the light passes through before it hits the sensor.

I've just noticed the field flattener you're using, is it a Stella Mira FF? If it is, I got one so I could use it with my Evostar 100ED DS Pro to allow me to use the full 900mm focal length and I never get good sharp images with it. I tried it once with my 80ED DS Pro and that was the same, so I now only use the SkyWatcher 0.85 RF/FF for each scope. It may be worth trying an imaging session on a target you've previously imaged with the FF, only try it without the FF to see if there's any difference with the star bloating. You won't get the flat field but concentrate on the centre of the image and see if there's an improvement or not.

No problem Lee, It doesn't matter which software you use for post-processing, they all take time to get used too so you know what they can do. When it's cloudy or I have some spare time in the evenings, I reprocess an older stack to see if I can make it better then the original. I also pick up hints & tips off videos and try them out. Some work, some don't but I can tune my workflow to include those that do. The best processing software is the one you're happy and confident using and the one which produces the best results for you.

The workflow I use in PI is to do the background extraction and noise reduction before stretching. Then use StarNet or StarExterminator to separate the stars from the background, so I can work each of them separately. Once stretched, the larger stars had more of a magenta fringing to them. PI has a script for removing this, which gave them a bit of the blue fringe, so I lowered the amount of blue using curves. Once I was happy with the stars, I moved on to the nebula and played with various tools to get that to where I thought it looked good, before combining the stars & background together again.

The main reason was that it was in the FLO sales at a much reduced price! Apart from that, the L2 is for general use with a corrector/reducer and the colour correction on my 80ED & 100ED isn't too bad. Having processed your Rosette image, the L3 may be the better option for your setup. I've done a process in PI and it's below. The focus is fine and there's good detail in there, I haven't removed too much of the background gradient because it would make it too black and remove some of the Ha nebulosity from the edges. The stars have been reduced, but not too much, and I removed the magenta from around them. There isn't that much noise in the image TBH, but it's easy to introduce it so sometimes less is more when processing. Anyway, here's what I got. I may have another go at it tonight as I'm not happy with the dark rings around the stars in the centre of the nebula and it's looking a bit washed out.

Both the ASI183MC Pro and ASI294MC Pro only have AR coated window. If you're not using any type LP filter then a UV/IR cut filter should help reduce star bloating, if you're seeing this in your images. Although the UV/IP cut filters are cheaper than other types of filter, you still get what you pay for, so I wouldn't go for the cheapest version. Something mid range from a good filter brand should do the job.

I've always put any filter right in front of the camera sensor, so it's the last thing the light passes through before it hits the sensor. Whether this makes any difference, I don't know, but it works for me. I have the 2" ZWO UV/IR cut filter and I've just replaced it with the L2 for use with my ASI294MC Pro in Bortle 2. I've not really had time to see if it makes a difference as I've only had a couple of clear nights when I've used it, but the last image is below. Mine is connected to SW Evostar 100ED DS Pro with a 0.85 FR/FF. How do you check your focus? I only ask because the image of the Rosette looks a bit out of focus, when looking at the dust, bottom right of centre, and this will effect star bloat as well. Processing can also have an effect, like over stretching the image trying to wring out that last bit of data. If you want to post one of your stacked files, I can put it through my normal work flow in PI to see what it looks like.

One other thing with using this type of filter with ASI294MC; if you find you're having issues getting the flats to calibrate correctly then use a gain of 200 and offset of 30 and they should calibrate correctly.

You should have a 1.25" filter adaptor which screws into the 11mm spacer on the front of the camera. This places the filter as close as it can be to the sensor, avoiding vignetting, reducing the chances of reflections and allowing the whole sensor to be used to capture the image. I've not used the ZWO Duo Band filter, I have the L-eXtreme which I use with my ASI 294MC Pro, but you'll need to use it on emission nebula, which mostly have Ha & Oiii, like the Heart, Rosette & California. They don't work well on planetary nebula and galaxies but they do allow you to take longer exposures during the full Moon period, which is what I bought the L-eXtreme for.

You should be able to run the ASIAir from the 12v cigar socket and then run the AZ Gti and the cooling for the 183MC Pro from the ASIAir power ports. The 183MC & 224MC should be fine running off the USB ports on the ASIAir. This means there's only 1x power cable from the tank to the mount and shorter cables on the mount, so less chance of snagging. Also, the cooling on the 183MC won't be running at 3a all the time, maybe just until it gets down to the set temperature, then it will idle until it needs a wee boost for adjustment.

The editor is normally a What You See Is What You Get style but there is a Preview button at the top of the text window, last on the right.

There are Pros & Cons, even to dark sites. I'm also one of the those 0.01% who live in a Bortle 2 area and the skies are fantastic. On the flip side; I also live in one of the wettest parts of the UK, with only 5 rainless days through Jan & Feb this year (that's rainless, not clear!). Between mid-May and mid-August we have Twilight all night, so it's too light to trying any imaging. By the time it does get dark enough to image, we're well into the season of Clan MacMidge, and that can last into October! Would I change location? Nah! Oh, and if you haven't experienced Clan MacMidge, here's a wee video for you, see if you can watch it without scratching:

Not really helpful if you're using StarTools but, I ran your image through PixInsight to see that I could get with the data and here's the result.

I thought I would enter this one as well. This has NGC3718 as the main focus with NGC3729 above it and ARP322, a galaxy chain, to the left. Subs taken on the 31st March and I used 1h21m 180s subs, taken with ASI294MC Pro on an Evostar 100ED DS Pro with 0.85 FR/FF. Stacked in DSS & processed in PI.

I put your stacked image through my normal workflow in PixInsight and there is colour in there, but it needed dragging out. As Vlaiv has already said, there is something not right with the stars. I my processing they have a blue halo on the right of the nucleus and the focus seems to be a bit out. A UV/IR cut filter will help with the halos and I would advise going for a mid-range one. The cheaper ones don't always do what you expect them too. With DSS stacking, you don't need to ditch the subs with satellite trails (star trails yes). In the Settings > Stacking Settings > Lights > Set the Stacking Mode to Kappa-Sigma Clipping and leave the other settings at default. This will remove the satellite trails for you. If you want to remove the green cast, which is normal on OSC camera because the bayer pattern has 2x green to 1x red & 1x blue, then on the same setting page as above, look towards the bottom of the page and click on "RGB Channels Background Calibration" > make sure "RGB Channels Background Calibration" is ticked > click "Options" > on the new tab "Calibration Method" should be set to "Rational" and set "RGB Background Calibration Method" to Minimum. Here's what I managed to get using a quick process of your stack: