Carl Zambuto Newton

    • Carl Zambuto Newton

      Carl Zambuto Spiegel = allererste Sahne

      Diese Newtonspiegel zählen zum Genauesten und Glattesten, was man bei Newtonspiegeln finden kann. Carl
      Zambuto dürfte unter den Spiegel-Herstellern, die ich bisher hier hatte, eine Spitzenposition einnehmen.

      Wenn man erst einen Sandwich-Spiegel aus China vor sich hatte, mit ca. 1 Lambda Astigmatismus, wobei die Fläche
      durchaus akzeptabel war, dann merkt man erneut, welche hohe Qualität dieser Carl Zambuto zu bieten hat. Ich kenne
      wenige Hersteller, die es mit dieser Qualität aufnehmen können. Berücksichtigen muß man allerdings, daß f/6 Spiegel
      sehr viel moderater und exakter herzustellen sind, wie die vielen f/4 Spiegel, die bei ungenauer Justage entsprechende
      Coma-Effekte zeigen. Für die Planetenbeobachtung sollte dieser Spiegel bei einem ganz kleinen Fangspiegel unüber-
      troffen sein.



      Der Ronchi-Gittertest eignet sich auch zur Hervorhebung besonders glatter Flächen: Wenn nämlich die weißen dicken
      Linien ungestört und gerade verlaufen, und wenn im dunklen Bereich dazwischen die Beugungslinie gut zu sehen ist und
      die schwarze Fläche ebenfalls nicht aufgehellt ist, dann hat man es mit sehr genauen und glatten Optiken zu tun.
      Gitterkonstante: 13 lp/mm im Doppelpaß intrafokal



      Eine nahezu ungestörte und weiche Fläche im Foucaulttest.



      Erst im Lyot- Rauhheitstest erkennt man kaum wahrnehmbare feine Zonen, die Foucault noch gar nicht zeigt.



      Beim Test am künstlichen Sternhimmel läßt sich ebenfalls die hohe Auflösung demonstrieren.



      Neu im Programm ist ein 200 lp/mm oder 5000 lp/inch hochgenaues Liniengitter. Damit läßt sich die Auflösung hoch-
      wertiger Optiken bis zur theoretischen Auflösungsgrenze darstellen. Diesen Test kann ich auch variabel durchführen,
      mit einer Auflösung bis zu 300 lp/mm.



      Ebenfalls bei Höchstvergrößerung ein Blick auf das 1 mm Durchmesser Lichtleiter Kabel. Marsbeobachtungen sollten also
      kein Problem sein.



      Eine weitere Demonstration läßt sich über die Sternscheibchen führen. Je ungestörter und gleichmäßiger die Fläche,
      umso zonen-freier die Spiegelfläche.



      Ähnlich gute Ergebnisse liefert der Spalttest, wieder mit HÖchstvergrößerung.



      Auswertung im Krümmungsmittelpunkt: ROC. AtmosFringe kann bei dieser Art Auswertung mittlerweile die Ideal Map
      zeichnen, was eine große Hilfe bei der Beurteilung der Interferenzstreifen ist.



      Nachdem der Radius mit etwa 0.1 mm Genauigkeit vermessen war, kam bei dieser Art Auswertung das folgende Ergebnis
      heraus. Der große Vorteil dieser Auswertung: Man führt keine weiteren opt. Fehler über Hilfsoptiken ein, die man dann
      rechtfertigen müßte. Voraussetzung allerdings ist der exakte Radius im Krümmungsmittelpunkt und der opt. wirksame
      Spiegeldurchmesser. Vor allem auch ein absolut rundes Interferogramm mit einem scharf abgegrenzten Rand. Hier muß
      vorher die Eigenart der aufnehmenden Kamera genau bekannt sein.



      In diesem Zusammenhang spielt auch der Ausschluß von eventuellem Astigmatismus eine Rolle, der hier auf zwei Arten
      durchgeführt wurde.



      Bei der Auswertung in Autokollimation, Doppelpaß genannt bei doppelter Genauigkeit unter der Vorrauissetzung eines
      hochgenauen Planspiegels, ergibt sich in diesem Falle ein noch höherer Strehlwert. Durch die Ideal Map, die AtmosFringe
      mittlerweile zeichnet, sieht man sehr gut die Restabweichung der Streifen jetzt als Null-Test bei einem Scale von 0.5



      Auch hier also das hohe Strehlergebnis



      Eine Spitzenleistung für einen Sternfreund, der Qualität zu schätzen bereit ist. Die Beobachtungsergebnisse werden ihn belohnen!

      teleporttelescopes.com/Optics.html


      The Primary Mirror

      <TABLE cellSpacing=0 cellPadding=5 width=627 border=2><TBODY><TR><TD width="50%">Each Teleport Primary mirror is figured, tested, and numbered by Carl Zambuto, one of the nation’s most respected optical craftsmen. It comes to you with his personal performance guarantee and signature on a copy of the photograph below.

      </TD><TD width=200>[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]Zambuto Optical Company assures each Teleport owner of the best possible mirror. Carl is as dedicated to making the finest optics as I am to building the finest telescopes. These are simply the best mirrors available; expensive and worth it.[/FONT]

      </TD></TR><TR align=middle><TD vAlign=top align=middle colSpan=2>[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]Carl Zambuto figuring a 14.5" Teleport mirror[/FONT]


      <TABLE cellSpacing=2 cellPadding=0 border=1><TBODY><TR><TD align=middle>


      </TD></TR></TBODY></TABLE>


      </TD></TR><TR vAlign=top><TD width="50%">[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]When I got the chance to develop the Teleport as a commercial scope, I sought out a mirror maker who could provide the kind of quality I envisioned for the scope itself. I contacted John Hall of Pegasus Optics, a mirror maker with a long and excellent reputation. John wasn’t making 10" mirrors, and he referred me to an optician named Carl Zambuto, in Ranier, Washington. He said he believed Carl could provide the very best mirrors in the size range I needed. Truer words were never spoken. [/FONT]
      [FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]Carl had made hundreds of mirrors over the years, had taught workshops and won awards all over the northwest, and had just recently begun his professional career. He liked what I was doing with the Teleport, and agreed to supply mirrors to me and three other PTM’s. It's been great. [/FONT]
      [FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]As I built the series of prototypes for the 10" Teleport, improving each in every way I could, I found that Carl’s mirrors were consistently outstanding. They raised my sights for what a 10" Newtonian system could do, and made me strive [/FONT]

      </TD><TD width=200>[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]each time for a scope that would take full advantage of them. The inspiration they provided caused me to put a lot of extra work into The Teleport development, and it paid off. The Teleport’s performance grew to something well beyond my original vision, reaching a place not previously thought possible for a 10" reflector.[/FONT]
      [FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]Carl’s mirrors deserve the best from a scope. I’ve told him I think my job is to support what his mirror can do and take nothing from it. Most telescope designs do take a number of things from what could be achieved, but their effect seems small if they are using an ordinary mirror.[/FONT]
      [FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]Special things in the Teleport like the tight intercept distance that lets a high quality small secondary still give great field illumination, the light baffles and shroud, the nine point cell, the cooling fan, and many other small details make a difference when they combine with the finest mirror available. So my thanks to Carl Zambuto for what he does to help make every Teleport the best it can be.[/FONT]

      </TD></TR></TBODY></TABLE>
      Herzlichen Gruß! Wolfgang Rohr---_ email: wolfgang.rohr@t-online.de Tel: 09521 5136 ---------------------------------------------------- r2.astro-foren.com/index.php/de/
    • AW: Carl Zambuto Newton

      mag1instruments.com/testdoc.html

      <CENTER>[SIZE=+2]ZambutoOptical Company[/SIZE]
      P.O. Box 1167 • Rainier,Washington 98576 </CENTER>
      [FONT=arial,helvet]<CENTER>[SIZE=+1]An Explanation of Your Test Document</CENTER>
      Yourtest data sheet is provided to document the quality of your primary mirror. The test used to make this documentation is a zonal Foucault test made with a Couder mask. Your test document has the following information:
      • Mirror specifications: this includes your mirror's physical diameter, radius of curvature, focal length and focal ratio.
      • Couder screen dimensions: these are the parameters for the mask used to make those measurements. The purpose of form is to provide you with information about how the mirror was tested. This information makes it possible for those with a working ability to perform this test to be able to replicate the test and verify the documentation.
      • Millies-Lacroix Graph: This section contains the information resulting from the test itself. The first column is an average of four sets of measurements taken in two orientations (90° apart) over the surface of the mirror, with two sets measured in each of those orientations. The next column contains the base numbers for a theoretically perfect parabola. The third column is the deviation in each zone of the actual test measurements from the ideal.
      • Data Reduction: This section contains the results of a mathematical analysis of the information derived in the previous processes, and are described in greater detail in the paragraphs below.

      Millies-Lacroix Graph
      The first graph on your document is a parabola-removed Millies-Lacroix graph of our knife edge measurements. The horizontal axis of the graph represents the radius of the mirror from the center (toward the left) to the edge (toward the right). The numbers along this axis represent the zones, given in inches, where each of the knife edge measurements were taken. The vertical axis is the deviation in inches of knife edge travel with respect to the theoretical parabola, given in hundredths. The horizontal centerline of the graph represents a perfect parabola. The envelope created by the upper and lower lines represents the tolerance of error in knife edge measurement for the light returning from the mirror to fall within the diameter of the Airy disk. Typically, when the zone plots are measured within this envelope simultaneously, the mirror is diffraction limited. For further information on the Millies-Lacroix Method, see Sky and Telescope Magazine 2/76 for an article about determining a tolerance for Foucault testing that will result in light from each zone being reflected inside the diffraction disk envelope.
      Wavefront Profile Graph
      This is a profile of one-half of the wavefront corresponding to one half of the mirror (the other half of the wavefront will be identical). The vertical axis scale on the left side of this graph, is given in millionths of an inch, and represents the amplitude of the mirror's wavefront in height, while the horizontal axis corresponds to the outside radius of each zone on the mask. There are two marked tolerance envelopes indicated on the graph. The larger, at plus and minus 1/10 wave, and the smaller, at plus and minus 1/15 wave, which is the graphical tolerance for this mirror using this test method. Note that this graph is also a profile of the mirror's surface except it has twice the amplitude of the mirror's surface error. This being the case, with the center line being the perfect parabola, the plots on the graph indicate the surface profile of your mirror with respect to the parabola, with the exception that it is exaggerated by a factor of two.
      Relative Transverse Aberration
      This is aberration compared to the diffraction disk at focus of the mirror. Relative transverse aberration, or RTA, is perpendicular to the optical axis of the mirror, thus the term “transverse". This value is descriptive of where the light is at the focal plane with respect to the airy disk, or diffraction disk. The vertical axis of the graph, between +1.0 rho and -1.0 rho represents one diffraction disk diameter (rho is the symbol for the radius of the diffraction disk) and is the tolerance for a diffraction limited mirror as per the Millies-Lacroix method. The RTA graph also has two envelopes for perspective. The larger, indicated by plus and minus 1.0 rho represents one diffraction disk diameter. The smaller envelope is from plus to minus .75 rho and represents three quarters of the diffraction limited tolerance, which is the graphical tolerance for this mirror. To visualize how this graph represents the actual function of the mirror at focus, imagine the diameter of the diffraction disk taking up the vertical distance from +1.0 to -1.0, with the center horizontal line of the graph being the center of the diffraction disk. Then imagine horizontal lines going across the graph from left to right, one for each zone plot, with each line going through the center of its respective plot. These lines would represent rays of light being returned from the mirror, passing through the airy disk at focus. Each zone of the mirror will return a ray through the disk at each indicated plot for that zone. So these plots are showing where each zone of the mirror returns light within the disk. The greatest error on the mirror will be the zone furthest away from the center, either on the plus or the minus side. The number for that zone will be the final result number for RTA, and is provided in the results section. For example, if the greatest error were a zone at either of the two 1.0 rho lines (plus or minus), this would indicate that light from the mirror would be passing through the edge of the airy disk at focus. In this case the RTA for the mirror would be 1.0, which is the maximum allowable tolerance for a diffraction limited mirror.
      Data Reduction
      This section contains the total values for each of the criteria given. RTA, or relative transverse aberration is a ratio of the diffraction disk created by this mirror compared to the diffraction disk created by a perfect mirror in this size and f/ratio. An RTA of 1.0 or less means rays traced from the mirror would pass within the boundary of the diffraction disk at focus, and that the mirror is diffraction limited by definition per the Millies-Lacroix tolerance. The smaller this number is, the more precise the mirror is.
      Strehl Ratio
      This is a ratio expressed as a percentage of the peak brightness at the center of the diffraction disk created by this mirror compared with the peak brightness of a perfect mirror. Strehl ratio takes into account mathematically the wave nature of light and is an estimate based on the wavefront graph. It is calculated using the average of the wavefront value over the entire mirror, based on the amplitude error in all of the zones. A Strehl ratio of 1.0 would be a maximum and indicate a perfect optic. As a note, a Strehl ratio of .8, or 80% is associated with the familiar ¼ wavelength Rayleigh criteria. The methods used in your test document to calculate the wavefront and RTA graphs and the final RTA value are consistent with programs such as "Admir" by Dick Suiter (author of Star Testing Astronomical Telescopes), and other data reduction programs. The information provided on this document can be plugged into these programs with similar results obtained. If you desire further data reduction information such as a peak-to-valley wavefront ratio you can calculate it using the measurement information on this document. Several software programs are available, some as free downloads from the internet, and others of reasonable cost. In the fabrication of your mirror, every effort was made to provide you with a finest quality optic that will perform well beyond its theoretical limit. It is our hope and desire that this mirror will provide you, our customer, with a lifetime of observations of exceptional experience.
      My best to you, and clear and steady skies, [SIZE=+1]Carl Zambuto[/SIZE] [/SIZE][/FONT]
      Herzlichen Gruß! Wolfgang Rohr---_ email: wolfgang.rohr@t-online.de Tel: 09521 5136 ---------------------------------------------------- r2.astro-foren.com/index.php/de/
    • AW: Carl Zambuto Newton

      Lieber Wolfgang,
      hab vielen Dank für Deinen ausführlichen Test des Zambuto Spiegels. Hat sich also das lange warten auf den Spiegel bei Carl gelohnt.
      Natürlich soll der Spiegel speziell für Planeten eingesetzt werden. Er soll die Beobachtungsmöglichkeiten gegeben durch meinen 200mm Schiefspiegler, welchen ich seit 1986 einsetze, „nach oben“ abrunden.
      Der Spiegel wir mit einem ProtoStar Fangspiegel, 46,5mm kleine Achse ausgerüstet werden. Dies ergibt eine Obstruktion von ca. 18% vom Durchmesser. Der Fangspiegel hat 1/13 ptv waves und 1/125 waves rms. Damit ist er der ideale Partner für diesen Spiegel. Das Teleskop wird selbstverständlich parallaktisch montiert werden.

      Himmlische Grüße

      Uwe
    • AW: Carl Zambuto Newton

      Dear Alan,

      this is easily explained: The first calculation is made with a fringes map in RoC (radius of curvature) There is no obstruction in the middle of the otpical surface as you see.

      The second calcualtion is made with a fringes map in autocollimation in front of a high quality flat with a hole. This fringes map has prinziply an obstruction in the middle as any Newton or other catadioptric system and this varies the MTF graph.

      But a Newton works with the secondary mirror and therefore this is a system with an obstruction. Normally Newton systems have a certificate from the main mirror and sometimes a certificate from the secondary, but no certificate to the complete optical system in an optical tube. So you can get fringes map in three ways: (1) In RoC in (2) compensation and (3) in front of a flat.
      Herzlichen Gruß! Wolfgang Rohr---_ email: wolfgang.rohr@t-online.de Tel: 09521 5136 ---------------------------------------------------- r2.astro-foren.com/index.php/de/