Pegasus FlatMaster USB EL Panel review

The Pegasus FlatMaster panel is ideal for intermediate and advance imagers.

Our rating 
4.5 out of 5 star rating 4.5
Price correct at time of review
Pegasus FlatMaster USB EL Panel

Flat frames are a very important part of the image calibration process but capturing them using somewhat variable natural light can be problematic. Using a readily available and repeatable light source like an electroluminescent (EL) panel can make things much easier.


However, as different filters pass varying amounts of white light, achieving the correct balance of exposure length for meaningful pixel saturation whilst allowing for shutter movement, where appropriate, can be challenging.

The Pegasus FlatMaster USB EL Panel has an adjustable light output and a usable illumination area of 120mm in diameter so it is suitable for telescopes up to approximately 120mm aperture if installed perfectly centrally on the optical tube or dew shield using the pre-installed adjustable support legs.

Pegasus FlatMaster USB EL Panel

Larger panel sizes are promised for the future. We used the panel on our William Optics 98mm aperture refractor for this review.

Very conveniently, the panel is powered and controlled by a USB cable.

The downloadable control software is ASCOM compliant but can also be used in standalone mode and gives 255 levels of light intensity adjustment although in standalone mode, 0 to 100 levels are available via a slider.

The panel can also be used manually with a push button switch delivering 5 levels of light intensity.

Using an ADU target of 22,000 and an exposure target of 10 seconds, to allow for our QSI camera’s shutter movement, the panel worked extremely well and was ideal for LRGB filtered imaging where there was ample brightness and adjustment.

Pegasus FlatMaster USB EL Panel

However, even with the brightness level set to full, exposure lengths for our narrowband filters were considerably extended so more brightness would have been useful (see table below).

The software control and ability to save light levels on a per filter basis was excellent and made capturing good quality flat frames very easy indeed.

The FlatMaster panel is ideal for intermediate and advance imagers although narrowband imagers might prefer a brighter panel to keep exposure times down.


Filter FlatMaster Level Exposure Time
Luminance 21 10.35s
Red 27 10.04s
Green 26 09.87s
Blue 37 10.20s
Ha 7nm 100 55.25s
SII 8nm 100 86.24s
Ha 3nm 100 145.87s
OIII 3nm 100 36.97s

Pegasus FlatMaster USB EL Panel

Vital stats

Price £165.00
Size 180mm x 180mm x 9mm suitable for up to 120mm aperture
Type Dimmable Electroluminescent (EL) Panel
Extras USB cable, storage bag
Weight 325g
Supplier Altair Astro
Contact 01263 731505