Exposure time - Bresser HD deep sky camera and Touplite

[matthasboldlygone]

Looking at Arcturus with the camera attached, at about 50ms exposure it's a bright little dot. Appears to be in focus. I thought if I increased the exposure to 10 seconds I would see a thin line as the star moved. But I seem to get a big blurred line, the length looks as I expected but it's wide and blurred (the image didn't save so can't share it)

Confusing me, is this normal? Am I misunderstanding exposure time? Sorry if this doesn't make sense, I'll try and get an image next time.

[Tommohawk]

13 hours ago, matthasboldlygone said:

Looking at Arcturus with the camera attached, at about 50ms exposure it's a bright little dot. Appears to be in focus. I thought if I increased the exposure to 10 seconds I would see a thin line as the star moved. But I seem to get a big blurred line, the length looks as I expected but it's wide and blurred (the image didn't save so can't share it)

Confusing me, is this normal? Am I misunderstanding exposure time? Sorry if this doesn't make sense, I'll try and get an image next time.

Arcturus is bright so 10 sec exposure will tend to burn out/bloat the image. Depends to some extent on ISO and lens type. Also it might be that when brighter you can see that its not well focused. Some more info would help:

How are you focusing? What camera is it? What lens? What ISO? How are you viewing - Viewfinder/laptop/liveview?

Ooops - just seen header with camera and software! 

So maybe gain too high..... and/or poorly focussed? 

Edited July 1, 2020 by Tommohawk
Didnt read post properly

[matthasboldlygone]

Thanks Tom, gain is set to 0, focus with the big sticky focus wheel on the scope  

ISO, completely forgot to check that. I'll give it another go tonight hopefully, I'll check all that info and post back if I still have issues. 

[don4l]

Are ther other stars in the shot?  How did they look?

Arcturus is very bright, and several things could make it look "wide".  A bit of haze in the atmosphere could make it "glow", for example.

[matthasboldlygone]

16 hours ago, don4l said:

Are ther other stars in the shot?  How did they look?

Arcturus is very bright, and several things could make it look "wide".  A bit of haze in the atmosphere could make it "glow", for example.

Nothing else in shot, playing the waiting game now to try again, fingers crossed for tonight ☁️