dithering with NINA and PHD2

[myk68]

Hi All

As far as I am aware I have set up both NINA and PHD2 correctly witht he right figures to dither about 20-30 pixels in the main image randomly.

Everytime I try to set it on for a sequence I get a NINA error of PHD2 with error code 1

Anyone know that error as I cant find it in searches

Clear skies all, except in the UK as Bonfire Night always buggers that up

Mike

[Budgie1]

I'm still quite new to dithering and I only use APT but a 20-30 pixel dither seems a lot.

Normally something up to about 5 pixels on the guide camera is all that's needed because your guide star won't be much more than that in size. It could be that you're asking it to dither too much and it's loosing the guide star during the dither process.

[myk68]

Hi Martin

I thought it seemed a bit high but there was a site with a formula on for matching your guide scope and imaging scope so maybe it 30 in the guide scope.

Ill try it next clear night

 

HaHA

[Budgie1]

In APT I started off with the default settings and went from there. Even with those it wasn't showing the streaks any more with my DSLR.

Maybe have a search of the forum and see what others have used.

[ollypenrice]

Usually the guide scope-camera is working at a coarser pixel scale than the imaging camera so a 1 pixel dither at the guider will give an imaging dither of more than 1. An imaging dither of 12 pixels is often used to combat 'colour mottle' in DSLRs. If all you are trying to combat is small scale noise you don't need anything like that.

Olly

[david_taurus83]

Start off with a small scale dither and make sure PHD can recover within the allotted settle time. When PHD performs a dither, it doesn't move the mount instantly. It simply moves the cross hairs by a random amount, depending on the scale you have set. If you set to 2, it will select a new location somewhere within 2 pixels and then gradually issue commands to the mount to move the guide star back into the cross hairs. If its set to 30 it may take some time to move the guide star to the new location. All the worse if you have backlash to remove as well.

[newbie alert]

20-30 pixels seems a little excessive...I think I use 10 or 12 off the top of my head and even then had to change settings in APT as it didn't recover quick enough before the next exposure was taken

[myk68]

Thank you all for the help

Through clouds last night I found that the error was when PHD hasnt started, or had stopped guiding. so thats that one

I have cut the dither to about 8-10 pixels and will see how that goes, but the clouds thickened

Also found that the X2 barlow I have is Rubbish. so not a wasted night of clear sky to find all this out

Thanks once again

Mike