Photometric light curves show apparent spot concentrations separated by 180 degrees in longitude that are commonly referred to as `active longitudes'. These spot concentrations have been observed to change in strength resulting in the `flip-flop' …
We report the detection of the 2s$^2$2p$^2$$^3$P$_1-->0$ line of Si IX using the McMath-Pierce telescope on Kitt Peak. Observations were made of the solar disk and at various heights above the limb between 2002 May 13 and 17, under nonideal sky …
We have obtained images in solar coronal emission lines under high sky- background conditions by making precise differential measurements between the coronal emission line and the near-by continuum, which is primarily due to scattered light from the …