Andrew's Astronomy Blog

Jupiter on the 20″

Andrew — Sun, 29 Aug 2010 11:00:41 +0000

Friday evening at the Observatory was spent showing some visitors around. As it was clear we were able to look at Venus, Mars, Jupiter and Uranus as well as the Moon through the 20″. Although the planets were all very low and suffering from massive amounts of atmospheric dispersion they went away happy.

After that, it was down to the main business of the night, measuring periodic error on the 20″ drives. This shows that we have some more work to do to stop drift on the altitude drive and also that we have about 7 arc seconds peak to peak periodic error on the azimuth axis.

By this time, Jupiter was high in the sky so we finished up putting my modified Philips webcam on with a 2.5x PowerMate for some video images. Jupiter is more favourably positioned for Northern hemisphere observers than it has been for many years and it was nice to see it at a decent altitude with lots of detail visible in the eyepiece.

Messier 103

Andrew — Sun, 15 Aug 2010 20:59:20 +0000

Discovered by Mechain on the 27th March 1781, M103 became the last entry in Messier’s original catalog. Interstellar extinction of about 1.5 magnitudes makes determining the precise distance difficult but it probably lies about 7200 light years away. The cluster diameter is 17 light years and the bright star in the field is Delta Cassiopeia.

This was the first time that I’d tried out a new piece of software, DSLR_Logger from the AstroTrac Yahoo group. It’s main purpose is for determining precise polar alignment of the mount. I will write more about this program when I’ve had a chance to explore it rather more fully.

This was also the first outing for my new Williams Optics Field Flattener 3 on the 70mm.

Perseids (2010)

Andrew — Fri, 13 Aug 2010 13:40:21 +0000

Looking through the images I collected last night revealed 6 meteors, 2 aircraft & a lot of satellites. I’d taken 10 90 second images of the area around Cassiopeia which were stacked to provide the background. The images with meteors trails were then selected and using painted selection masks superimposed on the background using Photoshop.

Next time I will acquire the images slightly differently. Downloading them to the laptop results in a considerable time lapse between images. Capturing jpegs directly to the camera flash card with the camera locked on repeat would minimise the chance of missing meteors.

Perseid Meteor

Andrew — Fri, 13 Aug 2010 08:48:07 +0000

Last night was the peak for this year’s Perseid meteor shower and the weather was reasonably kind with only occasional cloud until 2AM when it clouded over.

I’ve got a lot of photos to sort through but this image came from one of the longer exposures aimed at capturing the star background. A single 90 second exposure at ISO1600, f/3.5, 18mm.

M45 - The Pleiades

Andrew — Sat, 31 Jul 2010 11:19:14 +0000

Searching through some old folders on my PC I came across 5 images of the Pleiades that I hadn’t previously processed. Taken on the Astrotrac with a 75-300mm Canon zoom lens set at 200mm, each is 3 minutes long for a total of 15 minutes exposure.

The resulting stack had masses of red sky noise but removing this and applying a non-linear stretch starts to show the dust cloud around the brightest stars of the cluster.

Sagittarius

Andrew — Sat, 19 Jun 2010 19:24:14 +0000

From the northerly latitudes of the UK, Sagittarius is low down on the Southern horizon during the summer months. Looking towards the centre of our galaxy this region hosts some of the most stunning star fields of the night sky and is also home to some bright nebulae. Two of these are captured in this wide field image; M8, the Lagoon nebula and M20, the Triffid nebula. Also in the frame is the open cluster M21.

Whilst these objects appear close together in the sky, M20 is a foreground object with M8 considerably further away along with M21. The apparent size of the long axis of M8 is about 1.5 moon widths and the object is rather larger than the Orion nebula (60 x 40 light years).

Being a bright naked eye object (under a dark sky) means that reasonable results can be obtained from relatively short exposures. This image consists of 18 minutes of luminance frames and 9 minutes each of red, green and blue.

Observatory: Moorock, Australia

Telescope: Takahashi STL-11000M

Camera: SBIG STL-11000M

C/2009 R1 (McNaught)

Andrew — Sun, 13 Jun 2010 12:58:23 +0000

Comet C/2009 R1 (McNaught) is currently travelling through Perseus, low down in the pre-dawn sky. I managed to get a single 60 second exposure from New Mexico on GRAS-14, a Takashashi FSQ 106ED with an SBIG STL-11000M-ABG camera. The comet is currently 177 million kilometres from Earth and makes it’s closest approach on 15th June at 170 million kilometres.

I’ve had to remove a substantial background gradient on this image as this was just before dawn and it’s binned 3×3 to reduce the image size.

Messier 10

Andrew — Sat, 05 Jun 2010 17:33:23 +0000

We got back from the evening at Kielder at about 1 in the morning and as it was clear, albeit, not very dark I setup to take some pictures of M10 in Ophiuchus. By 2:30 it was already getting light and the dawn chorus was getting going but I got 15 3 minute exposures at ISO 800 for this image. Telescope is the ZenithStar 70mm F/6.

Diffuse nebulae in Cygnus

Andrew — Mon, 31 May 2010 11:28:16 +0000

At the beginning of the holiday in Northumberland we had an evening where the cloud passed through just as the moon was setting. Having a restricted southern horizon I looked instead to the East where Cygnus was rising and decided to image the region around the bright star Sadr. Some puzzling over the hit or miss drifting I’d been getting with the AstroTrac lead me to the conclusion that I needed the polar scope on the left side of the mount to get good results. This has subsequently been confirmed by some recent posts on the Yahoo group and the problem is due to the scopes being manufactured with the tubes slightly misaligned. There is a mod available to correct this that involves fitting a collar with three grub screws around the tube. This will be worth a closer look.

Polar alignment was pretty close on this occasion so I took 16x 3 minute exposures with the ZS70 and unmodified Canon 350D and stacked the results.

The bright star to the left of centre is Sadr. There is an open cluster (NGC 6910) to the left of Sadr. The remainder of the image consists of HII emission nebulae that are catalogued in the DWB index. One Barnard catalogue object (B344) is visible just to the right of the bright orange star top centre of the image.

Kielder Observatory

Andrew — Sun, 30 May 2010 11:34:09 +0000

While on holiday in Northumberland we took advantage of an open evening at the Kielder Observatory. The evening started with a talk by the Director, Gary Fildes about the Universe and our place in it. This was followed by a tour of the facility and views of the Moon and Saturn through the 20″ Newtonian and 14″ SCT telescopes as the sky didn’t get dark enough to look at anything fainter.

http://www.kielderobservatory.org/