Dinosaur Point March 2, 2008

Albert Highe

I had two fair nights at Plettstone on Thursday and Friday, but those sessions only whetted my appetite for more ancient light. The sky contained some high cirrus during Sunday afternoon, but the CSC and satellite images indicated clear skies would prevail at Dino.

On the other hand, the wind was a concern. We are approaching the windy season at San Luis Reservoir. The automated wind number reported 10-15mph breezes during the afternoon. Conditions were the same on Saturday, and the wind died that evening. I expected similar conditions on subsequent days. So, Sunday afternoon I headed out with the 13" f/4.5.

As expected, the cirrus dried up by astronomical twilight, leaving clear skies all night. Temperatures dropped to the mid to low 40's. The relative humidity never got above 68%. Seeing was adequate - six stars in the Trapezium, although Saturn was a little mushy. The 10-15 mph breeze that turned windmills during the afternoon died after sunset, leaving us with a calm, dry lot. There was no hint of dew.

Five of us enjoyed very nice conditions. I made over 50 observations, but 31 were new. I re-observed a number of challenging objects that I'd seen previously with the 16". For some reason, I was stoked. I felt like I usually do when observing in Australia. Despite the long drive the day before, I didn't feel tired while observing. Even when I quit at 1AM (first to arrive, last to leave), I felt good. But fatigue finally caught up to me about half way home. I'm glad I left when I did.

I'm trying to finish off all the NGC objects by constellation. Usually the stragglers on my lists are faint, obscure, questionable, or non-existent objects.

Selected observations (using 7mm Nagler T6 unless otherwise noted).

Orion

NGC 1671, a.k.a. IC 395 (mag 12.9, 0.9' x 0.6') There is some doubt about the identity of NGC 1671. The NGC/IC webpage speculates that it may be IC 395, which I did observe. Small oval 5' ENE of mag 11 star. Visible with direct vision.

NGC 1707

Small asterism of four faint stars 0.5' across that appear nebulous. Lies 2.5' S of the business end of a hockey stick asterism. I found the hockey stick more interesting.

NGC 2163

Nebulosity visible steadily with averted vision and without filters. Elongated N-S around mag 11-12 star. Star appears off-center to the south. DSS shows more detail I didn't pick up in the 13". Note to return.

Taurus

Close galaxy pair 3-4' NNE of a trio of brighter stars.

NGC 1633 (13.5, 1.2' x 1.0') Small, faint, slightly oval core with hint of slightly larger faint halo with indistinct outline. Just visible steadily with averted vision.

NGC 1634 (14.1, 0.5' x 0.5') Small oval, somewhat brighter than N1633 40" to the north. Visible steadily with averted vision.

NGC 1474, a.k.a. IC 2000, IC 2002 (13.8, 1.3' x 1.0')

There is some doubt about the identity of N1474 and the proper ID of the suspected IC counterpart. Uranometria labels the galaxy at this location IC 2002, but the NGC/IC webpage says it should be IC 2000. I observed a small hazy spot 6.5' E of a mag 11 star and held it 80% of the time with averted vision.

NGC 1896

Hourglass-shaped arrangement of approximately 15 stars 4' wide x 6' long approximately 5' NE of mag 9 star.

Sextans

NGC 3015 (13.9, .06' x 0.4') Small oval with smaller, somewhat brighter core. Just visible with direct vision and larger halo visible steadily with averted vision.

2MASX J09491349+0110397, a.k.a. LEDA 101406 I was armed with a DSS image for N3015 and noticed this nearby very small, faint smudge 3' NW. Eventually I was able to hold it 30% of the time with averted vision.

NGC 3022 (13.2, 1.6' x 1.6') Small to moderate size circular galaxy with somewhat brighter central area. Visible steadily with averted vision.

The DSS showed three faint nearby galaxies.

MCG-1-25-44 (14.5, 0.9' x 0.7') 4.5' WSW of N3022. Smaller oval with more uniform brightness. Visible 80% of the time with averted vision.

2MASX J09494388-0515339, a.k.a. LEDA 154365 One of close pair (50" separation) of very faint, elusive galaxies 5.5' SSE of N3022. Very small oval (?) with brighter central area. Eventually was able to hold it 60% of the time with averted vision.

2MASX J09494709-0515219, a.k.a. LEDA 1047171 The other member of the close pair of very faint, elusive galaxies 5.5' SSE of N3022. Even smaller and fainter oval. Eventually was able to hold it 50% of the time with averted vision.

Sextans A a.k.a. MCG-1-26-30 (11.5, 5.5' x 4.5) Large, low surface brightness galaxy, one of the dwarf satellites of our Milky Way. A brighter off-center circular knot 1' across shows up 95% of the time with averted vision using 9mm Nagler. I occasionally detected a somewhat larger (3') even glow.

Sextans is now complete.

I finished up working on Leo. It was an enjoyable night. Considering the forecast and commitments for the weekend, I may make the drive again mid-week.

Albert