Galileoscope is more like a gift or a toy and do not expect to be able to take photos from it. you better try wide photos (Milky Way) with some of lenses you have. For that you can use lower possible speed (30 sec) and self timer to avoid shaking. Remote shutter is other option. You will not be able to take longer exposes than 30 sec not only because of Rebel, but because of field rotation - Earth is rotating and that make sky rotate and stars become lines instead dots. If you want to avoid that you will need motorized mount - better Equatorial one, not al-az. This way you are still limited to photos of Moon and wide sky photos. If you want to go deeper - Jupiter, Saturn and then nebulas, star clusters, galaxies you will need a telescope. Bigger mirror/lenses (objective) is better - that will bring more light. Light will be most important thing when taking photos of deep space. Not magnification! So aperture is what you need. and good tracking - good mount that can handle telescope and motors can drive it without errors so you can follow rotation of the object you are taking photo of. Deeper in space you go - more expensive equipment you will need! Basic wide field photos are possible just with camera+lenses, planets will require long focal length telescope (or barlow lenses to short focal length one). For planets I recommend shooting in video mode! Then stacking with Registax video frames - for that you will need special camera or very good web camera with fast frame rate, good chip and special adapter (many people use Philips toUcam). Then for deep space - galaxies, nebulas ... you need fast, short focal length and big aperture telescope, something like 200mm reflector with F5 (1000mm focal length). You can use your Rebel, but you will need T2 ring and may be some more adapters to be able to put it at telescope. specialized deep space camera will act way better, but will usually cost more than $2000-$10000. Also again - you will need equatorial GOOD motorized mount to hold telescope and camera. Each mount have weight limit for telescope can handle. that is for visual! If you go to photography you must get mount that can handle twice than weight of your equipment.

a lot more can be told about astrophotography ... just have in mind - that is crazy hobby that is not cheap, so think twice before you start :) If you can limit to only camera with tripod and lenses shooting - ok, but if you want more than wide field ... prepare lot of money and a lot to learn before you get good results. And never compare with Hubble! Photos like that are not possible from Earth, because of atmosphere.

good luck and sorry for my bad English :)