refractor - News - Actualités - Les Observatoires du Clain2024-03-28T14:35:16Zhttp://debeerst.ning.com/profiles/blogs/feed/tag/refractorRestoration of a 81mm Sécretan refractor, +/- 1920http://debeerst.ning.com/profiles/blogs/restoration-of-a-81mm-secretan-refractor-19202016-08-30T06:21:46.000Z2016-08-30T06:21:46.000ZXavierhttp://debeerst.ning.com/members/Xavier<div><img src="http://storage.ning.com/topology/rest/1.0/file/get/3314850208?profile=RESIZE_400x&width=400"></div><div><p><span class="font-size-3" style="font-size: small; font-family: verdana,geneva;">Secretan, Marc Francois Louis<strong><br /></strong></span><br />
<span class="font-size-3" style="font-size: small; font-family: verdana,geneva;">Nationality:  Swiss</span></p>
<p><span class="font-size-3" style="font-size: small; font-family: verdana,geneva;">Brief Bio:  1804-1867, mathematician; scientific instrument maker, Swiss</span></p>
<p><span class="font-size-3" style="font-size: small; font-family: verdana,geneva;">until 1844 - professor of mathematics at Academy of Lausanne;</span><br />
<span class="font-size-3" style="font-size: small; font-family: verdana,geneva;">1840 - worked with Friedrich von Martens and Samuel Heer producing daguerreotypes;</span><br />
<span class="font-size-3" style="font-size: small; font-family: verdana,geneva;">1844 - moved to Paris;</span><br />
<span class="font-size-3" style="font-size: small; font-family: verdana,geneva;">1845 - partnership with Lerebours as Lerebours & Secretan; used joint name until 1880s and beyond.</span><br />
<span class="font-size-3" style="font-size: small; font-family: verdana,geneva;">1855 - after retirement of Noel Paymal Lerebours became sole proprietor of Lerebours and Secretan, and signed himself as "Maison Lerebours et Secretan / Secretan, Successeur" and as "Opticien de S.A.M. l'Empereur." He also did work for the Paris observatory.</span><br />
<span class="font-size-3" style="font-size: small; font-family: verdana,geneva;">after 1860 - Secretan also issued catalogs as sole proprietor after 1860</span><br />
<span class="font-size-3" style="font-size: small; font-family: verdana,geneva;">Collaborated with William Eichens, designer of telescopes.</span><br />
<span class="font-size-3" style="font-size: small; font-family: verdana,geneva;">1860s - worked with Foucault, improved silvering techniques.</span><br />
<span class="font-size-3" style="font-size: small; font-family: verdana,geneva;">1867 - succeded by his son, Auguste Secretan (1833-1874) and nephew, Georges Secretan (1837-1906 )</span><br />
<span class="font-size-3" style="font-size: small; font-family: verdana,geneva;">1874 - succeded by his cousin, Georges.</span><br />
<span class="font-size-3" style="font-size: small; font-family: verdana,geneva;">c. 1900 - succeded by Paul Victor Secretan</span></p>
</div>Maurice Manent 80mm refractor, +/- 1920http://debeerst.ning.com/profiles/blogs/maurice-manent-80mm-refractor-19202016-06-13T13:55:42.000Z2016-06-13T13:55:42.000ZXavierhttp://debeerst.ning.com/members/Xavier<div><img src="http://storage.ning.com/topology/rest/1.0/file/get/3314844154?profile=RESIZE_400x&width=400"></div><div><p>It's hard to predict how an antique telescope will perform.</p>
<p>The Manent is fantastic. Made in the 1920 - 1930 by the French telescope maker Mauric Manent. It's a pleasure to observe with. Even the lenses are uncoated it still gives a very good contrast and color. Sharp and beautifull color. Even at 250x the images were crisp and the color with no aberrations. The focuser is very nice.That's the kind of telescopes I like very much.</p>
<p><a target="_self" href="http://storage.ning.com/topology/rest/1.0/file/get/3314846601?profile=original"><img width="550" class="align-center" src="http://storage.ning.com/topology/rest/1.0/file/get/3314846601?profile=RESIZE_1024x1024" width="550" /></a></p>
<p></p>
<p><a target="_self" href="http://storage.ning.com/topology/rest/1.0/file/get/3314851636?profile=original"><img width="550" class="align-center" src="http://storage.ning.com/topology/rest/1.0/file/get/3314851636?profile=RESIZE_1024x1024" width="550" /></a></p>
</div>Nice German Scopehttp://debeerst.ning.com/profiles/blogs/nice-german-scope2016-02-27T20:47:21.000Z2016-02-27T20:47:21.000ZXavierhttp://debeerst.ning.com/members/Xavier<div><img src="http://storage.ning.com/topology/rest/1.0/file/get/3314860570?profile=RESIZE_400x&width=400"></div><div><p>New find. 90mm f1170mm refractor on altaz fork mount.<br />
The lens is extremely good. Sharp and good contrast. The lens has no coating. Must be made between 1900 and 1914. No indication of a brand.<br />
Original wooden box for the telescope and mount.</p>
<p><a target="_self" href="http://storage.ning.com/topology/rest/1.0/file/get/3314862114?profile=original"><img width="300" class="align-center" src="http://storage.ning.com/topology/rest/1.0/file/get/3314862114?profile=RESIZE_320x320" width="300" /></a><a target="_self" href="http://storage.ning.com/topology/rest/1.0/file/get/3314860656?profile=original"><img width="300" class="align-center" src="http://storage.ning.com/topology/rest/1.0/file/get/3314860656?profile=RESIZE_320x320" width="300" /></a> <a target="_self" href="http://storage.ning.com/topology/rest/1.0/file/get/3314861128?profile=original"><img width="300" class="align-center" src="http://storage.ning.com/topology/rest/1.0/file/get/3314861128?profile=RESIZE_320x320" width="300" /></a></p>
<p>The eyepiece has a strange diameter: 22mm. No standard diameter</p>
<p><a target="_self" href="http://storage.ning.com/topology/rest/1.0/file/get/3314862674?profile=original"><img width="300" class="align-center" src="http://storage.ning.com/topology/rest/1.0/file/get/3314862674?profile=RESIZE_320x320" width="300" /></a><a target="_self" href="http://storage.ning.com/topology/rest/1.0/file/get/3314861312?profile=original"><img width="300" class="align-center" src="http://storage.ning.com/topology/rest/1.0/file/get/3314861312?profile=RESIZE_320x320" width="300" /></a><a target="_self" href="http://storage.ning.com/topology/rest/1.0/file/get/3314860570?profile=original"><img width="300" class="align-center" src="http://storage.ning.com/topology/rest/1.0/file/get/3314860570?profile=RESIZE_320x320" width="300" /></a></p>
<p>The central colon of the mount be raised.<br />
The mount and tripod are very stable.<br />
The telescope, mount and tripod have been repainted by a former user.</p>
</div>Other telescopes by František Kozelskýhttp://debeerst.ning.com/profiles/blogs/other-telescopes-by-frantisek-kozelsky2016-02-21T19:57:28.000Z2016-02-21T19:57:28.000ZXavierhttp://debeerst.ning.com/members/Xavier<div><img src="http://storage.ning.com/topology/rest/1.0/file/get/3314863924?profile=RESIZE_400x&width=400"></div><div><p>In my research for more background information about the <a href="http://debeerst.ning.com/profiles/blogs/vilem-gajdusek-and-frantisek-kozelsky" target="_self">Gajdusek-Kozelsky</a> telescopes from the <a href="http://debeerst.ning.com/profiles/blogs/tale-of-an-abandoned-czech-public-observatory" target="_self">Zdanice Observatory</a> I found an article in the Slovak astronomy magazine about a similar 20cm refractor build by Kozelsky.</p>
<table style="width: 80%; background-color: #ebe9e9; margin-left: auto; margin-right: auto;" align="center" border="0" cellspacing="15">
<tbody>
<tr>
<td style="text-align: left;">
<p>After more than two years of hard work, the famous telescope builder <a href="http://debeerst.ning.com/profiles/blogs/vilem-gajdusek-and-frantisek-kozelsky?context=tag-gajdusek-kozelsky" target="_self">František Kozelský</a> from Old Běleja (Ostrava) build a refractor for observatories in his workshop.  The telescope will be installed in the observatoriy of Kysucké Nové Mesto.</p>
<p>It is the largest device of this type made by  František Kozelský and one of the  largest refractors in the Slovak Republic, dedicated to  amateur astronomy. We asked  the telescope designer a more detailed description of the new apparatus. He is willing and show the huge telescope. The telescope was completely setup in the hall of his house.  It’s the only place where he can mount the telescope.<br />
In the next editions of our magazine we will report on the further installation of the telescope in the observatory<br />
<br />
The device is built on a strong conical steel frame which ensures the stability of the telescope. The lens is from Zeiss Jena (type AS, 200 mm, f = 3000 mm). Equatorial mounting is driven by a synchronous electric motor (10 W, 3000 rpm] via a gear box with a planetary gear, which allows using the second electric motor, A hand box allows guiding in the right accession.  The drive is mounted in such a way that there is no vibration. The gearbox is permanently filled with oil. The telescope is equipped with hour circles for fine adjustments . On the setting circles eyepieces are installed for a detailed read out.<br />
<br />
The focuser is designed for rapid exchange of eyepieces and other auxiliary equipment. On the telescope tube a Schmidt Camera is mounted with a mirror diameter of 200 mm f: 2.44.  The camera has a field of view of 7 degrees. The diameter of the film cartridge is 58 mm. The Schmidt camera was made by Ing. Wilhelm Gajdušek.<br />
<br />
The telescope is equipped with a viewfinder with a diameter of 80 mm ff = 450 mm], which magnifies 16x. the viewfinder includes eyepieces for 75, 110, 150, 200, 313 and 600x.<br />
<br />
Other accessories are: a zenith prism, also a Herschel wedge for direct observation of the Sun with polarizing filters and various other filters, a 3 eyepiece revolver for quick exchange of eyepieces and a solar projection screen 35 x 35 cm.<br />
<br />
František Kozelský spend 2.5 years building this telescope<br />
<br />
Kozmos, March 1980</p>
</td>
</tr>
</tbody>
</table>
<p><br />
The 20cm telescope described in this article is still in use in the <a href="http://www.hvezdaren.org/" target="_blank">Hlovohek Observatory</a>.</p>
</div>First light of the 16cm f:15 Gajdusek - Kozelsky refractorhttp://debeerst.ning.com/profiles/blogs/first-light-of-the-16cm-f-15-gajdusek-kozelsky-refractor2015-09-14T22:19:56.000Z2015-09-14T22:19:56.000ZXavierhttp://debeerst.ning.com/members/Xavier<div><p>7 June 2015</p>
<p>Last first light for the Gajdsuek_Koselsky 16cm refractor on the Alt Azimuth mount.<br />
I don't know when it was the last time scope saw star light?</p>
<p><a target="_self" href="http://storage.ning.com/topology/rest/1.0/file/get/3314842309?profile=original"><img width="350" class="align-center" src="http://storage.ning.com/topology/rest/1.0/file/get/3314842309?profile=RESIZE_480x480" width="350" /></a><a target="_self" href="http://storage.ning.com/topology/rest/1.0/file/get/3314839277?profile=original"><img width="350" class="align-center" src="http://storage.ning.com/topology/rest/1.0/file/get/3314839277?profile=RESIZE_480x480" width="350" /></a>Two photos of how I found the scope laying in one of the domes.</p>
<p><a target="_self" href="http://storage.ning.com/topology/rest/1.0/file/get/3314846319?profile=original"><img width="350" class="align-center" src="http://storage.ning.com/topology/rest/1.0/file/get/3314846319?profile=RESIZE_480x480" width="350" /></a><br />
The other photo is the scope standing in the garden ready for observation.</p>
<p>Refractorphil and his son joined for the first light.</p>
<p>It was a little puzzling to find the right pieces to fit the eyepieces. When you use an Altaz mount it's difficult to use high power eyepieces. Between 60x and 150x were ideal.</p>
<p>First object was Venus. Clean view with no secondary colors. Second object was Jupiter. Splendid view. Lot's of details in the clouds and a beautiful shadow transition. Details of the poles. Crispy.</p>
<p>Startest: textbook. What I hoped.<br />
Double-Double in Lyra: clear split at 100x.<br />
M13: Beauty<br />
M57: lot of details.</p>
<p>Conclusion: The scopes is great. Easy to use. The focuser is a joy. Simple mount.</p>
</div>The Frantisek Kozelsky focusers from the Zdanice Telescopeshttp://debeerst.ning.com/profiles/blogs/the-frantisek-kozelsky-focusers-from-the-zdanice-telescopes2015-09-14T22:07:37.000Z2015-09-14T22:07:37.000ZXavierhttp://debeerst.ning.com/members/Xavier<div><p>A family shot of the different focuser of the scopes.</p>
<p><a target="_self" href="http://storage.ning.com/topology/rest/1.0/file/get/3314838213?profile=original"><img width="550" class="align-center" src="http://storage.ning.com/topology/rest/1.0/file/get/3314838213?profile=RESIZE_1024x1024" width="550" /></a>On the left the Cassegrain Focuser, middle the 16cm refractor focuser and right the 20 cm focuser.</p>
<p><a target="_self" href="http://storage.ning.com/topology/rest/1.0/file/get/3314840710?profile=original"><img width="350" class="align-center" src="http://storage.ning.com/topology/rest/1.0/file/get/3314840710?profile=RESIZE_480x480" width="350" /></a><a target="_self" href="http://storage.ning.com/topology/rest/1.0/file/get/3314841243?profile=original"><img width="350" class="align-center" src="http://storage.ning.com/topology/rest/1.0/file/get/3314841243?profile=RESIZE_480x480" width="350" /></a>The eyepiece attachment system is very similar to the Zeiss system.<br />
This are the 3 different eyepiece dovetails from the different focuser's. It are Zeiss style dovetails. Or are it original Zeiss dovetails?<br />
More and more I find indications that Kozelsky knew very well the Zeiss Jena material.<br />
The large Zeiss Jena scopes were "common" in Eastern Europe.</p>
<p>The sizes are:<br />
The smallest from the Cassegrain: focuser side: 63.5mm, eyepiece side 54,7mm<br />
Medium size from the 16cm refractor: focuser side 71,6mm, eyepiece side 71,2mm<br />
Large size from the 20cm refractor: focuser side 94,5mm, eyepiece side 88mm</p>
<p><a target="_self" href="http://storage.ning.com/topology/rest/1.0/file/get/3314838794?profile=original"><img width="350" class="align-center" src="http://storage.ning.com/topology/rest/1.0/file/get/3314838794?profile=RESIZE_480x480" width="350" /></a></p>
<p><a target="_self" href="http://storage.ning.com/topology/rest/1.0/file/get/3314849731?profile=original"><img width="350" class="align-center" src="http://storage.ning.com/topology/rest/1.0/file/get/3314849731?profile=RESIZE_480x480" width="350" /></a></p>
<p>All the focuser and draw tubes have different sizes.</p>
<p>For the people who love stories.  Found all the adapters in a cooking pot in one of the hotel chambers ;-)</p>
</div>