3 Feb 2003, Surveying Cancer, and a little more Sextans

by Robert Leyland


I left the car packed up from yesterday, and went out again for a rare Monday night session. Traffic was heavy through Petaluma, and it took 1.5+ hours to get to the lake, usually this is about 65 minutes.

I arrived about 5:30pm, to find David Silva already here. After a leisurely setup and chat, while waiting for darkness to fall, I took in casual views of M42; the Zodiacal light (again); and M35, with its cluster-in-a-cluster.

Steve Gottlieb arrived about 6:30, and we had a nice chat about Sextans galaxies, nomenclature and cosmological theories.

ObserverRobert Leyland
Date3 Feb 2003
Time1900-1230 PDT (UT -8, or 0300-0830 4 Feb 2003 UT)
LocationLake Sonoma CA, 3843'N 12302'W Elev ~900 (Grey Pine Flat)
Weather6-10C Temp, 75% Humidity
SeeingLM 6+, transparency 9/10, steadiness 9/10, no wind
Equipment17.5" F5 Dob, Telrad + 9x50 finder scope, Pentax XL EPs

Early evening I started a survey of Cancer, while waiting for Sextans to rise sufficiently so that I could continue that session. During the evening we shared views of a number of things. Steve went after quasars and Sharpless nebulae. David went planetary with his Starmaster, taking in super views of Saturn at 600x plus.

CANCER

M44Beehive Cluster, Praesepe - hard not to begin here when viewing Cancer, easily visible unaided, and a nice sight in the finder scope. Even with a 40mm Pentax (55x) it is too large for the telescope to encompass in one field of view, appearing as a scattering of very bright stars. at 100x (21mm) I can follow several chains of bright 9and faint) stars across and out of the beehive.
M67a nice open cluster, moderately loose, but with large numbers of stars visible (I counted over 150). Easily seen in the finder, and overlooked next to its beg brother. When typing this, I realized that this was the first time I had logged M67, probably not the first time I had viewed it, since I had scanned 80+ M objects in a mini marathon with my 8" a couple of years ago :-)
Iota CNCa very pretty blue-gold double star. The larger component is yellow, and the pair is quite reminiscent of Albireo. This is a good double to show people at star parties.
NGC 2608A galaxy just a short starhop away from Iota, a small oval shape, with a mottled halo and small faint core detectable with averted vision at 210x.
NGC 2623a very small oval galaxy; faint, small brightening at the core (again at 210x with averted vision). A difficult galaxy.
NGC 2535, 2536Very difficult, 2535 appears as a diffuse fuzz patch; no core but a couple of very faint stellar points near the galaxy, one of which is 2536.
NGC 2554small oval 3:1 elongated galaxy with a point like core.

CANIS MAJOR

At this time Steve G provided us with a very nice diversion. He had found Sharpless 2-308 (aka LBN 1052), which we each took turns studying, and then bringing up in our own telescopes.

This is a huge H2 region in Canis Major, that isn't recorded in the common amateur astronomy books. It is really only visible with an OIII filter, and low power as it occupies a circular region some 45' in diameter.

Sharpless 2-308 is next to 16 CMa, opposite the Collinder 121 cluster (RA=6h54m13s Dec=-2355'42"). It has a scalloped edge that is sharply defined along a chain of stars, and some bright puffy regions scattered across its somewhat circular shape. Sseen at 55x with an OIII filter, and all but invisible without. Only one area is (just) detectable unfiltered, and this is the brightest, diffuse, region furthest from 16 CMa.

Well worth checking out, just scan the area due S of 16 CMa with an OIII filter.

CANCER

NGC 2577approximately 4:1 ratio oval galaxy with an elongated core. Quite near to a mag 10 star, with another faint fuzzy patch on the opposite side. U2K lists this as UGC 4375 (Chart 75), it shows as a stellar core surrounded by a faint halo.
NGC 2562,2563A nice galaxy pair, both are ovals with small bright cores. They are approx 1/4 apart and elongated roughly 90 to each other. 2563 is more circular perhaps 3:2 ratio, while 2562 is about 3:1 elongated. These are members of the "Cancer Cluster" , U2K shows around 20 galaxies in this area. A good place to revisit!
NGC 2545A small bright oval (3:1), an easy starhop from Mu CNC, to a bright triangle asterism. Probably an outlying member of the Cancer Cluster.
NGC 2598Small, faint slightly elongated smudge with a faintly brighter core. Not a galaxy to write home about.
NGC 2599faint, diffuse and circular with with a stellar core, slightly larger than 2598, but otherwise unremarkable.
PK 208+33.1I tried quite hard to find this Planetary Nebula, scanning at a variety of magnifications with an OIII filter, around what I believe to be the right place, without success.
NGC 2672, 26732672 is a nice circular galaxy with a well defined core. A small faint, almost stellar point due W of the halo is 2673. Starhopped from Delta CNC, right beside M44.
NGC 2744, 49, 52triple galaxy too close to Jupiter for comfort, I was momentarily dazzled by the big planet in the finder. Darn those planets. ;-)
NGC 2764neatly bracketed by a pair of 10th mag stars and next to Xi CNC (a grouping of three stars), shows as an stretched out smudge (2:1) with no visible core.
PK319+31.1Planetary nebula - very large; used an OIII at 100x to see a dull glow with several stars nearby, one inside the glow but not central.
NGC 2775large lozenge shaped galaxy with a bright, but soft, core - very nice.
NGC 2777very hard - tiny, faint blob near 2775, couldn't see any central brightening. needed averted vision at 100x, but could hold directly at 210x.

SEXTANS

Before Steve Gottlieb left we looked at Sextans B, and he verified my sighting. I continued to cover the remaining NSOG entries for Sextans, and to revisit a couple from last night. I also tried for Sextans A, and Pal 3.

NGC 3246large but faint galaxy, forming an oval glow approx 3:1 extension, but with no core. I found this to be a difficult object, and frankly don't understand NSOG's *** rating.
NGC 3423large diffuse oval (3:2 ratio) softly brightening towards an elongated core - quite nice - soft but noticeable brighter and nicer than 3246. Long star hop from Beta SEX.
NGC 3166, 3169 and 3165A nice pair of galaxies, revisited from the prior evening. At 210x I can see arc like mottling in halo of 3169. NGC 3165 is visible only with averted vision, as an adjunct to 3166.
NGC 3156 nearby to the 3166,69 pair, beside a triangle of bright stars, easy sight.
Sextans Aattempted sighting (RA=10h10m30s Dec=440'), starhopped down from Alpha SEX to an flattened circlet of stars, midway between the thick end of the arc, and a small triangle of stars, found an irregular brightening of the background - needed averted vision and motion to truly see it. At SB of 14.8 this is a questionable observation.
Pal A (Sextans C?)extremely faint brightening - probably my imagination - exact star hop from U2K chart 113 proejction from Alpha SEX and distance - so I'm in the right place - very difficult object.
IC 590also on the U2K chart, and relatively easy rewards after struggling with the dwarf galaxies. This is a tiny faint 4:1 ellipse with a 10th mag star at the tip of the galaxy. A breeze at SB=13.7 :-)

It's now 12:47 AM, getting colder and dewy time to pack up. Sporadically a trashcan at the edge of the flat would get thumped by some critter. I yelled at it once, and things quietened down, I hope it was just a raccoon.

Great night, good company, and good seeing, can't really ask for more.