Mono or OSC, your suggestions

[smr]

Mono or OSC. I'd like to hear what you suggest... have you gone from Mono back to OSC and why? Or have you gone from OSC to Mono and not gone back to OSC and why ? 

At the moment I have an unmodified DSLR and I'm at the point where I have gained enough experience setting up, autoguiding etc. but my camera is holding me back by not being Ha modified. 

I can't mod my DSLR as I use it for other photography so it's either an OSC astro camera or a Mono. 

Is narrowband and OSC worth considering nowadays too, with the advancement of filters and OSC cameras in general? I notice from astrobackyard and others that they're using duo or triad narrowband filters etc. with their OSC cameras.

I really love nebulae more than anything. I have bortle 5 skies and image from a village in a semi-rural location.

Edited August 20, 2019 by smr

[StarDodger]

This will prompt some good replies as it’s a question asked a lot...

I personally have both mono and OSC CCD Cameras, but I started with a DSLR and then had it modified...this was great for a year or two, then I bought a mono Atik 383 CCD, I tried it a few times and got some great images in mono, then ventured into LRGB filters with it, that’s when I lost a little interest as it was taking me too long to gather enough data to create an image..

So I then bought an SXVR M25c OSC large sensor CCD camera, as I had read it was one of, if not the best OSC CCD camera out there...and it ignited my passion again for imaging, as each night I could produce a decent image...

Then I sold the Atik and stuck with OSC for about three years, then ,last year I bought an SXVR h18 (same mono sensor as the Atik I had) and the idea was to use this for Ha images, and add them to my SX OSC data...and that has worked well, and that is where I am now, I do now own a set of narrowband filters but have never used them in anger....

I have never even considered one of the newer CMOS cameras, CCD all the way for me, but I do know they are popular, as many people will tell you.

One person who will have an opinion on OSC v MONO is @ollypenrice....  and he will disagree with me for sure that mono takes longer than OSC to get an image.... 😀😀

Good luck with your journey...

[carastro]

I started with a DSLR and then decided to get a CCD camera for cooling and better detail.  So on advice I bought a mono Atik383L and was knocked out by the improvement in detail, also you can see on fast looping if you have the nebula in the FOV if you adjust your brightness correctly and bin while you are framing.

I then had the idea of buying a OSC to speed up the process of gathering data and having a dual rig.  So I bought a QHY8L.  I had no end of problems, some of which were to do with the dodgy cable, but it took me back to the bad old days of DSLR imaging when you could not see the target in the FOV plus only saw the very brightest stars, and I found doing focus a real pain.  I suffered this for about a year and in the end threw the towel in and sold it, and stuck to Mono which I thought was so much easier.

I overcame the "takes forever to get colour" aspect by binning the colour and am now totally sold on Mono.  On the odd occasion I use the DSLR for some reason (travelling and can't take full regalia), I can't wait to get back to Mono again.  PLUS of course you can use narrowband.  Yes I know some people do narrowband with OSC and DSLR cameras, but I am sure it must take a lot lot longer. 

I have never used CMOS, so can only speak for CCD.

Carole 

[fwm891]

I started with DSLR's (and still have them), one a standard Nikon 800E the other a modified, full spectrum mono D5100. I have a cooled mono SXTrius 825 which I use in conjunction with a filterwheel with LRGBHa filters. I have however just bought a ZWO ASI294MC Pro Cooled CMOS camera.

Before moving house my kit was observatory based and when skies cleared it was easy to just start imaging. After the move I had to set-up each time I wanted to image and shooting filtered images proved to be frustrating because I never seemed able to complete a sequence of filters on a given night. Now I have a new observatory perhaps I'll go back to shooting filtered mono but the new ASI294MC Pro is far more of a camera than I first thought possible with an OSC. I still feel that some objects are more suited to mono others to OSC where colours are more subtle and have a more natural look.

Starting out now I'd go with a CMOS OSC and add mono later.

Edited August 21, 2019 by fwm891

[pete_l]

If you have Bortle 5 skies (i.e. pretty dark) then your DSLR won't stop you getting some good quality images.
A dedicated CCD/CMOS camera will set you back at least £1000 and if you want narrow band with a mono sensor, close to double that!

Yet £300-400 will get you a good s/h modified DSLR which will provide many years of imaging before you run out of targets for it.

[ollypenrice]

9 hours ago, StarDodger said:

 

One person who will have an opinion on OSC v MONO is @ollypenrice....  and he will disagree with me for sure that mono takes longer than OSC to get an image.... 😀😀

Good luck with your journey...

 I do disagree. Mono is faster for at least three reasons, the first and most obvious being that it can capture luminance data when an OSC cannot. Every pixel of an OSC camera has a colour filter in front of it all the time, each one blocking about 2/3 of the light. (Google Bayer Matrix Passbands to see graphs giving a more precise figure.) However, a mono camera shooting Luminance is capturing red and green and blue at the same time. It isn't distinguishing between them but that doesn't matter. The distinction is made later using the RGB data. Quite simply, more light gets onto the chip in an LRGB shoot than in an RGB/OSC. That is why the professionals invented the LRGB system. It saves time.

The second reason is that you can, if you wish, shoot RGB binned 2x2, an obvious way to save time.

The third is that emission nebulae will respond very well to narrowband filters,  particularly Ha. You can shoot Ha in an OSC camera but only a quarter of the pixels receive any light. You can, therefore, make good, efficient use of moonlit nights with a mono camera.

At one time I had both Atik 4000 mono and OSC together. As an imaging provider I felt this would make my evenings simpler but, in the end, I decided to use two mono cameras with electric filter wheels. I didn't find the capture was much simpler with the OSC and processing was often harder for some reason. The OSC camera was slower, decidedly so on faint targets.

Some OSC users argue that you don't need to refocus between filters. I think they are mistaken: what they should say is that you cannot refocus between filters. Non-parfocality is not usually caused by the filters but by the optics so the single focal position found in the OSC is a compromise no different from the compromise a mono user could make if he or she chose to. (I only focus 'per filter' on our high res rig.)

If you're imaging in high resolution a mono has another advantage: if the seeing is bad or the object is low you can shoot colour and wait for good seeing/high elevation to shoot luminance (where it matters.)

It remains that, in on-off imaging situations, OSC can be less frustrating but quicker it ain't.

Olly

Edited August 21, 2019 by ollypenrice
Typo

[FLO]

Olly’s argument in favour of Mono is well practiced, well reasoned and clearly born from experience but consider he lives on a mountain in France where clear skies are the norm. Here in the UK we are less fortunate so the case for OSC cannot be so easily dismissed. 

Horses for courses 🙂

Steve 

[Chris]

My background - Started with non modded DLSR's, then modded a bunch of DLSR's, then moved to small sensor CCD's both mono and colour, and now I'm back to DLSR for the time being. 

I kind of depends on budget, but if you like Nebula I would recommend buying a second modded DLSR as this will give you a large sensor and increased Ha sensitivity for not much money, and you're already familiar with how your DLSR works. Then I would keep the modded DLSR as they are always handy and buy a mono camera for planetary nebulae and galaxies.  

 

[ollypenrice]

36 minutes ago, FLO said:

Olly’s argument in favour of Mono is well practiced, well reasoned and clearly born from experience but consider he lives on a mountain in France where clear skies are the norm. Here in the UK we are less fortunate so the case for OSC cannot be so easily dismissed. 

Horses for courses 🙂

Steve 

Yes, very fair. I do acknowledge this at the end. One argument would say, 'If sky time is short, get the fastest.' The other would say, 'If sky time is short, get something which will give you a complete result even if it's short on total time.' I don't know how that can be resolved, but it's probably best left to the individual to make a personal choice. My main concern is to debunk the idea that mono must be inherently slower because of the need for separate filters. This argument, which is not uncommon, is based on some incorrect assumptions.

It might also be worth floating the idea that OSCs (and especially DSLRs) seem to work best in fast optics. The only DSLR images I can remember which are CCD-like come from fast optics.  Many of these images are DSLR/Tak Epsilon: https://www.mauricetoet.nl/DeepSky/  Indeed Maurice Toet is the only imager I know personally who has gone back to DSLR from CCD, something the OP asked about. There are plenty of CCD OSC images which are every bit as good as mono ones.

Olly

[smr]

9 minutes ago, ollypenrice said:

Yes, very fair. I do acknowledge this at the end. One argument would say, 'If sky time is short, get the fastest.' The other would say, 'If sky time is short, get something which will give you a complete result even if it's short on total time.' I don't know how that can be resolved, but it's probably best left to the individual to make a personal choice. My main concern is to debunk the idea that mono must be inherently slower because of the need for separate filters. This argument, which is not uncommon, is based on some incorrect assumptions.

It might also be worth floating the idea that OSCs (and especially DSLRs) seem to work best in fast optics. The only DSLR images I can remember which are CCD-like come from fast optics.  Many of these images are DSLR/Tak Epsilon: https://www.mauricetoet.nl/DeepSky/  Indeed Maurice Toet is the only imager I know personally who has gone back to DSLR from CCD, something the OP asked about. There are plenty of CCD OSC images which are every bit as good as mono ones.

Olly

I guess there are quite a few variables and facets between imagers though (sky quality, elevation, camera gear, location etc.) with Maurice I can see he has a dedicated astronomy camera with the D810a and a £5k scope in that ultra light gathering f/2.8 aperture. But as well as this he is also in France where clearer skies are more frequent than here in the UK with 21.2 mag skies too.

[ollypenrice]

1 minute ago, smr said:

I guess there are quite a few variables and facets between imagers though (sky quality, elevation, camera gear, location etc.) with Maurice I can see he has a dedicated astronomy camera with the D810a and a £5k scope in that ultra light gathering f/2.8 aperture. But as well as this he is also in France where clearer skies are more frequent than here in the UK with 21.2 mag skies too.

He's sometimes in France (and sometimes at our place!) but his fast, portable rig means he can image after making short journeys from his home in the Netherlands without needing huge volumes of kit.

Olly

[MattJenko]

Having done DSLR and mono imaging, I think the key point is 

2 hours ago, ollypenrice said:

OSC can be less frustrating but quicker it ain't

There is indeed a kind of elemental fury that surfaces when a mono imaging run ends up with only 1 or 2 usable images with a filter with lovely full set of subs for all other filters. The knowledge that you have collected more photons with the other filters than you ever could with OSC that evening kind of slips into irrelevance when you realise you won't be able to do a great deal of processing without the missing data. If you are regularly set up and regularly rely on multiple sessions to gather data for a single image, then this is no big deal, but for the setup/teardown weekenders like myself it can amount to heart bursting sorrow.

I have tried ways to try and limit this, by looping through RGB subs (3 at a time) but the additional refocusing needed etc eats into the overall time and adds more possibility for murphys law to strike.

I am a CMOS user mainly now as well, to counterbalance all the CCDers here.

[spillage]

I can only agree with @ollypenrice when it comes to the speed of a mono. The images I can get from the asi1600mm in 20 minutes far exceeds what I could achieve with my modded dslr. If you have the money to spend I would really suggest that a mono camera would be the best option. If money is an issue then maybe look a a cheap modded dslr and keep an eye on the second hand market for when funds are available to you.

Do I think mono processing is harder? Not really I am in the habit of renaming one of the images as "reference" and just use this in DSS for each filter and this is the most time consuming part vs using osc for me.

I know there is the argument of osc giving you a quicker result but I think on the whole the mono images will be superior and at the end of the day people spend years collecting data from targets so if takes you a month or two does it really matter.  

 

PS I do one focus on the L filter and do not refocus on the filter changes. In fact I only use one set of calibration data across all of my 7 filters.

Edited August 21, 2019 by spillage

[Adam J]

I went mono and to be honest I am happy with that choice, I will spend 30 hours intergration on an image and in the UK that can mean 1 - 2 images per season due to weather. As such I have no issues with the idea of shooting different filters on different nights as I know that in the end 30hours of LRGB or Ha/OIII is always going to give me a better result in comparison to an OSC sensor of the same type. 

However....the counter argument to this is that if your not willing to spend more than one evening imaging a given target and your happy with the result you might well be better off with OSC as it will always give you a single image in a single night. Some of the new duel narrow band / tri narrow band filters are great for imaging in light pollution with an OSC. Another thing I would consider with OSC is using it in a highly mobile setup, so something you would take on holiday with you. Same reasons, you get all your data in one night and if your like me then if your taking your kit then its because your going to some place dark when light pollution is not an issue and you will be shooting Broad Band anyhow.  

But in the end across the board Mono is higher performance if your committed to putting time into your imaging. 

Adam 

[alacant]

I'd try modifying your dslr first. It will cost you under €100 and you get colour thrown in. To get colour images in monochrome of anything like the same size is gonna cost you at least €3000.

I witness monochrome imagers frequently. By the time they've found out why the filter wheel isn't spinning, we've got 20 frames from our cheepo 450d.

I'd say that if you had decent skies and an observatory, try monochrome. Otherwise go with what you already have.

I've a modified dslr. My next move would be an asi294.

I'll see myself out!

[smr]

Very interesting replies. 

I am actually leaning towards mono a bit... but I'm still not sure.

I'm happy gathering data on multiple nights. My last image of M31 was taken over two nights, about two weeks ago whilst on Holiday. In that week there were only two clear nights with extended spells of clear night at that. After the second night I was still looking at the forecast and bearing in mind the Moon's position with regard to wanting to image more and gather more data on top of the 5-6 hours I had achieved. If the whole week was clear skies I'd have imaged every night, Moon permitting, possibly coming away with 10-15-20 hours of data.

I was actually making a mental note to myself to carry on imaging M31 when I got home from my garden and add as much data to it as I can but haven't been able to now because of the Moon. That combined with the fact that since my Holiday we have had one clear night, and that was on Tuesday I think of this week with the Moon almost full. So pointless gathering anymore data. So then I've got this data on my computer and I want to see what the stack looks like... so you begin processing and then carry on, and carry on, and think that looks nice. So you go about finishing it whilst cursing the cloudy and moonlit skies you've got at present, using them as an excuse for just calling that project wraps. I guess that comes down to partly patience though, and learning to keep the data but just add more to it when you can, if you want the best results possible.

I guess it also comes down to a choice with such skies ... moon and cloud etc. as to whether to concentrate on one target as much as possible per season, going for 15+ hours of data and trying to get as much as possible data before diminishing returns apply, or whether you want to image more targets in the same amount of time at the caveat of having inferior results.

My Rosette Nebula image taken last winter (first time on that target was taken over 3 to 4 nights), M42 was also taken over over 3-4 nights too, so I'm firmly not in the camp of having to or needing to image one target a night.

I really like Hubble palette images too so I guess mono + narrowband would make more sense.

I'm not ruling out OSC at all though.

 

[smr]

Having said that I could imagine being quite happy with the results of say, 7 hours on Bodes and Cigar I have got this year, 5 hours on Rosette and 4 hours on M42 with a cooled OSC and much increased sensitivity to Ha with the ASI294MC Pro or the 071MC Pro.

[smr]

53 minutes ago, Adam J said:

I went mono and to be honest I am happy with that choice, I will spend 30 hours intergration on an image and in the UK that can mean 1 - 2 images per season due to weather. As such I have no issues with the idea of shooting different filters on different nights as I know that in the end 30hours of LRGB or Ha/OIII is always going to give me a better result in comparison to an OSC sensor of the same type. 

However....the counter argument to this is that if your not willing to spend more than one evening imaging a given target and your happy with the result you might well be better off with OSC as it will always give you a single image in a single night. Some of the new duel narrow band / tri narrow band filters are great for imaging in light pollution with an OSC. Another thing I would consider with OSC is using it in a highly mobile setup, so something you would take on holiday with you. Same reasons, you get all your data in one night and if your like me then if your taking your kit then its because your going to some place dark when light pollution is not an issue and you will be shooting Broad Band anyhow.  

But in the end across the board Mono is higher performance if your committed to putting time into your imaging. 

Adam 

There seems to be quite a bit of a trend with narrowband and OSC imaging now, with Trevor Jones and his 294 / STC Duo narrowband images etc. I see Altair have a Tri and Quadband filters for OSC as well now which seem to be priced very well compared to some of the other tri/quad filters, though I notice the bandwidths aren't as narrow compared the more expensive filters.

Edited August 21, 2019 by smr

[ollypenrice]

There's also a sub-text here about integration time. If we look back over images posted on SGL in the last ten years we see that they have been getting better, as have the amateur images chosen as APODs etc. Now contrary to what might be assumed, much of the kit used 10 years ago is still in use today.  This is true of my main (and favourite) CCD camera. I'm sure that the improvement in image quality has various sources but I'm equally sure that increased integration time is the main one. The multi-night image was slightly exotic when I was starting out whereas now it's routine. Many imagers are prepared to put in the time for a better result. (This doesn't make it compulsory, though. Enjoying a one-night grab of a target is a perfectly valid thing to do.)

Olly

[vlaiv]

43 minutes ago, smr said:

There seems to be quite a bit of a trend with narrowband and OSC imaging now, with Trevor Jones and his 294 / STC Duo narrowband images etc. I see Altair have a Tri and Quadband filters for OSC as well now which seem to be priced very well compared to some of the other tri/quad filters, though I notice the bandwidths aren't as narrow compared the more expensive filters.

I do understand OSC/Narrowband imaging when one already has OSC camera, no budget to invest into mono camera and they want to try something new or combat LP.

Choosing OSC camera based on ability to do narrow band is rather wrong. Even if you used duo/tri/quad filters. Mono is simply more sensitive in this role, and difference is quite large.

Only 1/4 of sensor is sensitive in Ha/SII wavelengths, about one half in OIII, and one quarter in Hb. These are rough figures, buy you get the idea.

Duo/tri/quad band filters let you image certain wavelengths at the same time, but this is not restricted to OSC sensors - they can be used with mono sensors as well, and I think it is great way to incorporate LRGB approach to narrow band. Multiband filter will be used as luminance and single band filters for color.

[Tim]

Nebulae imaging?  Mono camera with narrowband filters - no brainer

I have both ways and each have their uses, there is very little crossover to be honest.

If you are lucky enough to image with a scope without CA, then OSC can be useful for our rubbishy UK skies.

If I was to just choose one, then it would be a mono, for most versatility. But OSC certainly have their place.

Just my $0.02

 

Tim

[Ouroboros]

11 hours ago, MattJenko said:

Having done DSLR and mono imaging, I think the key point is 

There is indeed a kind of elemental fury that surfaces when a mono imaging run ends up with only 1 or 2 usable images with a filter with lovely full set of subs for all other filters. The knowledge that you have collected more photons with the other filters than you ever could with OSC that evening kind of slips into irrelevance when you realise you won't be able to do a great deal of processing without the missing data. If you are regularly set up and regularly rely on multiple sessions to gather data for a single image, then this is no big deal, but for the setup/teardown weekenders like myself it can amount to heart bursting sorrow.

I have tried ways to try and limit this, by looping through RGB subs (3 at a time) but the additional refocusing needed etc eats into the overall time and adds more possibility for murphys law to strike.

I am a CMOS user mainly now as well, to counterbalance all the CCDers here.

What you describe here is one reason why I have never ventured beyond DSLR imaging. I have to set up on each occasion and only get a handful of good imaging sessions a year. However, if I had a permanent set up I'd have no hesitation in going for mono. 

What is odd is that I've never quite managed to persuade myself to go for OSC either. Maybe I just prefer the familiarity of using my trusty DSLR. 

[StarDodger]

9 minutes ago, Ouroboros said:

What you describe here is one reason why I have never ventured beyond DSLR imaging. I have to set up on each occasion and only get a handful of good imaging sessions a year. However, if I had a permanent set up I'd have no hesitation in going for mono. 

What is odd is that I've never quite managed to persuade myself to go for OSC either. Maybe I just prefer the familiarity of using my trusty DSLR. 

A DSLR is one shot colour imaging....

[smr]

Indeed a lot of Astro cameras have DSLR sensors in them dont they? 

Therefore the only advantage in them is that they have cooling and are also without the IR filter found in most DSLRs (with the exception being astro DSLRs like the Canon 60Da).

I have seen some great images taken with the camera I have but they can be the result of using fast lenses/scopes or very dark skies, as well as the camera having been modified. 

Another point about the Canon 80D is that its 'ISO-less' meaning I shoot at ISO 200 and that helps with noise.

The biggest noise problem however can be light pollution.

[vlaiv]

8 minutes ago, smr said:

Therefore the only advantage in them is that they have cooling

But that is very significant advantage. Not so much in lowering dark current and associated noise, but advantage in being able to perform proper calibration.