View Full Version : Comet 17P/Holmes and the 13mm Tele Vue Ethos, 2007/11/7

Dave Mitsky
2007-Nov-08, 06:06 PM
I observed Comet 17P/Holmes again last night from a location near my residence, first with my Burgess Optical 15x70 binocular and then with my 101mm f/5.4 Tele Vue refractor. Conditions were quite good at first but later the transparency started to degrade a bit and frost began to form.

The binocular framed the comet quite nicely with Mirfak, Delta Persei, and Melotte 20. The coma seemed fairly uniform through the binocular, with perhaps a hint of a central brightening.

As it so happened, this was first light for my 13mm Tele Vue Ethos with that particular telescope and the view through the Ethos was simply outstanding. I also used my 35mm TV Panoptic, 19mm TV Panoptic, 13mm TV Nagler T6, 8.8mm Meade UWA, 5mm TV Nagler T6, 4mm Burgess Optical/TMB Planetary Eyepiece, and 3-6mm TV Nagler zoom. This was the first opportunity that I've had to directly compare the 13mm T6 with the Ethos and it was amazing just how small the 82 degree AFOV of the Nagler seemed in comparison to the 100 degrees of the Ethos.

The coma seemed even more uniform than the last time I had seen 17P/Holmes, which was on Sunday night. I could only make out the comet's pseudonucleus at higher magnifications. The coma almost filled the 22' true field of view at the 4mm setting (135x) of the Nagler zoom and more than filled the 17' TFOV at the 3mm setting (180x). No trace of the faint outer halo was detected.

I also viewed M31, M32, M41, M42 and the rest of the Sword of Orion, M45, M110, the Double Cluster, Stock 2, and a few other celestial objects, with the Ethos excelling once again, before calling it a night.

Dave Mitsky