A long exposure noise reduction method for astrophotography is the use of a 'dark frame'. In principal it's similar to LENR but the practice is different. A number of images are captured with the camera lens/telescope cover in place (i.e. - dark frames), I typically take them when I'm finished with my imaging and am putting my equipment up. The exposure length is the same as that used for the images ('light' frames). The dark frames are averaged in post and a master dark frame created which is then subtracted from each light frame prior to stacking the lights. Ideally, the darks are captured at the same temperature the lights are captured at. I suppose it would be possible to create a library of master darks at various temperature ranges, but the sometimes (or usually?) random nature of the dark frame noise might preclude that. In addition to the dark frames, a series of bias frames are also captured, similarly averaged and subtracted. These are dark frames at short exposure taken to create a master bias frame that hopefully captures the readout noise which is also subracted from the light frames prior to stacking. With the D60 years ago, Canon was first out the gate with a low noise sensor capable of astrophotography....the reason I and many others adopted Canon DSLRs for astro.
Reason I mention all this is that if you're contemplating a lot of long exposure work, you may find these techniques useful. For exposures of a few seconds, LENR is probably more practical. My astro work involves exposures of 90 seconds to 10 minutes, LENR is just not a good option at that point.