PHD1 guiding + Nikon D90: manual dithering for PI drizzling?

[rofus]

Hi all,

funny enough now that I can autoguide for 10+ minutes, I have another problem: noise! Recent imaging sessions recorded that across 1:30h of imaging (eq5 autoguided with Skywatcher 150 refractor) my image offset was just 2px, that is quite good but indeed means that averaging does not kill much noise, and I cannot use drizzle in PI.

Because I use a Nikon I don't have direct control from computer, I just have an automated wifi remote bulb system that takes long exposures and via USB I receive the images in realtime on my Mac.

I was thinking about using dithering, and so moving slightly the frame between images. As my understanding I should get two advantages:

1) noise reduction by averaging between images

2) drizzling and getting higher resolution images

I have about this two questions: can I do a manual dithering in PHD1? Or in PHD2? I can do it manually between the images, not a problem. Also to use drizzling while stacking in PI, what should I do?

Any suggestion is welcome...I was suggested by many that using dithering could be another step improving quality of my images now that I can do very long exposures.

[glowingturnip]

yep, all very possible !

1) in PHD2, do Tools/Manual Guide, and there's a button there for 'dither', you can press that when you like during guiding and it will dither immediately according to the settings (I'd go for +/-3, scale 1 and RA-only unticked)

2) PI recently released a drizzle integration tool, which I've been using - details here:  http://pixinsight.com/forum/index.php?topic=7151.0

[rofus]

yep, all very possible !

1) in PHD2, do Tools/Manual Guide, and there's a button there for 'dither', you can press that when you like during guiding and it will dither immediately according to the settings (I'd go for +/-3, scale 1 and RA-only unticked)

2) PI recently released a drizzle integration tool, which I've been using - details here:  http://pixinsight.com/forum/index.php?topic=7151.0

That's brilliant, thank you very much, will try tonight if weather stays good

I'll probably have to wait a few secs between a frame and another to allow guiding to settle (usually it takes 15/30secs) after dither, and I'll use the default scale x2 of PI drizzling...curious to see the improvement, seems it could be massive!

[glowingturnip]

yes, I usually allow quite a bit more between frames since my DSLR is noisy and gets hot with amp-glow - I'd usually wait 2 mins between frames for 5 minute frames so that it can cool a bit, and dither during that time