16. May 2017 · Write a comment · Categories: Astronomy, Radio · Tags:

Listening to the ISS portion of a direct contact via F8KGY with students from Lycée Hélène Boucher, Thionville, France on Thu 2017-04-27 with astronaut Thomas Pesquet, KG5FYG. Sorry about the wind noise!

Equipment used:
Antenna: Arrow II Antenna
Radio: Yaesu FT-817ND

When I was in school, I remember being told that it was possible to tune an FM radio do a free frequency low in the band and during a meteor storm you could ‘hear’ when meteors struck the atmosphere as the FM signal from distant radio stations would be reflected back down from the ionised meteor trail. This may have been possible as back then there were plenty of high powered FM stations from Eastern Europe using a lower portion of the spectrum and receivers often went below the 88.5 that is the limit on the dial now. But I never heard anything. Over the years as my interest in meteors and radio was peeked I looked into it again, but the number of stations to use was dwindling and there were few artificial sources that could produce an audible ping. More »

I’ve been having a problem over the past few months of the focus in my scope drifting unacceptably out of focus when imaging targets around the sky. Even when staying on same target for extended periods of time there was a noticeable shift. In some extreme cases the collimation also appears to be way off. This seemed to be a rather severe case of mirror shifting that larger SCT’s suffer from. The solution to which is to securely fix the primary mirror within the cell, usually by threading bolts into the mirror from the back of the scope. This seemed to fit the symptoms I was seeing, though some people did mention that I shouldn’t bee seeing this sever an effect with a relatively small scope. So yesterday I decided to disassemble the scope and see what the back of the primary was like and if it would be possible to secure it. It didn’t take me long to discover a more likely cause. More »

One of the people at our table at the COSMOS star party this brought up the topic of long distance radio communications and the use of geostationary satellites to facilitate such communication. The idea of trying to image some of these satellites then came up and we discussed the possibility.

So last night I decided to give it a go. More »

Motivation

My main interest st the moment is in minor planet astrometry, particularly of brighter Near Earth Asteroids. In order to get precise astrometry of these objects it helps if they are not moving in a single frame. Slow NEO’s can have rates of several arcseconds per minute so being able to take short exposures and stacking them is often required to get precise enough astrometry. It is possible to compute the minimum exposure needed for an asteroid by ensuring it’s movement does not exceed the FWHM of stars in your image, e.g. if an NEO is travelling at 4”/minute and you have a FWHM of 4” then an image one minute in duration will not show trailing. However it is also necessary to understand what the minimum exposure you can take with your setup is to minimise noise and maximise the signal to noise ratio. And it was necessary to understand the camera characteristics in order to make that determination. More »

m82sn Supernova in M82 from Earlier in the week, now designated SN 2014J. Quite a bright supernova. It’s bright because it’s practically next door – 12 million light years. This is a Type Ia supernvoa caused by a white dwarf in a binary system gaining enough mass to trigger new nuclear fusion and cause the supernova explosion.

On Christmas Eve the Catalina sky survey spotted an object that had not been seen before. Shortly after McDonald observatory in Texas confirmed the object and further observations were needed to help nail down it’s orbit.

We had clear skies on Christmas night so I checked the Minor Planet Center NEO page to see if there were any possible targets and sure enough the object, provisionally called UY31A3B, was within the range of my equipment. More »

More of a note-to-self than a blog post… How to go about confirming NEO’s listed on the NEOCP. More »

I’ve recently tried taking some long exposure images just to see how the observatory handles the light pollution. To make life easier I’m using an Astronomik CLS-CCD filter with the DSLR. The one I currently have is for a t-ring, though since these images have worked out well I think I’ll get the clip in version to experiment with regular lenses. More »

Astrometrica is a great piece of software to analyse images to search for and record the positions of objects. However getting it to work with a DSLR image can be a bit tricky. Here’s how I do it: More »