Thanks Alex,
Having watched the video, the next time I am out I will look for this effect on a defocused star to determine whether I am seeing tube currents or whether the viewing is just affected by thermal currents in the atmosphere.
To date, I can't say I have paid that much attention; other than looking at globular clusters & centring stars when aligning (I defocus as part of the centring process in the absence of a reticule eyepiece) I haven't really looked that closely at stars.
Planning to start looking at splitting binary stars soon & having a look at the star testing of my optics...
My passion for astronomy has taken off since upgrading to an 8 inch SCT & my thirst for knowledge has deepened so as to get as much out of my viewing as possible. I've learned more in the past month from some of your & others posts than I have learned in the past 5 years of very casual observing through an 80mm refractor & I love it.
Regards
Carlton
Quote:
Originally Posted by mental4astro
Carlton, I've just found a great Youtube video that shows tube currents in a C14 over the course of a few hours. Clip is a couple of minutes long, and it shows the C14 cool over this time and the tube currents that afflict it. Towards the end the author puts a warm hand in from of the scope, and the effect is quite dramatic.
You'll notice that the plumes of heat pretty much follow one direction, and is a totally different effect from poor seeing with a defocused star.
Gosh, the Cassini Division in a 60mm scope! Blooming awesome! 
Alex. |