Messier 97, the Owl Nebula

Here’s a classic object for this time of year, the ghostly Owl Nebula, in a false-colour image taken through H alpha and OIII filters.

It gives the impression of two spherical shells of gas displaced from one another, but, unlike some other planetaries, it has very little colour, looking much the same in H alpha as OIII light.
Taken over three nights, and processed with Nebulosity 2.5.3 and Photoshop CS4. (Click to enlarge)

Messier 97

The Sun ( H alpha) 2013 May 03

It’s the time of year for solar observing again, and there was a nice active disk yesterday in both H alpha and white light.

Here’s an image taken by the method I’ve been using for a couple of years now, using the DMK 41 camera in combination with the Lunt LS60 double-stacked to take an image in two parts and stitch it together. On this occasion I used DoubleTake for the Mac to do the stitching and balancing, and it does a good job.

Taken in mid-afternoon in warm conditions (27C), seeing was poor. (Click to enlarge)


Messier 81 2013 March 02–14

This is an LRGB image with the L from a light pollution filter, but it is rather undersaturated as the data is dominated by the luminance; true RGB from such a light-polluted environment  as I work in is probably impossible. It was taken over three nights.

Processing was with Deep Sky Stacker and Photoshop (with Gradient XTerminator & Neat Image plug-ins playing a role).

The slight non-roundness on the star images is probably due to chip non-orthogonality, which needs fixing. (Click to enlarge)

Messier 81

Saturn 2013 March 31

The seeing looked steady visually on this occasion, but on-screen it was rippling very fast at a small scale (not surprising for 27º altitude). Three sequences of RGB were captured, and all combined for a 14 minute run, interspersed with IR captures. This is the first image I have produced using the PierroAstro dispersion corrector in the imaging train.

There’s no evidence of any spots, though Encke’s division is faintly apparent.



Comet C/2011 L4 (PanSTARRS) 2013 March 29

Tonight I finally obtained an image of C/2011 L4 (PanSTARRS), after all these cloudy evenings. There was a gap in the cloud for about 30 minutes which I exploited. The comet is going behind a nearby fir tree during the course of the exposures, obscuring the frame on the right hand side.

Slightly later I observed it visually from an upstairs window using 10×50 binoculars, but it was only just visible in those, looking much fainter and more diffuse than when I last saw it on March 14. (Click to enlarge)

Comet C/2011 L4 (PanSTARRS)

The Moon 2013 February 19

I went a bit mad with imaging the Moon on this night, doing it with three different cameras and telescopes. So I did my usual whole Moon with the 80mm refractor, but I also made this redundant by taking a much larger whole Moon image with the 100mm f9 which is mounted with my C-14, in IR with DMK41 camera at 15fps. This can be zoomed in to examine parts of it in detail; it won’t fit on a monitor at full size (second image down, click twice). It has been so successful I will certainly use this combination again.  Finally I imaged Copernicus with C-14, Flea 3 and 3x Barlow, the same arrangement as I use for Jupiter.

With the very large image scale for Copernicus, one fact, or maybe opinion, that comes into my mind is that when attempting very high resolution imaging of lunar features on the terminator, and processing using stacking software and wavelet sharpening, you very easily hit the diffraction limit of the telescope, because the contrasts are so great, in a way you don’t when imaging Jupiter or Saturn with the same telescope (but you do when imaging double stars). You can see this looking at the central peak of Copernicus, standing out as a star-like point: it has a diffraction ring around it. The appearance of other features in this image is also influenced by edge diffraction, and this is a thing you regularly see in similar images.
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