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INDI Library v1.9.6 Released (21 May 2022)

Bi-monthly INDI Library released with new drivers and bug fixes.

Am I dithering here?

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Am I dithering here? was created by Tim

I fairly new to Kstars and Ekos so I'm still in the discovery phase.I'm getting quite a bit of rain type noise in my stacked images so I wanted to understand it I was dithering or not. For good or bad I have so far done next to nothing in terms of changing any guiding parameters. I'm using the internal guider and it does a really good job without me changing anything, which is quite astonishing to me. However I do want to make sure I am dithering (I thought this would be the default). If I go to Options>Dither, there are specifically PHD2 parameters on this dialog.

 

Does this mean all the parameters apply to PHD2? If the not, why is the default set to NOT dither, that doesn't make sense to me since there is everything to be gained by dithering but nothing to lose? Or maybe the internal guider has some parameter for dithering somewhere else? Sorry I'm a bit confused at what I am looking here.Many thanks
4 months 2 weeks ago #80344
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Replied by Hy Murveit on topic Am I dithering here?

1) You need to set the dither checkbox and click Apply in order to dither.

2) Many of the parameters apply to the internal guider. Note that the PHD2-specific parameters are greyed out.

3) Not sure whether dithering always on should be the default or not, but it isn't, so please enable it if you want to dither.

Best of luck,
Hy



 
AP1100 & Orion Atlas Pro, WO/ZS105 w/Moonlight V2 focus, GSO RC10 w/RSF focus
ZWO ASI1600, Astronomik Filters, ST80, QHY 5L-IIm.
KStars/Ekos/Indi on NUC10 & RPi4 w/SSD -- Ubuntu
Projects: Greedy Scheduler, Terrain, Polar Align, Analyze, Linear Focuser, SEP MultiStar & GPG Guide, FITS autostretch.
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4 months 2 weeks ago #80354

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Replied by Alfred on topic Am I dithering here?

I once had these rain patterns in my pictures, too. The issue was caused by a too small number in the "dither pixels" field. In your screenshot you're using 2 pixels. Set it to 7 or so and I bet you'll get rid of the pattern.

CS!
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4 months 2 weeks ago #80356

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Replied by hades on topic Am I dithering here?

Hi Tim, if the checkbox is disabled, you are not dithering, it is so simple. And there is one thing that you lose when dithering is enabled: the time, which is dithering consuming. In my case it typically takes 5-15 seconds between two exposures if dithering is enabled.
Alfred: I am not sure about so big setting (7 pixels). It may depend on your resolution. I am using the default 2 pixels and so far it is enough. My resolution is 1,5 arcsec/pixel.
Hy: I agree with Tim about the default ON setting of dithering. Can you please take it as a "feature request"? :) Thank you
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4 months 2 weeks ago #80360

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