ISS imaging attempt...what did I do wrong with regards to exposure?

[MKHACHFE]

Hi all,

 

Hope you are all doing well. 

I have been trying to get the motivation to start doing AP again after a very long hiatus due to personal and family issues. With that in mind, i tried to image the ISS yesteray. For context, this was my 4rth attempt in the last 3 years. 

Unfortunately, i didn't note down the sharpcap settings i used for the other attempts, which are the 3 together below (shwing my improvement) and i no longer have any of the capture files. 

The first image below is last nights attempt. I know it's out of focus and not great quality (i only stacked a handful of frames to test out what i got), but what im confused about is that blown-out hilight. Considering how dim the rest of the structure is, i don't understand why that central section is showing up like that. It never used to, even when i had my settings too high. This is a recent thing that seems to be happening (it happened once earlier in the year). 

I tested out the exposure and focus  settings earlier in the evening with Venus, and then dropped the gain down a few notches since Venus was a bit brighter than the ISS. 

I have also attached a single frame of my captures. 

My setup:

- XT8 manual

- ASI120MM-S

-Sharpcap pro

-PIPP and Autostakkert to do aligning and stacking

 

It's just weird that i never go this hilight burn effect before and it didn't seem to happen when i did a quick capture test with Venus. 

Here are the capture settings 

 

[ZWO ASI120MM-S]
Pan=0
Tilt=120
Output Format=SER file (*.ser)
Binning=1
Capture Area=1280x720
Colour Space=MONO16
Temperature=19.2
High Speed Mode=On
Overclock=30
Turbo USB=100(Auto)
Flip=None
Frame Rate Limit=Maximum
Gain=70
Exposure=6.4E-05
Timestamp Frames=Off
Brightness=4
Auto Exp Max Gain=80
Auto Exp Max Exp M S=45000
Auto Exp Target Brightness=80
Apply Flat=None
Subtract Dark=None
#Black Point
Display Black Point=0
#MidTone Point
Display MidTone Point=0.5
#White Point
Display White Point=1
TimeStamp=2023-05-15T21:39:11.7965386Z
SharpCapVersion=3.1.5169.0

 

 

Im sure i did something silly as im still a relative newbie, but any advice would be amazing. Thanks for reading

 

 

My previous 3 attempts with the same setup

22_39_11.CameraSettings.txt

22_39_11.histogram.csv

Edited May 16, 2023 by MKHACHFE