J. Brit. Astron. Assoc., 106, 4, 1996

Letters

(Note: The Association is not responsible for individual opinions expressed in articles, reviews, letters or reports of any kind.)


New NASA bulletin for the total solar eclipse of 1998 February 26

From Drs Fred Espenak and Jay Anderson

On 1998 February 26 a total eclipse of the Sun will be visible from within a narrow corridor which traverses the Western Hemisphere. The path of the Moon's umbral shadow begins in the Pacific, continues through northern South America and the Caribbean Sea, and ends at sunset off the Atlantic coast of Africa. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes parts of the United States and eastern Canada, Mexico, Central America and the northern half of South America.

A new NASA solar eclipse bulletin covering this event is now available. Total Solar Eclipse of 1998 February 26 (NASA RP 1383) is a 97 page publication containing detailed predictions and includes besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for over 1000 cities, maps of the eclipse path, weather prospects, the lunar limb profile and the sky during totality. Tips and suggestions are also given on how to safely view and photograph the eclipse. NASA's eclipse bulletins are prepared in cooperation with the IAU's Working Group on Eclipses and are provided as a public service to both the professional and lay communities, including educators and the media.

Single copies of the bulletin are available at no cost and may be ordered by sending a 9×12 inch SASE (self addressed stamped envelope) with sufficient postage (11oz. or 310g). Use stamps only; cash or checks cannot be accepted. Please print either the eclipse date (year & month) or the NASA RP number in the lower left corner of the SASE. Requests from outside the US and Canada may send nine international postal coupons to cover postage. Exceptions to the postage requirements will be made for international requests where political or economic restraints prevent the transfer of funds to other countries. Professional researchers and scientists may order the bulletins directly (no SASE is necessary). Bulletin requests may be made to either of the authors. Other eclipse bulletins currently available are: Total Solar Eclipse of 1995 October 24 (NASA RP 1344), and Total Solar Eclipse of 1997 March 9 (NASA RP 1369).

The NASA eclipse bulletins are also available over the Internet. Formats include a BinHex-encoded version of the original MS Word file + PICT + GIF scanned GNC maps, as well as a hypertext version. They can be read or downloaded via the World-Wide Web using a Web browser (e.g.: Mosaic, Netscape, Microsoft Explorer, etc.) from the GSFC SDAC (Solar Data Analysis Center) home page: http://umbra.nascom.nasa.gov/sdac.html. Most of the files are also available via anonymous ftp. In addition, path data for all central eclipses through the year 2005 are available via http://umbra.nascom.nasa.gov/eclipse/predictions/year-month-day.html, where the string year-month-day is replaced with the date of interest (e.g. 1999-august-11). For more details, contact Espenak. A bulletin for the total solar eclipse of 1999 August 11 will be published during the last quarter of 1996.

Fred Espenak
Planetary Systems Branch, Code 693, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 USA [espenak@lepvax.gsfc.nasa.gov]

Jay Anderson
Environment Canada, Laboratory for Extraterrestrial Physics, 900-266 Graham Ave., Winnipeg, MB, Canada R3C 3V4 [jander@cc.umanitoba.ca]


'Observations concerning the planet Venus'

From Mrs S. Beaumont and Mr P. Fay

We wish to express our thanks to Richard Baum for his review of the above mentioned book in this Journa (1996 April).

However, we think it worth pointing out that our brief was simply to translate and annotate the text. Bianchini's book provides valuable information about the scientific instruments and methods at his disposal, as well as the attitudes of many of his contemporaries to the current state of astronomical theories. The outstanding investigation by Alan Binder, cited in the review, dealt with long-focus tube or girder type telescopes, but these were not the aerial telescopes devised by Huygens to dispense with the need for massive feats of engineering and favoured by Bianchini for planetary detail. Moreover, Alan Binder used the modern formulation of Huygens' eyepiece, not the original.

Finally, we would wish to acknowledge gratefully the role of Patrick Moore in instigating and inspiring the whole venture.

Sally Beaumont
Peter Fay

The Nab, Oakthwaite Road, Windermere, Cumbria LA23 2BD


Back in the fold

From Mr J. C. Vetterlein

How good to come back into the fold and find things much as I left them in my heyday – Venus in daylight, Schröter's effect and so on.

Although out of the BAA for some fifteen years I have not been astronomically idle. I am able to report an unaided eye noon observation of Venus from a peat hag on top of an Orkney hill, and to have shared the event with two passing hill walkers. In fact, this elongation of Venus has given us the finest opportunity for daylight observation in many years, with the planet almost circumpolar from these latitudes.

As far as Schröter is concerned: I recall the learned papers on the topic and micrometrical measures by myself and colleagues back in the sixties. At this dichotomy, and using a modest 85mm Wray equatorial refractor, my analysis of observations from two dozen (unprepossessing) school pupil observers, is that east of the meridian the phase was more than 50%, and west of the meridian 50% or less!

And Hyakutake? Wish you could all have been here...

John Vetterlein

Springfield, Rousay, Orkney KW17 2PR


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