bad sensor?

[Iceman120]

hi guys, new to this so bare with me. last night i went out to try and capture an image of comet neowise with my canon 300d dslr camera with a 50mm lens. I used ISO 800 with an exposure time of about 4 seconds. the lens is a F5.6. i used manual mode and set the image to save as RAW. when i got back from work this evening i opened it with photoshop and increased the exposure and this is the image i get. you can just about make out the comet on the upper left hand side, well i think it is lol but is this a camera setting that is wrong or is it the camera itself?

[Iceman120]

not to worry, it is my fault which i thought would be the case. just looked at the details panel on photoshop, says the ISO is actually only at 100 which is my own stupid fault. hopfeully get some clear skies this weekend and i can try again