radio scatter

Radio scatter of July Meteors

Here is the July meteor data based upon radar backscatter from Graves. As commented by http://meteorshowersonline.com/july_radiants.html

“Although the July radiants do not individually produce strong rates, activity from the Aquarius and Capricornus regions in July and early August, as well as minor activity from other radiants, cause hourly rates to basically rise between the middle and end of July for observers in both the Northern and Southern Hemispheres. Therefore, clear, moonless nights can be quite enjoyable for anyone observing during late July. “

there is a definite increase in activity towards end of month, where we are also entering the Perseid stream ( July 23 – Aug 22nd) and there has been a noticeable increase in fireballs picked up by NASA all sky monitors ( see Spaceweather.com)

Moderate Activity:

Radiant Duration Maximum
Southern Delta Aquarids (SDA) July 14-August 18 July 28/29

Minor Activity:

Radiant Duration Maximum
Alpha Lyrids July 9-20 Jul. 14/15
July Phoenicids (PHE) July 9-17 Jul. 14/15
Alpha Pisces Australids July 16-August 13 Jul. 30/31
Sigma Capricornids June 18-July 30 Jul. 10-20
Tau Capricornids June 2?-July 29 Jul. 12/13
Omicron Draconids July 6-28 Jul. 17/18

 

I have also combined last years daily counts with this years for comparison:

although the count rates vary, there is some mirroring of variation early in the month, but there appears to be an increase rather than decrease in activity during the latter stages of the month. Notice also the diurnal nature of activity, particularly during the second half of the month, where activity is very high during the early hours of the day ( see Hourly meteor rate) .This is a good pointer to observing the Perseids later this month, with peak activity from midnight , through the early hours of the 12-13 Aug, a waning Gibbous moon will be rising around midnight which might interfere with viewing, but it stays relatively low in the sky as the Perseid radiant climbs higher. The shower is active from July 23 till Aug 22nd with best views during the nights of the 11, 12 and 13 Aug. Definitely worth getting those all sky cameras we have made up and running to record shower activity.

clear skies

 

Pete H

Testing radio astronomy equipment to determine whether it is capable of detecting meteors

I have been experiencing difficulty detecting meteors at LRO.

Today, I obtained the following advice from my radio amateur friend, Bill Watson. As the advice is particularly useful, I felt I needed to pass it on:

If I can detect the GB3VHF Kent Beacon 144.430KHz at LRO then I will be able to pick up meteors from Graves’ radar. Simply put, if this signal can be detected by my meteor radio scatter detection equipment then I should be able to detect meteors adequately for meteor rate recording. The signal will not be large but it will be detectable. If I can not detect the Kent Beacon then I will not be able to detect meteors.

To detect the Kent beacon set receiver to 144.430KHz and CW mode. The beacon is always on (unlike meteor showers!) so if I can’t detect it then there is a problem with my set-up.

(Note Graves is on 143.049MHz and side band).

There is also something else that this test will do which is important – many radio receiver dongles are not accurate on their frequency and the user needs to determine an offset frequency. Once determined this can usually be entered into the software settings to correct the dongle’s frequency. If this has not been done then the frequency on the computer will be inaccurate and meteors will not be detected because the dongle is not correctly set to Grave’s frequency.

To determine the offset simply find the Kent beacon around 144.430KHz – any difference in frequency shown on PC from 144.430KHz is the offset frequency needed.

At LRO (Lichfield Radio Observatory) we are using Moxon aerial (homemade by Bill), FunCube Dongle Pro Plus, Spectrum Lab software, for radio meteor scatter detection from Graves in France.

Andy