Combine CCD + dSLR images

[dmahon]

I'm still torn between a mono CCD and OSC.

Given the lack of clear skies we get, I thought that OSC might be a better bet to get an entire image in one go and not be left without the blue channel for example - plus the same amount of money will get me a significantly better camera (after factoring in the cost of a filterwheel and filters for the mono camera).

BUT

If I were to get a mono camera, and didn't get the filterwheel and filters straight away, could I use it for luminance and add in colour from my DSLR? Would the pictures be any good?

[Freff]

Listening with intertest.

[steppenwolf]

I chose an OSC for my first CCD camera for the same reason as you have suggested and it certainly worked for me. I do have a mono CCD camera as well now but I currently only use that for narrowband imaging, especially Hydrogen Alpha (Ha).

However, if you did buy a mono camera now for you could most certainly add colour data from a subsequent OSC to your luminance data. Many of us do this routinely.

[Zakalwe]

Also watching with interest.

[Glider]

Do the chips have to have the same number of pixels and pixel sizes or can software match up different resolutions?

I've done this with a mono and a colour Meade DSI but here things where the same.

[steppenwolf]

No, they don't have to match up. Several software packages will adjust one of the images for both size and rotation so that they match up - Registar and MaximDL immediately spring to mind.

[Glider]

Now that is good to know, opens up a lot of possibilities, cheers.

[ollypenrice]

My take on mono versus OSC (I have both) is not the same as Steve's though I see his point. For me these are the issues;

Mono plusses,

- For a given quality, mono is faster. The matrix robs you of some sensitivity.

-You can gain more time by binning colour.

-The mono is very consistent. The OSC, in my experience, sometimes does mysteriously badly, often on galaxies. I have had this several times but cannot explain the phenomenon.

-If guiding is an issue the mono is better when exposures are short. The OSC really does need longer subs to shine.

-Some clear nights are moonlit. Use them to shoot great Ha.

-With an electric FW you can sequence L,R,G,B or double L,L,R,G,B.

OSC plusses,

-Cheaper,

-At least something guranteed.

-Needs less surveillance during capture. Bed is possible...

-Flats, only one set. Bliss!!

Processing, nothing in it. Swings and roundabouts.

As above, Registar will combine anything, a map of Greenland in Ha with a ticket for the Royal Wedding on a Box Brownie. But DSLR images usually have little star colour. Do we know why?

Olly

[roundycat]

DSLR images lacking star colour - not that I care as I don't use one. Could it be a function of the ABG gated chip? All three channels will tail off in a similar manner due to electrons being bled off by the ABG gate. Could it be that?

Dennis

[Psychobilly]

Not "exposing" for the stars leaving them burnt out maybe... its possible to get colour in the stars with DSLR images... it's there in shorter exposures typically used for clusters and asterisms...

Tools like Noels astro actions can usually bring it back form the "halo"...

Billy...