Adam's Hyades Tips

Locate the Hyades, both on ECU and in the sky. The bright star Aldebaran is a good aid to finding the Hyades.

Not all stars in the region of the Hyades will be members of the cluster. A reputable list of Hyades members is essential for observing. One such list is included in Griffin et al (1988), which also includes radial velocities. Note that several more extensive lists have been published in the last decade, most obviously the Hipparcos catalogue.

Choose target stars carefully, they must be bright enough to be observed but not so bright that they will saturate the CCD. Choosing reasonable targets will often be a case of trial and error. It is also essential that target stars can be easily identified within the field in question. Note that the convergent point method will work best with targets from a wide area of sky; Hyades members may extend between an RA of around 2h to 5h and a DEC of 5^o to 30^o.

Once a target catalogue is selected, you are ready to make observations. All that is left is a consideration of the mathematics of determining proper motions from a combination of your images (using UCAC4 for the astrometry measurements if possible) and the archive data from the USNO-A2.0 catalogue which lists positions and the epoch of the photographic plates. USNO-A2 is also available on the Astrolab fileserver. Good sources outlining the methodology include Perryman et al's paper of 1998 and a chapter of "Astronomy : Structure and the Universe" by A.E. Roy and D. Clarke, available in the main library.

(It is essential you acquire an understanding of the terms epoch and equinox as they apply to proper motions, again see "Astronomy : Structure and the Universe" by A.E. Roy and D. Clarke.)

jrl

2020-Jun-17 13:48:59 UTC