Help! What the heck is this in my images?

[Bloodbean]

Okay so I've just started out imaging with my 40D mounted on my HEQ5Pro and I keep getting this dark horizontal line through my images in the same exact spot. Doesn't seem to matter which lens I'm using or how long my exposures are or what ISO setting I have chosen. I have been using the ICNR. Please see attached 30 second exposure @ISO1600 f/9 using a Canon 70-200mm F/4L @200mm. Pic is of Venus although doesn't seem to matter what the target is.

Thanks for any tips! :P

Troy

[Terry B]

Try taking the same exposure via the camera and via the computer. It looks like noise from the download via the cable. I sometimes get variable horizontal lines if I use a desktop rather than a notebook to image. Mine relates to draping the cables over the desktop box.
Not sure why it would be in the same place though.
Another possibility could be a sticking shutter.

[kinetic]

Troy,

It seems to have a slight curvature.....
It's not a hair on your CMOS sensor?

Steve

[Garyh]

Hi Troy,
Does the line appear also when you preview the shot on camera? If so maybe like Steve mentions, maybe a hair or some other foreign body near the cmos? Maybe worth making sure all is clean and that the shutter and mirror are working correctly.
cheers Gary

[Bloodbean]

Thanks guys I'll check everything suggested. ;) I can't see anything on the CMOS sensor but may see if I can find a magnifying glass to have a even closer look. I've formatted the memory card so will have another try the next cloudless night with checking if it shows up in camera as well. I've checked my regular daytime shots and can't see any fault at all. :shrug:

Troy

[Ian Robinson]

Maybe if the problems is coming from data downloading in real time via the cable, it may be better to record the images on memory card incamera - well this is what I will be doing , it's easy to download the images later .

Just a thought , I have a 40D too , mine hasn't been turned on the stars yet.

[leon]

It appears very much to be electrical interference of some sort, are your data cables very close to the power supply cables by chance, this may have some effect on your images.

Leon

[acropolite]

Might be worth also taking an image of comparable exposure without any PC connection, then remove the memory card and upload to your PC from a card reader, that will prove whether the corruption is coming from the sensor.