Saturday, January 20, 2007

20070117 - Rasky Tables

Session name: 20070117.2035

Since 2003 I purchase the Royal Astronomical Society of Canada Observer's Handbook from John Pazmino. I see it often referred in print as the "OH" and hear it called the "Observer's Handbook", but for reasons unknown or forgotten I call it "Rasky". The 2003 copy has a few notes scribbled in on the margins of some All-Sky maps. That copy timestamps the year when my earnest observing program began in the Fall.

2003. October 2003. (in the same vein as Bond.)

In the following years, checkmarks accompany notes in the margins of two sections in the Chapter NEBULAE AND GALAXIES, both written by Alan Dyer. The sections, The Messier Catalogue & The Finest NGC Objects, contain tables organized by season. I use them as convenient checklists for DSO objects observed. The intent is to check off objects observed only from TotL.

With this in mind, I planned to journey in the Winter Sky led by Rasky. The Messier objects in the table listed are, in order of right ascension reading columns across:


Three objects in the list above are very challenging. I won't call them impossible because two of them just required larger optics to finally get captured. From the middle of Central Park I have seen all but M1, M46, and M78 with the Takahashi 4" refractor. It took the Teleport 10"reflector to add green ticks to M1 and M46. To date, I have not observed M78 from TotL or anywhere else. Most of the open clusters, except M46, have been observed in optics as small as 7x50 binoculars, even handheld.

My favorites on the list are M1, M42, and M37. Noteworthy is the background Milky Way sky around the Aurigae clusters. We can't see, at least haven't seen, the Milky Way from TotL but in the eyepiece I can see and feel the grainy, whitish, background. I don't know if I would use the word nebulousity but I wouldn't hesitate to call the sky crunchy.

This session I was surprised not to have resolved M1 confidently. Similar to a session in late December with Kin, I suspected a spot in the 1.1° field of view at 75x. Even though I sketched it where I thought it to lie relative to the field stars, I can't say I absolutely saw it. There have been only two TotL sessions that M1 was positively observed by myself and others, no filters in each case. M78 continues to remain quieter than contrast permits.

M46 strikes me as similar in character as M37 though fainter and slightly less dense. They are both pretty large and rich with faint stars. At 25' that is just smaller than the Full Moon. In all my TotL observations, the planetary nebula, NGC2438, in northern part of M46, escapes detection. I can recall sessions at the other end of the lawn, TPO, where Ben & I would scour the sky around M47 hunting for this cluster. There is a distinct obvious red star on the trail between the two but the other end was always empty, until TP10's glass turned on it. I have since returned with the 4" only to resolve the 2 or 3 brighter stars that lie in a NW-SE line on the SE edge of this cluster. Without having seen the cluster, the faint light of the hundreds or thousands of stars that expresses this type of nebula, resists discovery.

I bounced around the sky a lot. In spite of the absence of other TotL'ers, about a dozen and half people still passed by, stopping to have peeks through the scope. Early on M41 or M42 were the two objects I put most in the eyepiece and I provided the soundbite of "the leaves in the river" description for open clusters or the stellar nursery for the Great Orion Nebula. Later, others would be treated to a marvelous view of Saturn with 3 moons aligned to the west. In all 5 moons were observed including Enceladus hugging the inside track almost in line with Tethys, Dione,and Rhea. The disk's shadow becoming a black hairline but still greater than fine line of Cassini Division. (Is opposition close?) Since I was in Leo at one end of the Sickle, I pushed the scope up to the other end, checking on NGC2903. I took in the view of a very small, very dim, low contrast nucleus but didn't dare share this after showing Saturn.

Occasionally, I deviated from the Messier list observe other nearby NGCs. Leaving M35, a worthwhile open cluster in both bins and scope, I pulled the scope down and nudged it east to NGC2392, the Eskimo Nebula, treating my eye to color and the blinking effect. From M93, I pushed the Dob west into Canis Major to observe NGC2362, Tau Canis Majoris Cluster. This delightful little open cluster nestles the bright tau CMa in a arrowhead-shaped nest. Like most open clusters, I prefer to observe them in low power, wide field. Just my preference but I like the blushing, unresolved glow that they can display. Sometimes the scope just blows them apart where a different kind of study is performed.

I won't give up trying to check off M78 in the winter sky table, as I didn't with M1 and as I don't with M110. I'll try and try hoping that I happen to be looking at those two faint stars when all the factors are favorable and a faint nebulousity paints the sky. I don't expect the Wow! factor other than filling the red square with a green check mark.

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