Sunday, 28 December 2008

Jones 1

...or to give it it's proper title, PK 104-29.1 . This planetary nebula was not picked up during the first great sky survey of about 10,000 deep sky objects for the New General Catalogue and the Index Catalogues. It is about 12.7 visual /15.1 photographic magnitude and its blue glow is spread over the two main arcs of a twisted ring over 5' in diameter. I saw the glow from one arc in the 20", but using a Lumicon UHC filter I could see both arcs and make out the ring - it was faint but easy after 10 minutes dark adaption - both of us present saw it visually this way. The central star is very blue and magnitude 15.7 easily captured in this image comprising of 9 x 30 second exposures (without detrailing). It is easily located (but not seen!) by going 1ºSSE of 72 Peg which is just north of the Square of Pegasus.

How many galaxies can you spot?

Sitting in the control room below the main dome, I was browsing the deep sky software and decided to slew the 20" toward the hitherto unknown (cliché) Pisces Cloud. I went upstairs and visually located NGC 403 and hopped over to the galaxies, which I could see as a few fuzzy patches strung out more or less in a straight line. I stuck the camera on and collected lots of trailed 30 second exposures. This is the current problem with the scope - not that it doesn't know where it is, but something somewhere is causing a quasi-periodic error. I later detrailed these and got 14 reasonable shots that I stacked and aggresively processed. You can see the purple amplifier glow at the bottom right and some headlight/light pollution residual artefact across the picture (taking flat-field images addresses this issue but make the problem worse before they make it better in these circumstances). I think it looks cosmic.

Venus, Jupiter and a Plane

Here's one of the scenic examples of my shots. It is of the observatory building showing the dome glinting in the moonlight and also features a plane flying in the distance behind it and the planets Venus and Jupiter. This wide-field photograph of 15 seconds at f/5.6 was taken on December 6th shortly after sunset at 1730 UT and has also captured some annoying but in this case quite aesthetically pleasing light pollution.

Looking back to the summer sky in an icy winter wind

This picture of M57 was taken from the observatory dome with an icy wind blowing in the opening, soon after dusk twlilight with Lyra and Cygnus still reasonably high in the western sky. The only problems being 1. car headlights and 2. a buffeted telescope. I couldn't get any 30-second shots without trails, so I de-trailed them all (phew!) and stacked the best 16 of them. Despite the de-trailing artefacts which appear as streaky noise you can easily make out IC 1296 the 15.1 magnitude spiral galaxy to the right.

Using my f/10 SCT at f/4

As I do astronomy on a budget, I like to see what I can fudge together or get away with. I do not have sophisticated tracking equipment on my SCT, just the R.A. motor and a manual guiding 1 x sidereal rate hand controller. This would suffice if I were to enjoy spending hours typically at -2ºC, hunched over an eyepiece, trying to counter the effects of wind and drift in my motor versus the sidereal rotation of the earth. I can't be doing with this and my knowledge of optics tells me that at f/4 compared with f/10 optics, the light gathered per area is 2.5x2.5=6.25 times greater thus shortening exposure times. I got hold of a second f/6.3 field flattener and after many long attempts with various coupling adapters I found a combination that worked with the focus at the end of its travel. I had to use a 1 1/4" adapter (I will get hold of a 2" version ASAP) so the vignetting (edge-of-field clipping) is quite severe; still it gives it a lovely 'through the telescope' quality! This is the Pleiades with an effective focal length of 800mm and aperture of 200mm in a single shot of about a minute.

Wednesday, 3 December 2008

A fire in space

I am very pleased with this picture of the Flame Nebula. Enjoy.
Mae'n dda gen i gyda hyn Lluniau y Niwl Ffagl. Mwynhau.
Ich bin mit dieser Abbildung des Flamme-Nebelflecks sehr erfreut. Genießen Sie.
Είμαι πολύ ευτυχής με αυτήν την εικόνα του νεφελώματος φλογών. Απολαύστε.
Je suis très heureux avec cette image de la nébuleuse de flamme. Appréciez.