Edge HD first light

[Miguel1983]

Hi,

i've recently got an 9.25 Edge HD and yesterday i got first light with it after some hassle with SGP and Phd2 i might add.

Picture below is a 2min sub of M106 and a render with the aberration script in Pix.

Can someone weigh in on what might be the the issue here with the stars in the outer edge of the field ?

I'm using the Celestron 0.7 reducer - PrimaLuceLab Esatto 2" - 10mm spacer - Zwo OAG - 10mm spacer - Zwo EFW - Zwo 294mm pro (bin2)

The backfocus is about spot on (145.8mm from what i can measure) , and if not, since the focuser is behind the reducer i would think that lowest HFR with autofocus is the perfect backfocus position.

So i'm thinking collimation ? I've eyeballed it to be perfect, but you never know i guess...

 

Thanks for looking

Edit

This is my collimation 

 

Edited April 15, 2021 by Miguel1983

[CraigT82]

Looks like coma since the corner stars have tails that radiate from the centre. Are you definitely measuring the spacing from the FR to camera sensor correctly? 

 

 

[Miguel1983]

9 hours ago, CraigT82 said:

Looks like coma since the corner stars have tails that radiate from the centre. Are you definitely measuring the spacing from the FR to camera sensor correctly? 

 

 

Hi,

yes, i'm quite sure of my measurment, i've placed my image train (focuser down, camera up)  flat om my table, and rested my caliper on the filterwheel, sliding down until i hit my table.

Then i needed to subtract 9mm from the Esatto adapter to SCT and add 6,5mm from the camera backfocus, this gave me 145.8mm.

But as i said, even if it would be slightly off, i think the focuser would correct this, no ?