25 January 2009

IYA2009, Venus, new Barlow, & Turkeys


The above photo was taken yesterday through a window (two panes of glass and a screen). The three turkeys are shown at the base of a tree where a couple of bird feeders are hung. The turkeys seem to be attracted to the seeds that are scattered about on the ground. The same three turkeys have been dropping by for the past week. They tend to not trust humans and quickly run away if anyone ventures outside.

Orion's new 5x HighLight Barlow: As with most products, this one has some strengths as well as some weaknesses. I've made extensive notes concerning the barlow's performance. I checked out vignetting and kidney-beaning in the daytime with all of my 1.25" eyepieces. Color correction was checked out (with good results) on Venus using a high quality telescope. The magnification factor was checked with a Celestron Micro-Guide eyepiece . . .

This barlow is not threaded for filters. I found it helpful to add a ring of tape around the barrow in order for it to seat a bit better when inserted into an eyepiece holder. The set-screw that tightens and loosens the clamp that secures the eyepiece in the barlow has unusually coarse threads. One needs to be careful not to loosen it too far - else the set-screw may fall to the ground. There's a limit to how far an eyepiece may be inserted into the barlow before encountering a smaller diameter obstruction (I don't have my notes handy at the moment to provide the actual limit). Most, but not all of my eyepieces could be inserted all the way into the barlow.

If I get ambitious I'll do a reasonably detailed review at some future date. I would like to do a little more testing on the moon and/or planets under good seeing conditions. So far I'm satisfied with the barlow's optical performance. I don't find the various drawbacks to be overly severe. This barlow was purchased primarily for use with my Micro-Guide eyepiece to provide sufficient magnification to better make measurements of double stars, etc. It looks like this barlow may prove beneficial for other purposes, such as lunar and planetary observing, as well.

Venus is looking good! This planet is very well positioned in the evening sky for northern hemisphere observers. The planet's phase is slightly less than quarter. I've made a couple of Venus observations this year. A #58 green filter was used for sketches, but the filter was removed to check out the 5x barlow's color correction. I was easily able to spot the planet with the unaided eye shortly before sunset one evening.

2009 is the International Year of Astronomy! Four hundred years ago, in 1609, Galileo began his ground-breaking adventures in telescopic astronomy.