Astrophotography Equipment

Optics

Canon EF 200 F/1.8L camera lens. Now out of production. Built-in 48mm filter holder. Camera rotation ring built into lens tripod mount. Usable fully open @ F/1.8, but with some loss of sharpness traded for the short exposure times. Field is very flat and stars are consistent in size and shape from center to corner of APS-C frame at all f-ratios. Bright stars at F/1.8 appear slightly triangular at 100% resolution - this effect is overtaken by diffraction spikes at narrower apertures. The maximum number of stars detected for a given exposure time peaks at F/2.8. Sharpness does not improve appreciably past F/4 - F/5 after which diffraction effects come into play. Relative exposure times compared to F/1.8 are x2.5 for F/2.8, and x5 for F/4 - a heavy price to pay for the resolution improvements. This is especially true for Ha filtered shots that don't suffer from chromatic aberration. Sharpness test figures are: F/1.8 ~2.04px FWHM, F/2.8 ~2.00px FWHM, F/4 ~1.93px FWHM (6.4uM pixels). Results based on best of 3x15sec IR cut filtered exposures of Pleiades at each focal ratio, using CCD Inspector for analysis. Strong vignetting at F/1.8, mimimal at F/4.

Borg 101ED F/6.4 native. F/5.4 with flattener/reducer. Ultra-portable, lightweight and modular 4" telescope.

Meade ETX90

Camera

Hutech modified Canon 20D DSLR. IR cut filter removed and replaced with clear filter. 8.2megapixel 12bit RAW resolution. Serial port based shutter control cable. Christian Buil provides a good technical overview of the 20D here.

Filters

Mount

Takahashi EM10 Temma 2 Jr

Guider

SBIG STV with efinder

Aquisition and Image Processing Software

SkymapPro 11 with Chuck Faranda's ASCOM Temma telescope driver

Mike Unsold's ImagesPlus

Adobe Photoshop CS, with Russell Croman's GradientXTerminator plugin

Paul Kanevsky's CCD Inspector

Auriga Imaging Registar

Observatory

Pulsar-Optical 7' Dome