First light with DMK

[rat156]

Hi All,

Got my new DMK21AF04 today, had to try it out.

Seeing was average, actually I think it was pretty bad, Jupiter was doing that lava lamp thing.

Anyway got some shots in.

Luminance taken with DMK @ 60fps, colour added from Toucam image in PS.

Meade 8" LX200GPS @ f20.

Cheers
Stuart

[ballaratdragons]

That's your 1st image with a new camera!!!!!!! Well done Stuart!!!
Nice sharp image :thumbsup:

Can only go forward now :)

[[1ponders]]

Not too shabby at all Stuart :thumbsup: :thumbsup: ;)

[Ric]

A great start and a great capture Stuart.

Top stuff.

[iceman]

That's a great first light, Stuart! Well done.

Nice and sharp and good colour.

How long did you record for with the DMK? How long did it take you to swap in the ToUcam? and how long did you record the colour data for?

Did you have to rotate the channels to match them up or did you ensure the cameras were oriented the same way?

I did the same thing when I first got my DMK - captured luminance with the DMK and colour with the ToUcam. It worked well until I got the colour filter wheel. It gets quite frustrating to have to swap cameras, refocus etc, especially when you've got a short period of time as with Jupiter.

[rat156]

Hi Mike,



A minute for each, DMK @ 60fps, Toucam @ 15fps. It takes me about 15 seconds to swap the cameras, I use a flip mirror, with one in each eyepiece hole. Then quickly set the focusser (I have a moonlite with the stepper motors on it so can quickly move between positions, bought right here in the classifieds section).



Because of the flip mirror I had to flip the colour channel horizontally, then rotate by about 3.5deg in PS, then they aligned pretty well, possibly could use Registax for this later on. The colour doesn't have to match super well +/- a pixel and you won't notice.



That would annoy me too, as all the avi's would be different orientations etc. I already had a flip mirror, so it was a no brainer for me. Next step is to see how long the colour lasts. Can I take a colour avi, then several mono ones, and still use the original colour?

Cheers
Stuart

[iceman]

Hi Stuart



ah, a flip mirror. Excellent! Makes it much easier than having to take them out and swap them.


I guess you could, as long as they were in quick succession. But any more than 5 minutes and I expect you'd notice some rotation and you'd have to shift the colour image too far to line it up. You might end up with no colour data on the limbs, which may or may not look too bad.

Here are the 2 images I took using DMK as luminance and ToUcam as colour, back in end-June 2006 when I first got my DMK. You can even see from those images the greater sensitivity and resolution of the DMK.

[leon]

Wow, for a first light that is pretty stunning, can only imaging what the forth coming images will be like, very nice indeed.

Leon

[matt]

Hope this isn't a dumb question, but I've noticed a different image size/scale when capturing Jupiter using the DMK and ToUcam.

I'm aware they've got the same CCD chip, so it's no-doubt the result of the distance of the chip from the barlow (I mostly use the 3x) caused by the slightly different size adaptors on both units and possibly the different positions/depth the chips are housed in their respective casings.

Given this small difference in image size or scale, how do you then make them the same size to combine in PS so the data lines up? In my case, how do I make the DMK mono/luminence channel the same size?

Is it just a case of resizing or increasing the scale of the DMK image in PS until it is close enough to the ToUcam colour channel? Or is there a more precise way of matching them?

Many thanks.

[rat156]

Hi Matt,

The barlow (Meade S5000 2x telextender) is before the flip mirror, so the backfocus position should be the same, I did tweak the focus between colour and mono, but I'll setup the helical focuser on the flip mirror properly next time so I don't have to. This should result in exactly the same image scale as the two CCD's have the same pixel size.

Cheers
Stuart

[matt]

Hi Stuart. Thanks for the reply.

I guess the point I'm making is that you can increase image scale by moving the chip further away from the top lens of the barlow. In my case, a 3x Televue.

So, the scale will vary depending on the distance from focal plane of the camera to the upper lens in the barlow.

I seem to get an image of slightly different size depending on which camera and it's associated 1.25" adapter I use.

My question was more geared toward how you make both colour (ToUcam) and mono (DMK) images the same size for when you overlap (layer) them in Photoshop???

Hopefully, that makes more sense?

Cheers

[iceman]

Hi Matt

Which image is larger? The ToUcam (colour data) or the DMK (luminance)?

In photoshop, there's 2 ways to do it.

a) Resize the (smaller) image before pasting over the other
b) Resize the (smaller) layer after it has been pasted on top of the other.

For the purposes of an example, let's assume the ToUcam (colour) data is slightly smaller than the DMK (luminance).

1) Process your images as normal, save from Registax as TIFF.
2) Open both images in photoshop.
3.1) If doing as Point (a) above, go to Image->Resize and enter the (larger) number of pixels (or percentage). This may take a bit of trial and error and a few tries until you get it exactly right.
3.2) If doing as Point (b) above, copy the ToUcam image, and paste it over the the DMK image (it will create it as a new layer). Go to edit->transform->rescale and resize the layer to make it the same as the layer underneath.
4) For the ToUcam layer, change the blending mode to "color".

And there you have it. You'll have the "detail" from the luminance layer and the colour from the ToUcam layer.

You can verify by using the "eye" to blink on and off each layer to see what is revealed.

[matt]

Thanks, Mike:)

Do you find you have to make the same slight adjustment when combining ToUcam and DMK images?

[iceman]

I don't use that method anymore - with the filterwheel and DMK I haven't touched the ToUcam since then :)

The only time I did combine them (as posted above), I don't believe I had to resize the images to match. Though it was over a year ago so I can't remember exactly.

[matt]

Sorry. Should have written 'Did' (past tense), rather than 'Do'.:)

The good news is we've found a place to live in Brisy, which has a reasonable backyard, so I'll be back into the imaging in about another fortnight.

Boy, it's been hard not being out there for so long.

Will have a go at this ToUcam + DMK data as soon as I can.