Mono v OSC CCD Camera?

[BlueAstra]

Just in case anyone has not noticed it, I came across this rather good comparison of OSC v Mono CCD cameras. Very interesting stuff:

ST2000XM-XCM Camera Match

[MikeWilson]

Thanks for posting this. It answers a lot of questions I've been having in the OSC vs. Mono debate.

[Coco]

Thanks for posting this. It answers a lot of questions I've been having in the OSC vs. Mono debate.

Did it? 

[ollypenrice]

That's a pretty good piece of work. Thanks for the link. I have never had any doubt that mono is faster and this guy comes to the same conclusion even when comparing just OSC and mono RGB. To me, though, the real point about LRGB is that L is (at least)* x3 faster than OSC or RGB since it is passing all colours at once while the other systems are not. And you don't need all that colour information collected by OSC and RGB only.

I used to agree that taking just one set of flats was an OSC boon but, since then, and moving to a sealed electric wheel, I've found that my L flats work perfectly well on all filters so I no longer do separate ones. This is not something we can be sure will always work but I know one or two other people who do this as well.

Olly

* I say 'at least' x3 faster because if I take a 3 hour RGB and extract from it a synthetic luminance layer to add to a 3 hour true luminance layer I find it does not merit blending at 33%. The optimal S/N ratio usually appears to come up with around a 25% application of the synthetic L. However, I may be missing a trick or two in how best to extract the syn L. I don't know.

[lensman57]

Just in case anyone has not noticed it, I came across this rather good comparison of OSC v Mono CCD cameras. Very interesting stuff:

ST2000XM-XCM Camera Match

That is interesting but I would be interested to know how the Ha image from the OSC was obtained as this is not clearly discussed. The quality of the final image from the OSC will depend to a great degree on how the RED data was separtaed from the none existant R and G. Thanks for posting.

Regards,

A.G

[ollypenrice]

Just to revive this for a sec, I came across a link posted by Macavity on the science board and it set me thinking again. Why does OSC use RGGB (double green) and should it do so for astronomy?

My conclusion is that it shouldn't,  that this is ineffective in astronomy, and it also led me to see a further advantage in the luminance filter. I started a thread here; http://stargazerslounge.com/topic/227656-the-mysteries-of-green/#entry2453546

Olly

[StuartJPP]

I have seen this article before and is one of the reasons I still shoot OSC (albeit with a DSLR)

Mono will almost always be the better option for getting the best possible outcome (like-for-like conditions/kit etc.) and lends itself to NB imaging.

However the differences are not orders of magnitude different in RGB colour images and in some cases the difference is minute (others it is more obvious).

In fact with all the hurdles against OSC I am surprised it does as well as it does.

I can equate it to my expensive lens, image wise it is better than a Sigma 500mm but that doesn't mean that I am going to win an award with my lens and the other guy isn't...just means that in identical situations my image will be sharper...but if he can process his image better than me then he may take the prize.

Regarding the "incorrect" Bayer matrix I think it was answered in the other thread...OSC astro cameras are using off the shelf sensors which are designed for markets other than astro...mono ones are just that...the same sensors with no Bayer matrix.

[AstroAndy]

If you live in this geographically unfortunate zone, better to go w/ OSC.

[ollypenrice]

If you live in this geographically unfortunate zone, better to go w/ OSC.

Why? Mono is faster by a minimum of 6 to 4. If you bin the colour it gets an even bigger advantage. If you have an electric wheel and sequencer you shoot LRGB, LRGB, etc. You can also use better colour filters with mono and you are not obliged to shoot too much green, as you are with OSC. Have a look at the other thread.

Olly

[StuartJPP]

Why? Mono is faster by a minimum of 6 to 4. If you bin the colour it gets an even bigger advantage. If you have an electric wheel and sequencer you shoot LRGB, LRGB, etc. You can also use better colour filters with mono and you are not obliged to shoot too much green, as you are with OSC. Have a look at the other thread.

Olly

Olly, we only get enough imaging time here in the UK to image one colour filter per year (regardless of sub length as cloud coverage scales proportionally) so OSC is MUCH faster than mono by a minimum of 2 years (3 years if you include Luminance, 4 with Ha)

[lensman57]

Olly, we only get enough imaging time here in the UK to image one colour filter per year (regardless of sub length as cloud coverage scales proportionally) so OSC is MUCH faster than mono by a minimum of 2 years (3 years if you include Luminance, 4 with Ha)

God knows how many times I have loaded the filters and then ended up with nothing due to inadequate exposure. The weather up here is the culprit then LP. The most satisfying imaging experience for me is loading the Ha filter as I love Monochrome ( my photography past ) but not all targets are suitable for Ha imaging so the OSC camera is always at the ready like a reliable Colt 45 at the side just incase the automatic decides to jam up. The chances of having two clear nights up here one after the other is very slim in the winter time when most targets are available.

A.G

[ollypenrice]

Olly, we only get enough imaging time here in the UK to image one colour filter per year (regardless of sub length as cloud coverage scales proportionally) so OSC is MUCH faster than mono by a minimum of 2 years (3 years if you include Luminance, 4 with Ha)

Right, so with time pressing you have the brilliant OSC idea of shooting half your subs in green. Yes, brilliant, Holmes!  Why brilliant, asks Watson? Brilliant, says Holmes (in an uncharacteristic intellectual lapse) because you can ask HLVG or SCNRG to throw them away!

But, says Holmes, it gets better! It does, says Watson? Yes, says Holmes. When the moon is out we can't use our OSC so we can send the Baker Street Irregulars out for more opium! Now you're talking, says Watson. I'm sick of astrophotography!

lly

[ian_bird]

Right, so with time pressing you have the brilliant OSC idea of shooting half your subs in green. Yes, brilliant, Holmes!  Why brilliant, asks Watson? Brilliant, says Holmes (in an uncharacteristic intellectual lapse) because you can ask HLVG or SCNRG to throw them away!

But, says Holmes, it gets better! It does, says Watson? Yes, says Holmes. When the moon is out we can't use our OSC so we can send the Baker Street Irregulars out for more opium! Now you're talking, says Watson. I'm sick of astrophotography!

lly

Classic!

Nice one Olly!

Cheers!

Ian

Too many exclamation marks? I think so!

[AstroAndy]

Olly

I have read the articles with interest, and find merit in them..maybe I should consider going the mono route, however, even after having read all this, at the same time, I'm still partial to OSC, simply because of the less effort aspect.