The Canon 400D is very capable of taking Astrophotographs. I use one all the time. Some of my images are here >>
http://southcelestialpole.org.au/blogs/astroman.php
Really must update it with some latest images, such as..
http://www.iceinspace.com.au/forum/a...1&d=1189223283
and...
http://southcelestialpole.org.au/for...ach=8342;image
and...
http://southcelestialpole.org.au/for...ach=8344;image
These were taken with various equipment from a 18,,055mm kit lens to an 8" f6 Newtonian.
What focuser does the Scope have? Does it have tracking ect... I know someone with an old Tasco from what I have seen of his it only had a .975" focuser which is inadequate for hooking uquipment ep to a DSLR. You also may find that you will not have enough in focus, so the Primary Mirror needs to be bought forward slightly... Some things to think about. Astrophotography is really enjoyable but without the right equipment can be very frustrating. Also it take alot of work to get many of the images you see around the place.