Mono & OSC cameras same as LRGB..

[Astroboffin]

Hi,

i have a question for you guys

Taking the cost out of the equation, will imaging with a mono camera and LRGB filters, give more or less the same results as imaging with a mono and OSC camera, as long as the camera are the same model, ie, two Atik 383L+ cameras, one mono and one color, then combine the images together..my logic being that the mono will give all the detail and the RGB from the color camera...

what are your thoughts other than being more expensive which is obvious..

AB

 

[Daniel-K]

you fancy that 383 on ABS 

[ngwillym]

Maybe I'm wrong, but a colour camera will have some sort of Bayer matrix in from of it and this therefore reduces the number of pixels that receive any specific colour - and therefore, by my reasoning it equates to a lower native resolution?

[pipnina]

3 minutes ago, ngwillym said:

Maybe I'm wrong, but a colour camera will have some sort of Bayer matrix in from of it and this therefore reduces the number of pixels that receive any specific colour - and therefore, by my reasoning it equates to a lower native resolution?

But in colour data, having 1/2 resolution doesn't matter that much compared to having 1/2 Luminance/Narrowband. Some people bin colour because it can reduce colour noise and the colour data doesn't really do anything besides... add colour. All the detail is in the Lum/NB.

IMO, it could be plausible that using a mono for Lum/NB and an OSC for colour channels might be ok. But you'd have to do 3x the exposure and probably create super-pixels in DSS or whatever stacking software is in use, then separate the colour channels in Photoshop / GIMP (it's a pain in GIMP though, PS would be much nicer, a friend showed me PS on his macbook, he just did a dropdown menu, selected "LAB" and it changed, he could paint in LAB in colour and fdshfeioqmfehsi... In gimp, you have to decompose, edit individual channels without colour being present and recompose... A RIGHT PAIN)

It would probably reduce the risk of forgetting to change a filter around and ending up with an image that contains only Luminance and red... But other than that I don't see A problem with the plan. Would save on buying the colour filters & filter wheel I guess.

If you were loaded, though... A scope for each channel: Lum, Ha, Hb, OIII, HeII, SII, R, G, B. "You have 9 telescopes in your back garden? you can't possibly use them all!" "You have no idea"

   ~pip

[carastro]

I don't see why this wouldn't work.  You would have to make sure to get both cameras aligned with each other otherwise you'll be cropping loads off the edge.  I think a mono camera with RGB filter might give better detail, but as mentioned above, you don't really need the detail in the colour.

Indeed I have several times combined colour from old DSLR images to Luminance or Ha with my CCD cameras.  So no reason why this cluld nto be done with Mono and OSC cameras.

Carole 

 

 

[ollypenrice]

Hang on, the OSC camera does not work on a naive resolution of R+G+G+B equalling one super-pixel of a quarter the resolution of four mono pixels. It's cleverer than that. The software interpolates structures within the 'RGGB superpixel' in a virtual luminance layer not controlled by the imager. So the loss of resolution is nothing like as bad as it might seem. How well the interpolation is done depends on the software and they vary in 'skill.'

So how about OSC colour and Mono luminance captured either together in parallel scopes or separately in the same scope? Set out below is the light capture sum for a 'three hour per camera' shoot. (Six hour total.)

Lum 3 hours.

Red 45 minutes

Green 90 minutes

Blue 45 minutes

This does not strike me as being at all a good idea. I would far rather have 3 hours lum and an hour per colour. I would also like to have the opportunity, at appropriate focal lengths, to bin the colour 2X2 which you cannot do on a colour camera. The big Bayer problem is the double set of green filters which works for terrestrial photography but is all wrong for astrophotos.

When I ran OSC and mono atik 4000s I never used the mono for L and the OSC for colour. I always used the mono for Ha and OIII and the OSC for the base image. The OSC never 'filled' the mono very effectively.

If you set parallel cameras to be aligned along RA ad Dec (expose while slewing to see the orientation of star trails) then aligning them is easy if you have a tilt pan device such as newly introduced by FLO.

Having tried using an OSC and a mono I now use, and vastly prefer, two monos.

Bear in mind that the RGB filters placed over a chip are not a patch on the RGB interferometric filters supplied by Baader or Astrodon or Astronomik.

Olly

[ollypenrice]

Please ignore. Sorry.

Olly

[Astroboffin]

1 hour ago, Daniel-K said:

you fancy that 383 on ABS 

Lol...yes

 

[Daniel-K]

Cracking price. I would have gone for it if I wasn't going to SGL next month 

[Astroboffin]

42 minutes ago, Daniel-K said:

Cracking price. I would have gone for it if I wasn't going to SGL next month 

Yes, I have emailed the guy,  very tempting..... 

[Astroboffin]

44 minutes ago, Daniel-K said:

Cracking price. I would have gone for it if I wasn't going to SGL next month 

How you getting on with the 414ex now Dan ?

[Daniel-K]

22 minutes ago, Astroboffin said:

How you getting on with the 414ex now Dan ?

Only had it out once. Got it all up and running. Just need to sort out my guiding woes.  Im happy with it at Go it frames galaxy's just they way I had hoped.

[Astroboffin]

The reason behind this question, is that I while looking for an Atik 383L+ OSC I was offered a mono version at a steal of a price, much too low to say no too, it is mint.

now the OSC one has come up on ABS for a good price, I thought that I could have the two for less than a new 383L+ would cost, so a no brainer really, and with the cost of a filter wheel and 36mm filters running to around £800 it will actually work out cheaper also, and the weight issue on my focuser would be resolved at the same time..so,win win..or not

so as for the problem of havimg twice as much green in the OSC  image as the other two colours, this may be a stupid question, but couldn't I just adjust the green channel in post processing. .? Or is that too easy and I am missing something ?

thanks for the replies guys and gals..

AB

 

[ollypenrice]

15 minutes ago, Astroboffin said:

The reason behind this question, is that I while looking for an Atik 383L+ OSC I was offered a mono version at a steal of a price, much too low to say no too, it is mint.

now the OSC one has come up on ABS for a good price, I thought that I could have the two for less than a new 383L+ would cost, so a no brainer really, and with the cost of a filter wheel and 36mm filters running to around £800 it will actually work out cheaper also, and the weight issue on my focuser would be resolved at the same time..so,win win..or not

so as for the problem of havimg twice as much green in the OSC  image as the other two colours, this may be a stupid question, but couldn't I just adjust the green channel in post processing. .? Or is that too easy and I am missing something ?

thanks for the replies guys and gals..

AB

 

You'll have to adjust the green channel (indeed all colour channels) but imaging is based on the signal you have captured, not the signal you have not captured. But on the financial side, sure, you're in a good position.

Olly