Colour or mono ccd

[Dave grim]

Hi guys I've just been reading Making Every Photon Count by Steve Richards and in it he was saying when he was a beginner in astrophotography he first a dslr then progressed to a colour ccd instead of mono as his thoughts were that we don't get that much time to image in this country ,so instead of having to spend ages with different filters he went for osc ccd . In the next 3/4 months I will be buying a ccd so don't know wether to go for colour( less time consuming) or mono (a lot more sensitive but time consuming , I would like feedback from you guys please to help me make up my mind , I know if I go mono route I will eventually need filters and filter wheel , but I think that could come at a later date.

Cheers

Dave

[Leveye]

After viewing picture after picture of Jupiter and Saturn I went the color route and am quite pleased. I'm doing all lunar,solar and planetary with it.I love the results i get.  If I had the bucks and a larger camera I would sure go mono with filters for everything wide field though.

[Andy Mitchell]

I went for Mono with an integrated filter wheel, deep sky is my main thing.

I've not done (L)RGB imaging but I understand it works out quicker with this sort of setup, you have to do 3/4 times as many images but they can by much shorter - each exposure is at the full sensitivity of the sensor and every pixel captures the colour not 1/2 of them for green and 1/4 for other colours.

Narrowband imaging is what I'm currently learning to use, and that is very much best done with a mono camera. It cuts through light pollution brilliantly but you do have to take very long exposures.

The big downside with mono is you need to spend more for the filter wheel and decent filters are not cheap.

[Shelster1973]

Have contemplated this for my step up to CCD when it eventually happens and have decided that I will go for the mono version.

As Andy says, you get the full sensitivity of the sensor capturing the colour of choice (or narrowband) so save time there.

When weighing up the fact of the not so long imaging time we get here in the UK also thought long and hard and decided that if I did not get enough data in one imaging session, I can always go back and capture some more.....I have plenty of time and unless something goes catastrophically wrong then the target I am imaging will be around for a hell of a lot longer than I will be....

Just need to save like a loon to get CCD...and fliter wheel.....and filters......and power supplies.......and then something else.......followed by something else......

[Andy Mitchell]

[Chris]

I was somewhat inspired to look at OSC after reading Steve's book also

I've imaged with both DLSR's and Mono cameras previously but very recently decided to buy an OSC to see if it would be a good compromise?

With DLSR I liked getting the colour in one but not the signal to noise, with mono I love the sensitivity but I don't often get round to finishing full LRGB images due to weather, family etc, I think I've finished 3 LRGB images in total and about 15 I've just left as L or Ha. I don't mind the filters if they are in a filter wheel but I must admit I personally find there to be a lot more steps in processing 4 sets of data to combine rather than one, this can be hard with kids jumping and screaming all over you I've found. I've never given narrow band a proper go but this might be less processing? 

In short, mono is faster for getting X amount of data but there are many more steps involved. Ideally I would like matching mono and OSC CCD's but CCD's arn't cheap!

I've only managed literally 2x60 seconds with the OSC before the clouds rolled in on my session last week, but I'm very pleased with the image for just 2 minutes total exposure, and the processing took me ten minutes so very kid onslaught friendly so promising so far!

Don't get me wrong though, I really like mono as well, it really just depends on your lifestyle, time, weather, LP as to which is sensible as a sole camera. Both is best

[Dave grim]

I haven't really got the problem of kids about as they are adults now and don't live at home ,it's just when the grandson comes round could be a problem he is only 4 and very inquisitive. I think the only limiting factor apart from cloud would be my work pattern as I work from midday to about midnight ish, so probably could do LRGB images when I'm of , I would like eventually to get into narrowband as well so think mono would be way to go . I will have to throw myself in the deepend as it were and learn as I go along with help from experienced imagers on here hopefully.

[Chris]

Sounds like you have a plan of action Just start of by shooting L to get used to the camera and take it from there. Some objects look nice just in L such as the horse head nebula. 

[Dave In Vermont]

I looked at the question this way regard the answer:

Which is the one that makes the most sense? Is it simpler to (and less expensive) to turn a mono-chrome image into a colour image? Or is it simpler (and less expensive) to turn a colour image to a mono-chrome image?

I went for the colour-cam. If I had deeper pockets, and lots of time to kill, I may well of decided on the mono-chrome gear. But that's me. And hey there, Andy M. - I love that anti-dope poster! It is the most honest one I've seen. Tells it like it really is: Astro- anything is far more addictive and, by proxy - expensive - than ANY drug addiction! But I'm not quite sure the real intent of the creator of it's intention..... !

Clear & Dark Skies,

Dave

[ollypenrice]

One shot colour is slower that mono by at least a ratio of 4 to 6, so 4 hours mono equals 6 hours OSC. In reality the mono advantage is greater than that. Here is why I say this;

An OSC camera has a colour filter in front of every pixel all of the time. A colour filter, by definition, blocks 2/3 of the light. (A red filter blocks blue and green, a green blocks red and blue, etc.) At no point in an OSC shoot are you ever collecting more than 1/3 of the incoming light. On top of that the Bayer matrix on nearly all colour cameras condemns you to shoot RGGB (two doses of green) because that works for terrestrial photography. It is utterly daft for astrophotography. Nobody shoots twice as much green as red or blue! In fact they use software programmes to pull the green down even more. (Pixinsight SCNR Green or the free Hasta La VIsta Green.)

Now in mono you can shoot some RGB (without wasting time shooting more green than you need) but then you can shoot luminance which is R and G and B all at the same time, and that's three times faster. That gives you the basic 6 to 4 advantage of LGB over OSC. But there's more.

Emission nebulae are strong in H alpha. When the moon is around you can collect that in a mono camera and very soon you will have an enhanced red layer which blows a standard red layer out of the water. This is my favourite example. On the left RGB from an OSC CCD. On the right HaRGB with Ha added from a mono CCD. The field of view is identical. 

If you are imaging at a scale of maybe 2 arcseconds per pixel you can bin your colour 2X2 in a mono camera with minimal losses in final resolution because your unbinned L layer will restore that resolution. So the mono LRGB advantage grows still more.

There will be no war between me and Steve because we get on well, and I take his point entirely that OSC gives you something even if the clouds cut you off in your prime. I made the same point in an old Astronomy Now article on OSC/mono some years ago. However, the arrival and wide acceptance of electric filterwheels means you can scroll LRGB, LRGB, etc and have a figthing chance of something to play with in the morning.

Phew, after all that the LRGB monochrome system was invented to save time. Somehow it is perceived as being slower than OSC. It isn't!!!! 

Olly

http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/22435624_WLMPTM#!i=2266922474&k=Sc3kgzc

[ollypenrice]

I looked at the question this way regard the answer:

Which is the one that makes the most sense? Is it simpler to (and less expensive) to turn a mono-chrome image into a colour image? Or is it simpler (and less expensive) to turn a colour image to a mono-chrome image?

I went for the colour-cam. If I had deeper pockets, and lots of time to kill, I may well of decided on the mono-chrome gear. But that's me. And hey there, Andy M. - I love that anti-dope poster! It is the most honest one I've seen. Tells it like it really is: Astro- anything is far more addictive and, by proxy - expensive - than ANY drug addiction! But I'm not quite sure the real intent of the creator of it's intention..... !

Clear & Dark Skies,

Dave

See my point above. Digital colour images don't exist at the captures stage. The sensors are all monochrome. With your OSC camera you use filters. With my monochrome filters I use them. The difference is that, to put it bluntly, you use yours with considerable inefficiency! You shoot more colour than you need, you shoot twice as much green as you need and when you shoot in H alpha you use only a quarter of your pixels.

Olly

[gajjer]

Hi Dave

after a lot of messing about with DSLRs both modded and un-modded I have finally bought myself a mono ccd.

I am mostly interested in narrowband. The theory is that I will be able to get over some of the light pollution problems I have where I live.

As you say, there are precious few nights to image but I am assured that with narrowband I should be able to get useable data even

on moonlit nights - within limits.

So it might take longer to get the data but there will be more nights that I can do it on.

If this plan fails then I'm off to Arizona!

cheers

gaj

[harry page]

Hi

Don't do green down too much , have you tried to do brown without good green signal

Harry

One shot colour is slower that mono by at least a ratio of 4 to 6, so 4 hours mono equals 6 hours OSC. In reality the mono advantage is greater than that. Here is why I say this;

An OSC camera has a colour filter in front of every pixel all of the time. A colour filter, by definition, blocks 2/3 of the light. (A red filter blocks blue and green, a green blocks red and blue, etc.) At no point in an OSC shoot are you ever collecting more than 1/3 of the incoming light. On top of that the Bayer matrix on nearly all colour cameras condemns you to shoot RGGB (two doses of green) because that works for terrestrial photography. It is utterly daft for astrophotography. Nobody shoots twice as much green as red or blue! In fact they use software programmes to pull the green down even more. (Pixinsight SCNR Green or the free Hasta La VIsta Green.)

Now in mono you can shoot some RGB (without wasting time shooting more green than you need) but then you can shoot luminance which is R and G and B all at the same time, and that's three times faster. That gives you the basic 6 to 4 advantage of LGB over OSC. But there's more.

Emission nebulae are strong in H alpha. When the moon is around you can collect that in a mono camera and very soon you will have an enhanced red layer which blows a standard red layer out of the water. This is my favourite example. On the left RGB from an OSC CCD. On the right HaRGB with Ha added from a mono CCD. The field of view is identical. 

If you are imaging at a scale of maybe 2 arcseconds per pixel you can bin your colour 2X2 in a mono camera with minimal losses in final resolution because your unbinned L layer will restore that resolution. So the mono LRGB advantage grows still more.

There will be no war between me and Steve because we get on well, and I take his point entirely that OSC gives you something even if the clouds cut you off in your prime. I made the same point in an old Astronomy Now article on OSC/mono some years ago. However, the arrival and wide acceptance of electric filterwheels means you can scroll LRGB, LRGB, etc and have a figthing chance of something to play with in the morning.

Phew, after all that the LRGB monochrome system was invented to save time. Somehow it is perceived as being slower than OSC. It isn't!!!! 

Olly

http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/22435624_WLMPTM#!i=2266922474&k=Sc3kgzc

[ollypenrice]

Hi

Don't do green down too much , have you tried to do brown without good green signal

Harry

I like brown but I don't shoot double green to get it!

Olly

[Chris]

Brown aside, that star colour is gorgeous! Please tell me you can at least get nice star colour with OSC? I sometimes struggled with my DLSR's I'm guessing due to well depth?

[harry page]

Hi

Must be my light pollution problem as I often need more green than Red and Blue

Harry

[ollypenrice]

Brown aside, that star colour is gorgeous! Please tell me you can at least get nice star colour with OSC? I sometimes struggled with my DLSR's I'm guessing due to well depth?

You can. In fact I used to find my OSC CCD gave better star colour than my mono (and Harry used to tick me off, quite rightly, for posting images with white-cored stars.) So now I try to remove luminance from stars in order to make them RGB only. Most of my starfields have RGB-only data and not that much of it, even when the main target has vast numbers of hours. Eg http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/i-SHnPvp3/0/X3/M33%203SCOPE%2030HR%20HaLRGB%20ODK%20CoreV2.-X3.jpg

Olly

[Chris]

Thanks Olly, good to hear from my current standing, I think I'll take a stab at a glob next to make the most of that

[ollypenrice]

I wouldn't shoot L for a globular. Nearly all it will do is cook the stellar cores. It might pull out a fiew of the fainter stragglers though. Experiment is everything.

Olly

[Chris]

I wouldn't shoot L for a globular. Nearly all it will do is cook the stellar cores. It might pull out a fiew of the fainter stragglers though. Experiment is everything.

Olly

It would be with OSC Olly

[steppenwolf]

I do indeed advocate the use of a OSC camera in my book for beginners although I also discuss mono and filters in some depth. I use both OSC and mono + filter cameras to this day and both most certainly have a valid place in my imaging armoury. Remember that the whole ethos behind 'Making Every Photon Count' is to get the reader up and running, taking good images in a short period of time and an OSC camera to my mind (and from my own experience) best suits this path, especially in the UK.

Once the reader has got the bug and started to achieve good/excellent results, the path will naturally lead to experimenting with narrowband for either enhancement or as a palette in its own right and here, a mono camera is a requirement. However, there is absolutely no reason why a beginner shouldn't start with a mono CCD camera and filters but it will add an additional layer of cost (filters, filter wheel) and complexity to the early learning process and that is against the aim of the book!

I haven't put Olly's maths to the test and neither do I need to as he knows what he's talking about (generally :grin: !) but my perception is that I can get a more than acceptable (RGB) colour image quicker with my OSC camera than I can with faffing around with my mono and filters system but I do enjoy bi-colour imaging with my mono camera.

YOU NEED BOTH really .......

[ollypenrice]

YOU NEED BOTH really .......

Heheh, and this was the cop-out conclusion my old AN article as well. Having both is certainly good but I'll stand by the speed claim. I was never entirely sure that processing OSC was easier, though.  Yes, in some ways it is in pre-processing but I think I had more 'problem' images in OSC than in LRGB, that is images that for some reason just didn't want to play nicely in post processing. Of course this is both subjective and anecdotal so it doesn't get my usual four hour guarantee!!!

Olly

[Marky1973]

YOU NEED BOTH really .......

And there you have it - both dedication and a fat wallet! 

[steppenwolf]

And there you have it - both dedication and a fat wallet! 

.... and more importantly, an understanding wifykins .......

[Marky1973]

Hah! Oh she understands.....she understands she gets peace and quiet if I'm outside looking through a cold metal tube!

This has been a great discussion though as I am still planning to move onto CCD imaging later in the year....but I still have to get a new mount and suss out guiding first!