All posts by albertw

Trooperstown SOTA Activation

Last Monday I had a meting at the Wicklow Mountains National Park office, and with Trooperstown so close I thought it would be a shame not to go up and do an activation. It’s a 4point summit, EI/IE-035.

Coillte provide a car park just before the bridge over the Inchavore River (T 160 970), but if you are feeling lazy you can drive up the forest road and park where the trail up Trooperstown starts (T 164 962). I found the forest road fine in my wifes Ford Fiesta, there is parking for a couple of small cars at the trailhead.  Continue reading Trooperstown SOTA Activation

Corraun Hill SOTA Activation

While in Mayo last week I decided I’d take a few hours to try a SOTA activation. There are plenty of summits to choose from, 8 around Achill and another 25 between the Nephin range and Ceide Fields. Robert Lloyd Praeger in 1937 wrote that “the Nephinbeg range of mountains is I think the very loneliest place in this country” and so it’s no surprise that many of the SOTA summits here remain unactivated. Slieve Carr, the highest mountain in the Nephin range, is about 14km from the nearest road and is surrounded by bog. An activation would probably require an overnight camp, but you would be camping in Irelands first Dark Sky Park so the view of the un-light-polluted cosmos alone would be worth it. All that though is part of the allure of these mountains. If you do feel the call of wild Mayo and want some help or perhaps a guide, get in touch with the nice folks at www.terrafirmaireland.com. 
Continue reading Corraun Hill SOTA Activation

Tonelagee SOTA activation with sotabeams linked dipole

I thought I’d try taking part in the IRTS 40m counties contest from a SOTA summit. My location and antenna at home isn’t great, so I figured that since it was a nice day that operating with only 5W on a summit would still be better than operating at home! The band was pretty poor for the contest but I did get 7 contacts and so managed the activation on 40m alone. I did bring a 2m antenna also just in case, and managed to get plenty of contacts into Wales and a Summit-2-Summit contact into the Pennines. 20 QSO’s altogether.

Continue reading Tonelagee SOTA activation with sotabeams linked dipole

Detecting Meteors from radio reflections

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. Continue reading Detecting Meteors from radio reflections

C9.25 tube wobbling

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. Continue reading C9.25 tube wobbling

Imaging geostationary satellites

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. Continue reading Imaging geostationary satellites

Analysing CCD characteristics and Determining minimum optimal exposure time.

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. Continue reading Analysing CCD characteristics and Determining minimum optimal exposure time.