[3] He has been acknowledged especially for his wide-field photographs of the Milky Way nebulae and for public outreach, for which he has received Amateur Achievement Award of the Astronomical Society of the Pacific.
The pictures were investigated by Adolf Witt, an astronomer of the University of Toledo in Ohio, who found out that the nebulae surprisingly contained carbon.
[8] In 2004 Mandel started to work on the Mandel-Wilson Unexplored Nebulae Project aimed at their discovering, cataloguing and photographing.
In 2004 he founded the Advanced Imaging Conference in San Jose, California,[3] where about 250 amateur astronomers[6] and manufacturers of astronomical equipment and software[3] meet annually to discuss technology, imaging techniques and possibilities of scientific contributions.
[6] He created the so-called Hubble Award, given at the conference to an astronomer who made significant contributions to astrophotography.