Yearly accomplishments for the period of 1 April 1998 through 31 March 1999

by
Christian A. Hummel

I have performed the following routine tasks:

	1: 	Scheduling of NPOI observations based on input from the
		Time Allocation Commitee, notification of PIs on stars
		observed, submitting summaries of the proposal's 
		observational status to the TAC.
	2:	Reduction of every night's data (almost 80) obtained 
		during the reporting period through CONSTRICTOR (raw data 
		processing) and OYSTER (scan averages), maintenance of a 
		database of observed stars, dates, etc.

The accomplishments include:

	1:	Published Hummel et al. 1998 on "NPOI observations of double
		stars Mizar A and Matar" in the Astronomical Journal.
	2:	Published a 10 page contribution to the proceedings of the
		SPIE conference on "Astronomical Interferometry", titled
		"Images of spectroscopic binaries with the Navy Prototype
		optical interferometer".
	3:	Produced 25 maps of Mizar A for a PowerPoint movie which I
		showed at the IAU colloquium 170, "Precise stellar radial
		velocities". At this conference, I also gave a talk on
		"Imaging and modeling of double stars with the Navy Prototype
		optical interferometer: a continuation of the Mark III double 
		program". Some of the Mizar A images were requested by 
		WH Freeman Publishers for the new edition of their textbook
		on Astronomy by Comins/Kaufmann.
	4:	Obtained maps and derived combined NPOI/speckle preliminary
		orbital elements for several spectroscopic and speckle binaries.
		These are Zet Ori, Kap UMa, Phi Her, Sig Her, 1 Gem, Nu Gem,
		Alp Com, Bet CrB, Xi Tau, and Bet LMi.
	5: 	I gave three presentations at the Lowell workshop on optical
		and IR interferometry.
	

Here I list separately what I have done to maintain and improve the NPOI
data reduction software, comprising CONSTRICTOR and OYSTER:

	1:	For CONSTRICTOR, I added code to allow to effectively increase
		the instrumental coherent integration time, do a better 
		visibility bias correction, and flag group delays based 
		on the SNR.
	2:	For OYSTER, I added code which simulates arbitrary observations 
		of hierarchical stellar systems, uses logarithmic limb 
		darkening coefficients for modeling, and improves the reduction
		of astrometric data. I have also maintained the manual and 
		web pages with additional help on this software.