by Rüdiger Proske
Every PlaneWave user knows the problem: SecureFit is an extremely robust connection, but it makes a quick change-over (e.g. between native focal length and reducer) impossible. Likewise, rotation of the optical train is only possible at the predefined hole spacing and the coupling has to be loosened for this. The second problem can indeed be solved by using a rotator, but this makes switching to the reducer and back even more complex and expensive. The change-over system was tested on a CDK14 with a ZWO ASI6200 camera including filter wheel. The total weight is then about 1.5 kg.
Relief is promised here by 3,5" Quick Changer and Instrumentenrotator for Planewave (#1324000 , € 395,- ) for the PlaneWave optics:
Unboxing and mechanical impression
I received the quick-changer and the two interchangeable rings in the usual functional packaging. Appropriate imperial screws are supplied with each component. Apart from the clamping block made of brass, the solid components are high-quality black anodized. The scales feel very premium and promise long service life.
With a back focus (changer + ring) of only 20 mm, the entire assembly is very short.
The combined weight of 530 g for the changer (335 g) and ring (195 g) is certainly notable, but it is exactly what you would expect from this level of quality.
Installation
Installation is typical SecureFit. However, there is one important point to bear in mind: The quick-changer is designed for the SecureFit diameter of the Hedrick focuser (88.9 mm). On the camera side this diameter is larger than the SecureFit of the subsequent spacer sleeves on the camera side (82.55 mm). Since I have replaced my Hedrick with an Optec Gemini focuser-rotator by now, which has the smaller SecureFit, the diameter did not match: The spring of the quick-changer was too large. Together with Johannes Baader a solution was quickly found: Baader enlarged the Optec sleeve slightly so that the spring would fit.
There was also a further small challenge on the camera side. The interchangeable ring likewise has the “large SecureFit” size. This means that if a reducer is to be screwed on, its spring is not form-fitting and has about 3 mm of play. Either you fix the reducer by eye or you have a reducing flange manufactured. I chose the latter.
Once again, many thanks to Baader.
Handling
Inserting the interchangeable ring is completely straightforward. At first I was a little concerned, because the clamping occurs only on the last quarter of the final thread turn, but this is perfectly sufficient and safely prevents the brass jaws from pressing into the aluminium. Very little force is required for a secure clamp.
To remove the ring completely, the clamping screws have to be unscrewed quite far. This is an additional safety feature; it prevents the ring from accidentally falling out when the clamp is loosened in order to rotate the instruments.
For quick changes I have added a hex-key screwdriver to my kit. This allows the ring to be swapped and firmly secured in under a minute.
Conclusion
A quick change between payloads has finally become possible. Rotation is also feasible without having to go with PWI’s highly expensive rotator solution. Mechanically, the system offers the expected Baader high-end quality. The only drawback is the different sizes of SecureFit connectors, that are ultimately PWI’s responsibility. You should therefore analyze carefully in advance which connectors to choose.
The price is certainly not neglectable, but still far below the cost of a rotator. It is only through this that quick changes become possible and the reducer no longer gathers dust in its storage box.
The purchase has definitely paid off for me.
Pros and cons
- Quality and workmanship
- Secure hold of instruments
- Allows quick instrument changes
- Mechanical rotation of devices on SecureFit possible
- Two SecureFit sizes
- Relatively high price, but reasonable
- Weight may be too high for some applications
