Rigel Systems PulsGuide - Guiding Eyepiece Illuminator
Pulsguide is a simple but effective solution that pulses the reticle illumination of a guiding eyepiece during an exposure. The reticle brightness can be adjusted and the unit is compatible with many existing guiding eyepieces.
PulsGuide pulses the reticle illumination to let the eye rest between pulses. Improving the contrast between reticle and faint guide stars for easier guiding and better astrophotographs or acquisition of faint object in your finderscope.
2 knobs let you independently tailor on and off blink times from continuous on to long-on/short-off or short-on/long-off or anything in between.
Comes with RED LED which you can switch to YELLOW LED by unplugging RED and plugging in YELLOW. Some astrophotographers find low level YELLOW makes the cross hair clearer and sharper, and makes guiding even easier.