Observing

I am sure every sky-watcher can recognize CORONA BOREALIS, the beautiful constellation of the Northern Crown found in the spring sky, rising high in the East after dark.

After many years at minimum brightness (and I mean as faint as magnitude 15), the variable star R Coronae Borealis is slowly brightening again. If you have binoculars, you can watch it brighten slowly this spring until it reaches magnitude 6 again.

R CrB variables are normally bright, but can accumulate a cloud-like covering of carbon. Until that carbon shell is burned off, these stars can be dimmed up to 10 magnitudes. This star has a habit of dimming and then regaining its brightness within a few months.

Strangely, since 2007 R CrB has been only 1/10,000 its normal brightness. Moreover, whereas R CrB usually springs back to magnitude 6 quickly, this latest recovery is taking a long time. The AAVSO chart below graphs R CrB's visual brightness for the last 10 years. You can see the star's swift dip and recovery in 2003, contrasted with the several years at minimum and the most recent - very slow - recovery.

This is a star worth watching again!

This evening Jim, Mario and I had the opportunity to test out the new loaner scope that has been donated to the club. It's a 90mm achromat refractor from Skywatcher on an alt-azimuth mount with slow motion controls and a couple of eyepieces.

There was a light cloud but Jupiter proved bright enough to shine through. Often this can enhance planetary views, as the clouds cut down on glare. The seeing was quite steady and the scope proved worthy.

Using eyepieces of 25mm, 12.4mm, 9.7mm and 6.4mm we were able to obtain a variety of magnifications. The scope held up well even with the highest magnification of about 150x. Jupiter showed all four moons on one side of the planet, with one quite close to the planet's limb. Jupiter itself showed both equatorial belts, the temperate belts, darkening at the poles and the red spot. Detail was visible in the main belts, and the views were very pleasing. One aspect that could use improvement is the diagonal. The scope came with a correct image Amici prism, which is great for terrestrial viewing, but doesn't give as good a view as a good quality right-angle diagonal. Maybe somebody out there has a spare that can be used with this scope.

All three of us were very satisfied with the new scope. This is a truly fine beginners scope. The clouds prevented us from any other observations, but I'm sure that those who are lucky enough to use this scope under the loaner program will have many enjoyable views.

The Taurids Meteor Shower is nearly here, and although it is a fairly weak shower, the meteors that you see are likely to be good ones. With two streams of meteoroids to pass through, we should see a peak on the night of November 4th and then again on the night of the 11th. Since they are faily broad streams that we are passsing through, you may see the shower as a very long but weak one lasting most of this week.

The Taurids are rather slow moving but large meteors, so they tend to look slow and bright in the sky. This shower produces a fairly high proportion of fireballs. You never know when you might see a meteor that will be the talk of the next meeting, so get out and observe the Taurids!

Later this week will see the peak of the Orionid meteor shower. Although you can see a meteor any night, meteor showers are caused when the Earth passes through the debris left behind after a comet passes. In the case of the Orionids, the source comet is Comet Halley. In a way, this is your chance to see Halley's Comet!

This year a fairly weak showing is anticipated because we are expected to pass though a particularly thin part of the debris trail left by the comet, but take heart! Not only is there a fairly small moon for this year's shower, meaning a fairly dark sky, but the Orionids are known for producing bright meteors, so the few that we get could be good ones! (and let's face it; meteor showers are somewhat unpredictable, so even though we expect a weak show this year, that is not a guarantee. Anything could happen!)

Although the shower doesn't hit its peak until Saturday night (October 20th) the Orionid shower is rather spread out, so you could see meteors any time this week or next. Enjoy!

Comet Hergenrother has unexpectedly brightened to about 9th magnitude and should be visible in small telescopes or large binocs. More information, including a finder chart and co-ordinates for the comet can be found here:

Comet Hergenrother

Update October 12 - took some unguided images of the comet tonight from the backyard using our 7" refractor and a dslr. The image below is cropped from a single 1 minute exposure. The comet is small, dim and star-like. I could not see it at all in the binocs.

Comet Hergenrother - October 12, approx 10:30pm