By John George Williams

ISBN-10: 0002190273

ISBN-13: 9780002190275

Show description

Read or Download A field guide to the butterflies of africa PDF

Similar science & math books

Download PDF by D.E. Johnson, etc.: A Handbook of Active Filters

Hardcover with gilt lettering with out airborne dirt and dust jacket

New PDF release: 50 Ways the World Is Going to End: The Biggest Threats to

Dying via Euphoria. Dysgenics. inhabitants demise Spiral. Genetic Superhumans. Geomagnetic Reversal. Galactic Collision. Strangelets. even if we adore it or no longer, everything's going to return to an attractive disagreeable halt on our planet at some point soon sooner or later. What we do not comprehend is what shape our extinction is probably going to take.

Additional info for A field guide to the butterflies of africa

Example text

References NGC 2392 1. 2. 3. 4. 5. 6. This bright planetary nebula was found by William Herschel in 1787 and COnsists of a bright star centrally situated in an interesting double-shell nebula. The inner, brighter shell is about 13" in diameter and the outer shell ~bout 46". , 67, 253, 1955. , 121, 604, 1955. ; Rev. Modern Phys. 30, 1048, 1958. Recillas-Cruz, E. ; Astron. , 97, 398, 1981. , 196, 191, 1975. H. ; in IAU Symposium No. 103: Planetary Nebulae (ed. R. Flower), D. Reidel, 1983 (p. 523).

A myth has arisen among amateur astronomers that the use of high powers is counterproductive as it "spreads the light" and reduces the object's contrast. However, if the magnification does not exceed about 20 times per cm of telescope aperture you are likely to find high power extremely valuable. The reason is that the resolving capability of the eye is much reduced in dim light. Therefore, details in very faint objects can only be resolved if they are large. You can establish you own optimum range of powers by experimentation.

Recillas-Cruz, E. ; Astron. , 97, 398, 1981. , 196, 191, 1975. H. ; in IAU Symposium No. 103: Planetary Nebulae (ed. R. Flower), D. Reidel, 1983 (p. 523). 78 79 Chapter 5. Catalogue and Atlas of Planetary Nebulae A detailed study of the morphology of NGC 2392 has been made by Louise (ref. 1) using monochromatic photographs, and a three-dimensional model of the nebula has been derived by Reay et at. (ref. 2) using observations made with the TAURUS Fabry-Perot interferometer. This latter work indicates that this planetary nebula consists of two concentric spheroidal shells, viewed along their major axes.

Download PDF sample

A field guide to the butterflies of africa by John George Williams


by Jeff
4.5

Rated 4.10 of 5 – based on 20 votes