WOW! Those are some great images... What are the LASCO instruments? Obviously the large central disk is an occulting disk, allowing the corona to be photographed; I assume the smaller central circle is the true diameter of the Sun. The LASCO C3 image contains a lot of starfield background, so I suppose we could place the solar image on a starchart, given the date and time of the image. Any idea what the horizontal line artifact through the brightest star is? We know that Saturn is in the opposite part of the sky this year!!
Dave Bell On Wed, 3 Jan 2001, Richard Langley wrote: > According to a NASA Web site: > > The MDI (Michelson Doppler Imager) images shown here are taken in the > continuum near the NiI 6768 Angstroms line. The most prominent solar > features are the sunspots on the solar photosphere. This is very much > how the Sun looks like in the visible range of the spectrum (for example, > looking at it using special 'eclipse' glasses: Remember, do not ever > look directly at the Sun!). > > -- Richard Langley > > On Wed, 3 Jan 2001, Gordon Uber wrote: > > >John, > > > >I think that the SOHO images are updated at least once a day. The latest > >sunspot image was taken at 10:16 UT today. The satellite is in a > >zero-gravity region between the earth and the sun, so I would think that it > >is always on our side of the sun, although I don't know for certain. The > >sun's rotation period is a function of latitude, 25 days at the equator, 33 > >days at 75 degrees (Skilling and Richardson, 1947). > > > >SOHO images are at > >http://sohowww.nascom.nasa.gov/data/realtime-update.html > > > >Gordon > > > > > >At 07:14 AM 1/3/01 -0700, you wrote: > >> >Hello all: > >> > >>I just looked at the SOHO solar satellite photos of the sunspots and noticed > >>that the spots were different from the ones I saw on Christmas morning. > >>Could it be that SOHO was on the opposite side of the sun when the picture > >>was taken? Or maybe the sun's rotation since Christmass brought the sun's > >>farside into view. > >> > >>If an earthboud observer wants to see both sides of the sun, how long will > >>he have to wait between observations until the sun rotates 180 degrees? > >>What is the rotation rate of the sun? > >> > >>John Carmichael > >>Tucson Arizona > > > >Gordon Uber [EMAIL PROTECTED] San Diego, California USA > >Webmaster: Clocks and Time: http://www.ubr.com/clocks > > > > > > > > =============================================================================== > > Richard B. Langley E-mail: [EMAIL PROTECTED] > Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ > Dept. of Geodesy and Geomatics Engineering Phone: +1 506 453-5142 > University of New Brunswick Fax: +1 506 453-4943 > Fredericton, N.B., Canada E3B 5A3 > Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ > =============================================================================== > >
