Adreneline

Welcome to SGL!

Much prefer this version - nice one! Adrian

Hi Emil, I pre-process in APP (which I prefer to PI because I can do all the filters at once) and then take the resulting .fit files and StarAlign and DynamicCrop them in PI, followed by ABE (or DBE if I'm feeling super keen) and then lots small incremental HistogramStretch; I will typically do 10 or 12 small stretches each time making a small correction to the black point each time. I then take just the OIII (or Blue) as a 16 bit .tif into PS and apply AAA star size reducer action three or maybe four times. I then take the resulting tif back into PI and combine in PixelMath or ChannelCombination. Once combined and I'm happy I usually take the resulting image back into PS to make small level adjustments and align the histograms followed by as little noise reduction as I can get away with (using Dfine) and then finally a little bit of a lift to the colour, but nothing too much as I prefer the toned down subtle colours in my images. HTH Adrian

+1 for these settings and advice. I have found they work a treat for me and I have been delighted with the results from 120s and 180s NB exposures. In my particular location shorter exposures have also meant less wastage (compared with typical CCD exposures of 300s+) as I am right on the flight path for EMA - a busy place at night! Good luck.

Very nice Emil. I have had exactly the same issue with my OIII filter (and my Blue filter). I've tried all manner of things to reduce the problem and at the moment my favoured (no doubt cheating) approach is to take the OIII (or Blue) image from PixInsight into Photoshop where I apply a star size reduction action from Annie's Astro Actions. I apply the action three or maybe four times and then take the resulting image (tif) back into PixInsight to combine with Ha and SII (or R and G). For me this method works but I am sure that others will have a better approach. There is no doubt a suitably complicated way of doing it in PI involving all manner of masks, etc. but AAA's are much easier and well worth the $15 or whatever I paid. (P.S. I am a big fan of PI believe it or not) I'm not sure whether it is a short-coming of the OIII (or Blue) filters or a shortcoming in my optics (ED80/ZS71/Samyang 135mm) or a combination of both. It worked very well on my most recent HOO iamge here: HTH or gives you some ideas. Adrian

Thank you Mick. I really like taking wider field images; I can't remember the last time I used my ED80. I know I don't get the detail with the 135mm and it's undersampled but I like seeing these large nebula set in their surrounding star field. I'm also not so keen on 'in your face' colours - I much prefer the subtle approach. Thanks again. Adrian

This is 41 mins of Ha, 37 mins of OIII and 4 mins of Red! Clouds and (low) aircraft conspired to ensure that essentially the same amount of subs were consigned to Trash! Taken with a Samyang 135mm + ASI1600MM-Pro at 139 gain, offset 56. Guiding was troublesome probably due to poor seeing. There is minimal cropping so stars at the extreme corners are not a good shape; possibly a shortcoming of the Samyang? The Ha and OIII were 120s and 180s duration and were pre-processed and combined in APP as a multi-session image. Red were just 60s. Ha, OIII and Red were processed in PixInsight and combined in PixelMath. Finally there was a small amount of noise reduction in PS and a very slight colour boost. As ever critical comments are welcome. Thank you for looking. Adrian

Hi! I'm really not sure to be honest. Every time I put together a new arrangement my experience tells me that trial and error is the way to go. I've read all the theory and all that stuff and then find that spacers never go together quite as you think, or they engage too much in the filter holder and stop you withdrawing the filter, or something. The end figure is never far from the theoretical figure but then Atik quote a tolerance on the exact position of the sensor (I read +/- 0.5mm somewhere) so trying to come up with the perfect theoretical spacing is not necessarily going to work either! I'm still getting used to the ASI1600 but so far I like the fact that I can get very rewarding results with much shorter exposure times so I get less wastage due to aircraft (which regularly take off or land over the house). Not surprisingly I spent an age sorting out all the spacing again because the back focus on the ASI is 6.5mm. Joy! Good luck with your trial and error Adrian

This worked/works for me. Image shows a Samyang 135mm on the left, a TS 2" filter holder centre, and the Atik 428ex on the right. The red tape shows the position of the sensor in the camera (close as I could get it). I had to mess around with a few custom spacers to get it to focus at f2. HTH Adrian

Very nice MG. The modded and cooled 40D has done an amazing job. This is one of my favourite targets to image, especially in NB - it is so rewarding. Love the colours, especially the blue, which I always seem to struggle to achieve in my images. Thanks for sharing. Adrian

Hi Emil, I like them both and would be more than happy if I had taken them. In answer to your question I feel the second one reveals better defined detail in the structure of the nebula. As for natural colour - what's that?! - I much prefer the colour of the second one as well. If I were you I would be convinced it is better Adrian

Thanks very much guys for the very kind comments. I did have a couple of sessions at gain 200 but in the end I did not see any great benefit and it just complicates the whole business of calibration frames. In the end I have decided to stick with unity (139) gain and an offset of 56 (based on advice given in a post by @vlaiv). Adrian

Hi Martin, I know this is a few months ago but I now own an ASI1600 and I am seriously considering buying the Canon 200mm (also for use with my 70D) and would be really interested to know the gain and offset you used on your 5 min subs. So far I have been using the 1600 with either a Samyang 135mm or a WO-ZS71 with 139 gain and 56 offset but limiting exposure length to 2 mins in an attempt to get less wastage due to clouds. No worries if you don't have the details. Many thanks. Adrian

I was only trying to help - a “thank you” would have been nice.

I too have been experimenting with combining HO with RGB and find it very difficult to get what I consider to be a pleasing end result. I combine the Ha and OIII in PixInsight using R:Ha, G:0.4*Ha+0.6*OIII, B:OIII. I process the RGB in PI and use ArcSinhStretch to pull out the star colours. I then use PS to combine the two images using layer with a 'hide all' mask using a 15% opacity/25% flow brush to carefully blend the two images. It takes ages! I should preface all of the above with "currently" because my ideas may change next week. Love the framing of your image - not something I am likely to achieve with my setup. Good luck! Adrian

I'm still trying to find the best way to incorporate HO with RGB without it looking like a Cecil B DeMille movie poster. This is 20x120s of Ha and OIII combined with 6x60s of R,G and B from an ASI1600 (139 gain, 56 offset) with WO-ZS71; fully processed in PI and combined in PS using layers and masks. Despite my best efforts and following advice gratefully received from others 57Cyg still boasts a good sized case of blue bloat; hopefully it doesn't detract too much. As ever CC always welcome. Thanks for looking. Adrian

Thanks Tony and Ole. To be honest there was a marked lack of rgb data on this image - the clouds were against me - as ever! I will certainly take your advice and have a look at the rgb data again and see what I can find. I also wonder whether I suffer from the dreaded 'blue bloat' but I had hoped my UV/IR filter might help alleviate/correct that problem. This image was taken with the Samyang but I also have problems at the moment with the ZS71 as well which suffers terribly from droop - the focusser is not at all good at holding the reducer once it is loaded with the ASI1600 and ZWO-EFW, and it plays havoc with the star shapes. Thanks again for your advice. Adrian

Hi Everyone, This is primarliy NGC7000 along with IC5070 and IC5068 taken with my ASI1600 and Samyang 135mm lens - heavily cropped to remove the very worst of the blue halos (predominently on the left hand side of the image only) and the dodgy star shapes in the corners of the image (predominently top right!). This is an RGB+HaO image. The RGB was processed separately and stretched using ArcSinhStretch to bring out the star colours. The RGB and HOO images were then combined in PixelMath and tweaked in PS. CC welcomed, along with any thoughts on why the blue halos are predominently on the left hand side of the image. Thanks for looking. Adrian

Just as well it was my turn to get the washing in otherwise I would have missed this brief break in the clouds. Taken hand-held with a Canon 70D and 70-300mm lens. Adrian

The nights might be short and the moon might be big but when the sky is clear you have to have a go and see what can be achieved. This is 20x120s of Ha and OIII using the WO-ZS71 and ASI1600MM-Pro at 139 gain, 56 offset and -20 degrees C. The image includes not only NGC 7635 the Bubble Nebula but also the largest yet discovered proto-star NGC 7538, Sharpless 157 the Lobster Claw Nebula, the open star cluster M52 and 4Cas. I also took 20x60s of R,G and B but I am struggling to combine the two to get some colour into the stars. I've combined the Ha into the R channel using a Lighten layer but it is knowing how best to utilise the OIII with the G and B. Everything I've tried so far looks rubbish and there is still a marked lack of colour in the stars. I also processed the RGB separately and stretched using ArcSinhStretch in PI to reveal lots of star colour so I know it is there. Any advice or tips on combining the two would be much appreciated. Thanks for looking. Adrian

Works well for me too - but I did change the offset to 56. Thank you

Very nice Pieter - excellent result. I would be very interested to know the gain and offset you used on the 1600; I have one myself and I am still very much at the experimenting stage. Adrian

Hi. I was in a very similar position to you three years ago (ED80 + Canon 70D) experiencing exactly the same feelings with what I considered to be disappointing images (except Andromeda which looked great!). Modding the 70D was never going to be an option for me; I also use the 70D a lot for everyday photography and really didn't like finding it covered in dew after a night of imaging. I opted for the Atik414 osc and it transofrmed my imaging and gave me lots of pleasure to use. OSCs seem to be derided by many but they have their place and I still use mine for the ocassional astro session when I use the ED80 to which it is permanently attached and 'ready to go'. I eventually progressed(?) / moved on to an Atik428ex mono and now a ZWO1600MM-Pro Cooled but I learnt so much from the osc. Have to say most of the time I now use the ASI1600 with either a Samyang 135mm or a WO-ZS71 but that is largely because my interest shifted from imaging galaxies to narrow band imaging of nebula. Good luck!

Well I cannot answer that one! I was a committed PI user and had tried with limited success to complete mosaics to an acceptable standard. Yes it can be done but to be honest I have better things to do in life than the excessively protracted procedure required to get good results. (I know others will argue differently). With APP you just load in the lights and calibration frames and it gets on with the job with minimal intervention. For mosaics it is a dream. I still use PI to process the image and PS to colour tweak but I now use APP pretty much exclusively for all pre-processing. Adrian

Astro-Pixel-Processor. I chose to 'rent' as opposed to buy - either way it is good value IMHO.