Sun as Asteroide

[Ron Hillstromb]

Hello All

  I have a Meade LXD75 mount with an AutoStar 497 controller I will be using during the solar eclipse.  Dick "ETXAutoStar" Seymour and several others have provided elements that approximate the Earth on the far side of the Sun for the Autostar 497, 497EP and AudioStar controllers.  If the mount you are using allows you to manually input an Asteroid you may be able to enter the following data and get close to the Sun.  This can be used anytime you want to get close to the Sun for whatever reason.  Remember to use adequate Solar filters on whatever ever optical device you are using 

 

NAME = SUN
EPOCH = 1.5 Jan 2005
ECCENTRICTY= 0.0167
SEMI MAJ AXIS = 1.0
INCLINATION = -0.0001
LONG ASC NODE= 168.7394
ARG OF PER = 114.2078
MEAN ANOMOLY = 357.5172
ABSOLUTE MAG = -12.0
MAG SLOPE = 0
... if any of the lines "don't fit" (such as 114.2078) just round them ( 114.208 )

 

  The LXD 75 mount is lower middle cost mount at the time it was released ($800-900) range.  You get what you pay for, not exactly a super precision mount.

 

  An addendum to the previous post concerning the -.35 percent of sidereal motion of the Sun for Tracking.  Dick said the Sun doesn't follow a strait line across the sky.  If using a German Equatorial Mount (GEM) you may have to tweak the position of the Sun over time.

 

Good Luck.

 

Ron
 

 

[s3igell]

Ron,  This is great information  (USEFUL DATA).

However, just to be slightly pedantic:  It is actually the Earth that causes the Sun's image to trace a Great Arc across the Sky (Earth's Inclined Axis of Rotation and Earth's Equatorial Bulge).  Hey, to complicate matters further, the additional Inclination of the Moon's Orbit causes the Eclipse Track to not be a Straight Line (nor a Great Arc).  And, the Sun does not Traverse the Sky at exactly Sidereal Rate (although many Mounts have a Solar Tracking mode - some even account for Date and Latitude to truly Track the Sun).

All this said, your suggestion of using the "Track Asteroid" trick is a Good Idea.

[Ron Hillstromb]

Hi s 

  yes it helps those of us whose mount controllers try to keep us from looking at the Sun and then litigate why they damaged their eyes. ha ha ha

    On the matter of things getting complicated  This link shows how various eclipses will happen.  You can put in cities but I found that the computations and animations go to a nearby city if the city input isn't in the data base.

  https://www.timeanddate.com/eclipse/solar/2017-august-21

    Put in Corpus Christi Texas and watch the partial eclipse they will view.  The moon hooks a sharp right turn in mid eclipse.  Surprised me.

  Thanks for the comments.  Dick Seymour said sever factors would complicate keeping the Sun in the center and beyond being able to correct it in the 497.

 

Ron