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Black Integration / Preview Filter error

3 Posts
2 Users
Neutron Star
Joined: 4 years ago
Posts: 77
Topic starter  

Hi, I just ran an Integration overnight.

Everything went succesful, except the unexpected black output. I digged into the console text and found this:

08:22:16 - PREVIEW FILTER: filtering new frame:UGC9749_RGB_553mm_f5_1_ISO3200_180_m_4°-RGB-session_2.fits
08:22:16 - PREVIEW FILTER: converting 32bits FLOAT data type frame to normalised 32bits FLOAT data type frame with range [0,1]
08:22:16 - IMAGE CONVERTER: image conversion not needed, data is already normalized...
08:22:17 - PREVIEW FILTER: conversion succesfull
08:22:17 - GENERAL IMAGE LOADER: frame /Users/jochenscharmann/Pictures/Astro A7Mk3/20220325/UGC9749_RGB_553mm_f5_1_ISO3200_180_m_4°-RGB-session_2.fits was loaded successfully
08:22:17 - PREVIEW FILTER: creating clone of frame...
08:22:17 - PREVIEW FILTER: auto DDP, black (B) point set to 1,000000
08:22:17 - PREVIEW FILTER: auto DDP, white (W) point set to 1,000000
08:22:17 - PREVIEW FILTER: auto DDP, reset gamma correction (G) to 1.0
08:22:17 - PREVIEW FILTER: auto DDP, setting stretch (ST) parameter to �
08:22:17 - PREVIEW FILTER: auto DDP, setting base (BA) pedestal to 0,025000
08:22:17 - PREVIEW FILTER: starting 32bits preview filter
08:22:18 - PREVIEW FILTER: 32bits preview filter finished successfully
08:22:18 - PREVIEW FILTER: sending frame to IMAGE VIEWER


Why would Blackpoint and Whitepoint be set to the same value? I am not sure I get what's the point in this.

Then I tried to adjust the preview sliders manually to blackpoint = 0 but I only get an all white screen with a thin, black line in the top section or an all black view withBP= 1,000 , nothing in between

And btw, the stretch parameter is ticked (enabled) - not sure about the question mark in the console text.







Universe Admin
Joined: 6 years ago
Posts: 5708

What version of APP are you using? It may be that this is an issue in an earlier version, could you check and download the latest and try again?

Neutron Star
Joined: 4 years ago
Posts: 77
Topic starter  

Hi Wouter I used 1.083.2 which is the tatest for MacOS.

I looked at the saved integration in StarTools (which I use for Post) - the image is all white except 3 black horizontal lines,of maybe 2-3 pixel width. At the border I could see black Stacking Artefacts, so obviously Registration worked, but normalization seemed to fail which made the Preview Filter raise the blackpoint. Hence Preview Filter behaviour seems to be expected, but Stacking derailed at some point. I did use 4th degree LNC, though I do not believe this has any impact.