extended light source

基本解释

But Mars is much closer than the distant stars and an extended source of light.
不过火星比遥远的恒星距离我们更近，光源也更为扩展。
Therefore, a suitable size of extended light source can be chosen, considering the requirement of SNR in the optical design.
因此，需要在设计中结合系统信噪比的要求，选取合适尺寸的扩展光源。
It was found that the coherent length became shorter and the spectrum resolving power became lower as a result of solid angle produced by the extended light source.
分析表明，扩展光源存在的立体角导致系统的相干长度变短，光谱分辨率降低。