If you got the 150P all you'd need was a T ring adaptor, yes. However, views through a scope obviously are magnified and things will move across the field of view very quickly. So realistically, if you want long exposures, you need to have what's called an equatorial mount, which rotates the scope around the earth's axis, and it must also be motor driven to match the earth's rotational speed - this will keep the objects still within the frame. These are more expensive and even WITH a motor driven EQ mount, you're limited to a couple of minutes unless you get what's called a guided mount, which uses a second scope, camera and computer to make micro adjustments to the drives... then we're getting into serious money.
Equatorial mounts are tricky to use, and they need polar aligning with the earth's vertical axis (usually by aligning it with Polaris, the north star).
If you want to photograph anything more than the moon, it gets very complex, very quickly I'm afraid. Astro-photography is just one of those hobbies.. like photography, that has a steep learning curve.
http://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-eq3-2.html
That's the 150P. You can see the difference in price between the non driven and driven versions. The driven version also has a GoTo facility which will point thr scope automatically to anything you want from it's database... and then track it for you. You still have to align the mount first though.
With serious astro-photography, the mounts are more important than the scopes actually.
