Rod Pommier

“The PlaneWave L500 mount is mounted equatorially on the observatory pier via a PlaneWave Wedge. The Wedge is attached to a PlaneWave Pier Adaptor Plate, which is bolted to the concrete pier. The wedge has adjustment bolts that allow the polar alignment to be adjusted +/- three degrees in both azimuth and altitude. The PlaneWave Pointing Model software will plate solve images and determine the error in the polar alignment and advise how many turns of the azimuth and altitude adjustment knobs are needed to achieve better polar alignment. After that, the Pointing Model will compensate out virtually all errors and the L500 will beautifully center targets. Of course, with a fork mount, no pier flips are ever required.”

Rod Pommier – Pommier Observatory | Portland, Oregon USA

Rod Pommier Astrophotography

“The new imaging system in the new Pommier Observatory is a PlaneWave CDK400 system. A CDK 400 system consists of a CDK17 (17-inch) telescope mounted on an L500 mount.

The CDK17 is a fantastic telescope. It is fast, at f/6.8. The optics are truly superb. It produces a completely flat field with stunning clarity and pinpoint stars from corner to corner of my 35 mm CCD chip. It has a fused silica mirror and carbon fiber trusses that resist expansion and contraction and hold sharp focus throughout the night regardless of how much the ambient temperature changes. The CDK17 has many built-in fans that help it reach ambient temperature quickly and blow air across the primary mirror surface to remove the boundary layer of air that can blur images. I added several accessories to the CDK17, like the IRF90 rotator/focuser, the Electronic Focuser Accessory, and the Delta-T Heater dew control system. See those pages for details on them.

The L500 is an equally amazing mount. It is direct drive, so it has no gears and therefore no periodic error and no backlash. Once it builds a pointing model, it precisely centers targets on the CCD chip. It tracks flawlessly for long periods of time. Although I usually still auto-guide when there is a suitable guide star (see page on the IRF90), I can also now image subjects with no available guides star by just letting the L500 run all by itself and I still get perfectly round stars even with long sub-exposures. This enables me to image subjects I never could with my Compustar C14 due to lack of a suitable guide star. The L500 has through-the-mount cabling to prevent cable wrap.”

Check out Rod Pommier’s PlaneWave page, here!

Rod Pommier – Pommier Observatory | Portland, Oregon USA

Rod Pommier Astrophotography

“This is the new Pommier Observatory. It consists of a 10’6” diameter Ash Dome on a supporting structure building. I absolutely love this new dome. It is the real thing!

It has independent upper and lower shutters. The lower shutter covers the sky from the horizon up to 30 degrees above the horizon and I will rarely image things in that part of the sky. Therefore, I can leave the lower shutter closed and it greatly reduces stray ambient light in the dome. The shutter motors are quiet and the dome rotation motor is very quiet.

The door is below the dome and I can enter and leave as often as I want without interrupting imaging. The dome electronics keep the dome slot centered on the telescope’s position and updates every few seconds, so it tracks my targets across the sky flawlessly.

An enormous advantage of a dome observatory compared to a roll-off roof observatory is protection from the wind. Wind will not enter the dome through the dome slot, simply because it has no exit. So the telescope remains rock steady for imaging even on the windiest of nights. Wind can still hit a telescope in a roll-off roof observatory and shake it, leading to jiggly stars. Also, wind hits a flat wall of a roll-off roof observatory and creates turbulence that spills over the telescope, degrading seeing conditions. In contrast, wind will flow smoothly around the curved surfaces of a dome observatory maintaining better seeing conditions.”

Rod Pommier – Pommier Observatory | Portland, Oregon USA

Rod Pommier Astrophotography

Rod Pommier – Pommier Observatory | Portland, Oregon USA

Rod Pommier Astrophotography

NGC 6960, the Witch’s Broom (also Western Veil or Sharpless 103) Nebula is a remnant from a supernova about 10,000 years ago. Its amazing filamentary structure is due to compression of expanding shells of gas as they meet the resistance of the interstellar medium. That much of what we see as “empty” space is filled with dark dust is evidenced by there being more background stars visible below the nebula, where it has swept space clear of dust, than above it. The bright star, 52 Cygni, is a type K star and a foreground object with no physical association with the nebula but adds to the drama of the image. Please compare this image to my previous image of it taken with my Celestron Compustar C14, shown under Nebulae. The difference in sharpness, clarity, and detail is jaw-dropping.

Telescope & Mount: PlaneWave CDK17 on an L-500 mount

Exposures: Ha:L:R:G:B = 300:245:95:95:95 minutes = 11 hours, 40 minutes total exposure at f/6.8.

Rod Pommier – Pommier Observatory | Portland, Oregon USA

Rod Pommier Astrophotography

Rod Pommier – Pommier Observatory | Portland, Oregon USA

Rod Pommier Astrophotography