Drizzle anybody?

[TerryMcK]

I've always wondered how to successfully use drizzle in my processing. Sascha explains all in this great video https://youtu.be/xfRGitQ7usk?si=_s1PjKLCiLR5-h6Y.

 

AstroPixelProcessor and PixInsight are two applications which can process drizzle integrations. Also Russell Cromans website has a free to use MTF Analyzer https://www.rc-astro.com/mtf-analyzer/ to work out if your camera and scope combination may be over or undersampled. It can make recommendations whether or not to drizzle.

 

I entered my RedCat51 and ASI183MM specifications into the MTF Analyzer and found indeed that it would benefit from use of drizzle x2.

 

 

The red area shows it is undersampled slightly.

 

When drizzle x 2 is applied the undersampled red area disappears.

 

 

 

This is fine in theory but does it work in practice?

 

I took some data I recently shot of the Bat Nebula then ran the Ha subs through PixInsight's WBPP script with drizzle x2 and Drop shrink of 0.8 applied.

 

I compared a zoomed in view of the master produced with one from a none drizzle master light I did a few weeks ago and the results were clear.

 

Both the following images have had a slight GradientCorrection, BlurXTerminator and NoiseXTerminator applied. They are unstretched with STF applied to view them.

 

None drizzle first

 

Now drizzle x2

 

The blocky stars have gone and there are more fainter stars (more detail) showing up! Admittedly I am zoomed right in on a very small area of sky but I think drizzle is the way to go for me.

There are caveats though:

• You need a minimum of 30 subs
• Also the data needs to have been acquired with dithering between subs. I always do this so it is not an issue for me.

 

 

 

[AstronomyUkraine]

I'm fortunate enough that my Esprit doesn't need drizzle data on it, but my ED80, definitely could use it. I'm in the process of trying it out on some data from NGC 2264.

 

Other good news is you can produce drizzle data in the NSG script, which I prefer over the SubFrameSelector process. The NSG script also opens ImageIntegration, and DrizzleIntegration with the correct settings after analysing the data.