OBSERVATION OF NGC 7139, HCG10 & IC10 Sketches courtesy of Jeff Young

Further sketches from Jeff can be found at The Observatory at Rokeby Hall

Click on the individual sketches for more detail.

NGC7139

12/13/2009 22:30 UT; Pickering 6, NELM 5, SQM 20.4, 400mm Mak-Cass @ 150X, OIII

Invisible unfiltered below 450X. Difficult averted-vision at 450X and at 150X to 335X with UHC. Oddly, it's easier to re-acquire at 335X, but harder to hold.

Slightly easier with OIII at 235X, and direct-vision (just) at 150X. Sketching reveals a central star (unfiltered), but it's not visible with the PN (which requires filtration).

HCG10

12/13/2009 23:51 UT; Pickering 6, NELM 5.5, SQM 20.6, 400mm Mak-Cass @ 150X

2 galaxies readily apparent, the brighter (NGC536) with multiple stellar cores (or foreground stars), and the other (NGC529) with very weak condensation and a semi-stellar core.

IC10

12/14/2009 00:31 UT; Pickering 6, NELM 5.5, SQM 20.6, 400mm Mak-Cass @ 150X

Somewhat easier than I was expecting: definitely averted-vision, but fairly easy to acquire with panning. No condensation and no structure (aside from 5:1 elongation along the NW-SE axis).

NGC 40 - Observation Notes

....Just got a copy of Roger Clark's Visual Astronomy of the Deep Sky, which makes for very interesting reading. It reminded me of a comparative study I did recently of NGC40, showing how magnification and image scale can reveal its subtle detail. Anyway, thought it might be of interest here....

All sketches done through a 16" Mak-Cass. While they cover two different nights, conditions were broadly similar.

Click on the individual sketches for more detail.

Bright star with bright halo unfiltered at 150X.

UHC accentuates halo a bit, but it doesn't really need it.

235X unfiltered reveals better scale and a brightness gradient with the S end being somewhat dimmer.

335X better yet, revealing a slight pinching along N-S axis, with brighter sections to the periphery to the E and W.

450X really getting into the swing of it with knots along the W brighter edge.

600X reveals last knot in the chain (to the S) to be a foreground star, but the nebulosity is starting to wash out at this magnification.