ic1396 osc vs mono - a PERSONAL comparison on a single target with totally different camera sensors.

[powerlord]

So.. I posted ic1396 a few days ago, shot in a single night of 9 hours with my asi2600 and L-ultimate filter.

THIS IS NOT A OSC vs MONO which is better thread!! keep yer hair on 🙂

 

Over the past few weeks I've also been imaging the same target, with the same Redcat but with my asi1600 and 7nm Ha, 7nm Sii, and 6nm oiii filters. The L-ultimate of course is dual 3nm.. so not a fair test, but the point of it for me was more 'is it worth doing mono any more' ? I wanted to do a far from scientific comparison - not hour for hour, but how I'd usually shoot to get what I'd consider 'enough'.

In the end, that means 9 hours sii, 9 hours oiii and 6 hours of Ha - 24 hours of subs for the mono. And 9 hours of subs for the OSC. Pixel size on both cameras is the same. same redcat, same mount.

So.. what were the results ?

Well, tbh I found the mono pretty terrible. This was shot with 50-100% full moon as was the OSC.  I've posted both below, and also a video that flips back and forward between them.

I tried my best to balance colours, but of course it's dual vs triband, and well.. it is what it is. For me, I think it has raised the very real question for me of whether I need to shoot mono any more really. Sure, I'll lose the sii.. but on the other hand.. it's so much quicker, AND imho I get better results with OSC.

What are folks thoughts ?

OSC:

MONO:

VIDEO (4k available):

 

Edited October 10, 2022 by powerlord

[Elp]

Either way they both look impressive.

They've been processed differently, to me the mono looks more detailed but the higher contrast difference could be the cause.

The two cameras are also slightly different specs wise in FWD, Bit depth (which will make a massive exponential difference) depending on the gain setting you were using.

I know where you're coming from though, I often wonder whether I should switch mainly to OSC rather than mono, but shooting narrowband in mono in light polluted conditions is difficult to beat.

[powerlord]

16 minutes ago, Elp said:

Either way they both look impressive.

They've been processed differently, to me the mono looks more detailed but the higher contrast difference could be the cause.

The two cameras are also slightly different specs wise in FWD, Bit depth (which will make a massive exponential difference) depending on the gain setting you were using.

I know where you're coming from though, I often wonder whether I should switch mainly to OSC rather than mono, but shooting narrowband in mono in light polluted conditions is difficult to beat.

I did try and process them the same as much as possible.

after stacking - for OSC I split out r and g for ha and oii. I create a fake sii (0.6xr+0.4*b).

after that processing is the same for both:

- each channel goes through siril for stretching.

- each then goes through starnet2++

- I then take each channel in to affinity photo, and adjust with levels, curves and some noiseX as required so all 4 channels are similar histograms and balanced.

- I then composite in siril (ha lum)

-I scnr and save out into affinity.

- i put stars back in from ha in layer, and I then work on the main nebula colours in affinity. For the mono, I kept the OSC version on screen to try to match as much as possible.

Once you adjust FOV to be the same (as in video), they are as similar as I can make em.

It's not like for like of course it's 3nm vs 7nm. But for me, OSC with 3nm comes out top here by a country mile frankly. mono with 3nm might be better, but I'm not spending what would be..1200 quid odd on a set of 3nm filters to try it.

tbh, I'm more inclined at the mo to flog my asi533, asi1600, filters and filter changer and get another asi2600 and l-ultimate!

 

[Stuart1971]

I think the only fair comparison here, would be between ASI2600c and ASI2600m and I think you would find the 2600m would be better….👍🏻

[tomato]

They are both first class results and on the  images presented, I prefer the OSC version and of course it was captured in less than half the time of the mono.

But…

As @Stuart1971 has pointed out, it isn’t a direct comparison of the same sensor.

So is there anybody out there with both flavours of the IMX571 sensor and the necessary filters, preferably on a dual rig so nobody can argue the imaging conditions were different?

[Elp]

I'm more than happy to test the 533 for you...

[tooth_dr]

7 minutes ago, tomato said:

So is there anybody out there with both flavours of the IMX571 sensor and the necessary filters, preferably on a dual rig so nobody can argue the imaging conditions were different?

I have been doing this with my dual rig of LZOS 105mm, with mono and OSC IMX571 cameras, and as stated above, the mono is just better.  The colour is absolutely great, but mono Ha with a 3nm filter is a different league.  I also shoot ha/oiii with a dual band filter on my OSC when the moons out and again, the NB data isnt as good as the mono camera, especially the Oiii, but that will be influenced by the band pass.

Edited October 9, 2022 by tooth_dr

[Elp]

I didn't use the same cameras but when I did the Veil last I found the mono in ha and luminence was far cleaner/detailed than the RGB OSC. The OSC seemed more "convenient" however.

Edited October 9, 2022 by Elp

[newbie alert]

You can see it's processed differently and on a different image scale... Put it on a level playing field and you can have a more accurate measure of things..

Both are great images btw

[powerlord]

Thanks for all the comments chaps, but I think you've missed the point of the comparison. It's firstly and foremost a personal one on whether it's worth me keeping the asi1600.

Plus a asi1600mm kit vs a 2600+lutimate is a far fairer cost comparison for people making a choice IMHO?

I mean obviously 2600mm vs 2600mc both with 3nm filters will have mono win... AND its about twice the price - you'd kinda hope so.

I think I'll post a stretched jpg of each unprocessed channel for info.

And just to be clear as a few fold have said this now, the pixel size is the same, so scale is the same. And processing has been very similar.

Once you've had a look at the jpgs, maybe I can post the raw stacks for folks to play with.

[teoria_del_big_bang]

Nice images and a good test albeit maybe not actually a comparison of mono V OSC but as you say it is a good test of your current OSC setup v your current mono setup.

I think both are good cameras as for a long while value for money wise the 1600mm seemed to be considered one of the best on the market and for around the £1K mark (which it was before recent price rises) was a great buy.
The 2600mm and other makes with same spec are a breed apart being a far better camera. But that's not  in question.

I am no expert at all so cannot really say for definite what path I would take given the same circumstances.
But, this is one target and if I am right it is very strong in Ha with some OIII and very little SII emissions. The little bit of SII I think is mainly the very outer dust and there is definitely more  thin stuff in the outer part of the nebula  in the mono + filters image.
So maybe it depends on what targets you want to image:
For LRGB then the 2600 C is a clear winner.
For Dual band Ha / OIII I think from your image and many others I have seen using the same dual pass then again I am sure the 2600C is more than adequate or better than the 1600mm + filters.
I know many have good arguments why the mono is better but at the end of the day the 2600 is a better camera (greater sensitivity and lower noise) and more to the point much easier to use so given the choice if I had both setups would probably opt for the osc + dual pass filter approach.
However, for any targets with very strong in say Ha but do have significantly weaker OII you may struggle to get enough OIII and targets with any SII emissions, you are going to miss  it altogether.

Like I say mine is not an expert opinion just my thoughts (I I could be wrong) as I have often contemplated going OSC, using a dual pass filter for NB targets but what has put me off so far is that currently most of my limited imaging time is from my backyard which is Bortle 4 with some LP but not too bad, however, I live in cloudy Yorkshire and I get very limited RGB imaging time as my few clear nights are often accompanied by near full moon and so generally look for NB targets if that is the case and so my main concern is not being able to obtain SII data, or indeed devoting more time to the weaker OIII channel if required.

Steve

Edited October 11, 2022 by teoria_del_big_bang

[Lee_P]

Thanks so much for sharing your results. I really like these kinds of "real-world" tests. I found the video to be particularly well put-together as well. Sure, you're not comparing apples with apples, but you're open about that and it's still useful, especially as the price-points are similar, as you say.

I think that the mono result is good but the OSC is better, especially when you consider the shorter integration time. Give that this is ultimately a test to see what you should image with, I think that image quality is just part of the answer. The other important question is, what did you find more fun to use, in terms of data acquisition and processing: the mono or OSC? 

[powerlord]

Good points Lee, and for me I've decided. Osc.

In fact... Not known for long decisiin making processes, I've just bought another 2600mc!!

So on  classifieds later today,  an asi533mc pro, full asi1600mm kit (lrgb, sho + efw),  1.25in lextrene, 2" l extreme!

[scotty38]

Both great images but I am going to be contrary and say I prefer the mono.....

[Adam J]

14 hours ago, powerlord said:

So.. I posted ic1396 a few days ago, shot in a single night of 9 hours with my asi2600 and L-ultimate filter.

Over the past few weeks I've also been imaging the same target, with the same Redcat but with my asi1600 and 7nm Ha, 7nm Sii, and 6nm oiii filters. The L-ultimate of course is dual 3nm.. so not a fair test, but the point of it for me was more 'is it worth doing mono any more' ? I wanted to do a far from scientific comparison - not hour for hour, but how I'd usually shoot to get what I'd consider 'enough'.

In the end, that means 9 hours sii, 9 hours oiii and 6 hours of Ha - 24 hours of subs for the mono. And 9 hours of subs for the OSC. Pixel size on both cameras is the same. same redcat, same mount.

So.. what were the results ?

Well, tbh I found the mono pretty terrible. This was shot with 50-100% full moon as was the OSC.  I've posted both below, and also a video that flips back and forward between them.

I tried my best to balance colours, but of course it's dual vs triband, and well.. it is what it is. For me, I think it has raised the very real question for me of whether I need to shoot mono any more really. Sure, I'll lose the sii.. but on the other hand.. it's so much quicker, AND imho I get better results with OSC.

What are folks thoughts ?

OSC:

MONO:

VIDEO (4k available):

 

You say these are the same optics but there is something very off about the stars in the mono shot. They look to me for all the world like stars that are suffering from optics with bad astigmatism. Little Maltese crosses all over the place. Yet the OSC data is not showing the same optical fingerprint. Something not right here. 

Adam 

 

[Stuart1971]

9 minutes ago, Adam J said:

You say these are the same optics but there is something very off about the stars in the mono shot. They look to me for all the world like stars that are suffering from optics with bad astigmatism. Little Maltese crosses all over the place. Yet the OSC data is not showing the same optical fingerprint. Something not right here. 

Adam 

 

This astigmatism, is something I get in one corner of my images, when using my 2600c camera on my Tak FSQ85, without the flattener, it’s due to the small pixels, tak have brought out an extra new flattener to combat this as when the scope was designed it was for large pixel cameras…so I guess it’s the same issue only worse, but with a different refractor, as the odd stars are all over the mono image above…

But as you say the OSC image is fine, so deffo looks like different optics used….🤔🤔

Edited October 10, 2022 by Stuart1971

[geeklee]

14 hours ago, powerlord said:

9 hours sii, 9 hours oiii and 6 hours of Ha - 24 hours of subs for the mono.

I think the only conclusion I'd come to from this much data in mono is that acquisition, equipment or processing had some challenges.  That much mono data on a bright object like IC1396 should have produced something quite different in my view.

For a laugh, I applied 60 minutes of Ha from an Atik 460EX (Yes, a CCD! 😲) and 6nm filter as Lum to the JPG above (so far, far from ideal processing wise), but still got something sharper, with good stars and more subtle detail (and that's 6x less Ha than quoted).  The 460EX Ha was just HT stretch and a little NR.

I couldn't fix the colour!

[powerlord]

same optics. It's a real world test, it is what it is.  stuart, lee - not sure what's being suggested here ? Im clearly not lying.

Was the 1600 data as good ? maybe not. It was real world. maybe seeing was bad, maybe somehow something was out of alignment, though don't see how - its all screw fitting with the redcat.

I'm glad you got better results, and I suppose everyone is reading to much into this because of the title - it reallty wasn't MEANT to start a fight - that was a Harry Hill reference.

each to their own - peace onto the world.

As I say, in the past months I've been almost only using the asi2600mc - nb and wd. for the second mount it's had my asi533 on it far more than the asi1600. So for me, I've decided for now to get out of the mono game. I'm happy with the hobby experience and results from the 2600. IF i want sii on a target, I can use an sii filter but I'm not fussed mostly. I am not and never did suggest that osc was better than mono generally. My decision is just that FOR ME, my asi2600 is getting used much more than my asi1600 - and that comparison, ineffectual and full of issues as it undoubedtly is, was a clincher for me. It is far from the best results I've had with mono, and it is quite possible that the data was substandard compared to other nights - but it is what it is. warts and all.

What it is NOT is some sort of personal insult to anyone who shoots mono, or some sort of claim that OSC rules the roost. I have updated the title to make that clear.

[geeklee]

7 minutes ago, powerlord said:

stuart, lee - not sure what's being suggested here ? Im clearly not lying.

Of course not! I don't think anyone is implying that.

Your test is suggesting that 24 hours of mono data doesn't produce an image anywhere near as good as your OSC equivalent (for you).  I don't personally think that would/should be the case and I'm unsure why your image doesn't reflect that.  As you say, so many variables.

I don't think there's been any sort of fighting either  

Edited October 10, 2022 by geeklee

[powerlord]

The oiii I gathered was particularily rubbish on the mono. Not sure why, but you are right there - it was far below what I've managed before on the target.

I'll post the stacks if anyone wants to have a go - I admit it just seemed clear to me when I started editing that the mono data wasn't as good for whatever reason, so I didn't maybe put the effort into editing it that I should.

However, tbh - I do much prefer the process with OSC, and at the end of the day that's what it comes down to - which you enjoy most as @Lee_P said. If I'm honest the fact I'd chosen to image mostly with the 2600/533 over the past months meant I'd more or less decided, and I used this as a sort  of confirmation of my choice - and you know what those are like - you bias them to confirm your choices.

[powerlord]

For anyone that cares, here's the raw stacks.

the oiii is 6nm Astronomik, rest are 7nm ZWO.

ic1396.sii-Sulphur_II-session_1.fits ic1396.oiii-Oxygen_III-session_1.fits ic1396-ha-Hydrogen-alpha-session_1.fits ic1396-RGB-session_1.fits

[Shibby]

There does seem to be something awry with your mono image/data. It's very blurry compared to your OSC and the stars are very square. Will be interesting to see the raw data.

Ultimately, I wouldn't blame you at all for focusing on OSC, it's all about how happy you are with the result in comparison to how may headaches the setup and processing gives you!

[Lee_P]

Could the 1600 data be exhibiting microlensing? That's a known issue with the camera, although I think it's just the case with bright stars so I'm probably barking up the wrong tree.

[powerlord]

hmm, you are right, I think that might be the first time I've ever used the redcat with the asi1600.. and those stars are weird. even in a single sub they are weird square things in the Ha...sii and oiii look ok ?

I have no idea what's happened there I'll be honest.

[geeklee]

Thanks for sharing the data @powerlord

I wonder if whatever is causing these diffraction (?) patterns clearly seen on brighter stars is also causing all smaller stars to be square/diamond?  Then maybe impacting the data in general.  The Ha is really clean.

Two simple crops at 1:1 from the Ha stack.

EDIT: sorry you beat me to it @powerlord

Edited October 10, 2022 by geeklee