IC 1805 - First Image Post and Tecnosky 80/480 OWL First Light

[endless-sky]

I would like to share my first picture ever posted and the first real picture captured with my Tecnosky 80/480 APO FPL53 Triplet OWL Series (not counting the test shots for "first light").

This is IC 1805, also known as the Heart Nebula, taken over 4 nights, under my Bortle 5 home sky.

Total integration time: 8h 52m 20s.

Here are the acquisition details:

Mount: Sky-Watcher NEQ6 Pro

Telescope: Tecnosky 80/480 APO FPL53 Triplet OWL Series

Camera: D5300 astromodified

Reducer/flattener: Tecnosky 4 elements, 0.8x

Guide-scope: Artesky UltraGuide 60mm f/4

Guide-camera: ZWO ASI 224MC

2020/10/07: Number of subs/Exposure time: 1@60s + 80@90s. Notes: No filter, Moon 70% illuminated

2020/10/13: Number of subs/Exposure time: 2@60s + 11@180s + 1@200s + 12@240s. Notes: L-Pro filter, no Moon

2020/10/27: Number of subs/Exposure time: 59@180s + 1@240s. Notes: L-Pro filter, Moon 88% illuminated

2020/10/28: Number of subs/Exposure time: 48@180s. Notes: L-Pro filter, Moon 93% illuminated

Total exposure time: 31940s = 8h 52m 20s.

Pre and post-processing: PixInsight 1.8.8-6.

Unfortunately, the best out of the 4 sessions (no Moon and L-Pro filter) was also the shortest one. But, after waiting for 5 months for my telescope, I couldn't pass up the few clear skies opportunities I got since it arrived, Moon or no Moon.

Here's a link to the full resolution image: Heart Nebula (IC 1805)

Thanks for looking and commenting!

[Adreneline]

9 minutes ago, endlessky said:

8h 52m 20s

Wow! That is an awesome amount of integration time - well done you for sticking at it and producing such a good result.

The stars are quite dominant. I have found it can be helpful to make a duplicate of the image before going non-linear. Do a few partial stretches with HT on the original and then whip the stars out using Starnet. Continue to stretch and process the starless image to your satisfaction. Once you're happy with the starless version you can put the stars back from a lesser stretch duplicate using PixelMaths or maybe using layers in something like GIMP, PS, etc.

Great image though. The Heart is one of my favourites.

Thank you for sharing.

Adrian

 

[endless-sky]

Just now, Adreneline said:

Wow! That is an awesome amount of integration time - well done you for sticking at it and producing such a good result.

The stars are quite dominant. I have found it can be helpful to make a duplicate of the image before going non-linear. Do a few partial stretches with HT on the original and then whip the stars out using Starnet. Continue to stretch and process the starless image to your satisfaction. Once you're happy with the starless version you can put the stars back from a lesser stretch duplicate using PixelMaths or maybe using layers in something like GIMP, PS, etc.

Great image though. The Heart is one of my favourites.

Thank you for sharing.

Adrian

 

Thank you very much for commenting and for the tips! I really appreciate them.

I am quite new with PixInsight, and this is my first "serious" work. Before getting the telescope, I have been imaging with a Nikkor kit zoom lens, 70-300mm, and was never quite satisfied with the results. The lens suffers from incredible amounts of tilting and coma and I could never make myself "waste" more than one or two hours on any given subject, not because of lack of willpower to go longer, but because I knew the results were going to be poor. I have been imaging with that lens since the start of my digital astrophotography journey at the end of January of this year.

At the end of May I ordered the telescope and I finally received it October the 2nd, after many months of clear nights gone, where I couldn't make myself go out and image with the zoom lens anymore. I have been out every clear night I got, since I got it.

I decided it was time to invest some serious hours on a target, since now I had a performing telescope.

Yes, I agree with you: the stars are quite dominant, and I will try reprocessing the image again, following your tips. I also did some star erosion with PixInsight, but maybe I didn't do enough or was too afraid of artifacts.

[Adreneline]

7 minutes ago, endlessky said:

I also did some star erosion with PixInsight, but maybe I didn't do enough or was too afraid of artifacts.

I know star erosion can work but Starnet can be a game changer and although it can take a while (don't be tempted to set Stride to 128 - 64 is good enough) it is well worth doing and I have found has improved all my images. Following advice from @ollypenriceI have found the best approach is to use layers in PS (I use Affinity but GIMP works just as well) and use a Lighten layer to overlay a stretched (in PS etc.) duplicate image (post background extraction and noise reduction). I've even gone back and re-visited some of my previous images and been very pleased with the end result.

My previous attempts always looked like the stars had been 'stuck on' and two-dimensional whereas using Olly's approach the end result looks much more natural and retains more depth.

It's a constant learning game and with all these restrictions I've got plenty of time to investigate processing techniques.

Good luck.

Adrian

[Adreneline]

The approach is detailed in this thread:

Adrian

[endless-sky]

1 hour ago, Adreneline said:

The approach is detailed in this thread:

Adrian

Thank you for the link. I will read it for sure and try again!

[KyleStoke]

4 hours ago, Adreneline said:

Wow! That is an awesome amount of integration time - well done you for sticking at it and producing such a good result.

The stars are quite dominant. I have found it can be helpful to make a duplicate of the image before going non-linear. Do a few partial stretches with HT on the original and then whip the stars out using Starnet. Continue to stretch and process the starless image to your satisfaction. Once you're happy with the starless version you can put the stars back from a lesser stretch duplicate using PixelMaths or maybe using layers in something like GIMP, PS, etc.

Great image though. The Heart is one of my favourites.

Thank you for sharing.

Adrian

 

Starnet, remove the stars then add them back in in PS layer set to screen. I've being experimenting with it so stars don't get white clipped. 

[endless-sky]

17 hours ago, Adreneline said:

The approach is detailed in this thread:

Adrian

Thank you again for pointing me to this link, it seems like a very powerful method. I really like the idea of giving a small stretch to the linear part of the image with only the stars, before adding it back in to the starless image. This way, the stars don't go through all the heavy stretching the rest of the image will go through, for obvious reasons.

I assume the same noise reduction routines need to be applied to both, though, otherwise you will see the difference in how smooth/soft the pixels in the stars are, compared to the rest of the image. I guess some small amount of convolution could be done to the star layer as well, before applying it, to soften the transition between the star cores and the background. I'll be sure to try out these techniques the next time I process an image, or if I reprocess this one of the Heart Nebula. Plenty of humid/foggy/cloudy nights in this period, unfortunately, so might as well invest the time increasing my post-processing skills.

Since I would like to do all my post-processing in PixInsight, is there an equivalent to adding back the star layer with a "lighten" (or "screen", as suggested by Kyle, above) option, but using PixelMath in PixInsight? It would really be awesome if it could be done without having to change software.

EDIT: looks like I answered my own question. For who might be interested, here's the list of the blending mode equivalencies between Photoshop and PixInsight PixelMath. Credit: Rogelio Bernal Andreo.

Edited November 2, 2020 by endlessky

[Adreneline]

48 minutes ago, endlessky said:

Since I would like to do all my post-processing in PixInsight, is there an equivalent to adding back the star layer with a "lighten" (or "screen", as suggested by Kyle, above) option, but using PixelMath in PixInsight? It would really be awesome if it could be done without having to change software.

EDIT: looks like I answered my own question. For who might be interested, here's the list of the blending mode equivalencies between Photoshop and PixInsight PixelMath. Credit: Rogelio Bernal Andreo.

What a great table! I'd not seen that one - and I've bought his book! It's funny how you only see what you're looking for when you refer to a book and can quite happily scan past things that could be really useful.

Thank you for link - I shall be giving it a go for sure as I am no longer using PS as a matter of principle. Have to say Affinity does nearly everything I need except it is more difficult working at the channel level - layers are good - channels are a challenge.

In answer to your question, I take a duplicate after I've cropped, background extracted and reduced the noise using MLT. I have never used convolution/deconvolution because it always seems to introduce more problems that it solves, but that is probably due to operator incompetance.

Good luck and I look forward to seeing more of your images.

Adrian

[endless-sky]

26 minutes ago, Adreneline said:

What a great table! I'd not seen that one - and I've bought his book! It's funny how you only see what you're looking for when you refer to a book and can quite happily scan past things that could be really useful.

Thank you for link - I shall be giving it a go for sure as I am no longer using PS as a matter of principle. Have to say Affinity does nearly everything I need except it is more difficult working at the channel level - layers are good - channels are a challenge.

In answer to your question, I take a duplicate after I've cropped, background extracted and reduced the noise using MLT. I have never used convolution/deconvolution because it always seems to introduce more problems that it solves, but that is probably due to operator incompetance.

Good luck and I look forward to seeing more of your images.

Adrian

Glad I could be of help! It's always nice to be helped, but it's just as nice to be able to give back/help others. Even if I only started about 9 months ago, I try my best to spread the little knowledge I have acquired so far.

I'll try your workflow, as you mentioned. I usually do a second pass of noise reduction after the stretch, in the non-linear phase, but that's just to smooth out the background after the stretch/curve transformations. I guess that since these won't be applied to the star layer, the second noise reduction shouldn't be necessary, either.

I have also tried many, many times with deconvolution, but I don't seem to have found the "magic" settings for it, yet. I can get the process to make the stars tighter and bring out more details on the nebular features, but it also introduces a sort of "orange peel" effect on the background. I would definitely like to learn how to make it work, because I feel it's a very powerful tool to have in one's post-processing tool box.

Thank you for the appreciation of my image, I'll keep posting as I capture more, now that I finally have optics that perform as I like. You don't want to see what I captured in these past 9 months with the 70-300mm zoom lens. Unless you want to see comets, instead of stars...

I also saw (and liked) your H-alpha image of the Heart Nebula and I must say it's very impressive and nicely processed!

Matteo

[Adreneline]

1 hour ago, endlessky said:

I also saw (and liked) your H-alpha image of the Heart Nebula and I must say it's very impressive and nicely processed!

Thank you. With the run of clear nights last week I managed to get some OIII and SII as well and managed to produce this:

I'm a bit anti deconvolution really. As I understand it the technique was developed to correct out of focus stars on the initial Hubble images. Seems better to me to get the optics in focus in the first place! I stand to be corrected.

Good luck - and one other piece of advice - enjoy the hobby and don't get too OCD about it. If my wife likes the images I produce I'm good to go and I can include them in our Apple TV screensaver and enjoy them whilst listening to our favourite music mix. Success!

Adrian

Edited November 2, 2020 by Adreneline
Typo

[endless-sky]

Sorry, one more question. If I remember correctly, the image needs to be in its non-linear form for StarNet to work. How do I remove the linear version of the stars, if I need to stretch the image before obtaining them? This would inevitably stretch the stars, as well, which is what we are trying to avoid, in order to paste them later, with a more subtle stretch.

[Adreneline]

17 hours ago, endlessky said:

Sorry, one more question. If I remember correctly, the image needs to be in its non-linear form for StarNet to work. How do I remove the linear version of the stars, if I need to stretch the image before obtaining them? This would inevitably stretch the stars, as well, which is what we are trying to avoid, in order to paste them later, with a more subtle stretch.

Sorry for the delay in getting back to you.

Once I have my master image which I've cropped, applied DBE/ABE and then MLT I duplicate that image (right click on the image and select Duplicate); at this stage the original and the duplicate are linear.

I then start to stretch the original and after three (maybe four) stretches I apply Starnet and remove the stars; once they are removed I continue to stretch the image and then do whatever additional processing I think it requires.

I have been experimenting with the table formulae you sent me. Lighten works very similar to what I'm used to in Affinity. I have modified the formula slightly to read max(starless,0.75*Blend) but the 0.75 needs experimentation depending just how much you end up stretching the duplicate. My duplicate (becomes Blend in the formula) is a ChannelCombination of my R,G and B components (which may be Ha,OIII,SII in whatever order I fancy). I have found a second application of ABE removes any background cast and I have also found an application of SCNR removes any halos (magenta halos are removed by inverting the image and then applying SCNR).

The end result is not too disimilar to my version with Affinity.

Apologies again for the delay. We are living a daily nightmare here thanks to the legal profession who are making a complete meal of exchanging contracts on our house sale - they've been trying for over two weeks. Maybe today the gods will look kindly on me.

Adrian

 

Edited November 3, 2020 by Adreneline

[endless-sky]

1 hour ago, Adreneline said:

Sorry for the delay in getting back to you.

Once I have my master image which I've cropped, applied DBE/ABE and then MLT I duplicate that image (right click on the image and select Duplicate); at this stage the original and the duplicate are linear.

I then start to stretch the original and after three (maybe four) stretches I apply Starnet and remove the stars; once they are removed I continue to stretch the image and then do whatever additional processing I think it requires.

I have been experimenting with the table formulae you sent me. Lighten works very similar to what I'm used to in Affinity. I have modified the formula slightly to read max(starless,0.75*Blend) but the 0.75 needs experimentation depending just how much you end up stretching the duplicate. My duplicate (becomes Blend in the formula) is a ChannelCombination of my R,G and B components (which may be Ha,OIII,SII in whatever order I fancy). I have found a second application of ABE removes any background cast and I have also found an application of SCNR removes any halos (magenta halos are removed by inverting the image and then applying SCNR).

The end result is not too disimilar to my version with Affinity.

Apologies again for the delay. We are living a daily nightmare here thanks to the legal profession who are making a complete meal of exchanging contracts on our house sale - they've been trying for over two weeks. Maybe today the gods will look kindly on me.

Adrian

 

No worries, thanks for answering and very nice image, by the way!

I don't know if I understood correctly, but I'll write how I understood it and apply it to a DSLR (no narrowband filters, just light pollution filter) workflow. Then, if you have time and are willing, you can tell me if I got it right.

Here's my current workflow:

1) - Crop, DynamicBackgroundExtraction, BackgroundNormalization, ColorCalibration
1b) - Deconvolution: as I said, I mainly give it a try, but end up discarding the results
2) - TGVDenoise, MMT (yes, in linear, but I found that following Jon Rista's tutorials, it's the only way my background does not end up having an orange peel effect)
3) - Stretch (I usually just apply the ScreenTransferFunction autostretch to HistogramTransformation, seems to work quite well)
4) - More denoise if needed (ACDNR, TGVDenoise and MMT again: still going by Jon Rista's tutorials)
5a) - Adjustment of black point with HistogramTransformation
5b) - CurveTransformation for contrast/improving saturation
6) - DarkStructureEnhance script if needed
?) - Star erosion: up until now I didn't really know where to do it/how to do it effectively

After reading your suggestions, this is what I would do. I have one image at the end of step 2), let's call it 2A. I barely stretch 2A, with HistogramTransformation (I assume? - or with CurvesTransformation, by doing an arcsinh curve?) by bringing to the left the midpoint, until I see as many stars that I am happy with having at the end. I duplicate the image and call it 2B. I remove the stars from 2A with StarNet. I continue with 2A, doing the rest of the workflow: 3) to finish stretching it to its full potential, 4) to 6), etc.

I now blend back in the image with the stars (2B) using PixelMath lighten equivalent expression: max(2A,c*2B), where 0 < c < 1 (as you said, needs experimenting with the coefficient to find an appropriate blend).

Does this sound about right?

Thanks again and I hope everything goes well with the legal battles you are facing.

Matteo

[Adreneline]

39 minutes ago, endlessky said:

you can tell me if I got it right.

Hello Matteo,

I am not sure I know what is right but I am happy to tell you what I do, recognising that dealing with dslr/osc is a little different to RGB or narrowband.

I agree with (1) but I would not do (1b). I tend to prefer MLT but that is personal choice (influenced by the Light Vortex tutorials).

As soon as I have run MLT I then duplicate the image, one (original) for the starless and one (duplicate/clone) for the image that will keep my stars (the Blend).

I then do incremental stretches using HT, three maybe four times, and then apply Starnet to remove the stars. Once the stars are removed I continue to do multiple small incremental stretches, each time moving the black point a small way across the bottom foot of the curve. I can do as many as 10 or 12 separate stretches and always finish with a reset of the black point and no change in the mid-point.

At this point I have a nicely stretches starless image. I then use ColourSaturation to boost the colours to suit my taste. I don't use Curves Transformation because I would rather take the image at this point into Affinity and play around with the colour settings (Hue, Saturation, Colour Mix etc.)

Going back to the duplicate/clone I now have a choice, thanks to you!. I can take the image into Affinity and stretch using a Curve as shown by Olly and then blend with the starless image using a Lighten layer, or I can now stretch in PixInsight and apply the PixelMath formula you found once I have brought my starless image back into PixInsight. 

At this stage I'm pretty much done with colour and all I do is a final bit of noise reduction and try not to be too heavy handed. I don't use the dark structure script and I don't mess around with the stars (because I will almost certainly make it worse!).

I have used ArcsinhStretch and it can be really good for pulling out star colour in an rgb/osc image so you could certainly apply that on the duplicate instead of using HT. With all these stretch processes I find it is very easy to over do it. I nearly always get to the point where I think "just a minute - I've gone too far" at which point I press the Undo button a couple of times.

I tend to prefer a more pastel/soft palette but I understand many prefer a bolder palette with striking colours. My personal view is that space is beautiful but it is not garish or "in your face". It's a bit like facial make-up - lots is not necessarily a good thing. My mother came from Yorkshire and she would have said "there's now't natural about that!". My mother had something to say about most things  

Anyway, thank you for providing me with a distraction from legal matters. Once again I find myself waiting for an email or a phone call that says we have exchanged contracts - it has been like this every working day since 19th October!

Good luck and I hope I have been of some help.

Adrian

[endless-sky]

Thank you very much for the invaluable info, Adrian. I will try your method for sure - matter of fact, I just got back from work and I am going to give it a try right now.

I'll follow along your workflow and update you on the results. In the likely event that I make a mistake somewhere, I'll post here the problems encountered.

As far as pastel vs "in your face", I also prefer pastel, subtle colors. I hope I manage to show that with my picture. A previous one I post-processed, a very wide field of the Cygnus area (taken with a 50mm prime lens), was way oversaturated, compared to the photo I posted here. Looking back at it, I don't like it at all.

Time for some post-processing, now... 🙂

[endless-sky]

Ok, making some progress.

However, it seems the moment in which one decides to use StarNet is of vital importance with respect to the final result: if done too early (not enough stretches), then it leaves artifacts behind that get only worse and more evident with the following stretches. If done too late (after too many initial stretches), the stars will be quite "fat" and when StarNet removes them, they will leave "black holes" behind, where they were supposed to be. The end result, in this case, is that when I paste the blend layer (the linear duplicate with the stars), after minor stretches to just bring out the stars without making them too fat, they will all have a dark halo around them (the black holes left by StarNet in the starless image).

I think I got the gist of it, now it's just a matter of finding the correct balance between how much or how little to stretch before applying StarNet, and how little or how much to stretch the blend layer before pasting it back.

Definitely not easy...

[Adreneline]

2 hours ago, endlessky said:

it's just a matter of finding the correct balance between how much or how little to stretch before applying StarNet

I think this is the big difference with dslr/osc. I remove the stars from the Ha, OIII and SII originals after a small initial stretch so I've not had a problem with the 'holes' left behind. Tricky.

2 hours ago, endlessky said:

Definitely not easy...

"If it was easy it wouldn't be worth doing" - not sure who said that but sometimes difficult gets boring as well!

Good luck!

Adrian

[endless-sky]

55 minutes ago, Adreneline said:

"If it was easy it wouldn't be worth doing" - not sure who said that but sometimes difficult gets boring as well!

Good luck!

Adrian

I keep repeating myself that... 😅

I'll keep trying, I know I am stubborn enough to keep going at something, especially when I think it's worth it.

And I do think this technique is very well worth it. If I manage to find the combination that works, this could open up so many possibilities. One of which could even be taking a series of short exposures just for the star field and replacing the one from the original picture entirely. Goodbye saturation problems - M42, M45, the Horsehead Nebula, just to name a few examples.

Plenty of cloudy/foggy/humid nights, in this period. So time for processing is something I have in abundance.

[Adreneline]

4 minutes ago, endlessky said:

I do think this technique is very well worth it

A random thought occurs to me. Could you run your dslr/osc linear master through ChannelExtraction and remove the stars from the individual R,G and B channels, much as I do with my Ha, OIII and SII masters. I haveno idea if this will work but it might be worth some experimentation.

Edited November 3, 2020 by Adreneline
Added screenshot

[endless-sky]

Certainly an approach worth pursuing. I am still in the middle of the working week, so I probably won't take a serious stab at this before the weekend, but I plan to reprocess the whole image taking all your tips into account.

Fortunately I saved some intermediate steps, one of which is exactly the one needed: end of step 2), before going non-linear. So I can start from there.

[endless-sky]

I tried splitting the channels, but the results are even worse. Looks like there's a lot of work to do, I'll definitely try harder on my next image, maybe working in StarNet from the beginning of the workflow. DSLRs stars can really be overwhelming, especially with no narrowband filters.

For now, I took the easy (or rather, EZ, as in EZ Processing Suite, for PixInisght) way out and gave EZ Star Reduction a try, directly on the final step of the image posted at the beginning of the thread. I have to say that I am really impressed by the results. If it can do such a good job at the end, after all the stretches, saturation increases, curves, etc., it might be worth a try using it also in the initial stages of the workflow.

Here is the result with EZ Star Reduction (Adam Block's De-Emphasis Method - tried Morphological Selection, too, but I got worse results):

And here's the original, just so you don't have to scroll all the way to the top:

I think the star reduced version is much better, stars are not as overwhelming and the nebulosity stands out more. If I don't manage to get "manual" star reduction to work, I'll definitely keep using EZ Star Reduction in my workflows!

[Adreneline]

9 minutes ago, endlessky said:

I'll definitely keep using EZ Star Reduction in my workflows!

I might need to look at that one myself!

The star reduced version is much better in my view - the stars in the original were a little distracting but now the star of the show (excuse the pun), the nebula, is more apparent.

AP is a constant learning and adapting game when it comes to image processing, and what works for one image does not necessarily work for another.

Thanks for sharing and good luck.

Adrian

P.S. Tomorrow we move to darker skies! I'm thinking of dumping all my previous data and starting a fresh. I can't see the point of combining Bortle 5/6 with Bortle 3/4 and it'll save buying a new remote hard drive. It will also be the first time I've been able to image the western sky. Exciting! Might be a few weeks before I'm up and runnning though.

[endless-sky]

3 minutes ago, Adreneline said:

I might need to look at that one myself!

The star reduced version is much better in my view - the stars in the original were a little distracting but now the star of the show (excuse the pun), the nebula, is more apparent.

AP is a constant learning and adapting game when it comes to image processing, and what works for one image does not necessarily work for another.

Thanks for sharing and good luck.

Adrian

P.S. Tomorrow we move to darker skies! I'm thinking of dumping all my previous data and starting a fresh. I can't see the point of combining Bortle 5/6 with Bortle 3/4 and it'll save buying a new remote hard drive. It will also be the first time I've been able to image the western sky. Exciting! Might be a few weeks before I'm up and runnning though.

Thank you, Adrian. EZ Processing Suite definitely has its perks. I know doing things manually usually produces better results, but in the mean time, while I learn to do things on my own, it can't hurt to see what results my data is capable of, using processes already created by more advanced and skilled people than me. At least I know what to aim for.

As for you moving, lucky you! I am in a Bortle 5/6, as well, and I only got a chance of shooting from a Bortle 3/4 once, in February, from the mountains about 2 hours away from where I live (we spent the night there). I shot M42 with the same equipment I used from home (D90 + 70-300mm zoom lens at 300mm, on the NEQ6 Pro). Same total integration time (about 1 hour) and the result was much, much better than the same 1 hour taken from home (same gear). I also tried combining the data, but the sum of the two sessions was worse than the single integration from the darker sky - so you are definitely right about that!

I wouldn't throw away your previous data, though, if I was you. One day you'll want to look at it, to see where you started and how far you have gotten. I keep all my pictures (the final results from post-processing and the original RAW single frames, just in case I want to reprocess them from scratch, to test how much my processing skills have improved over time - I throw away all the intermediate calibration files). Hard-disks nowadays are not so expensive. Keep your old data, it always holds some value, as a reminder of how many nights you spent out there in the cold, memories that cannot be deleted. Is the new data from the darker sky going to be better? I can bet, given my own experience. Can it replace your old experiences/memories if you delete them all? No. It can only give you new ones.

[Adreneline]

2 hours ago, endlessky said:

I wouldn't throw away your previous data

Well maybe not all, but lots just isn't worth keeping. It took me a while to nail focus and guiding and whilst so doing I accumulated a lot of dodgy data. I also suffered a lot with "blue bloat" - not good! I might be a bit selective but I think I need a fresh start - that why we're moving! A new beginning in our retirement, just five minutes walk from the coast.