.. .. | |
Vir: Astronomy Picture of the Day via
AGO. translation into Slovenian by H. Mikuz. | Zvezdna karta. |
GS980-12" F/5 Dobsonian Specification: http://www.gs-telescope.com/content.asp?id=114 * 12" Parabolic primary mirror 1/12wave, BK7 glass * Focal length: 1520mm, F/5 * 2" Precision Micro 10:1 Crayford style focuser * 9 points mirror cell w/cooling fan. * Roller bearing wood base Standard accessories: * 8x50mm fully multi-coated achromatic Finder * Premium Plossl 9mm (1.25") * Premium widefield SuperView 30mm (2") * Moon filter included * 2" Eyepieces tray Teleskop Dobson GS980-12" F/5, D = 300 mm, f = 1500 mm Fokuser mikro 10:1 Crayford, 2 palca. Mehanizem za uravnavanje težišča. Azimutni krog za premikanje vilic - teflon in valjčni ležaji, zelo učinkovito. Ventilator primarnega zrcala. Okular Erfle 2 palca - gorišče je 30 mm in desno SuperPlossl 9 mm. Iskalo 8x50. Vse skupaj s poštnino vred stane 792 EUR. Teža sestavljenega teleskopa je 33 kg. ------------------ -- Aperture: 300mm / Focal length: 1500mm / Focal ratio: f/5 -- Main mirror substrate: BK7 -- Optical precision: Diffraction limited or better -- Resolution: 0.38" -- Limiting visual magnitude: 15m4 -- Max. true field: 1.8° -- Secondary obstruction: 25% -- Tube diameter: 365mm -- Tube length: 1450mm -- Tube weight: 19.5 kgs -- Rocker box dimensions: height 64cm / diameter 63,5cm -- Rocker box weight: 13.5 kgs Special Feature & Accessory Package: -- precisely figured, diffraction limited BK7 primary mirror -- computer optimized 9-point main mirror cell -- rigid metal tube for stability of collimation -- 2" Crayford focuser, dual speed 1:10. "the manufacturer's best focuser" -- powerful 8x50 finderscope, multicoated objective lens. This little telescope will show many objects in direct vision for easy location. -- 2" wide angle eyepiece ERFLE 30mm - for a very large true field of view -- Plossl eyepiece 9mm for a sharp image with medium magnification, e.g. for Planets and the moon. -- rocker-box mount for smooth movement in both axes -- innovative new friction and balance bearing in altitude. Improved functionality when compared with a classic altitude bearing. -- 94% enhanced coating for a brighter image GSO offers very HIGH quality parabolic mirrors for the people who want to build their own telescopes or DIY project. Our parabolic mirror size from 6" to 16", all of these mirrors were made by BK7 quality optical glass and all the mirror surface quality over 1/16 wave RMS at the least, typically better. All mirrors have an aluminum reflective coating, reflectivity is approximately 93%. The aluminum coating is protected by a properly applied protective coating (SiO2). Any custom made parabolic mirrors should be welcome! Item No. Aperture Focal Length F/Ratio Thickness Material AD096 153mm 600mm F/4 20mm BK7 AD046 153mm 750mm F/5 20mm BK7 AD045 153mm 900mm F/6 20mm BK7 AD131 153mm 1200mm F/8 20mm BK7 AD048 200mm 800mm F/4 25mm BK7 AD049 200mm 1000mm F/5 25mm BK7 AD082 200mm 1200mm F/6 25mm BK7 AD094 250mm 1000mm F/4 35mm BK7 AD081 250mm 1250mm F/5 35mm BK7 AD095 304mm 1200mm F/4 35mm BK7 AD017 304mm 1500mm F/5 35mm BK7 AD015 406mm 1800mm F/4.5 45mm BK7 Za PV je 1/12 velja strehl 0.978. BOMO POMERILI !!!!!!!!!!!!!!!!!!!!!!!!!! PV PV RMS Strehl razmerje dec. PV/3.5 ----- --- --- --- 1/12 .083 .024 .978 odlično 1/16 .0625 .0178 .987 odlično Približno velja za Strehl: Strehl = 1 - (2 pi * RMS)^2 Spodaj so ostale vrednosti. PV PV RMS Strehl Kvaliteta razmerje dec. PV/3.5 ----- --- --- --- ----------- 1/3 .333 .094 .71 1/4 .250 .071 .82 Rayleighjeva limita 1/5 .200 .057 .88 1/6 .167 .047 .92 dobro 1/7 .143 .041 .94 zelo dobro 1/8 .125 .036 .95 odlično 1/9 .111 .032 .960 odlično 1/10 .100 .028 .969 odlično 1/11 .091 .026 .974 1/12 .083 .024 .978 1/16 .0625 .0178 .987Prvi vtisi o teleskopu GS980-12" F/5 Dobsonian
V soboto, 4. avgusta 2012, sva s Klemnom v bližini Umaga postavila Luntov H-alfa teleskop in po ugotovitvi, da je pogled skozenj precej spektakularen, sklenila, da bova poskusila Sonce tudi narisati. Ker je pripeka ob treh popoldne nevzdržna, risanje pa ni ravno kratka aktivnost, sva si nad opazovalnim mestom najprej napela vrv in s posteljnim pregrinjalom, majico in brisačo improvizirala nekakšno opazovalnico:
Nato sva se lotila risanja, ki je vsakemu od naju vzelo približno pol ure. Rezultata sta bila takšna:
Že na licu mesta, še bolj pa po povratku v Ljubljano, sem se spraševal, kako točne takšne risbe pravzaprav so. Utrnila se mi je ideja in s spletnega arhiva posnetkov sonca v H-alfa sem pretočil posnetka, ki sta časovno čim bolj ustrezala najinim risbam (Sonce se dejansko zelo hitro spreminja – ogromen filament, ki se je tistega dne raztezal preko njegove ploskve, je imel ob koncu polurnega risanja občutno drugačen videz kot na začetku).
Opomnim naj, da sta najini risbi zaradi opazovanja skozi prizmo zrcalni glede na resnično stanje. Zgornja posnetka sem nato »masiral« v programu Gimp toliko časa, da sta bila vsaj približno podobna risbam (to je zahtevalo nekaj inovativnih pristopov in bi se morda dalo narediti tudi na lažji ali boljši način). Končno sem vsak par risbe in posnetka spravil v GIF animacijo, na kateri se zelo dobro vidi »risarska transformacija«:
Zanimiva vaja bi bila izumiti še postopek v obratni smeri: kako iz risbe dobiti nekaj, kar bo čim bolj podobno resničnemu posnetku. S tem pa se mi tokrat ni dalo ubadati in izziv do nadaljnjega prepuščam komu drugemu. :-)
|
|
|
DOMAČA STRAN AKGŠ NEPREKINJENO DELUJE ŽE OD LETA 1995! Čestitke ali - zvezdi siizmenjujeta gravitone. Nekaj zanimivosti iz zgodovine strani! |
Za astronomski krožek: ZORKO Vičar
E-POŠTA, RFC-822: Zorko.Vicar@guest.arnes.si