Sunday, 31 October 2010

I see 410

IC410 is the little patch of nebula in Auriga that I used to test the autoguiding mechanism of our big scope. I used 1 minute exposures; we previously had success with 5 minute exposures, but I was playing safe. The flat field pictures I took afterwards using a diffuser and skyglow seem to have added a lot of noise to the picture and it still required more tinkering with the background, hence the patchiness. I'll have to play around with using false or smoothed flats. This picture used 17 x 1 minute exposures at ~ f/3 on the 20", darks & flats. The Sky Quality was only 20.66 mag/sq" (a bit disappointingly light), which didn't help. This was taken after the successful (see 'littlebeck') 5 x 5 min picture of the centre of IC 405.

Wednesday, 27 October 2010

A winter spectacle seen on an autumn predawn

ON this wide picture of the Great Orion Nebula complex, you’ll see the beautiful clouds of gas and dust reflecting and fluorescing the light from the bright blue stars at the centre. If you step back and take in the grand scene, all 10 square degrees of it, you will start to see among the bright blue stars, a few little orange stars. And then, towards the lower right, a few of the background Milky Way stars start to creep into shot. Fingers of opaque, black dust can just be made out streaming off to the right, by virtue of the incursions of stars visible behind it. All of which gives you a clue to the real size of this patch of interstellar material. I find it very odd how a vertical line of four different types of object have arranged themselves on the sky like this, for us to see (check out Messier 8). Not bad for a 2 minute exposure (18/09/10).

Conjunction of jollity and magic

According to Gustav Holst, Jupiter is the bringer of jollity, and Uranus, the magician. Here we can see the two planets on the same photo, and not just that, but with moons. Jupiter is overexposed and overprocessed, so much so, that you can see its reflection in the lens. There is only 1 degree between the planets at this time. Uranus compares well in brightness with Jupiter’s moons. I couldn’t see the planet with my naked eye as it’s still too light polluted and/or misty here. Despite being easier to find, Jupiter’s glare contrarily makes Uranus more difficult to see.

Mercury Rising

It was the coldest night for ages, about 3 or 4 ºC, but finally at about quarter to six I saw Mercury emerging from the cloud tops near its eastern elongation from the sun. This is a stack of 4 pics that were slightly out of focus, but the composition looked better. Mercury was in Leo, hovering below the lion's front paw.

Thursday, 7 October 2010

Ganymede's little shadow

Sorry for the delay, but no mirror = no posts (also no clear skies). My own "little" Schmidt-Cassegrain Telescope has had motor drive problems so not many pics from that either. However, I did manage to see Mercury and Uranus with it on 18th Sep at dawn from behind the sand dunes on the east coast. The picture I chose to post was taken that morning, when Ganymede started to cast a little shadow on the edge of Jupiter at about 4:20. The Canon was inserted directly into a 2x barlow lens on my 8" Meade SCT, creating an effective 4m focal length at f/20. A few raw-format subexposures at ISO 100 were stacked.