TeleVue NP101is Imaging System, Nagler-Petzval-Apochromat 101 mm f/5.4
The NP101 (540 mm, f/5.4, 4") maintain their optical specifications yet with redesigned 4-element optical systems. Larger rear lens groups absolutely minimize vignetting in formats up to 50 mm diagonal. For these large chips an optional field corrector was developed so the corners would virtually be as perfect as the center of the field.
In order to take full advantage of the larger lenses, a non-vignetting focuser was developed to prevent any restriction of the larger converging light cone. The draw tube has a 3" front aperture and 2.4" rear aperture. This draw tube also permits quick change from visual to imaging operation and allows full camera rotation without focus change. In addition, it has the capability to correct for any residual focal plane tilt and accepts a "position stop" for TV´s digital micrometer to allow repeatable focus measurement to 0.0001".
To maintain squareness to the optical axis while changing camera orientation, the draw tube has four lock screws that tighten against a taper on the "imaging insert" ring. This insert is threaded to accept Tele Vue´s Imaging System accessories including large diameter extension tubes, optical accessories, and camera and CCD attachments, all with mating threads.
The Focusmate planetary ball type reduction focuser provides extremely sensitive focus adjustment, measurable with the optional Digital Micrometer Kit to better than 1/10,000". Also, the optional Focusmate Driver permits electronic motor control of the focusing process. The Focusmate Driver has direction push-buttons and adjustable speed. A tap on the button permits vibration-free focusing in steps as small as approximately 0.0005". The Focusmate Driver can be remotely computer controlled with Focusmaster Computer Interface.
Astrophotographic results obtained with this telescope on Astrobin
Here you can find some astrophotographs made with this telescope model:
Link to AstrobinOptional accessories from TeleVue:
B. LMK-2404 Digital readout kit for computer
C. 2" EVERBRITE Star diagonal mirror
D. FDR-2001 Motor focus
E. LCL-1069 Large field corrector LCL-1069
F. NPR-1073 0.8x reducer for medium size sensors
G. AFT-1105 Adapter for 2" filter
H. AD2-1110 Apogee U47 D2/Yankee Robtic adpter
I. AD7-1111 Apogee U9000/U16 D7/D9 adapter
J. STL-1071 SBIG STL adapter
K. TRG-1072 Standard T-Ring adapter
L. CWT-2070 Canon Wide T adapter
M. A2A-1107 2" accessory adapter
N. TLX-1108 Adapter for SC thread
O. TLA-0250 Extension 6.3 mm
P. TLB-0375 Extension 9.5 mm
Q. TLC-0500 Extension 12.7 mm
R. TLD-1000 Extension 24.5 mm