April Cover24-27 - Astronomy Technology Today

OPT AND PENTAXAdapters for US AstronomersAll of the Pentax Refractors distributed in the U.S.include an adapter chain that will go from the focuserdown to a 1.25-inch interface. This system reachesfocus only when 1.25-inch eyepieces are used in astraight through orientation. Knowing that most amateursprefer to be able to use a diagonal, we quickly realizedthat adapters would need to be fabricated for thispurpose, since they were not available from PentaxJapan. Consequently, OPT developed three adapters forphoto and visual use of the Pentax Refractors.Two of the adapters act as sleeves, stepping downfrom the 60.2-mm female interface, found in the standardfocuser adapters, to either a 1.25-inch or 2-inchfemale interface. This allows your current 1.25-inch or2-inch nose pieces, whether from camera adapters ordiagonals, to be used with the Pentax Telescopes. Thesetwo parts are the only way of using the Pentax 75SDHFwith diagonals; no other non-custom parts will allowfor infinity-focus to be reached. These adapters can alsobe used with the SDP series, and the 60.2-mm(1.25-inch) adapter is compatible with the 100SDUFII.The third adapter is a 2-inch photo/visual backdesigned to thread into the 84-mm thread used in thestandard adapter chain of the 100SDUFII, 105SDP,and 125SDP. This part is the only means of reachinginfinity focus with the 100SDUFII when using a 2-inchdiagonal and a 2-inch eyepiece. However, it is also themost practical and secure way of attaching any heavy2-inch nosepiece accessory to the SDP series.The Pentax line is available in North Americaexclusively through OPT at www.optcorp.com.All images wereshot by Eric withthe 100SDUFII.The top imagewas taken with aST-2000MX withAstonomik 13 nmH-alphafilter, and was3x20 minutes.The other twoimages are 3x10with a CannonEOS 20Da.TOP Rosette NebulaCENTER Trifid andLagoon NebulaRegionLEFT Pentax100SDUFIIBOTTOM LEFTSagittarius StarCloudAstronomy TECHNOLOGY TODAY 27