How to start? Color or mono

[Nova2000]

Hi sgl

Don't know if something like this post has been started before. Is so then I'm sorry 

Which ccd camera is good to start with. A mono or color!? 

[Pete Presland]

What are planning on imaging, also what equipment do you currently  use?

[Nova2000]

3 minutes ago, bunnygod1 said:

What are planning on imaging, also what equipment do you currently  use?

Hi. Dso. Neq6. Gso 10 f4 astrograph  and asi 290 guider with asi guide scope

[LightBucket]

I am currently having the same dialema, so will be watching this with interest....

[RayD]

I think most DSO imagers would advise you to go mono with filters.  Yes the OSC will give you an image out of the camera, but the resolution with the mono and filters will ultimately give you better images.

If you want a quick image out of the camera, then of course OSC offers this over mono, but for best quality images mono is the way to go.

I'm sure Olly would advise on the technical aspect i.e. all the light using all the pixels on mono, and the bayer matrix on OSC splitting the light R,G,G,B across each pixel.

[Nova2000]

Im ready to spend time imaging with filters. Just want to know how to start out. 

[Adam J]

Either start with a second hand modified DSLR (for reasons of it being cheaper) or move straight into dedicated mono camera (CCD or CMOS).

A color CCD sits in a weird space being almost as expensive as a mono but not nearly as effective. I have neither had a mono or color CCD and am using a cooled DSLR (which I see as being superior to a color CCD due to having a larger sensor and higher resolution meaning you can do h-a and OIII without a significant loss of pixel scale) but just looking at the images people post tells a big story mono is just better, you just have to pay for it.  

[RayD]

Just now, Nova2000 said:

Im ready to spend time imaging with filters. Just want to know how to start out. 

It depends on budget and how much automation you want.  You can get very reasonably priced manual filter wheels, which means being at the equipment to rotate on each filter change, and a fairly decent mono camera for producing very good images.  Obviously the wider field, higher resolution and cooling then starts adding cost.

I believe you were looking at the Moravian, which is very good, and would be ideal in your warmer climate because of the cooling.  Assuming you got one with a built in filter wheel, all you would need then is filters, and to start the Baader LRGB set is a pretty good buy, which if you want can later be upgraded to a higher quality set such as Astrodon (if you ever felt the need).

Add to the above some guiding of course, which you would almost certainly need for decent DSO imaging.

[geordie85]

Having only used a modded DSLR and a mono ccd I have to say the mono ccd can be abit frustrating at times due to limited time with our UK skies and having incomplete images for months on end. But once I get the image finished it's well worth it and I have a much better image to show for it.

[ollypenrice]

I'm going to say mono. I'm also going to disagree with Ray's idea that you get an OSC image 'straight out of the camera.' You won't. It will need calibrating with darks and flats, debayering and stacking just as will mono data. (Well, no debayering for mono.)

First off, let me tell you how 'hard' it is to make an RGB image out of separate  R, G and B images. I do this in AstroArt.

You open just the three colour channel images in AstroArt. You go to Image-Align All and click OK. Then you go to Colour-Trichromy and put the red file in the red box, the green file in the green box and the blue file in the blue box, Tick the White Balance and say OK. At this point you have an RGB image just as you would from an OSC. This cannot be difficult. Don't go away, I'm just going to time myself doing it for real. Back in a sec...

Nineteen seconds. 

With mono you can shoot Ha in the moonlight, you can shoot the right amount of colour (OSC shoots twice as much green as red or blue) and you can save masses of time by shooting Luminance-RGB instead of the less efficient RGB-only. (Luminance passes three times as much light as a colour filter, whether the colour filter is OSC or mono.) I don't think that, with a good debayering algorithm, an OSC is significantly inferior in resolution to a mono but mono is faster and not more difficult. Once you get into the post processing you may well find an LRGB image easier to process.

Olly

 

[LightBucket]

17 minutes ago, ollypenrice said:

I'm going to say mono. I'm also going to disagree with Ray's idea that you get an OSC image 'straight out of the camera.' You won't. It will need calibrating with darks and flats, debayering and stacking just as will mono data. (Well, no debayering for mono.)

First off, let me tell you how 'hard' it is to make an RGB image out of separate  R, G and B images. I do this in AstroArt.

You open just the three colour channel images in AstroArt. You go to Image-Align All and click OK. Then you go to Colour-Trichromy and put the red file in the red box, the green file in the green box and the blue file in the blue box, Tick the White Balance and say OK. At this point you have an RGB image just as you would from an OSC. This cannot be difficult. Don't go away, I'm just going to time myself doing it for real. Back in a sec...

Nineteen seconds. 

With mono you can shoot Ha in the moonlight, you can shoot the right amount of colour (OSC shoots twice as much green as red or blue) and you can save masses of time by shooting Luminance-RGB instead of the less efficient RGB-only. (Luminance passes three times as much light as a colour filter, whether the colour filter is OSC or mono.) I don't think that, with a good debayering algorithm, an OSC is significantly inferior in resolution to a mono but mono is faster and not more difficult. Once you get into the post processing you may well find an LRGB image easier to process.

Olly

 

That is all well and good shooting from where you are in the world and having the skies you have there, night after night, week after week,  but try to get enough decent LRGB data in one session here in the U.K., with sometimes a week or more between sessions, and it gets very frustrating waiting to get the data to finish an image.....

[MikeCM]

I have not been using a mono CCD for long but it is surprising how good an image can be obtained by limited LRGB subs.  With time I will be able to add further data to my image year on year and so allowing the image to be improved with time. I always take the long term view.

[ollypenrice]

2 hours ago, LightBucket said:

That is all well and good shooting from where you are in the world and having the skies you have there, night after night, week after week,  but try to get enough decent LRGB data in one session here in the U.K., with sometimes a week or more between sessions, and it gets very frustrating waiting to get the data to finish an image.....

I would counter this by saying that LRGB is faster, so OSC would be less of a problem for me than it might be for you! It is simply incorrect to assert that OSC is fast. It absolutely isn't. If you set your filter to scroll LRGB,LRGB,LRGB you have a fighting chance of getting a workable set.

I've run throught the LRGB versus OSC exposure time sum plenty of times already but the outcome is that LRGB is faster than OSC by a factor of 4 to 6 at the least.

Olly

[Nova2000]

Hi @ollypenrice

What do you mean by rggb? Why 2greens?. What's the importance of a luminance layer? 

[spillage]

11 minutes ago, ollypenrice said:

I've run throught the LRGB versus OSC exposure time sum plenty of times already but the outcome is that LRGB is faster than OSC by a factor of 4 to 6 at the least.

Olly

Sorry to sound daft but is this implying that if you run 5 each or LRGB you will get a much better result than 20 lights from a dslr as the maths would suggest you would collect more data from the dslr.

[LightBucket]

6 minutes ago, Nova2000 said:

Hi @ollypenrice

What do you mean by rggb? Why 2greens?. What's the importance of a luminance layer? 

2 greens because the Bayer matrix in front of a sensor consists of one red one blue and two green pixels, because the human eye sees twice as much green as the other two colours, then that's why photos look the same as what we see....

hope that makes sense...

[ollypenrice]

1 hour ago, spillage said:

Sorry to sound daft but is this implying that if you run 5 each or LRGB you will get a much better result than 20 lights from a dslr as the maths would suggest you would collect more data from the dslr.

I haven't said a word about DSLRs! I've only been talking about one shot colour CCD, as per the OP's thread. You'd need to tell us what maths you're talking about. Mine goes like this:

R 1/3 incident light.

G 1/3 incident light.

B 1/3 incident light.

L 3/3 incident light.

An OSC is condemned to shoot only through RGB filters so can never shoot at 3/3 as a mono camera can in luminance mode. That is why LRGB is faster than RGB (which is what OSC is, barring the pointless excess of green from the Bayer matrix.)

 

1 hour ago, LightBucket said:

2 greens because the Bayer matrix in front of a sensor consists of one red one blue and two green pixels, because the human eye sees twice as much green as the other two colours, then that's why photos look the same as what we see....

hope that makes sense...

No, the problem is this: Bayer's matrix of RGGB works well in daylight terrestrial imaging. He considers the green filters to be luminance and the R and B to be chrominance. (This is the terminology of his patent.) If shooting twice as much green were useful to the astrophotographer then astrophotographers with mono cameras would do it. But they don't. In fact they do rather the reverse, using algorithms like Hasta La Vista Green and PI's SCNR green to tame the green channel still further. An astrophotographer with a mono camera would never shoot twice as much green as red and blue. It would be insane. So why do it with an OSC camera? Because you have no choice. The astronomically inappropriate Bayer Matrix is all you are offered.

2 hours ago, Nova2000 said:

Hi @ollypenrice

What do you mean by rggb? Why 2greens?. What's the importance of a luminance layer? 

The importance of a luminance layer is its speed. It captures, simultaneously, red and green and blue. It is, therefore, three times faster than shooting through a colour filter. (Such is the theory. In truth I find, by measurement, that luminance is closer to four times faster than RGB/OSC.) You do not need  all your data to be colour data. You use the luminance to go as deep as possible as quickly as possible then you 'colour it in' with your colour data.

Part of the misunderstanding surrounding all this comes from terminology. There is no such thing as 'one shot colour.' It does not exist in digital imaging. The reality of 'one shot colour' imaging is that it is really 'quarter of a shot red, half a shot green, quarter of a shot blue' imaging. When yu put it like that it is easy to see why it is not a short cut. 

Olly

[spillage]

16 minutes ago, ollypenrice said:

I haven't said a word about DSLRs! I've only been talking about one shot colour CCD, as per the OP's thread. You'd need to tell us what maths you're talking about.

Forgive me. I was under the impression that a dslr and osc would work in the same way. I think that I am getting the time factor all wrong.

If I am right your meaning of time is the time sensor captures the specified LRGB and of course the mono would more efficient and you can control the amount of individual colours and not waste time collecting data that is not needed. I was thinking of time as in the time you spend taking the image.

My knowlege of ccd's is zero and only have used a dslr.

 

[RichLD]

One thing that hasn't been mentioned is that mono with filters beats OSC if money is no object...

[peter shah]

I do agree with Olly

18 minutes ago, RichLD said:

One thing that hasn't been mentioned is that mono with filters beats OSC if money is no object...

logically you would think that...however....you will not be happy and you will end up buying twice...I did

If you can afford to buy in one go build up your kit bit by bit...you can have a lot of fun with just mono no filters...

[RichLD]

8 minutes ago, peter shah said:

I do agree with Olly

logically you would think that...however....you will not be happy and you will end up buying twice...I did

If you can afford to buy in one go build up your kit bit by bit...you can have a lot of fun with just mono no filters...

I agree with your points but I'm sure that there are plenty of people out there who have bought OSC cameras that are very happy with the results that they get.

I own mono and OSC BTW.

 

[peter shah]

DSLR's have come a long way with noise and sensitivity.....but they do rely on software to reduce noise and can damage the raw data. Having said that I've seen some stunning images done with DSLR's.

1 minute ago, RichLD said:

I agree with your points but I'm sure that there are plenty of people out there who have bought OSC cameras that are very happy with the results they get.

 

Im a mono man through and through....but I do believe OSC and DSLRs do have a very valuable place in this dark art.....In fact I have a very capable Sony A7s which I also use, its ridiculous in low light levels.

[LightBucket]

1 hour ago, ollypenrice said:

I haven't said a word about DSLRs! I've only been talking about one shot colour CCD, as per the OP's thread. You'd need to tell us what maths you're talking about. Mine goes like this:

R 1/3 incident light.

G 1/3 incident light.

B 1/3 incident light.

L 3/3 incident light.

An OSC is condemned to shoot only through RGB filters so can never shoot at 3/3 as a mono camera can in luminance mode. That is why LRGB is faster than RGB (which is what OSC is, barring the pointless excess of green from the Bayer matrix.)

 

No, the problem is this: Bayer's matrix of RGGB works well in daylight terrestrial imaging. He considers the green filters to be luminance and the R and B to be chrominance. (This is the terminology of his patent.) If shooting twice as much green were useful to the astrophotographer then astrophotographers with mono cameras would do it. But they don't. In fact they do rather the reverse, using algorithms like Hasta La Vista Green and PI's SCNR green to tame the green channel still further. An astrophotographer with a mono camera would never shoot twice as much green as red and blue. It would be insane. So why do it with an OSC camera? Because you have no choice. The astronomically inappropriate Bayer Matrix is all you are offered.

The importance of a luminance layer is its speed. It captures, simultaneously, red and green and blue. It is, therefore, three times faster than shooting through a colour filter. (Such is the theory. In truth I find, by measurement, that luminance is closer to four times faster than RGB/OSC.) You do not need  all your data to be colour data. You use the luminance to go as deep as possible as quickly as possible then you 'colour it in' with your colour data.

Part of the misunderstanding surrounding all this comes from terminology. There is no such thing as 'one shot colour.' It does not exist in digital imaging. The reality of 'one shot colour' imaging is that it is really 'quarter of a shot red, half a shot green, quarter of a shot blue' imaging. When yu put it like that it is easy to see why it is not a short cut. 

Olly

You miss my point, I was only explaining why a Bayer matrix is RGGB that's all, nothing to do with imaging, I was not arguing about anything to do with imaging.....

[ollypenrice]

15 minutes ago, LightBucket said:

You miss my point, I was only explaining why a Bayer matrix is RGGB that's all, nothing to do with imaging, I was not arguing about anything to do with imaging.....

I was responding to, 'the human eye sees twice as much green as the other two colours.' This might be taken as an an argument for shooting twice as much green in AP as blue or red.

Olly

[iapa]

I wish there were equivalent mono and OSC cameras produced by a company that could be used for a side by side comparison to put this to bed  

However, assuming that there were, then the discussion would move to debating the differences between the materials of the Bayrer matrix on the OSC vs the filters used on the mono. Such is this hobby.

I currently use a modded DSLR and plan to move to a mono cooled CMOS camera with a filter wheel and LRGB filters (until I get the hang of it, then may go to narrow band filters).

Watching similar mono vs OSC discussion for a while, I, personally, without actually trying it yet, am of the view that the mono + filters will produce the better results. 

However, I am on a long term plan here, and will be happy grabbing LRBG as I can over several nights. 

I do see the, not so instant, but shorter term, gratification of OSCs having been using DSLRs for a couple of years; being able to get 20-30 x 600s images that I can stack is great (some people are really impressed at work, and home- this i snot may aim, I want me to be happy). I just want better

Having to remove 50% of the green from OSCs is a bit of a pain. I look forward to just taking each colour and processing them the same way.

Just my tu'pe'urth