Planetary Imaging - Mixing Images

[ribuck]

Hi all,

I was just wondering when doing planetary images of jupiter / Saturn is it possible to combine stacked images from a web cam, with iamges taken on a more sensative ccd such as a starlight xpress to bring out more detail.

Was just owondering if you could stack web cam images to get final result, then stack exposures from the starlight xpress and then merge the 2 together in photoshop.

[Reggie]

Surely you'd be better of just using the more sensitive camera in the first place for the imaging session? Or is the starlight xpress in question a single shot camera?

[ribuck]

no, but's it's an older mx916 which is mono, but i do have a filter wheel. I heard that webcams are extremely good for imaging planets, such as the Philips spc9000

[Reggie]

The philips are a decent cheap little cam for planetary work for sure I'm sure the pixel size and resolution are different between the cameras so I think you'd come across resizing issues somewhere along the line (hoping someone can come along and confirm that )

[ribuck]

I was thinking that that the resolution could be changed in photoshop to match, but not sure about the pixel size. Any ccd camera experts out there who can coment on this with regards to imaging ?

[Reggie]

the resolution can easily be changed in photoshop as you say but I'm wondering how much that will affect quality as well. It's definitely a nice idea, just not entirely sure how practical it is in practice I'm not even sure that pixel size is entirely relevant to resizing, although it will affect sensitivity and FOV for sure.

[ribuck]

Well Maybe this will be something to test once the skies clear, if they ever clear........sigh....Well looking on the bright side it's getting darker earlier every day now, so hopefully soon , i'll be able to get some imaging in.

Rich.

[Reggie]

This weekend I reckon Rich not putting the mockers on things, metcheck.com and the metoffice website appear to be in aligment over forecasts on the south/south east coast, usually a good sign.

[MarkAndLeanne]

I don't want to tempt fate, but Metcheck is actually getting better! Was reporting 11% cloud for Littlehampton earlier, but has now dropped to 2%, with the promise of a nice weekend! :sunny:

[ribuck]

Temp fate you say.....lol you have to be kidding lol..... , i know my fate and it's 90% cloud coverage.....and i'm not joking as you can see.....

(click to enlarge)

[ribuck]

Anyway back to the topic at hand, does anyone else have any more views about mixing data from a more sensative ccd with webcam images. ?

[frogbmth]

I have had a go at this, though with a lower end CCD. I took colour with an SPC900NC and monochrome with a DMK21 CCD. I have a small c90 spotter scope but got a better result than the webcam could provide. First image was with an SPC900NC only, second is combined with the DMK21 image. The C90 scope doesnt have much ability to get detail.

[ribuck]

definately a lot more detail there in the second mixed photo. have an 8" refelctor so will be interesting to see

[frogbmth]

My monochrome cam produces much better results than the SPC, I used PSPx2 to combine the images. I pasted the colour shot over the mono as a new layer, set transparency of the new layer to 50% and aligned them. Then I set transparency back and changed the blend mode to colour (legacy). The result is only the colour information from the webcam shot layer, merged into the detail of the mono shot. I will be using this method again, look forward to seeing what results you get in your 8"

Andy

[Reggie]

What res. is the monochrome cam? Those results are definitely interesting. I stand well corrected

[frogbmth]

the DMK21 mono is only 640x480,

Andy

[ribuck]

I have the Mx916 which is slightly higher resolution but much higher sensativity, so i'm dying to try it out as soon as the clouds clear. i'll post results if i ever see a clear night.

[Milamber]

Sorry to say this but it will likely not work. Webcam images tend to be stacks of hundreds - if not, thousands - of frames taken in a short timespan. That *short timespan* is of the essence since your target will have moved and rotated, possibly significantly, by the time you swap cameras. Also, without having the ability to stream video the SX will never be as good at planetary shots as the webcam and derivatives simply because it cannot capture the data fast enough.

In essence then, you may sort resolution/pixel size issues but you will have major problems getting, for example, two shots of Jupiter taken only 15 minutes apart to align.

Arthur

[ribuck]

Hi arthur, that's what i was afraid of. Once the weather clears i'll just try my spc9000 and see how i get on with that.