Baader Universal Filter Changer (UFC): Part 5 - The UFC telescope-side adaptors

This blog continues our series on the Baader Universal Filter Changer (UFC) system, with this one giving an overview of the telescope-side adaptors. Attaching a UFC system to a telescope may be done for example, by using a 1.25" or 2" push-fit nosepiece to go into a focuser drawtube for visual or imaging purposes, or to a focal reducer or field flattener for imaging use. 

The image below shows the current range of adaptors, as well as the spacers (extensions), that are available that allow you to attach the UFC Filter Base (shown below left in the pink box) to a telescope. There are ten telescope adaptors and four telescope-side UFC extension tubes. Except for the two RASA adaptors, all the other eight telescope adaptor "bodies" are fully anodised matt-black. The two RASA adaptors have their inner central portion anodised black (where the light emanates from the RASA front lens group assembly) to stop any reflections.

Current range of UFC Telescope-side extension tubes and telescope-side adaptors (green box)

Looking only at the telescope side adaptors in the green box - see below - the following information given is:

• Type of fitment that the telescope-side adaptor allows (e.g. T-2, M48 etc).
• Baader product code.
• The thickness of the adaptor contributes towards the overall thickness of the UFC system that takes up back focus. 

All of the above adaptors fit to the telescope side of the UFC Base (see part 2 in our series here), and which is shown in the image below.

UFC Base with the S70 opening awaiting an adaptor to be inserted

Every UFC telescope side adaptor features Baader's S70 (70mm diameter) dovetail on its camera side (i.e. the side of the telescope-adaptor that will face the camera once attached to the UFC Base). To attach one of these telescope-side adaptors to the UFC Base is simple. You simply insert the appropriate S70 adaptor for use with your equipment into the UFC Base's telescope-side S70 opening so that the adaptor is fully seated and tighten the six small hex-screws located around the UFC Base's edge (see here). These six screws when tightened clamp the telescope-side adaptor (and/or spacer) firmly and securely in place. The image below shows a T-2 telescope side adaptor fitted in the UFC Base.

UFC Base with a T-2 telescope-side adaptor in place

To see how one of these S70 adaptors are secured, the image below shows a side-view of an S70 dovetail adaptor (in this case the T-2 model) showing the dovetail "channel" around the edge. Also shown is one of the securing hex-screws being held with the small Allen-key supplied with the UFC Base. The hex-screw is shown up against the S70 dovetail "channel" to show how the screw (and the other five screws) are positioned (when tightened inside the UFC Base) to hold the telescope-side adaptor in place. 

UFC Base securing hex-screw in the S70 dovetail channel. The lower (smaller diameter) side of the adaptor is the side inserted into the S70 opening of the UFC Base.

Some points to note about the telescope-side adaptors:

• The following adaptors have female threads in their central opening to accept male threaded accessories: T-2 (e.g. a T-2 to 2" push-fit nosepiece), M48 (e.g. to attach to a reducer/flattener) and 2" SC. The T-2 and M48 also have a small 1mm plastic spacer ring for attaching threaded accessories that may have slightly longer threads. The C8/11/925 Hyperstar adaptors also have female threads for attaching to the male thread on the end of a Hyperstar unit. 
• The SP54 and M68 adaptors have male threads. The SP54 adaptor can be used with the Baader SP54 Stepper Rings so that the UFC system can be attached to a DSLR or camera lens. We will cover this in a later blog.
• The RASA 11" and 14" models are made to fit over the RASA's front lens group assembly and is held in place by the large knurled ring that is supplied as standard with the RASA. Machined into the adaptors are three elongated holes that are for access to the RASA collimation screws (with the adaptor in place).

In addition to the telescope-side adaptors, Baader also offer four UFC spacers (or extension tubes) that go between the telescope side of the UFC Base and one of the S70 telescope adaptor's. These spacers can be used when a camera that is attached to the UFC Base is required to be at a specific point in the optical path. For example, when a sensor is needed to be at a set distance from a focal reducer/field flattener or when a camera is being used with a Hyperstar System. The spacers are shown below.

The four extensions options include three fixed length adaptors of 5mm, 15mm and 40mm in width, and a VariLock variable extension tube that extends between 15mm to 20mm. All four extension tubes have an S70 camera-side dovetail for fitting into the UFC Base, and an S70 dovetail clamping side that also feature six small hex screws for securing a telescope-side adaptor (or another S70 extension tube). 

In the next blog we will look at some example of the UFC system in use.