TSFlip - Flip Mirror and Off Axis Guiding System in one device
A review of new TS device combining an OAG and a Flip Mirror in one slim body
TSFlip is a new device made by Teleskop Service. It's a combination of an Off Axis Guider (you can guide the DS imaging setup using a star from the edge of the field of view) with a Flip Mirror - you bounce the image up to the guide head and see it with an eyepiece (to find and center the object you are looking for). TSFlip looks like so:
How it works?
TSFlip has a guide head that can be moved up and down. When you move it down the prism will be centered in the optical path and will work as a diagonal/flip mirror. When you move the guide head up a bit it will see the edge of the field (not visible to the imaging camera) and will be able to work as an OAG - guiding on one of stars from that area. It can also be used for planetary photography - to center planets in the field of view.
On the telescope side TSFlip has a M48 thread. On the guide head and from the camera side - T2 thread. There are also optional adapters from M48 to T2 allowing you to screw T2 threaded nosepieces from the telescope side of the TSFlip. A complete setup may look like this:
You can move the head up and down after loosening a screw on the TSFlip body (marked with yellow line). Lowest position is the Flip Mirror function. Moving up you can move the whole guide head out so you need to control how much you raised the head (try looking in the eyepiece to see if you still see the sky glow / guide stars):
Screw marked with red line allows you to move the T2 collar a bit. This is handy for OAG focusing. You need to be careful as you can take the collar off if you raise it to much:
You can rotate TSFlip as you like - by 360 degrees from both sides. TS decided to put rings with T2 and M48 threads that are locked in place by screws. When you loosen the screw you can take off the ring or rotate the setup by any degree:This solution does work. NOTE: you can lock the rings by screwing 3 little screws on the sides. When you do so the rings will be able to rotate but they won't fall off.
Drawbacks and issues
Let start with a small one - the guide head has no fixed upper position, nor there aren't any markings on the guide head so you can't always go back to the same OAG position. That makes it much harder to prefocus the setup in the OAG position. For guide cameras like QHY5 it's essential to be at focus to see any stars at all.
When you want to rotate the OAG and you loose one of screws and start rotating the scope may loose balance a bit which may move it from the spot you have chosen.
TSFlip is a interesting device, something new, but it has some issues. It's thinner than a typical flip mirror but it's also much more expensive. As an OAG it may be hard to set up for work.