in stock
in stock

T2 Excenter unit

119,83 EUR
excl. VAT
excl. 4,65 € Shipping costs

T2 Excenter by Neumann - for locating guide stars

The T2 Excenter is an important tool for astrophotography. With this excenter a large field of about 40mm diameter can be patrolled for guide stars, without changing the guide scope orientation.

Hence the guide scope can remain fixed with respect to the main tube and normal tube rings suffice to install it. A much stiffer solution that minimized the danger of flexure between guide- and main scope.

Connection to the telescope:

At the telescope side the T2 Excenter bears a T2 (M42x0.75) female thread. In our "recommended accessories" section we offer the adaptations towards 1.25" or 2" (adapters TS FA 1 and TS FA 2) to connect the excenter to any instrument.

Eyepiece connection:

On the telescope side the T2 Excenter features a normal 1.25" barrel to accept standard eyepieces or autoguiders. If you prefer to adapt a camera using the T2 thread, we also offer the adapter TS FA 1 (see "recommended accessories").

Notice: Upon request, this Excenter is also available with M48 instead of T2 thread. Please specify with your order!

Using the T2 Excenter:

Look for a suitable guide star with a low power eyepiece, e.g. of 25mm focal length. This should be easy even with small apertures as the field of view is so large. To patrol the field you can move the excenter outwards (see picture) and you can rotate it by 360° around the optical axis. So you can reach each point in the field of view.

Once the guide star is centred and the position fixed in place using the two thumbscrews, you replace the low power eyepiece by the crosshair guiding eyepiece or the autoguider and you are ready to start.

Technical data:

-- T-2 Excenter - black anodized aluminum
-- telescope connection by femal T2 thread (M42 x 0.75)
-- connection at eyepiece side by M 36,4 (Vixen thread) and 1,25" push fit - the 1,25" barrel is screwed on
-- optical path length with 1,25" barrel: 43mm
-- weight 156 grams
-- radial rail on teflon tracks to assure a smooth operation.

Hint of Teleskop-Service:

The T2 Excenter is not only interesting for astrophotography but has various other uses as well:

Optical testing ... with the Excenter you can probe the image quality off axis even with high magnification. You see at once from which distance on the performance of the instrument degrades.

Solar observation with prominence adapters... here you work off-axis as well as you scan the edge of the baffled-out solar disk. The Excenter is extremely well suited for this purpose.

The short length of the Excenter

The picture to the left shows how compact the excenter is. It is not possible to make it shorter without losing stability.
Connectivities and adapters for the Excenter

Left to right:

Top left: TS FA 1 - adaption to 1,25" push fit
Middle left: TS SC-T2 - adaption to the SCT thread
Bottom left: TS FA 2 - adaption to 2" push fit

Mid: The Excenter unit itself

Right: Included adapter from M 36,4 to 1,25"
A particular short solution with 90° angle

Often guide scopes lack enough free focal range. If you for example connect the excenter to the telescope and put a diagonal behind it, or if you put the excenter down the diagonal itself, it may be that the image cannot be focused any longer.

From the manufacturer "BAADER" we offer a T2 prism diagonal (90°) which features T2 connections. So you can bolt on the excenter directly and you save about 30mm of optical path.

up ...
We recommend following products:

16,38 EUR*

TS-Optics Adaptor 1.25 inch focal adaptor for 1.25-inch focuser - adaption to T2 thread

instead 25,00 EUR
only 21,47 EUR*

TS-Optics Focal Adaptor 2 inch to T2


E-Mail: info@teleskop-service.de • Phone: +49 (0)89-9922875-0
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