Monthly Archives: October 2017

LIGO Announces First GW Detection of Colliding Neutron Stars

You probably heard about this announcement from LIGO yesterday, but I thought I should add some details, and shift the emphasis of the story to where it really belongs: The previous detections of gravitational waves (GW) all originated from the merging of large black holes.  Such mergers can produce relatively strong, but very brief GWs – just a small fraction of a second.  And they produce nothing else – no light or other electromagnetic radiation.  Therefore, these observations could not be confirmed by optical telescopes or other detectors. In contrast, this event, dubbed “GW170817” because it was detected on Aug. […]

A Baby Elephant

There are, of course, a finite number of objects that an astrophotographer can shoot.  It’s a large number, but definitely finite, and when you add restrictions (and, trust me, there are a LOT of restrictions) it can seem like a pretty small number.  So it’s encouraging to see that the same object can be photographed and processed in many different ways.  As an example, I have now photographed the Elephant’s Trunk Nebula at 3 different focal lengths; 640, 350, and now 200mm.  A much longer focal length is often used on this target to capture just the “trunk” itself (the […]


In my earlier attempt to capture the Spaghetti Nebula I found that the 200mm camera lens wasn’t quite wide enough.  And that a faster (lower focal ratio) lens would also be beneficial.  So I put an 85mm f/1.8 Nikkor lens (stopped down to f/2.8) on the QSI camera and tried again last night.  It didn’t work.  The moon was full last night, and even with a 3nm H-alpha filter, there was enough sky illumination to almost completely overpower the Spaghetti.  I’ll try it again when the Moon goes away, but I have to comment again on what this says about […]