I see, so the exposure time is too short that's why.
Could you please tell me what is the minimum exposure time? Or it's depend on sky and location condition?
Tonight I will try again as the forecast said the weather is good today but no excellent like last time.
For the mount, I did have Vixen polarie, is it alright? but I still try to figure out how to polar alignment and do other set up because it's not tracking correctly (star still trailing). I did try to follow the tutorial on the internet but it's not working. Do you have any suggestion for this matter? (I'm in southern hemisphere though with the clear view of SE and S view (the balcony of my apartment)
By the way, with longer exposure times and higher ISO, my raw images will be very bright right?
I will also try to prepare flat and bias frames as you suggested as well.
Thank you so much wimvb.
Best regards