Starklabs Nebulosity - Master Bias

[Robny]

I'm playing with Nebulosity (Demo at the moment) and trying to create a master bias frame, i know i can use it as its only a demo but i want to try the software and the workflow.  However, i don't know if i have created a master bias correctly, here is what i did:

• Imaged 221 Bias Frames in RAW (Canon 1000d - Modified, 1/4000, ISO 800)
• Stacked them all together in Nebulosity (Batch - Pre process Image Sets)
• Dumped them ALL into BIAS
• Nebulosity would not allow me to stack them unless one light frame was selected, I just chose one of the bias frames I created?
• After selecting one light frame (Bias Frame) and having 220 Bias Frames loaded into Bias 1 and hit go
• Nebulosity did its thing and i was left with a single black frame (Stacked I presume - with included watermark)
• Finally, I then selected 'Save current file'
• It saved as FITTS

After doing the above process, have i just created a Master Bias Frame?  I was hoping for an option saying 'Create Master Bias' but alas was not to be.  Is my above process correct?

Also, do people generally keep hold of the raw files shot from the camera once this master is created or do you delete it from the HD?

Many Thanks

Rob

[Robny]

I seem to have created two files, one of which seems to be automatically generated by Nebulosity - the other was the one that i saved?

Im getting a little confused, does Nebulosity automatically save after stacking so no reason to save again?

Please see attached

[Jessun]

Just go Batch, Align and combine images and click save stack, click none for alignment method, use average method and deselect the tick boxes down the bottom.

That will produce a master bias.

/Jesper

[Robny]

Just go Batch, Align and combine images and click save stack, click none for alignment method, use average method and deselect the tick boxes down the bottom.

That will produce a master bias.

/Jesper

Thanks Jesper

Most helpful - So the file i just created using the method you outlined produce somewhat of a different image then my first attempt.  My first attempt produced a black final image, this method i have just tried produce more of an off white/grey colour image.

I'm presuming the grey image is a correct master bias file?

Please see attached my two attempts, which one looks correct?  The artefacts in the Image is the watermark from the demo

Rob

[Jessun]

It depends on where you set your black and whitepoint in the view window, so don't worry so much about that. It's easier to create one master and then delete the individual calibration frames. For actual lights, I personally never delete them. You never know what software you'll use in the future so it's good to have the originals saved I think.

Next time you just put this master in the bias box, and your lights in the light box. Don't forget flats and darks too. You make them in the same way as bias - capture is of course different, but the process as such is the same - but for the flats you can add a little std dev filter (just click next to 1.25). Per default the flats are slightly blurred anyways, but this can be changed in the preferences.

/Jesper