TS-Optics 60 mm Angled Finder and Guide Scope with 90° View - 1.25" and T2 Connection

TS Optics 60mm angled finder with upright and non-mirrored image

The TSFRE60T2 is more than just a finder. The good 2-element objective with 60 mm diameter already shows many hundreds of deep-sky objects in combination with the illuminable reticle eyepiece TSIR20. With only 830 grams including tube rings, the 60 mm finder is only minimally heavier than a conventional finder and it also fits into standard finder shoes such as those from Skywatcher, Vixen, Celestron or TS-Optics.

The conversion into a guide scope for astrophotography is done in a few easy steps

When the prism is removed from the tube, you will find a T2 internal thread. From the internal thread you have a very generous working distance of 90 mm to the focus. So all common cameras and even correctors can be integrated. We particularly recommend the following adaptation:

TSHeli1 Helical focuser with male T2 connection thread on the telescope side, the focuser fits directly into the female T2 thread. The working distance from the T2 and 1.25" connection is from 33 mm to 43 mm.

You can shorten the working distance with the matching T2 extension tubes. The extension comes simply between the finder and the helical focuser.

The advantages and product features of TSFRE60T2:

High quality metal design for best possible stability

Good 2-element lens with multicoating

Focusing by rotating the 1.25" helical focuser on the eyepiece side for observation

Female T2 thread available for conversion into a compact guide scope

Solid clamping by compression ring

Upright and non-mirrored imaging through the 90° Amici prism

The viewing position can be rotated in the desired direction

The adjustable tube rings have metal screws with a plastic tip to avoid scratches on the telescope

The finder fits into standard finder mounts such as those provided by Skywatcher, Celestron, GSO, ...

Fitting eyepieces and autoguiders for TSFRE60T2:

The focus of the finder is about 5 mm above the 1.25" receptacle of the Amici prism. This is sufficient for many eyepieces, such as Plössl eyepieces. A very nice eyepiece for centering is the illuminable reticle eyepiece TSIR20, which is linked in the accessory recommendations.

Even without the T2 connection the finder is suitable for autoguiding. However, the autoguider must have a 1.25" housing, otherwise you will not get into focus. The T2 connection, on the other hand, will bring you into focus with all cameras.

Question:
How can I best adapt my autoguiding camera with T2 connection to this guide scope?

Answer from Teleskop-Service:
It is very simple and a pure calculation example. The distance from the T2 internal thread on the finder to the focal plane is 90 mm. Exactly in this distance the camera sensor must be brought.

Calculation example using the ASI290MM - distance from the T2 internal thread of the camera to the sensor is 12.5 mm:

90 mm minus 12.5 mm is 77.5 mm - this distance must be bridged. A good way is for example (from finder to camera):

T2a-T2a ... T2 thread reversal, turns the T2 inner thread into a T2 outer thread

2x TST2V26... T2 extension with 26 mm length ... makes 52 mm

TST2Vvar ... variable T2 extension tube from 20.5 mm to 30 mm

Then just connect the camera and the exact focusing is made simply with the variable tube. You only need to do this once.


Question:
How do I get to the T2 internal thread of the viewfinder?

Answer from Teleskop-Service:
It is actually a little more complicated to get to the T2 thread.On the tube, where the knurled screw is, with which you can rotate the prism, there are 3 more recesses with grub screws. Please loosen the knurled screw and unscrew the 3 grub screws further. Then you can remove the attachment with the external thread for the prism and you will come to the T2 internal thread on the tube for individual adaptations. The 3 screws fix the position of the rotation adapter.