SUMMARY / RELATED TOPICS

Postage stamps and postal history of South Africa

This is a survey of the postage stamps and postal history of South Africa. The Republic of South Africa The Union of South Africa, is a country located at the southern tip of Africa, with a coastline on the Atlantic and Indian Oceans. To the north lie Namibia and Zimbabwe. Before South Africa was united in 1910, each part of what would become South Africa issued their own stamps; these were: Cape of Good Hope Natal Orange Free State South African Republic Griqualand West Transvaal Stellaland British Bechuanaland New Republic Zululand Orange River Colony During the Second Boer War, some cities issued their own stamps. These were: Lydenburg Mafeking Pietersburg Rustenburg Schweizer Renecke Volksrust Vryburg Wolmaransstad; the first stamp of the Union of South Africa was a 2​1⁄2d stamp issued on 4 November 1910. It portrayed the monarch King George V and the arms of the four British colonies which formed the Union: Cape Colony, Orange River Colony and Transvaal. Most South African stamps issued between 1926 and 1951 were in pairs.

One was inscribed'SOUTH AFRICA' and the other'SUIDAFRIKA' or'SUID-AFRIKA'. The first set of the Republic was issued on 31 May 1961. From 1961 to 1966, stamps were inscribed "REPUBLIC OF SOUTH AFRICA REPUBLIEK VAN SUID-AFRIKA". However, from 1967 stamps were inscribed "RSA". Modern issues are just inscribed "South Africa"; the South African homelands of Bophuthatswana, Ciskei and Venda issued their own stamps. List of people on stamps of South Africa Revenue stamps of South Africa Postage stamps and postal history of Pietersburg Stamp Domain

Palomar Transient Factory

The Palomar Transient Factory, was an astronomical survey using a wide-field survey camera designed to search for optical transient and variable sources such as variable stars, supernovae and comets. The project completed commissioning in summer 2009, continued until December 2012, it has since been succeeded by the Intermediate Palomar Transient Factory, which itself transitioned to the Zwicky Transient Facility in 2017/18. All three surveys are registered at the MPC under the same observatory code for their astrometric observations; the automated system included an automated realtime data reduction pipeline, a dedicated photometric follow-up telescope, a full archive of all detected astronomical sources. The survey was performed with a 12K × 8K, 7.8 square degree CCD array camera re-engineered for the 1.2-meter Samuel Oschin Telescope at Palomar Observatory. The survey camera achieved first light on 13 December 2008. PTF was a collaboration of Caltech, LBNL, Infrared Processing and Analysis Center, Berkeley, LCOGT, Oxford and the Weizmann Institute.

The project was led by Shrinivas Kulkarni at Caltech. As of 2018, he leads the Zwicky Transient Facility. Image Subtraction for near-realtime transient detection was performed at LBNL. Photometric and spectroscopic followup of detected objects was undertaken by the automated Palomar 1.5-meter telescope and other facilities provided by consortium members. Time-variability studies were undertaken using the photometric/astrometric pipeline implemented at the Infrared Processing and Analysis Center. Studies included compact binaries, RR Lyrae, cataclysmic variables, active galactic nuclei, lightcurves of small Solar System bodies. PTF covered a wide range of science aspects, including supernovae, cataclysmic variables, Luminous red novae, tidal disruption flares, compact binaries, active galactic nuclei, transiting Extrasolar planets, RR Lyrae variable stars, microlensing events, small Solar System bodies of the Solar System. PTF filled the gaps in the knowledge of the optical transient phase space, extended the understanding of known source classes, provided the first detections or constraints on predicted, but not yet discovered, event populations.

The efforts being undertaken during the five-year project include: a 5-day cadence supernova search an exotic transient search with cadences between 90 seconds and 1 day. A half-sky survey in the H-alpha band a search for transiting planets in the Orion star formation region. Coordinated observations with the GALEX spacecraft, including a survey of the Kepler region coordinated observations with the EVLA, including a survey of SDSS Stripe 82 Data taken with the camera were transferred to two automated reduction pipelines. A near-realtime image subtraction pipeline was run at LBNL and had the goal of identifying optical transients within minutes of images being taken; the output of this pipeline was sent to UC Berkeley where a source classifier determined a set of probabilistic statements about the scientific classification of the transients based on all available time-series and context data. On few-day timescales the images were ingested into a database at IPAC; each incoming frame was calibrated and searched for objects, before the detections were merged into a database.

Lightcurves of 500 million objects had been accumulated. This database was planned to be made public after an 18-month proprietary period, subject to available resources; the Palomar Observatory 60-inch photometric follow-up telescope automatically generated colors and lightcurves for interesting transients detected using the Samuel Oschin Telescope. The PTF collaboration used a further 15 telescopes for photometric and spectroscopic followup. PTF uses a software code to assist a human in weeding out false positives when searching for small near-Earth objects. N. Law et al. PASP, 121, 1395:"The Palomar Transient Factory: System Overview and First Results" — This paper summarizes the PTF project, including several months of on-sky performance tests of the new survey camera, the observing plans, the data reduction strategy, it includes detailes for the first 51 PTF optical transient detections, found in commissioning data. A. Rau et al. PASP, 121, 1334: "Exploring the Optical Transient Sky with the Palomar Transient Factory" — In this article, the scientific motivation for PTF is presented and a description of the goals and expectations is provided.

G. Rahmer et al. SPIE, 7014, 163: "The 12K×8K CCD mosaic camera for the Palomar Transient Factory" — This paper discusses the modifications to the CFHT 12K CCD camera, improved readout, new filter exchange mechanism, the field flattener needed to correct for focal plane curvature. ZooniverseGalaxy Zoo Supernovae List of near-Earth object observation projects Intermediate Palomar Transient Factory