Using the WAT- 910HX/RC for timing occultations

Last updated 2014 August

The WAT-910HX/RC was bought from Modern Astronomy in March 2014 to replace the WAT-120N+ which will become second-station detector.
The picture (right) shows how I supported the remote control cable which has a white plug and 6 coloured wires. These wires can become detached (Reported by other users !!).
Here I use cable ties on a BNC connector so that accidental pulling doesn't break any connections. The bolt and washer was a first attempt. The bolt is now a camera orientation marker.

The supply of new120N+ was stopped in 2012, and a more sensitive camera was available late 2013. This camera is the WAT-910HX (above) with 6.4x4.8mm - Type 1/2" CCD. The 910 didn't include a power supply or 1.25" nose piece so I used the AC-DC12V stabilised adapter supplied with the WAT120N+.

The observatory instrument is a 30cm F/4 Orion Optics (UK) Newtonian on EQ6, detecting 13th magnitude stars by video (0,32s) using the older WATEC 120N+ integrating camera. In comparison the WAT-910HX has roughly twice the sensitivity of the 120N or 120N+. My camera is serial number 01106. Half the exposure ( e.g. 0.16sec) gives the same result. A 1.28s exposure just detects a 16.1 mag star. See my Log Page.

Any stabilised 12V supply will work e.g. 8 x AA battery clip, or TRACER

Variants of the WAT 910:
1) 910BD is the board camera, with no housing or power supply. It can be controlled by computer (if you have the code) and can support digital video.
2) 910HX, the model with no remote control
- discontinued ?
3) 910HX/RC new chip version (more sensitive) with serial number 1001 onwards and with cable remote control.

Review by Hristo Pavlov at the 2013 IOTA meeting

Unlike the 120N and 120N+ , the 910HX (or 910HX/RC) has On Screen Controls (OSC). MINTRON Users will already be familiar with OSC. BUT there are only two controls one needs to adjust on the 910HX (shutter and gain), and after a few button pushes it becomes a lot simpler, even the dark.


If the target is West of the Meridian, GOTO a prominent star in the West (or vice versa) attach in the WAT-910 to the focuser and connect auxiliary equipment ( GPS VTI, Video recorder or Laptop). Put the star in the middle of the camera field, focus and sync on the star. If you have a SC, a focal reducer might help. Offset to the target star and check the GPS text overlay is working. Also check the GPS time against a second clock.

Because the control settings are displayed on screen, you can record them.

Exposure> SHUTTER = 8/50s, Exposure>GAIN = 40dB

Most (indeed all) advanced setting should be turned off for occultation video. The most important controls set to OFF are:
SENS UP: auto exposure OFF
AGC: auto gain OFF
SHARPNESS = 0 [ default is 4 ]
3DNR : Dynamic noise reduction OFF

Settings for Occultations are:
SHUTTER = x2 to x256, EI*, 1/50th, 1/250th and shorter.
GAMMA: Set to 1
IMAGE REVERSAL is a useful function if you are using right-angled viewers.
Dark Frame subtraction is also possible (on the fly).

For focusing on the Moon (for lunar Occultations) use EI, and then change to 1/50th. or x2 for timing.
For Asteroid Occultations, use x2 (0.04), x4 (0.08), x8 (0.16), x16 (0.32). Longer exposure will be needed for faint object or smaller telescope aperture.