Measuring Mintaka STFA 14 Aa-C

[lunator]

I took some measurements of Mintaka last night using my illuminated reticle eyepiece.

I was in a bit of a hurry due to clouds rolling. As Mintaka is very close to 0 degrees declination it is ideal for measuring using an external PA dial.

I lined the scope up and could see the two stars clearly.

I switched the drive off and let the stars move across the FOV. From this I could get the West (270) angle. I let MIntaka move to the edge of the FOV and then put the drives back. I rotated the dial to read 270 at that point.

I re-centred MIntaka and turned the croshair illumination back on. The 2 stars were exactly in line on the illuminated wire. This confirmed that the Primary was due North (0) of the primary.

To calculate the separation I had to turn the wire to 45 degrees as if I kept them North/South the stars would transit at the same time.

I took the timing measurements and they avaraged to 4 seconds.

Applying the formula P= 15.0411x4xcosd/costheta-sintheta.

P= 15.0411x4xcos0.3/cos0=sin0 = 60".

The figures for 2003 are PA= 0 Sep 53".

The separation discrepancy is probably due to me not having the wires at exactly 45 degrees.

If it is clear tonight I will revisit this.

Cheers

Ian