[Startrek (Martin)]

Well my first few nights into Mono imaging with the 2600MM went really well , sort of……,
Clear nights
Chose NGC 253 Sculptor Galaxy for Broadband ( Antlia LRGB ) 90 sec subs in Bortle 8 ,4 hours worth, Gain 100
Chose NGC 7293 Helix for Narrowband ( Antlia 3nm Ha Oiii Sii ) 180 sec subs under Bortle 8 , 12 hours worth , Gain 100.
Ra and Dec balancing was easy ( only a slight adjustment from my 2600MC )
Camera and filter wheel operating perfectly
Camera temp stable at -10C
Subs looked great
Guiding was great 0.45 to 0.60 total over most nights
Captured Cal frames ( Bias and Flats ) similar procedure to my 2600MC

Culled all the bad subs in ASTAP

Now ……
Registered subs in DSS, chose best sub for reference frame for each channel
Stacked subs in DSS using a best reference frame ( and yes I unticked fits digital development when using a Mono camera )
Loaded each channel into Startools via Compose
Both Broadband and Narrowband auto stretched images on all individual channels had a small checker board matrix pattern across the background of the image ( see attached ) Never ever saw this with my 2600MC ???
Tried using different Alignment Transformation algorithms Bilinear , Bisquared , Bicubic etc… but no change
Tried using both Standard mode and Intersection mode for Stacking result , again no change
Tried stacking with lights only ( No Cal frames ) again no change
Tried stacking 1 night only ( no use of Groups or reference frame ) again no change
Then I noticed in Results tab, I had the box ticked that says “Align RGB Channels in final image” , so unticked it , again no change

I’m confident it’s a stacking issue but tried various settings with no change

I’d prefer not to use another stacking software as my 2600MC has performed flawlessly with broadband and narrowband imaging for many years now using DSS

Are there folk who use the 2600MM camera and use DSS for registering and stacking
I’d certainly welcome any advice right now

I won’t be using the camera again until I nail this issue

Thanks in advance
Martin