Author Archives: Peter Hill

August Meteors

Although not visually very active (clouds again!!) the Perseids were very prominent in the  radar data. In my post mid august the data showed a maximum daily rate of 313 on the 13th with a maximum hourly rate of 28 between 2-3am on 12th, and as the hourly plot showed the main activity was between 2 – 8 am hence missed by lots of people even if clear, Ed and Dave at Solarfest went to bed too early!!

The meteor count total for the month was 2999, with an average daily count of 97 and average hourly rate of 4.

The hourly and daily plots are below and for comparison below these  the August  daily count for the last 3 years, interestingly the shower peaked on the 13th in 2018, 2017 but on 12th in 2016, this however is only the daily count and a different set of conditional actions for recording events is now in use.

The final chart is a reposting of the 2018 shower data.

Perseid Shower 2018

The Perseids have been and gone, maximum hourly count was 28 between 2-3 pm on the 12th and the max daily count was 313 on the 13th. The hourly plot between 10th and 16th shows the daily shower distribution quite clearly, maximum activity picking up for 2pm onwards on most days , hence not many being seen, also the majority of counts were of low duration, so most not very bright, there were some longer duration signals associated with fireballs but not many and certainly not bright enough to trigger the all sky camera which I had running when sky was clear.( which wasn’t very often)

The Perseids are coming!

Monitoring of meteor activity using the reflection of the Graves radar signal with the fundongle pro+ shows a gradual increase in the daily count since start of month ( 78),  up to 109 for yesterday and the maximum hourly rate has now risen to 15, also noticeable is the higher frequency of longer duration events, that could indicate fireballs such as this trace below. The peak is due on the eve of 12/13 Aug but also possible to view on 11/12th , however forecast is not good for either night !! However with the increase in activity and higher incidence of long lasting trails it might be worth having a look on the eve 10/11th as at least it is supposed to be clear!

Sunday Observing / Imaging (05/08/18)

Started the day hoping to catch the latest sunspot  only to find once I’d set everything up it had disappeared, along with any filaments and prominences, absolutely nothing, even scanning the disc in the PST with the Hyperion zoom set on 8mm, nothing!

Come the evening I’d set up the 9.25″ Celestron SCT on HEQ5 pro under the carport to get a view south, by 9:30 pm Venus was very low in the Western sky and Jupiter was visible above my neighbours roof top, visually all 4 moons were visible and the major cloud bands were visible on Jupiter, imaging was a different story very wobbly, whether image was in focus or not was a bit hit and miss, even using the electric control on the feather touch focuser, using the ADC made some difference but not a lot. I captured an avi of 1000 frames using Celestron neximage5 camera the best 500 were stacked using Autostakkert and tweaked brightness, contrast RGB alignment and wavelets in Registax6 with a final tweak in Photoshop CS6. Really not worth the effort.

 

 

 

 

 

 

 

 

 

As Jupiter passed out of view Saturn was nicely placed , visually OK, Cassini divison clearly visible but imaging wise very hard work, same process as for Jupiter.

 

 

 

 

 

Just past midnight Mars came into view, very low, visually could make out S. polar cap and hint of some markings, poor atmospherics and the recent dust storm don’t help, a complete contrast to 2015 when it was a lot higher and major features like Syrtis major were clearly visible. Imaging , helped to enhance the dark light areas, processed as above Checking astronomynow.com/mars helped to identify features visible at time of observation.

July Meteors.

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.” ( http://meteorshowersonline.com/july_radiants.html)

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

The total number of meteors detected in July (2018) was 1824, with a mean daily rate of 59 and mean hourly rate of 2.5.

The maximum daily rate was 87 on the 26th July and the maximum hourly rate was 11, between 3-4am on the 27th and 30th.

The daily and hourly rates are shown in the first two charts below

These maxima coincide with the SDA shower and the trends over the month reflect the observation quoted at the start of this post. The trend of increasing activity towards the end of the month is borne out in the last chart below which compares the data over the last three years, the suggested trend is more pronounced in the 2016 and 2017 data than this year .

The Perseids are already with us peaking on the night of the 12/13th August, and with a new / very young moon there should be good viewing conditions as long as the clouds stay away.

Solar Images in H alpha, Calcium K and Visible

Most of my solar images have been taken in visible or H alpha , the Baader CaK filter in conjunction with a Herschel wedge provides a relatively “cheap” way of imaging in CaK.

Images in Visible light give detail of the photosphere , which we can consider as the Suns “surface”, above this is the chromosphere, the upper part of which is viewed in H alpha and mid section can be viewed in Ca K wavelengths. (Not quite this simple as there is some overlap, but broadly works this way) The Cak is sensitive to magnetic fields and the stronger the magnetic filed the brighter the image, this gives more detail of the plages around sunspots and more detail of how magnetic field varies in these areas.

After some time setting up a system to image in all 3 wavelengths a fine clear day arrived on Friday 22nd June and I imaged the sunspots and prominences , then went away, which is why I’ve only just finished processing images.

All images were taken using a mono CCD camera : Imaging Source DMK41, the H alpha images were taken using a Coronado PST, the Visual White light images with a Herschel wedge with a ND.3 filter and Baader continuum filter on the camera, using a Skywatcher Evostar 120 refractor. The Cak images were taken with a Baader Cak filter attached to DMK41 and using a Herschel wedge with either a ND.3 or ND 0.6 filter on Skywatcher  ST102 ( for full disc) and / or Skywatcher Evostar 120. All Images were 600 frame avi’s stacked in AutoStakkert, wavelets tweaked in Registax 6 and final processing in Photoshop CS6. Not having imaged for a while I soon realised that I needed to do some cleaning before the next session as the “dust bunnies”  were more numerous than usual, luckily I was either able to manipulate image to avoid most of them or eliminate them in processing.

I have left the images as mono as features show up better for comparison rather than processing in false colour.

Whole disc in CaK and H alpha, no prominences visible in CaK.

 

 

 

 

 

 

 

 

 

 

 

 

 

Main surface features in Cak in Evostar 120, left to right : faculae, AR2715, AR2713

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Faculae in Halpha x2 barlow

 

 

AR2715 In Cak, Vis,  H alpha (x2 Barlow)

 

 

 

 

 

 

 

 

AR2713 in Cak, Vis , H alpha (x2 Barlow)

 

 

 

 

 

 

 

 

Prominences x2 Barlow

 

 

 

 

 

Moon and Venus 15/07/18

Now 2 days old the moon at 11% illumination presented it self in the evening sky at an elevation of approx. 12 degrees at 21:30, easily visible, unlike yesterday when I could only pick it out using binoculars.

Its companion this evening was Venus, easily visible unlike mercury of the previous evening. Didn’t have to travel any further than front lawn for these shots.

Day old moon (and Mercury?????)

The day old moon was setting on the 14th July with mercury in close attendance, well I went to my usual spot for these events, set up Canon 450D on tripod with cable shutter release and 150-500mm Sigma zoom lens. Sunset well into the NW around 21:30 then patiently scanned horizon in W to WNW direction with 7×50 binoculars for sign of moon which was going to be a thin crescent of approx 3.4%. The more worrying feature was a low cloud bank across the horizon ( see Andys previous post to this) which made for a glorious sunset but was going to cause problems trying to view Mercury and in fact as mercury was about 1-2 degrees to left of moon and about 2 degrees below it never punched through the murk. First image of moon was at 21:46 and last at 22:06 as it slipped into the cloud bank.

1.F6.3,ISO1600, 1/500″, 500mm

2. F5.6, ISO1600, 1/1250″,289mm

3. F6.3,ISO 1600, 1/400″, 500mm

4. F6.3, ISO1600, 1/30″, 150mm

 

 

 

June Meteors

No major activity in June , the June Lyrids the most active around the 15th/16th of June, the peak is distinguishable on the daily count plot. The peak activity around the 10/11th, is probably the combination of the Theta Opiuchids and Saggitariids.  The rest of activity during the month a combination of the many minor showers present.

The dip in the daily rate on the 6th is due to Graves being off line between 01-05 hrs. The activity has dropped of to about 50 meteors / day towards end of month and has continued at this rate into July which is a relatively “quiet” month.

The plot is similar to the daily plot from 2017, although rates lower( this is probably dependent upon the density of the debris field the earth passes through )

I’ve listed the showers for June below as are the daily and hourly plots for June 2018 and the daily plot for June 2017.

Moderate Activity:

Radiant Duration Maximum
June Lyrids June 10-21 Jun. 15/16

Minor Activity:

Radiant Duration Maximum
June Aquilids June 2-July 2 Jun. 16/17
June Boötids June 27-July 5 Jun. 28/29
Corvids June 25-July 3 Jun. 27/28
Tau Herculids May 19-June 19 Jun. 9/10
Ophiuchids May 19-July 2 Jun. 20/21
Theta Ophiuchids May 21-June 16 Jun. 10/11
Sagittariids June 10-16 Jun. 10/11
Phi Sagittariids June 1-July 15 Jun. 18/19
Chi Scorpiids May 6-July 2 May 28-Jun. 5
Omega Scorpiids May 19-July 11 Jun. 3-6
June Scutids June 2-July 29 Jun. 27/28

Daylight Activity

Radiant Duration Maximum
Arietids May 22-July 2 Jun. 7/8
Zeta Perseids May 20-July 5 Jun. 13/14
Beta Taurids June 5-July 18 Jun. 29/30