Comet Lulin (C/2007 N1) 22 Feb. 2009

The above sketch shows the full-field view I had of Comet Lulin last night with 25x100 binoculars. Comet Lulin was easily visible to my unaided eyes from my dark-sky (Naked Eye Limiting Magnitude 6.5), rural location. North is up and east is to the left in the sketch. The field of view is approximately 2.3 degrees. From a dark sky any pair of binoculars will provide a pleasant view of Comet Lulin.

I've been observing this comet for a while now, but this is obviously my first blog entry on our latest celestial visitor. There's just so much to do these days . . .

Venus & Pythagoras

The above photo shows our visiting wild turkeys on the run. I like this photo for showing some of the resemblance between wild turkeys and their T-Rex and velociraptor relatives. Really though, I felt like showing something but didn't feel like putting in the work to polish up the evening's astronomical sketches.

Venus was easily found with the unaided eye shortly before sunset. I took out the 60mm refractor and made a more careful (than last time) sketch. This time I recorded some background colors to give a better idea of the visual impression of the planet as seen in the small, low-cost telescope. I might upload a sketch later . . .

Pythagoras is a large, 130km wide lunar crater. It was prominent (and greatly foreshortened) along the terminator of this evening's gibbous moon. Pythagoras's central peak was very obvious, standing out as a bright notch in the non-illuminated portion of the crater. The nearby 144km wide crater Babbage, with Babbage A within its border, aided in positively identifying Pythagoras.

I have only one 0.965 O.D. eyepiece -- the size that fits the 60mm refractor's diagonal. Therefore I'm currently restricted to using only one magnification (28x) with this telescope.

Venus - 02 February 2009

The above sketch of Venus depicts the general appearance of the planet on 02 February 2009 at 0:40 UT at about 30x with a 60mm f/11 achromat. West is to the lower left. North is to the upper left. Of course, at 30x the planet didn't look as large as it appears above, but the fat crescent was none the less sharply defined and easy to see.

Interestingly, a 60mm f/11 achromat is virtually free of false color at 30x. Venus as well as our own crescent moon were sharply defined with little false color (chromatic aberration). Galileo would have loved to use a telescope like this!

It was unnecessary to provide any specific cool-down time for the small refractor. The outside temperature was about 40 degrees (F) cooler than the inside temperature. Yet the image was sharp and crisp when I looked into the eyepiece. Smaller telescopes have some disadvantages, but they also have their advantages!

Meade Model 226 60mm Refractor

Shown above is a newly acquired, old, Meade model 226, 60mm alt-az refractor. I had to replace seven missing screws of one kind or another. When acquired, the scope was in its mount backwards. That situation was remedied prior to taking these photos. The prism diagonal had to be removed for a proper cleaning. Somewhat surprisingly, all optical surfaces were totally without visible scratches!

This fixer-upper scope will be used partially for educational purposes (how to make the most of the least, etc.) and partially for me to take notes and make sketches regarding what can be seen with such a telescope.

Note the stopped-down aperture of the finder: The purpose of a stopped-down aperture is to mask aberrations (distortions) that would otherwise be visible when looking through a telescope that has a poorly designed objective. Such finders can be useful under daytime and twilight conditions, but used under a dark sky for anything other than the brightest of targets they can become liabilities. I found it easier to see poorly illuminated terrestrial objects with the naked eye than with this finder! If your child's telescope has a finder like this I would suggest replacing it with something more useful such as one of the many 1x red-dot finders (or a 5x24 finder that is not stopped down) that are available now.

I'll keep the original finder on this scope for educational purposes and for those occasions when it remains of some use. An experienced observer would have little difficulty in sighting along the primary scope's tube to successfully point it as long as the telescope's magnification isn't too high, but a child might easily become frustrated without a more useful finder.

The telescope's objective is clean and scratch free, though when the scope was first acquired the objective was filthy!

At some future date, when weather and time permit, I hope to re-paint the telescope, re-finish the wood tripod legs and make some final tweaks to enhance the scope's usefullness.

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.

Measuring the Sky

Above is a sketch showing approximately what's seen when one looks through a Celestron Micro Guide eyepiece. The linear scale has a real length of 6 millimeters. Adjacent scale divisions are 1/10 of a millimeter apart. I'll be using the Micro Guide eyepiece to make a variety of measurements while using Excalibur - my 13cm refractor.

The separation distance between scale divisions will of course vary depending upon the magnification that the eyepiece provides with a given telescope. My measurements indicate that the divisions are about 24.80 seconds of arc apart when the eyepiece is used with Excalibur without a barlow. With my three barlows the divisions become 11.06, 10.36, and 7.84 arc-seconds apart.

The linear scale will be used to measure linear distances such as the separation of double stars. The outermost circular scales will be used to measure position angles.

I was stricken be a sore throat on the 5th of October. Some congestion and an occassional cough remains. Hopefully it's not progressed to bronchitus or pneumonia. Currently I'm not sure if this situation is getting better or worse, but at the moment I'm feeling healthier than I was earlier. I might be feeling up to at least a brief observing session tonight. I stepped outside this morning in time to catch sight of Saturn in the east-southeast with the unaided eye.

RA 20h 40m to 21h 00m, Dec -09 to -15

Last night I observed and sketched two double stars as well as M72, M73, and an un-named (as far as I know) small asterism similar to M73.

The session actually began with a sighting of the International Space Station gliding across the sky. The ISS appeared to be somewhat brighter than Jupiter -- a rather brilliant, white, moving light in the sky. Of course, as the ISS entered the earth's shadow it rapidly dimmed.

The seeing was 'good' -- a '6' on the modified Pickering Scale. I used 477x for the seeing check.

My NELM was 6.5.

Observations and sketches were all made at 135x, though other magnifications were used at times.

RA 20h 20m to 20h 40m, Dec -09 to -15

The mushroom cloud shown above was visible in the west this afternoon, but fortunately the smoke drifted south of me and the fire may have been successfully supressed by nightfall. The photo is an enlarged (and somewhat enhanced) portion of the original telephoto. The fire was not as close it may appear above. My sky appeared to be 'crystal clear' by the time I had begun my observing session.

In this region of sky (see title) I observed, split, and sketched seven double stars in the course of a little over an hour with the 13cm refractor. One was particularly nice, showing some color at low power. Another was a particularly close 'split'.

Seeing was much better on this evening (Tuesday evening, September 30th locally or October 1st UT) than it was on the previous evening. I rated it as being "Excellent" -- an "8" on the modified (for a 5-inch scope) Pickering Scale.

RA 20h 00m to 20h 20m, Dec -09 to -15

Four double stars were observed, split, and sketched in this region of sky last night. Seeing was 'good' (a '6' on the modified Pickering Scale). Temperature was +52 degrees F (+11 C). The 13cm refractor was used on an equatorial mount with clock-drive engaged.

My long-term goal: to cover the entire sky visible from my location - recording all visible objects of interest using my 13cm refractor. This isn't a new goal. Instead it's a revision of an earlier goal with a bit of modification. Time will tell if this 'new' program can stay alive.

Polar Doubles Revisited

Last night I re-observed the double stars listed in my previous blog entry. The seeing was a bit better this time around. Sketches, with north carefully noted, were made of all five double stars. A magnification of 135x was used for all of the double star sketches.

Prior to the double star observations I trained the scope on Jupiter -- as an object to focus on prior to adjusting the scope in its cradle. Balance is more sensitive for my home-made alt-az mount than it is for my equatorial.

As the bright twilight gradually faded, more stars popped out in the vicinity of Jupiter. A sketch was made at 43x of Jupiter, its moons, and some of the background stars. The seeing varied from poor to extremely poor at this point in time, but it had improved noticeably by the time I trained the 13cm refractor on the double stars.

My work schedule prevents me from making a more detailed post or refining and uploading sketches at this point in time.