IC5070

[Jules]

I am going to have to start dithering my images I think.

Regards

Julian

[Jules]

Final iteration of IC 5070

3 hours 15 minutes of Ha. I dithered the subs this time.

Regards

Julian

WO FLT 110
QSI 583 wsg and Astrodon 5nm Ha filter
Lodestar guider
NEQ6 mount
Acquired in MaximDL

Processed in PixInsight
Star align
Integration
Dynamic crop
Atrous Wavelet transformation
Histogram Transformation
HDR wavelets
Local Histogram equalisation

[Nocturnal]

Looks real good. I recommend uploading a less compressed version somewhere. JPG artifacts are ruining the image at 1:1 scale.

[Jules]

Sander

Thanks for the positive comments.

Try this http://gallery.me.com/julian.hancock

Regards

Julian

[Nocturnal]

Hi Julian,

that gallery is really fancy (smells like Mac) but the image is even smaller. The download button doesn't do anything.

[Jules]

Hi Sander

You are nocturnal then? I having trouble with this 'displaying an image which isn't more than a few kb big'?

Regards

Julian

[Nocturnal]

Hi Julian,

sorry, I don't know what you mean. When I post a picture here (it's been a while) I generally show a small picture here and add a link to my gallery to show the full sized one. Like what you've done. It's just that in your gallery the image is very small. I can see you uploaded a large image but I can't get to it. Perhaps I'm doing something wrong. Let's see if someone else comments. Still a great image though!

[georg.viehoever]

For me, the larger version of the picture in the gallery only became visible after clicking several times on the exclamation mark (!) that substitutes it on the first attempts. The download button is always inactive. This is on Win7-x64 with IE9.
Georg

[Jules]

Sander

It was the the time of your post, I thought your were living up to your name?


Regards

Julian

[Jules]

Hi

I have been experimenting with this image. I have used the deconvolution process on image and IMO it has made it a lot sharper. Where should deconvolution be placed in the processing sequence, before/after noise reduction etc?

Regards


Julian

[Lex]

Guys,

I am still kind of new; could anybody tell me please what dithering really is ( or give me a link )
Not the first time i hear this, but no idea what this is about and how it could perhaps help me; as help is everytime welcome 

Btw --> Very very nice picture!!!

Thanks

Lex

[Jules]

Hi Lex

Here is an explanation about dithering from the MaximDL website:

Camera sensors are not perfect. A common problem is "hot pixels" that have much higher dark current than the surrounding pixels. Hot pixels also have significantly more noise, as the random noise goes up as the square root of the number of electrons. Even after dark subtraction and stacking these hot pixels will still show up because of their higher noise.

There is a simple technique to eliminate the hot pixel problem. If you move the telescope slightly for each exposure, the hot pixel will fall on a different position in the sky. When the images are realigned for stacking, the hot pixel will appear in a slightly different place in each frame. Now during stacking you can use a technique such a Sigma Clip or SD Mask to almost completely eliminate the influence of the hot pixel, as those algorithms will recognize the "out of place" hot pixel and remove it. For more information on these algorithms please see the Stack command.

There are three modes for dithering; two are configured here. If you are autoguiding, select Dither Via Guider; the autoguider guide point will be repositioned slightly between each exposure. This will move the image slightly across the main sensor.


http://www.cyanogen.com/help/maximdl/Autosave_Sequence.htm

Thanks for the positive comments about my image.

Regards

Julian