[raymo]

From your post I am assuming that you are new to astro imaging. I obviously have not seen any of your pics, but I tend to think that your star blobs may be due to poor focus. Assuming that your DSLR has Live View,
magnify a bright star 10x and then manually focus the star until it is as
small as you can get it; carefully move to your target without disturbing
the focal setting. Turn off LV, and take your shot.
The EF 50mm is a good lens for astro, but is exposure time limiting
if you are not using any form of tracking. you can only use exposure times
ranging between approx. 6 and 30secs before star trailing becomes obvious; the nearer you get to the poles, the longer the permissible exposure.
To get started and get some pleasing results I suggest you use the
18-55mm set to 18mm at f4. This focal length will allow exposures
ranging from 20-100secs [0 to 80 degrees declination]. Experiment
with settings as follows and see which you prefer.
18mm f4 ISO 3200 15-20-25 and 30sec. Try the same series of shots
using ISO 6400. Make sure noise reduction is enabled.
You may be forced to limit your exposure time because of skyglow
or other light pollution. If so, you will have to use multiple short
exposures, and stack them in your computer, but that may be a little
further down the track. In case you are not familiar with noise
reduction, the camera will do some processing for the same length
of time as the exposure you have just taken, before you get to see the results on the LCD screen.
I hope this helps; and I hope it wasn't patronising.
P.S. If your DSLR is an older model without Live View, focus on
something bright in the far distance, such as a street lamp. It is
unfortunate that DSLR viewfinders are smaller than the old film SLRs,
and the image is not as bright either.
raymo