Author: admin

Categories
Galaxy

La Palma video

While at La Palma last year one of the things I did was to leave the camera taking pictures of the Milky Way for most of the night. Dan eventually shut it down at about 4am after I’d headed down the mountain to bed. Total count was 575 30 second images at ISO 800.

Once home I encountered some problems with automating the processing and the project got shelved until last weekend when I sat down and worked out how to script Maxim DL in order to stretch and convert the images. Onve in jpeg format I loaded one into Photoshop and worked out a processing sequence to remove as much of the noise as possible whilst stretching the image to bring out the faint detail. This sequence was saved as an action and then replayed on all the images in batch mode.

Finally, the images were loaded into Photoshop and exported as a video file (20MB, Quicktime required).

http://andrewluck.me.uk/video/Milky_Way.mov

Categories
Solar System Sun

Sun spots

The current active phase of the Sun continues apace with another large sunspot group crossing the face of the sun over the last few days.  I took this picture yesterday just before sunset which shows AR1520, the large grouping at the top of the picture with 1519 & 1521 the two at the very bottom.

Edit:At 16:53 UT on the 12th Jul sunspot AR1520 unleashed an X class solar flare in the direction of Earth. http://www.spaceweather.com has further details.

Categories
Deep Sky Galaxy

Remote imaging

Long time readers of this blog will know that from time to time I’ve used remote telescopes for imaging. On occasion, it may be the only way to photograph a particular target e.g. southern hemisphere, or it may provide access to equipment that is out of reach financially or just wouldn’t be practicable to implement at home. I know that this causes problems for some amateur astronomers who may feel that you can’t take ownership of an image if you can’t claim every stage of the process as your own, including actual possession of the equipment used. I take a wider view in that, provided you have identified the sources used, no one is being misled as to the provenance of the images. The individual astronomer still has an input in the collation and presentation of the data.

While attending a meeting of the Webb Society at the Cambridge Institute of Astronomy my eye was caught by one of the pictures on display, an image of a gravitational lens. Such objects were predicted by Albert Einstein and are formed when light from a distant object is bent (or lensed) by gravity around a massive foreground object. In this case the foreground object is a Luminous Red Galaxy (LRG 3-757) and the source is a star forming galaxy. The ring has a diameter of 10″, the LRG has a redshift of 0.44 (or 4.5 billion light years) and the source galaxy has a redshift of 2.379 (10.8 billion light years). Both components are approximately magnitude 20. For anyone interested in the detail the Astrophysical Journal paper is available here. Once home, I did some initial research on this object and went looking for images.

Some time ago I’d become aware of the Hubble Legacy Archive but not had the time to take a detailed look at it. A recent Sky & Telescope article by Robert Gendler rekindled my interest and having found the RA and DEC coordinates for LRG 3-757 I entered them into the search engine on the site (http://hla.stsci.edu). This returned a list of images in the archive for this object and three looked suitable for a colour image; 475nm, 606nm & 814nm corresponding to blue, green and red wavelengths.

Downloading this dataset took some time (each image was 300MB) and each was stretched in FITS Liberator before colour combining using Maxim DL. Once the colour balance looked roughly right I exported the tiff file into Photoshop for fine tuning and noise reduction.

The result is here:

Is this the ultimate in remote imaging? Well, I’ve finally got access to a telescope that’s unaffected by clouds and atmosphere & cost billions of dollars to build, commission and service. It seems a waste not to make full use of it.

Categories
Solar System Sun

More sun watching

A break occurred in the clouds just before sunset on friday so I took the opportunity to image the large sunspot group currently crossing the face of the sun. My front porch has a reasonable gap between the trees so I setup the Zenithstar on the Astrotrac and attached the Canon 350D.

Zenithstar 70 on Astrotrac

I stacked about 40 images from the Canon. Individual exposures were 0.003 seconds at ISO 100. The focal length is 420mm.

Categories
Solar System

Venus transit

My original plan for the transit was to observe from Ness Point at Lowestoft; the most easterly point in the UK. However, by tuesday afternoon, the forecast, which hadn’t been looking good was getting worse so I started looking for alternative sites. The Royal Astronomical Society had a webpage showing organised events so I started comparing the sites with the weather forecasts. Abingdon stood out as being behind the band of rain and the BBC were showing a clear spell developing about 4am.

Setting out just after 8pm I drove through the rain and was on site in the car park by 11:30 where I got my head down for a few hours sleep before dawn. Upon waking, I was puzzled for a short while by the bright light in the rear view mirror until I realised that it was the setting moon, the BBC’s cloud cover forecast was correct! A few of the Abingdon Astronomical Society members started showing up after 4am so I setup the Astrotrac with Zenithstar while waiting for both the dawn and the band of cloud in the north east to clear.

Unfortunately, the cloud stuck with only a couple of short glimpses of the sun through it. Frustrating, yes; disappointing, yes; but at least I’d had better odds than if I’d stayed at home. As the transit ended, right on cue, the clouds parted. I stayed around to take a few pictures of the sun. Venus is in the picture as well, you just can’t see it.


My thanks to the Abingdon Astronomical Society for setting up a fine event. Here’s to better weather in 2117!

Categories
Solar System

The Sun

As part of my preparation for the transit of Venus I constructed a Baader solar film filter for the front of my Zenithstar. I followed the instructions on the Baader website and used the card from the back of A4 photograph envelopes to construct the film holder. The resultant assembly fits snugly over the front of the dew shield.

As a practice run I took 20 exposures with the Canon 350D. Focusing is tricky and I elected to acquire the images using Maxim which displays the images on the laptop screen where they can be enlarged to any size. The images were stacked in Registax and the contrast was then stretched in Photoshop.

The resultant white light images show sunspots well and several large groups are visible in this image.


Mid point of exposures: 2012-06-04T18:04:47 UTC

Categories
Solar System

Saturn

Well, that was the third clear tuesday club night in a row. After the spring we had it’s certainly welcome.

After looking at the slender crescent of Venus as it moves towards transit in a few days time we turned our attention to Saturn. Using the club’s Imaging Source camera and a x2 barlow on the 20″, Dan and I shot a 7500 frame video. This is the result of stacking the best 1000 frames in Registax 6 followed by a slight blur in Photoshop.

Categories
Deep Sky Galaxy

NGC 4517

I found this galaxy in Sue French’s wonderful Deep Sky Wonders book while looking for a suitable target for the 20″. With the summer twilight we didn’t get started on it until after midnight and got 15 1 minute exposures. Of these, 6 were rejected due either to car headlights or star trailing so the result could use a lot more exposure.

What atracted my attention was that it’s an edge on spiral (as opposed to the Virgo cluster’s usual ellipticals}, it’s fairly bright and it’s also large at 11′ long.

The sharp eyed will notice that the picture’s identification is NGC 4437. This galaxy appears to have two designations.

Categories
Deep Sky Galaxy

The Sombrero revisited

I finally figured what I was doing wrong with the colour and here’s the final result. In a nutshell, auto-background equalisation coupled with too much contribution from the red channel was resulting in some pretty strange effects.

The Sombrero is never well placed from the UK and only gets to about 25 degreees elevation at the Breckland observatory.

Categories
Deep Sky Galaxy

The Sombrero Galaxy

Having just got back from the Kelling Heath star party I would normally be processing images taken there. The weather for the event this spring didn’t co-operate though so while we still had a great trip the actual astronomy time was zero.

So it’s back to an image I took with Dan on the 20″ last sunday of M104. I’m having real trouble adding the colour into this image so while I struggle with that here’s the luminance frames.

Frames: 30x 30 seconds
Bin: 2×2