On the trail of a few Palomars (July 9/10, 2010)

Here's the first installment of this summer's trip to Colorado:

July 9/10 NELM 7+, SQM 21.7 Foot of Boreas Pass, near Como, elevation approx 10,100 ft.

M12 1:06 MT; 10" Mewlon @ 180X
Medium-sized globular with 40 or 50 stars resolved across a milky background.



Pal 7 1:30 MT; 10" Mewlon @ 180X
Two dim field stars, the eastern-most surrounded by a difficult averted-vision haze.

Placement on sketch not quite exact; both dim field stars are to the W of its core, although the western-most one does roughly define the W edge, as sketched.



Pal 8 2:00 MT; 10" Mewlon @ 250X
Direct-vision fuzzy blob in a rich star field at 180X. 2 or 3 stars resolved. Slightly more difficult at 250X (borderline averted), but involved stars easier (2 definite, 2 further suspected).

This struck me as odd, since the V(tip) of Pal 8 is listed as 15.7, and my sketches are only going down to the mid-14s (and that's without a milky background). USNO-B1.0 lists some 15 stars within the boundary of the globular between 8.0 and 13.0 though, and I can't imagine that all of those are foreground stars -- so I think the listed V(tip) is wrong.



Pal 11 2:30 MT; 10" Mewlon
Not seen. Several suspect areas, but it's in a very rich star field and at least some of the suspects resolve into multiple dim stars. Nothing really to pick one grouping over another without a deep star-chart (which I didn't have).

Cheers,
-- Jeff

Nice sketches Jeff.

I've never considered looking for the Palomar globs, as I believe they would be washed out by the light pollution where I live. From your high, and clear, site, are they difficult to pick out?

Paul

Paul --

From Irish skies (with a 16"), I had nearly given up, having struck out on 3 or 4 of them and gotten a very difficult "maybe" on Pal 2.

But I've had much better luck in Colorado (with a 10", no less), where I've been getting maybe 60% of the easier ones. Pal 8 was surprisingly easy (certainly the only direct-vision one I've found so far), but the rest have been somewhere between easy and difficult averted-vision.

If you're going to try for them under mediocre skies, I'd suggest something on the order of a 30" Dob. With more moderate aperture, I've found the Arp peculiar galaxies (and Abell planetary nebulae to a lesser extent) to be better pickings.

Cheers,
-- Jeff.

I think with Dublin skies you would need Keck to see them.:laugh: