A Seagull On The Moon , And A Closer Look At M43

[cloudsweeper]

4.30pm, very cold, sky clear, still light of course, and Moon (past first quarter) showing in east.  Aligned 8SE on it for tracking.

MOON

Plato and Copernicus were clear, east of the terminator.  S-W of Plato in the Mare Imbrium was the Teneriffe Range and the distinctive, short, narrow and aptly named Straight Range.  (Going back to this later, it looked like a line of thick stitching in the lava surface of Mare Imbrium.)

An hour after starting, the view with the Hyperion Aspheric 36mm was lovely - crisp, clear, and "clean" (low mag), 1.28 deg FOV, mag x56, but still lacking detail since the sky was brightish.  At x68 with the ES 30/82, the Moon was still nicely framed, but the Ring Of Fire effect (with bright objects or daylight conditions) was off-putting.  The Meade 5000 20/82 showed more detail, a small amount of Ring Of Fire, and more shimmering along the limb.  (This shimmering diminished later on.)

Overall, the view at this point was nicest with the Aspheric, and I called a neighbour with his young son to enjoy the Moon's features.  The lad was very keen, and asked questions about the Moon and the 'scope.  Very satisfying!  (He told Dad he wanted a 'scope with a motor so he could track things.  Looks like another recruit!)

After another hour, further features in the lava on M. Imbrium were showing up well in the mainly smooth, uniform surface: Helicon and le Verrier craters, Dorsum Heim (a ridge) near the terminator to its west was - thanks to shadowing - looking like a large gull-winged bird with small crater C Herschel resembling its head. 

Yet another hour (and a meal) passed, and the Moon was very bright, so I upped the mag to x185 and focused on the Jura Range, west of M. Imbrium, round Sinus (bay) Iridum, and looking like a rough rocky arc with shadows to the west making the peaks there seem to leap out beyond the terminator.

I raised the mag to x339, and the image was still sharp, but getting wobbly, with focusing being more critical.  Dropping down a bit, I glimpsed just one the few pits/craterlets in the floor of Plato.  Had hoped for more, but the light was not favourable.

M42/43

The famous M42 Orion Nebula gets all the attention.  This bright emission(/reflection) nebula or HII region and stellar nursery has a small extension to the N-E, separated from it by a dark dust lane, going by the name of M43, de Mairan's Nebula.  So I thought I should pay some attention to this appendage of M42.  At x56 (good exit pupil for contrast) the nebulosity was clear even with the Moon almost overhead.  Focusing on the Trapezium, a line of three stars to the S-E followed a limb of the nebulosity, while two stars about 6 or 7 minutes to the N-E marked its upper limits.  The more easterly one had a clear dark band underneath it, and that star was NU Ori, the source of ionisation for M43.  Filters dimmed the fainter stars without enhancing the nebulosity, but anyway (and in spite of the Moon) I was happy to have clearly pinned M43 down.

8.15 - finished.  Another rewarding session, longer (and colder) than my usual ones.

Doug.

 

[alan potts]

Very nice report Doug, nice to sit and read as we have 12 inches of snow outside and it is still at it, it is also a cool minus 9 now and getting colder.

Alan

[cloudsweeper]

7 minutes ago, alan potts said:

Very nice report Doug, nice to sit and read as we have 12 inches of snow outside and it is still at it, it is also a cool minus 9 now and getting colder.

Alan

Thanks Alan.  Glad to be of service!

Doug.