Help! Purple Jupiters

[Cozzy]

Help! before i pull what hair out that i have left.

I have hit an impasse with my avi's, i can get half decent shoots but the images have purple tinges to them and when i put them through Registax this just intensifies the issue. I have tried playing with the white balance but this just turns the images from the web cam 'green instead of purple/blue'.

I 'am using the farely standard setting in sharpcap and afew other simular soft packs put the effect still happens, I even tried the fringe killer but no luck there. Other images on SGL for Jupiter almost all have cloud bands of tans and browns. my scope is F8 refractor, using 3X barlow with extension and Spc880 flashed.

[JamesF]

Can you post the camera settings used for this image?

James

[atmenterprises]

Is the gain or gamma up too high during capture maybe?

Here are the settings I last used in SharpCap to image Jupiter:

[m.tweedy]

do you need to use an ir/uv blocking filter.

[Josh Wilson]

I'd say it's one of three things: Gamma, Contrast, or Saturation. Try lowering the saturation a bit see if the purple goes away.

I might suggest that it is poor color correction on the cameras side. Do purple or odd colors show up in broad daylight?

[Cozzy]

James, these are the settings I used for this Avi, as you can see there's nothing exciting there.

[Philips SPC 900NC PC Camera]

Resolution=640x480

Frame Rate (fps)=10.00

Colour Space / Compression=I420

Exposure=-5

Brightness=38

Contrast=25

Saturation=-39

Gamma=2

ColorEnable=255

BacklightCompensation=0

Gain=40

atmenterprises very simular settings to yours, no major differencies really.

Micheal, the spc880 came with an IR/UV blocking filter, i assumed it's suitable for the task or do you think I my need another model?.

Josh, I don't know I've never checked it out in daylight, i'll give it go and see what i get.

[JamesF]

I'd definitely try setting the saturation value back to zero.

James

[Josh Wilson]

I'd definitely try setting the saturation value back to zero.

James

Wouldn't that make everything grayscale?

This would fix the problem but no color would be visible and the image wouldn't be as interesting...

[astromerlin]

Not sure if you can in Sharpcap as I use WXastrocapture but if you can bring up the webcam driver settings dialog there is a "Restore to Manufactures Settings" button. I find sometimes when I plug in my SPC880(flashed 900) the colour looks quite greenish. I click the afore-mentioned button which resores all the settings and the colour returns to normal albeit a little too blue which is normal for this webcam. You will then need to adjust the gain,gamma sliders and shutter speed.

[JamesF]

Wouldn't that make everything grayscale?

This would fix the problem but no color would be visible and the image wouldn't be as interesting...

Zero is the mid-point for the saturation setting. All my Jupiter images have been captured with the saturation setting at zero. They certainly don't look mono to me

James

[JamesF]

Not sure if you can in Sharpcap as I use WXastrocapture but if you can bring up the webcam driver settings dialog there is a "Restore to Manufactures Settings" button. I find sometimes when I plug in my SPC880(flashed 900) the colour looks quite greenish. I click the afore-mentioned button which resores all the settings and the colour returns to normal albeit a little too blue which is normal for this webcam. You will then need to adjust the gain,gamma sliders and shutter speed.

Could also be that the auto white balance is messing things up, I guess. There's a way to turn that off in SharpCap, but I can't recall how off the top of my head. Is it under "Options->Filters" or something like that?

James

[Josh Wilson]

It is in the Video Control Panel. Just uncheck the box that reads "Auto" next to it and the white balance is yours.

[Baz Pearce]

This used to happen with mine too. As James mentioned, put saturation to zero. In SharpCap, select options - video capture filter. Should bring up another settings box. Go to the Picture tab. Turn off auto white balance. Then choose outdoor and turn on auto again and hit save.

If your Philips is flashed the same way mine is. Digital zoom and a picture enhancer slider, should also be available under the general tab. Turn the enhancer on and put to maximum, and save again. The digital zoom comes in handy if you get some good seeing for adding a bit more power.

Baz.

[ollypenrice]

I'm wondering if the offset for debayering is correct. The debayering software needs to know which are the green pixels, which the blue and which the red. This can usually be selected in the programme. I don't use a colour webcam but I needed to do this for my OSC CCD camera.

Olly

[cgarry]

I'm wondering if the offset for debayering is correct. The debayering software needs to know which are the green pixels, which the blue and which the red. This can usually be selected in the programme. I don't use a colour webcam but I needed to do this for my OSC CCD camera.

Olly

Yes, those colours look very similar to when I have deliberately debayered with the wrong settings. Though this is unlikely to be the problem as the SPC880/900 does the debayering before outputting the data and there is nothing for the PC software to get wrong in this regard.

Cheers,

Chris

[Cozzy]

John and Baz thanks for your input as well, I will try all the above, and start with returning the spc880/900 back to it's original settings, and try again when the clear skies come back.

thanks again to you all, I owe you a pint if i see you about. ;.)

[hunterknox]

Fairly certain it's chromatic aberration. My achromatic refractor does a similar thing when imaging. My old ED refactor never did.

By the way - if that's taken with your Evostar then it's very impressive indeed.

[JamesF]

Fairly certain it's chromatic aberration. My achromatic refractor does a similar thing when imaging. My old ED refactor never did.

I'm fairly sure it isn't, to be honest. I had exactly the same issue with the Xbox camera when I used it with my 127 Mak. I didn't have it with the Lifecam Cinema or PS2 Eye cameras and I certainly don't get it with my SPC900.

James

[m.tweedy]

Micheal, the spc880 came with an IR/UV blocking filter, i assumed it's suitable for the task or do you think I my need another model?.

Existing one should be ok

[Cloudwatcher]

I'm not qualified to explain the cause of the purple tinge but this can be resolved in Photoshop with the use of Colour Balance and Hue/Saturation tool. Well worth the effort as you have a fine capture there with plenty of detail to be seen.

[Cozzy]

I'm not qualified to explain the cause of the purple tinge but this can be resolved in Photoshop with the use of Colour Balance and Hue/Saturation tool. Well worth the effort as you have a fine capture there with plenty of detail to be seen.

CW, you have done an outstanding job on that image, very impressive! :icon_salut:

Did you use a particular work stream in Photoshop? ie raise the reds drop the blues etc ??

I did have a try with this image in 'GIMP' but couldn't get anywhere near the desired Tans and Browns as you have.

I will try again with 'Gimp'. and hopefully next time out make life a lot easier get the colour captures correct.

CW thanks again nice work!

[Cozzy]

I'm fairly sure it isn't, to be honest. I had exactly the same issue with the Xbox camera when I used it with my 127 Mak. I didn't have it with the Lifecam Cinema or PS2 Eye cameras and I certainly don't get it with my SPC900.

James

James,I must admit that it did cross my mind in a blind panic I thought OMG my optics aren’t suitable for the task, (more expense). Then I calmed down a bit and thought it may have been my F: ratio, I think I’m capturing at about F36 ish but it couldn’t be that. The things that go through your mind when things aren’t going to plan, then you change things(usually for the worst) and try to remember what you did to get back to the start. LOL

[Cozzy]

Fairly certain it's chromatic aberration. My achromatic refractor does a similar thing when imaging. My old ED refactor never did.

By the way - if that's taken with your Evostar then it's very impressive indeed.

Yes hunterknox this avi was via the humble Evostar 120mm F8 refractor, it works very well for the price, a nice piece of glass.

[Cozzy]

I'm not qualified to explain the cause of the purple tinge but this can be resolved in Photoshop with the use of Colour Balance and Hue/Saturation tool. Well worth the effort as you have a fine capture there with plenty of detail to be seen.

Finally after Xmas and working I have had some time to have another go at my Purple jupiters.

After losing three years from my life and down to the last hair on my head here is what I ended up with.

some more practice I think, but no one said the dark art would be easy.

all comments are truely welcome.