Galaxies, PNs, and Darks / Flats Testing

[PeterC65]

I’ve managed EAA sessions on both of the last two nights, with the Explorer 200 and x1.7 Barlow, last night paired with the Photoline 72 and the night before with the Explorer 150 (the first time I’ve had both reflectors on the AZ-EQ5 mount – quite a sight).

I was planning to focus on galaxies and observed quite a few, IC2209, M82, M109, NGC2146, NGC2336, NGC2403, NGC2460, NGC2683, NGC2903, Leo Quartet, and Markarian’s Chain (well, part of it). I favour galaxies that show some structure, so face on spirals, edge on with some dust lanes, or the interacting galaxies.

My favourites from the two nights are the Dusty Hand Galaxy (NGC2146) which has both an unusual overall shape and lots of dust lanes …

and NGC2403 which is face on with some lovely spiral arm detail and perhaps a little colour …

I know it’s galaxy season, but I sometimes get bored, especially when the galaxies are a little bland, so instead, since I was set up for high magnification, I turned my attention to Planetary Nebulae, M97, NGC1501, NGC2392, NGC3242, PK164+31.1, and PK339+88.1.

The first four are all of the little blue / green disc variety, but I was pleased to see plenty of detail in the Eskimo Nebula (NGC2392) …

and I managed to see the shape of the Headphone Nebula (PK164+31.1) which is very faint and looked better with the Explorer 150 …

With one of the little blue / green discs, NGC1501, I decided to test the effect of using dark and flat frames which I’d captured for the Explorer 200. The dark frames removed all of the hot pixels, some of which the SharpCap hot pixel removal feature let through, and the flat frames calibrated out some vignetting which was lightening the background sky in the centre of the image.

Here is NGC1501 with the darks and flats …

and with just hot pixel removal …

Taking the darks and flats is a bit of a faff, and the darks take a while, but I think they are worth using at high magnifications and with the clear or visible filter. I couldn’t get them to work with the L-eNhance.

 

[Steve in Boulder]

Very nice, I particularly like NGC 2146 and NGC 1501.  For larger, fainter PNs like the Headphone Nebula (Jones-Emberson 1) and Abell PNs, a dual narrowband filter can be helpful, although you’ve certainly captured it as is.

Edited March 7 by Steve in Boulder