Dave Wallace's Adventures in Astronomy

10/13/2003 2300 UTC

I got set up around 7:20 EDT. It was already dark enough to sight Polaris by then so I didn't have to mess around with the magnetic compass and correcting for deviation.

First stop was Mars, shining brightly in the south, nearly at culmination. "GOTO Mars" overshot by around an hour of right ascension. Hmm... checked the time and daylight savings time setting -- nope, not wrong. So I did a local synchronization step (which makes the computer point more accurately in the area of the sky near the object synchronized to) and watched the Red Planet for a bit. Not a lot of detail visible, just one dark band running diagonally from the two o'clock to the eight o'clock position (NW to SE, given that my view is reversed left-right). The whole planet was pretty bright, so I couldn't tell if the polar cap was visible or not and I didn't want to drag out the moon filter because...

Next stop was Uranus. This planet is quite close to Mars in the sky at the moment. "GOTO Uranus" brought the seventh planet into the field of the 26mm eyepiece. Although this planet is technically a naked-eye object, I can't see it even if I knew exactly where to look due to the light local pollution. (Uranus is magnitude 5.8 at the moment. I have trouble seeing stars dimmer than about magnitude 4.0.) At 48X, the planet was almost indistinguishable from a star, but it did show a sort of turquoise blue shade. At higher power (I went up to 83X and probably could have gone to 96X), it shows a barely-discernable disc.

Cygnus was pretty much dead overhead by then (around 8 PM). Given the way the finder scope mounts on my OTA, when an object is near zenith there's just about no way to get your head around the finder. So I decided to pass on looking at Albireo this time.

But in wandering around in my star chart program, I'd noticed that there was a multiple star system in Cassiopea -- Eta Cassiopea, to be precise -- that has a nice mix of magnitudes. Knowing that the GOTO was iffy, I decided to first stop at Shedir and synchronize. Good thing, too -- the GOTO was off by around ten degrees. Anyway, with that minor detour out of the way, I got the scope onto Achird, which is listed as magnitude 3.5. The other components run from 7.3 to 11.8, with separations from 13 to 690 arc-minutes and position angles all over the place. I should probably have printed a map, but I did see at least three of the stars in this complex system.

As long as I was in the neighborhood, I set up to do Dr. Clay's Autostar Guided Tour of Andromeda by doing a GOTO on Alpheratz and synchronizing. Then I started the tour. I found nearly all the objects listed as "visible in ETX90 or below". The only ones I missed out on were the deep sky objects, with the exception of M31. M31 appears as a faint yellowish fuzzy oval about 1/4 of the field of view in the 26mm eyepiece. I switched to the 40mm eyepiece and the view was somewhat better -- still about 1/4 of the field, so I was actually seeing more of the galaxy.

One object on the tour was a nice-looking double: Almaak. This is similar to Albireo, in that it is a yellow-orange star and a blue companion. But the two stars are mismatched in magnitude: the brighter star (yellow) is magnitude 2.3, whereas the dimmer is magnitude 5.0. This makes an even more striking pair than the nearly-equal-magnitude pair in Albireo.

There was another nice (though faint) double on the tour, rather close and equally bright (mag. 6.1 and 6.7, separated by only 17 minutes): 59 Andromeda.

By then, the moon had risen. So I decided to do the Guided Tour of Cassiopea. I started to slew and all the lights went out on the Autostar keypad. Oh-oh: battery level? The scope got back to Shedir, more-or-less and I did a battery check. Sure enough: down to 50%. Since I didn't want to possibly corrupt the Autostar by having the battery drop out while slewing, I figured it was time to pack it in. I aborted the tour and parked the scope. End of session at about 9 PM. Dew was just beginning to accumulate on the equipment by then, so I probably didn't lose more than a half hour of observing time anyway.

Bottom line: I need to figure out why the GOTO is off by around 10% and fix that. Otherwise, operating with the Autostar is not much better than star-hopping manually. Which is not what it's supposed to be like. Maybe I can debug this in daylight; we're going to have a couple of days of bad weather. I don't understand what can cause the overshoot in RA that I'm seeing: location and time are correct. The only other possibility I can think of is that the RA gear ratio setting is incorrect or I need to re-do the Calibrate and Train Drives steps.

I must remember to replace the batteries before my next session. (That's another thing I need to look at: I can't operate off the car battery because the Autostar does "random slews" when I do -- "random slews" is supposed to be a symptom of an electrical noise problem in the motors. I'll probably have to open up the motor assemblies and add transient suppression networks.)