Nigel G

Thanks Ian. The restore tab was not highlighted so could not use it for some reason. Nige.

I too had a while on M42 with my LP filter. Tracking was great for the first 45 subs but then it would not track well at all, even after re aligning. I spent the next hour n half dumping subs, finally it started tracking again but the target had rotated to much to carry on where I left off so that was that. After 2 hours I only got 45 good 30 second subs. with flat dark and bias. So this is 22 minutes of 30s. with LP filter canon 1300D at 1600 ISO 150P Alt-AZ, DSS & ST. Still gradients visible lower left, If I had got my intended 1.5 hours that would not be a problem ! There's a very noticeable blue to the stars with the filter. I don't think this is quite as nice as my first but it is only 44 subs and 22 minutes compared to 120 subs and 30 minutes. The shorter subs seem to be better on the bright M42, maybe it's the filter but there's more in the first attempt without the filter. Managed to keep the running man in shot, would have lost it to rotation if I had carried on. I found a way to remove refraction spikes today so rotating the camera should not be a problem now so adding subs should be straight forward and the Bahtinov mask is great, focusing is so easy Cheers Nige. First, with LP, 2nd without.

StarTool users, A question for you. Can I go back to undo a done thing, previous to the undo tab if you know what I mean ?? In other words can I undo 2 applied mods. or do I have to start again.... Edit. Can I get a log of whats been done otherwise ? Edit Edit, found it in the startools folder Nige

Thanks Ian, that's a great link, after 10 minutes I'm actually beginning to understand whats going on in my camera and whats causing the different unwanted imperfections. Its a good start. Cuppa tea and carry on. Cheers A wiser Nige.

I'm totally lost in all this, I didn't realise there was so much to it, so many differences with every camera. I really don't understand at all. I'm trying to follow, here's how much I know, I thought noise was noise but there's read noise thermal noise sky glow and much more, even the exposure times baffles me still, how can 1x60s be the same as 60x1s, noise or no noise there has to be more detail in the 60s ? I have always been good with my hands but don't research enough on the technical side, I just do it and see what happens, but understanding it would only make room for improvement. I'm going to have a good look into these posts and links, hopefully I'll have some sort of understanding of astrophotography rather than just doing it. Weather's rotten, so good time to sit read and research. First I'm going to find out what read noise is Nige

I had the same problem with M42, the running man ran out of the frame, I rotated the camera to reposition but unfortunately the secondary mirror supports on a reflector cause refraction spikes and they didn't line up also the stacking artefacts made me have to crop , no problem with a refractor though and I do like an experiment

That's a lovely image, well done. Nice and crisp, stars are nice, round and clear. There's depth as well, something hard to capture with Alt-AZ mounts. Cheers Nige.

There's different opinions to this ☺I keep mine fully extended for wider footing and more stability , also it gives me a little more visual range over the roofs ☺ Nige.

It's looking good Jon, look forward to seeing it after the offsets are added

I just took the liberty to quickly have a look at your image and enhance a little, the detail is there, offset frames will help. This is a little work with photoshop express . You can clearly see much more emissions although I have highlighted gradients. I hope you don't mind. Nige.

Jon, that's looking good, be careful with processing M42, there's a lot of nebula emissions surrounding Orion which I mistook for background noise, I was given a lesson in StarTools processing on M42, the difference between my image and Ivo's image was vast. So much more detail . If your interested I will post the processing data for you to ponder over ? Yesterday I had a play around with my M42 data, I was amazed at how the slightest change in parameters changed the whole image for the worst. Even just cropping a slightly different size . I tried binning 50% instead of Ivo's suggested 38% the gradients were impossible to remove. Good luck Nige.

ILook forward to seeing your M42 Jon. Too many clouds here last night, again. All the recent talk of focusing and bahtinov masks I had to get one, it arrives today ?.hopefully focusing difficulties are in the past, I had noticed with the LP filter focusing was a bit harder. Now all that is needed is a very large fan to blow the clouds away.. Nige.

I have had a dabble with ISO settings a little. The best setting for my cameras seem's 1600, but had a good result using 3200 and the LP filter. 6400 seemed to much noise, I stacked 3200 + 6400 in the flame & HH nebula, very difficult to process, I removed the 6400 from the stack and a much better image with easier processing. 800 ISO is good too. I have not tried with lower than 800 yet though. Cheers Nige.

You have a better way of explaining this My experience with barlows, tracking is harder as twice the magnification will double the errors of the mount compared to prime focus ? roughly twice the exposure time needed due to loss though optics and reduced field of view ? Something like that. I may be completely wrong of course Nige

Using a barlow will shorten the possible exposure times by about 50% and also reduce the amount of photons reaching the sensor, I think your better off at prime focus and then cropping to required size. Good to get 30s with a x2 barlow WD Still good images though Nige.

This was direct from Ivo of StarTools on processing M33, It worked well for processing my M33. worth a try. You might have to change settings slightly or maybe not. The image this processing was used on was from a refractor scope originally, mine was with a reflector but still had a good result. Nige. --- Auto Develop To see what we got. Default settings. We see light pollution, noise, oversampling. Coma and/or camera not sitting quite flush. --- Bin To make use of oversampling and reduce noise. Parameter [Scale] set to [(scale/noise reduction 50.00%)/(400.00%)/(+2.00 bits)] --- Lens To mitigate coma (do this before cropping!). Unfortunately there is no exact science to this... YMMV. Parameter [Curvature Linked] set to [126.03 %] --- Crop Crop remaining artefacts and frame object a bit better. Parameter [X1] set to [10 pixels] Parameter [Y1] set to [17 pixels] Parameter [X2] set to [1105 pixels (-407)] Parameter [Y2] set to [920 pixels (-250)] --- Wipe Masked out the galaxy using Lasso tool. Parameter [Dark Anomaly Filter] set to [8 pixels] to catch any Dark Anomaly pixels. --- Auto Develop Like M31, region of Interest over a slice of the disc, representing a good sample of the dynamic range that we're interested in. Parameter [Ignore Fine Detail <] set to [6.0 pixels] Parameter [Outside ROI Influence] set to [8 %], reducing dynamic range allocated to non-RoI area a little. --- HDR To dig out a bit more detail. Reveal preset. Parameter [Detail Size Range] set to [1293 pixels] Parameter [Strength] set to [1.1] --- Color Used MaxRGB mode to balance the green a little. We're looking for a yellower inner disc, bluer outer disc, pink/purple HII areas dotted around, as well as a good representation of all star colors in the foreground stars. Parameter [Dark Saturation] set to [6.00] to introduce color in the shadows. Parameter [Saturation Amount] set to [129 %] Parameter [Blue Bias Reduce] set to [1.10] Parameter [Green Bias Reduce] set to [1.04] Parameter [Red Bias Reduce] set to [1.29] --- Life I used the Isolate preset (no particular mask set, just everything selected) to push back the noisy background. This technique is also good for busy star fields in very/extreme wide fields. --- Contrast To dig out a bit more detail from the core. There is a slight spiral structure to M33, it just hard to make visible. Parameter [Compensate Gamma] set to [Yes] Parameter [Precision] set to [256 x 256 pixels] Parameter [Dark Anomaly Filter] set to [7 pixels] --- Wavelet De-Noise Parameter [Grain Size] set to [15.2 pixels] Parameter [Smoothness] set to [82 %]

Nice image, good stars, just the slight colour issue, I use to have trouble with the colour module in ST but sussed the problem out. Set ANY colour balance to no or off in DSS, then open image in ST with the second tab, Linear, was bayered is not white balanced. I found that if I turned off the bayer arrangement under fits in DSS before registering I had terrible trouble with colours. so I set the camera to Canon Rebel which has the same arrangement. This seemed to sort the colour problem. Nige.

A comparison of 30s ISO 1600. With and without . .Different targets but same light pollution.

I have the Astronomik CLS CCD clip in filter for the canon EOS cameras, so far very happy with its performance, light frames are dark blue instead of the orange brown colour, they look like they have less detail in but the couple of images I have tested on have been far easier to process and NO loss of detail, if anything more detail, Its primarily designed for Modded cameras but works well on unmodded cameras. I took a 60s test shot at ISO 6400 to see how it looked , the resulting image was mid blue tone all stars visible with both flame and H/H nebula visible , not like a 60s at 6400 without the filter which is a total whiteout. Around £ 110 but worth it. Cheers Nige.

I believe it's 1 second exposures and 5 minutes of each rgb Nige.

I restacked the H/H without the 6400 frames and the dodgy flats, the final image is a vast improvement on the original. The bright ark at the top is much less, it was easer to process too. I had settled on 800 - 1600 ISO settings as the best outcome generally but with the new LP filter it needed ago, still learnt about ISO now thank guys. I'll post both to compare, the first is the original image. The second is 46x30s @ 3200 ISO I may have over done the red levels. Cheers Nige.

Thanks for the link. I guess I Neen to find the best settings for my cameras, All knowledge and improvement though Nige.