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 »


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 »

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 »

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 »

Before I built the observatory I used to only use the laptop when I was going to try imaging. Now the laptop is almost always used unless I really am only doing visual astronomy and don’t want to bother with planetarium software, in which case the laptop and camera are a distraction to trying to glimpse the universe through Dublin’s light pollution. Here’s how I have things set up. This may not be ideal for you.

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I’ve already posted this on facebook, so apologies to friends who’ve already seen it! Jupiter taken 12th January 2013, 22:17 : More »

Now that I have the scope in the observatory on a wedge it’s time to start doing a little more astrophotography. And one issue I immediately ran into, especially with the field flattener in place, was the need for decent flat field images. I needed to make a flat box…

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Over the past week or so I’ve been sorting out cables in the observatory and testing cameras. Still only on al alt-az mount without guiding, but a good enough setup to try a few things. More »

I tried taking some deep sky images last night for the first time in several years. Not an ideal setup for my C9.25 – altaz mount, no guiding, no PEC training, no electronic focuser, unmodded Canon 400d and a bright Moon. Given that, I’m happy with the result of 20x30s exposures on one of my favourite objects: More »