DSLR are great tools for modern astrophotography, but locating targets and sometimes even tracking when a camera is pointing may be difficult, especially in awkward positions (eg. near zenith) and when DSLR sits on the mount without the main scope / finder. This small Red Dot Finder is based on a commercial RDF with some elements allowing it to be attached into the flash shoe of DSLR. Two small pieces of aluminum angle stock was needed (one was 15 x 40mm, another 15 x 20mm) and a "foot" from discarded camera flash. For the foot, any lamp brand would do, it is only important that it has the locking ring, otherwise the pointing would not be repeatable.
After a couple of imaging trips with my Takahashi P2Z mount and DSLR equipped with 200mm lens I think this little accessory is actually invaluable. It allows for very easy and quick pointing as one would do with their scope, easy location of dim objects not visible to the naked eye and definitely not in the camera viewfinder. Pointing is quite repeatable but may need to be tuned at the beginning of imaging session. It is so precise that it allows one to locate a bright star or a remote chimney or mobile tower for auto-focus routine during the night - the target fits easily into the central focusing spot.
Definitely worth the investment of 2 hours in my cellar!