https://home.strw.leidenuniv.nl/~kaiser/wiki/ 2026-05-16T15:40:45+00:00 https://home.strw.leidenuniv.nl/~kaiser/wiki/ https://home.strw.leidenuniv.nl/~kaiser/wiki/lib/exe/fetch.php?media=wiki:logo.png text/html 2022-10-28T21:30:05+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:6-duims&rev=1666992605&do=diff The 6" Merz refractor History * Purchased in 1838 by Kaiser. * Manufactured by George Merz in the Optical-Mechanical institute of Fraunhofer, Utzschneider and Reichenbach. * It used to be on top of the academy building. * It was used to observe (small) planets, comets and binaries. text/html 2014-01-30T18:42:27+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:7-duims&rev=1391107347&do=diff When the observatory openend the big dome on the central building was equiped with a 7“ (18 cm) refractor. Much smaller than Kaiser wanted, but after the building was finished, there was no money left to order a bigger instrument. In 1885 Kaisers'successor managed to buy the bigger 10 text/html 2022-10-28T21:40:19+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:10-duims&rev=1666993219&do=diff 10-inch refractor History * Purchased in 1885 by H.G. van de Sande Bakhuyzen * Manufactured by Repsold un Söhne in Hamburg * The lens was manufactured by Alvan Clark & sons in Cambridgeport, Massachusetts, USA * It replaced the 7-inch refractor that used to be in the Northern dome text/html 2014-02-21T15:49:07+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:antique_sextant&rev=1392997747&do=diff Antique Sextant This is a cheap, but functional replica of an antique sextant. It has little to do with the history of the building, besides the fact that there used to be a marine instrument testing facility in the old observatory building when Kaiser first opened it. Here they built, tested and fixed many instruments used for naval purposes. And since most of those relied on navigation by sky, astronomy was not too weird of a combination. text/html 2014-01-29T13:18:12+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:arceerkijker&rev=1391001492&do=diff The Arceerkijker was a so called Schraffier-kassette telescope that stood in Koepel ... This telescope was ordered by Hertzsprung text/html 2014-01-28T11:07:24+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:azimuthkijker&rev=1390907244&do=diff Azimuth kijker Kijker die vroeger in koepel West stond. text/html 2014-03-09T09:33:25+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:balieruimte_kijker&rev=1394357605&do=diff Telescope reception area In reception area of the visitorcenter an old (Newton) reflector is present, as a demonstration device what a mirror telescope looks like. Mr. Pieter v.d. Veld from Voorschoten, an amateur telescope maker, made it in the sixties of te 20th century. It has no specific historical or market value. text/html 2015-04-11T11:58:53+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:bresser_skylux&rev=1428753533&do=diff Bresser Skylux [[The telescope]]This is Alex' private telescope. It has been put in the WLS space for general use together with the foot. Apparently this is one of the best selling telescopes in Europe thanks to its easy use. It comes with a tripod, a diagonal mirror and one eyepiece. text/html 2014-07-22T11:03:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:ccd&rev=1406026980&do=diff CCD Bright objects like planets and the sun can best be pictures with fast CCD camera’s. The DMK camera is used. A filterwheel (LRGB) is used for color. The necessary control software is Firecapture. Stacking is done with Registax. The camera operates with 1¼” nosepiece and adapter. text/html 2014-02-21T16:02:47+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:davis_sextant&rev=1392998567&do=diff Davis Mark 3 The Davis sextant is a plastic student sextant, intended for people who need to learn how to use a sextant. This makes it a great demonstration model, as it is easy to use, explain and largely foolproof. Everything that you need to know about the sextant can be found in the manual: text/html 2014-07-22T11:02:34+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:dslr&rev=1406026954&do=diff DSLR For faint deepsky pictures with long total exposuretime Canon EOS camera’s are used. Either with or without the original built in visual filter. A remote wired controller is needed to run exposure times above 30 s. Preferably the camera is run from a PC with Cannon’s “Canon Remote capture software”. Runs of many shots of a few minutes each can the be run automatically and stacked later. DeepskyStacker can be used for stacking. text/html 2022-08-02T18:40:59+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:fotograaf&rev=1659465659&do=diff Astrograph ("Fotograaf") Short facts * Arrived in 1898 * Largest refracting telescope in the Netherlands * Telescope was built by Gautier * Lenses were manufactured by the French Henry brothers * It has an English mount * Location: 52° 9’ 21” North, 4° 29’ 7” East text/html 2017-05-22T11:14:16+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:heliostat&rev=1495451656&do=diff Heliostat The Heliostat is the first crowdfunded telescope in the Old Observatory, meant to project a 80cm solar images onto the walls of the visitors center. It was an initiative started by Leiden Observatory in cooperation with Leiden University as a test for crowdfunding in Leiden. The University was looking for suitable projects after the previous successful funding of the text/html 2015-09-03T12:00:47+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:huff_telescope&rev=1441281647&do=diff Julius Huff Telescope [[Huff telescope in the Oortroom]]In 2015 this telescope showed up during a cleanup of the directors office, it was an antique telescope that was once gifted to the director (we are not sure if it was Huub or not.) and forgotten over the years. On the telescope one can find the inscription text/html 2017-07-11T17:01:25+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:huygens_kijker&rev=1499792485&do=diff Huygens "aerial" telescope In 1681 Christiaan Huygens started to construct long focus telescopes with no tubular castings. With these large focal-ratio designs, he diminished the effect of chromatic aberration of the singlet lenses used in those days. The objective lens was mounted on a balancing device on top of a pole of 70 ft or higher. The eyepiece was connected to the objective lens by a string. The height of the objective lens was controlled by a pulley. text/html 2015-09-20T13:01:03+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:land_surveying_tools&rev=1442754063&do=diff Survey Equipment In 2015 Johan and Alex went by an old land surveyor who wanted to pass on some of his things. From him we obtained a few typical surveying equipment from roughly 50 years ago. On this page you can see these items and their story. Please be very careful with these instruments, as they are very fragile. text/html 2016-04-16T19:36:05+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:lunt&rev=1460835365&do=diff OBSERVING THE SUN. For solar observations the WLS has a dedicated portable telescope which shows the sun in Hα light (656.28 nm). The bandpass is very small: with the basic set-up “single stack” less than 0.075 nm (0.75 Å), and about half of this (0.055 nm) with the second text/html 2015-04-11T19:13:24+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:meridiaankijker&rev=1428779604&do=diff Meridiaankijker Short facts Objective lens diameter: 6.4“ Focal length: 102” History of telescope In the middle of the 19th century astrometry was a central activity for astronomers. So Kaiser ordered a state of the art instrument from the workshop of Pistor&Martins (Germany). It got a prominent place in the western room connecting the central building and the directors' house. text/html 2017-09-11T20:06:42+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:minnaerttelescopes&rev=1505160402&do=diff Minnaert Telescopes [[The pillars that once supported the telescopes.]][[A Minnaertkijker]]These telescopes are a subsection of the old observing gear once used in the observatory. They were stationed on the roof of the Huygens building on pillars specially made for them. This was done in the 80's ish era. They have a 4 cm objective and work with 0.968' objectives. text/html 2017-08-17T16:46:07+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:pyrheliometer&rev=1502988367&do=diff Pyrheliometer [[Pyrbolometer in Sonneborgh]]These pyrheliometers are from the 50's and were used for the observing practical to measure the temperature of the sun. The front side is covered by baking paper in order to diffuse the light and shine it onto a brass element that can be found inside the tube. The brass is painted black in order to absorb all the light, which in turn makes the temperature of the brass go up. This difference can be seen on the thermometer and be used to calculate the f… text/html 2015-04-03T11:38:53+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:quadrant_snellius&rev=1428061133&do=diff Snellius' Quadrant A quadrant was a straightforward angle measurement device developed in the pre-telescope area. Placed vertically it measured elevantion, placed horizontally it measured azimuth. Tycho Brahe obtained a precision of about 1' with such instruments. The quadrant shown was the first instrument of Leyden Observatory, bought in 1629 by the first director Jacob van Gool (Golius) from the widdow of Willebrord Snel van Royen (Snellius). The man most known from the refractive index and… text/html 2015-04-03T11:44:42+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:radio_telescopes&rev=1428061482&do=diff Radio Telescopes * Radio astronomy started in Holland with a the hardware from a Würzburg Riese radar station from the Atlantic wall in WWII.[First steerable radiotelescope] It detected the 21 cm line of HI. The succes lead to the bulding of the 25 m dish in Dwingloo, in operation from 1956 -2009. Now it is a monument, run by amateurs. text/html 2015-04-04T23:26:10+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:reflector_by_rieks_roelofs&rev=1428189970&do=diff Reflector by Rienks&Roelofs Already in the 18th century Friesland had a triving telescope industry. In 1818 Sieds Johannes Rienks (1770-1845) and Arjan Roelofs (1754-1828) received an order from King William I (1772-1843) for two big 55 cm telescopes. One for Leiden Observatory and one for Utrecht. They were designed to be able to serve as Newon-, Gregory- and Cassegrain-telescopes. text/html 2014-07-21T21:32:55+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:seben&rev=1405978375&do=diff Seben Universal Adapter The Seben universal adapter is a tool by seben.com, this adapter when combined with a mobile phone clamp can be used to make most cameras and mobile phones compatible with most telescopes. In the images below we can see the Seben on the text/html 2015-12-10T09:58:22+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:seeing&rev=1449741502&do=diff Seeing Leiden has massive seeing, in 2014 Danielle van der Werff measured the seeing with the student telescope for her Bsc research project. Her results showed that the seeing was between 3 and 5'', depending on the filter. text/html 2014-02-21T15:54:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:sextants&rev=1392998040&do=diff Sextants Currently there are two sextants at the ostrw, a Davis Mark 3 and an antique replica sextant. Both are fully functional and usable for tours and demonstrations. text/html 2014-02-08T21:23:10+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:smartdish&rev=1391894590&do=diff SMART Telescope The SMAll Radio Telescope (SMART) is a DIY millimeter/far IR telescope. Made by Alex in 2014, it is currently the only available radio telescope in the old observatory. (Something which we want to change soon.) It currently is being stored in the WLS storage room, across from the visitors center reception desk. text/html 2017-01-13T16:52:51+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:student_telescope_koepel_west&rev=1484326371&do=diff Student Telescope West Dome Short facts The Student Telescope is located in the West Koepel at the Old Observatory. The control room for the Student Telescope is located under the 10-duims telescope. The Dome for the telescope is fully manually operated, which means that during exposures you need to track the dome by hand. The Telescope is mounted on a high pier, which also houses all power and network connections. text/html 2013-12-29T09:43:55+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:student_telescope&rev=1388310235&do=diff Student Telescope (Koepel West) Tours do NEVER go to this telescope. Even if [enter reason here], it just is not possible. text/html 2015-04-03T11:44:11+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:telescopes_abroad&rev=1428061451&do=diff Telescopes Abroad South Africa: Starting with the directorate of de Sitter observations on request by observatories abroad were pursued. Hertzsprung even demanded such access when he cam to Leyden. Later a major source of observing time was obtained by long term agreements, allowing astronomers to stay for a longer period abroad. text/html 2015-04-03T11:44:58+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:telescopes_in_space&rev=1428061498&do=diff Space Telescopes The Netherlands was responsible for two satellites: * Astronomical Satellite Netherlands (ANS), 1974-1976. Mapping UV and soft X-rays. The orbit was intended to be polar-circular at 500 km, but became elliptical. * Infra-Red Astronomical Satellite (IRAS), 1983. Mapping infrared 12-100 µm, at 900 km height. text/html 2017-08-17T16:32:52+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:telescopes&rev=1502987572&do=diff Telescopes The old observatory has a bunch of telescopes, a few very old and some newer. Also our collection is growing! Telescopes currently in the observatory Permanent telescopes * 6" * 10" * Astrograph * Zunderman reflector * Huygens telescope * Reflector visitors desk * Minnaert Telescopes * Heliostat * Student Telescope (West Dome) * WLS Telescope(s) (East Dome) Portable telescopes text/html 2015-04-25T15:54:40+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:van_der_wall_reflector&rev=1429977280&do=diff Van der Wall Telescope [[The Van der Wall in the old Observatory]] The reflector of Jacobus v.d. Wall which was on display in the Old Observatory, and is again on display in the Oort Building. It is now an ornamental antique, but at it's time in 1742 it was state of the art.[[The van der Wall in it's current position.]] Van der Wall was a rich merchant with a keen interest in telescope building and mirror grinding. He installed it in a building at the edge of Amsterdam. However his interest was… text/html 2014-03-23T20:05:40+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:wls_portable_telescoop&rev=1395605140&do=diff Portable Celestron-8 Older but of reasonable quality for e.g. public demonstration. An 8” SCT (f=2000 mm) with a 240V drive on a equatorial wedge. Eyepieces: 6, 9, 12, 32 mm, and zenith prisma. Portable Meade LX-10 A comparable portable instrument from Meade is also available. It is also an 8 text/html 2015-04-23T22:46:31+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:wls_telescoop_koepel_oost&rev=1429829191&do=diff WLS Telescope(s) East Dome Either an 8“ SCT reflector or a 5.5” APO refractor are installed in the East dome. Telescope 1 Reflector A somewhat older Meade LX-200 8“ refractor is mounted in the East-dome, and operated with private auxiliaries. This instrument is maintained and operated bij the text/html 2015-04-03T11:42:37+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:zenith_telescope_talcott&rev=1428061357&do=diff Talcott Telescope In 1898 the observation hut East of the observatory was specifically build for a telescope which should measure with great precision the latitude of the observatory. The polar motion of the Earth was discovered a decade earlier. This motion is the movement of the point where Earth's rotational axis intersects its surface. It consists of two quasi-periodic components and a gradual drift. It amounts to a few 0,1”, but is enough to spoil meridian observations. As it is not well … text/html 2014-01-31T00:28:20+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:zenithkijker&rev=1391128100&do=diff text/html 2022-11-07T15:17:37+00:00 Anonymous (anonymous@undisclosed.example.com) https://home.strw.leidenuniv.nl/~kaiser/wiki/doku.php?id=telescopes:zunderman&rev=1667834257&do=diff Zunderman reflector Short facts * Reflector Nasmyth optical design * Building started by chief of the workshop Zunderman in 1937 * Operational in 1947 (after WW-II) Main telescope * Focal length: 6918 mm * Primary mirror: 453 mm * Focal ratio: F/15