Discussion in 'My Astrophotos' started by ROBERT T SCHAEFER JR, Jul 19, 2020.


    ROBERT T SCHAEFER JR Cyanogen Customer

    May 13, 2018
    152mm A+M Refractor(OfficinaStellare-1200mmF/L) thru a TeleVue 2.5XPowerMate for an effect of 2960mmFL using a BreakThrough X4-UV 49mm filter with step-rings to 49mm , and a CanonEOSII RebelT7i modified UV-IR @ Hutech . The sky was cloudy last night-Saturday nite and I wanted to do the Trifid but I couldn't see the TeaPot but I did three RAWMonochrome 200secISO6400 images thru MaximDL Pro V6.16 and I Average stacked them and I removed the background haze coloring on this NGC6401 'GlobularCluster' 9.5 mag. next to ' B 82 ' . The sky never became clear enough all nite and I thought about how it was difficult to find some 'guiding' stars with a TeleVue TV60is 'guide-scope' I use and a ZWOASI120MC-S webcam at Bin2 that I use for 'guiding' ...;.. I have been doing the 'guiding' without a Simple Auto-Dark and I tried a 10sec exposure and I looked at the large star in the image and there was speckled snow all around , I 'un-checked' the 'Small Stars' box in the 'Settings' for Camera2 and another image looked the same . Then I 'opened' the 'Options' for Camera2 and I set the 'Default Auto-dark Pedestal' to ' 100 ' and I made sure the 'Auto-dar Subframe Extraction' check-box was 'checked' and I pressed 'OK' . I did another 10sec Guide exposure and I followed the prompt to cover the scope and then pressed 'OK' and an Auto-dark is taken and another prompt says to un-cover the scope and I did and then pressed 'OK' and the image appeared and it was dark in the background but some extra small stars were visible and the 'screen-stretch' window showed the data being clipped in the left side which makes it darker and the stars are just visible , and before doing the Simple Auto-dark this way I 'opened' the 'Information Window' and I used the 'Area' option and the 'Std-Dev' was about ' 750.0 ' and I thought maybe the Pedestal should be set to three times the 'Std-Dev' which would be a little over ' 2100 ' but I used ' 100 ' as the beginning of the experiment . I set the 'Default Auto-dark Pedestal' to ' 2500 ' and I tried again but first I did a 'Dis-Connect' and then 'Connect' so the prompt to cover the scope would appear and this time the 10sec Guide exposure had the data away from the left edge in the 'screen-stretch' window and and the image was brighter and the small stars were also brighter with more of them showing . I then did the same thing again with the 'Default Auto-dark Pedestal' set to ' 4500 ' and the image was even brighter so I'l keep it that way . A good idea when you are at an 'object' is to do a 10sec Guide exposure with 'No-Calibration' and check the 'Information Window' with 'Area' for the 'Std-Dev' and try to use more than threes times the 'Std-Dev' in the Camera2 'Options' for the 'Default Auto-dark Pedestal' because star content in the Guide image might change the 'Std-Dev' values .? .x

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