Author: Roland Roberts

Okay, I’m a physicist, but I kinda slept through the optics part, so I’m okay on the concept of dispersion and having index of refraction being a function of wavelength, but I’m a little weak on just what that Abbe number means in absolute terms. But I do know bigger is bettter (as far as …

Eyeglass Material II, Abbe NumbersRead More

I took a trip to my local optometrist this afternoon as I need new glasses. Having joined the over-40 crowd a few years ago, I’ve taken to wearing bifocals. I gave up on the progressive lens version as I simply couldn’t get used to them. That’s apparently a common problem, but annoying to find out …

Eyeglasses and DispersionRead More

Okay, this is not an astronomy topic, but I got stumped on this for a long time and searching the web, while helpful, didn’t make it exactly obvious. Why would you even want to change GID or UID? Well, I needed to synchronize UID and GID with my NFS server for file sharing. We have …

Changing UID/GID on Mac OS X 10.5Read More

I’ve been busy not writing (that is, doing other things) and have discovered that Linux can control both of my Canon Digital Rebels at the same time. It turns out there is a bug in gphoto2 that ignores the –port setting if you didn’t also supply a –camera setting. If you supply –camera, you must …

Canon DSLR and Linux IIRead More

Well, in the past couple of days I got both a pleasant surprise and a bit of a let-down. First, I discovered that sometime in the past year or two, the gphoto2 folks have been very busy with Canon DSLRs. They’re reasonably well supported (in spite of what appears to be a lack of any …

Canon DSLR and LinuxRead More

I reassembled the wiring harnesses for my equipment along more functional lines. I had put things together by type of connection which was pretty silly in hindsight. So now I have two four-cable harnesses for each Canon 350D (one DC power line, one serial line for the shutter release, one USB connection, and one heater …

Getting Ready for Summer Star PartyRead More

Despite the full moon, I got out with my AstroTrac, modified Canon 350D and Borg 45ED. With the light-polluted skies of NYC, I put a Lumicon H-alpha filter on and shot as low as ISO 100 in order to test with 5-minute exposures. The conclusion?

Well, I managed to get out and use my AstroTrac under reasonably dark skies just north of Cape Girardeau on the night of July 13/14. The moon didn’t set behind the hills until around 1:30 am, but I shot across the sky from it at M31 using my Borg 45ED. I used the laptop for …

Disappointing AstroTrac First UseRead More

Well, Richard Taylor of AstroTrac got my polar alignment scope back to me before we left on vacation. Alas, the new scope has the same image scale problem as the old which makes it a bit difficult to align. Not impossible by any means, just more difficult. So I packed everything up and carried it …

AstroTrac and CanonRead More

Back at NEAF, I purchased an Astrotrac unit hoping to put it to good use for wide-field astrophotography. I had been looking at the unit for the past couple of years since it first showed up in a few magazines and saw the early units at NEAF. So finally I got my own. I got …

Astrotrac WoesRead More