Banner
Wednesday, 17 December 2014

VM - Shopping cart

 x 
Cart empty

VM - Search in Shop

VM - Currencies Selector



Gallery Stats

  • Images:   411
  • Categories:   94
  • Hits:   322919
  • Comments:   13
  • Votes   195

SearchBox

 
Home of South Common Observatory
Comet C/2014-E2-Jacques PDF Print E-mail
Written by Richie Jarvis   
Sunday, 31 August 2014 23:55

Tonights image of Comet C/2014-E2-Jacques taken from East Sussex with a TMB 114mm @ F/5.6 and a -30 degree C Starlight Xpress SXVR-H18, and astronomik LRGB filters whilst tracking the comet.  Combined in MaximDL and processed in Photoshop.  You can clearly see that I shot with a clear (luminance) filter first - the long white lines (stars trailing as the comet moves), and then followed up with a sequence of 2 minute images through a Red, Green and Blue filter.

One of the green exposures has a faint satellite flare just beneath the comet coma.  This happened at 2014-08-31 22:14:22GMT+0 - plus or minus 1 minute, and shows clearly on the exposure.  Another satellite also passed during the luminance exposures at 2014-08-31T21:27:27GMT+0, plus or minus 2.5 minutes - the faint white line passing to the right of the coma from top to bottom.

12 x 300 second Luminance
5 x 120 second RGB

Full details and a click-to-zoom version here

Last Updated on Monday, 01 September 2014 00:14
 
Photographing an Iridium Flare PDF Print E-mail
Written by Richie Jarvis   
Friday, 01 August 2014 15:50

Last night, I was taking 2 minute exposures of the constellation of Cygnus the Swan from my observatory.  This morning when I went through the exposures, I discovered I had caught something in one of the exposures.  It didn't look like a meteor, as it appeared to rise and fall in brightness over a period of time, whereas a meteor I would expect to start off dim and get brighter and then vanish.  My suspicion was that it was a satellite - specifically one of the Iridium group of satellites.

The Iridium satellites are used for satellite phone calls.  They are named because it was originally intended to launch 77 satellites providing call coverage around the globe.  However, it was determined that all 77 satellites were not needed to provide full worldwide coverage, so there are currently 66 operating satellites in orbit, with 6 spares in a holding orbit. The orbital height of the operational satellites is 485 miles on average.  They are travelling at 16,832 miles per hour, and complete one orbit of the Earth every 100 minutes.

The reason for the flare seen in the picture is that these satellites have 3 door-sized antennas angled at 40 degrees away from the main body of the satellite itself.  They are arranged equally, with 120 degrees between them.  When the light from our Sun hits the antenna, about 4-5 times a day the reflected light create a 6.2 mile wide circle of light on the surface of the Earth.  To an observer, this appears as a bright flash of light which suddenly gets brighter, then dimmer as the satellite moves over their head.  The date and time of each flash is easily predictable, as the orbit and attitude of the satellite is known precisely.

To find out whether I had accidentally caught an Iridium flare, and check which satellite and antenna  my camera saw the reflection from, I checked on http://www.heavens-above.com, which provides detailed prediction for most satellites circling the Earth, including the International Space Station and Iridium Flares.

I was able to determine exactly which satellite I had captured - Iridium 72 - and the reflection was from the front facing antenna (its direction of travel).  At the time of the flash, the satellite was 640 miles away.

Here is the track of the satellite from Heavens-Above.com showing the predicted position of the flare:

I PDF'd a version of the Flare information from Heavens-Above.com, which you can download here.

Attachments:
FileDescriptionFile size
Download this file (2014-08-01-010147-Iridium72-FlareDetails.pdf)2014-08-01-010147-Iridium72-FlareDetails.pdf 598 Kb
Last Updated on Friday, 01 August 2014 16:42
 
Work in Progress - Veil Nebula Mosaic PDF Print E-mail
Written by Richie Jarvis   
Saturday, 19 July 2014 15:22

I've taken many pictures of parts of the Veil Nebula over the years - you can see them in my Galley.  Back in the days when the New General Catalogue was compiled (thats where the NGC designation comes from), the parts of the Veil Nebula were given separate designations.

This year, I decided to see if I could take a picture of the whole of the Veil Nebula.  My camera (SXVR-H18) and telescope (101mm @ F/7) combination can only see 1.4 x 1.1 degrees at F/5.6 with my Televue Focal Reducer, so to get the complete veil requires taking images of different areas of the sky, and stitching them together.  You can see the boundaries of the panes in the image above.  Each 'pane' is the result of stacking many images together.  So far there are 97 images making up this mosaic.  So far, I have been concentrating on the Hydrogen emission wavelength with my Ha narrowband filter.

This will be a several year project, as I then need to shoot with an Oiii (Oxygen) filter, and then choose whether to shoot with an Hb (Hydrogen Beta) or Sii (Sulphur).  I might even be able to incorporate some of the data from previous imaging runs - time will tell.  I have some gaps to fill in the Ha band - I just need some clear nights!

Here are some of the other pictures I hope to incorporate should the inclination take me:

NGC6992/NGC6995/IC1340 is known as the Eastern Veil, or Network Nebula
NGC6992 is the bright area, NGC6995 is the 'rectangle' element of the Eastern Veil Nebula.  Between the Eastern and Western Veil, Pickerings Wisp is the fainter triangle shaped structure
NGC6960 is known as the Western Veil, Witches Broom, Finger of God, of Filamentry Nebula

At a distance of 1,470 light years away, the Veil Nebula is the result of a supernova which is thought to have exploded 5,000 to 8,000 years ago.  The resulting gas and dust released spread out into this 3 degree area of sky (roughly 6 times the diameter of a full moon) in the time since the explosion.  It is one of the largest, brightest features in the X-ray band.  The dust and gas is estimated to be travelling at the huge speed of 370,000 miles per hour away from the original star which spawned it.

Read more about the Veil Nebula and see a beautiful picture from the Hubble Space Telescope here: http://www.space.com/4136-veil-nebula-pierced-hubble-gaze.html


 
2014-01-22 - Supernova in Galaxy Messier 82 PDF Print E-mail
Written by Richie Jarvis   
Wednesday, 22 January 2014 21:14

This morning, I saw an interesting email come into my inbox.  It reads as follows:

Subject: [vsnet-alert 16812] Re: PSN J09554214+6940260: bright (11.7 mag) supernova in M82
At UT 2014 Jan 22.305, we obtained a spectrum of PSN_J09554214+6940260 (discoverer: S. J. Fossey) with the Dual Imaging Spectrograph on the ARC 3.5m telescope. We classify this as a Type Ia supernova with a Si II velocity of 20000 km/s. The best superfit match is SN2002bo at -14d. The supernova has a red continuum and deep Na D absorption.

A type 1a supernova is what happens when a binary star system starts to tear itself apart.  In essence, a very small dense white dwarf rips the material from the surface of its neighbouring star.  It appears to be relatively common when one of the stars in a binary star system inflates when it becomes a red giant.  The surface of the red giant is now much closer to the companion star, and so matter starts to transfer from the red giant to the smaller star.  As the smaller star accepts matter from the giant, the system becomes unstable, and the small white dwarf explodes violently.

The velocity quoted above shows that the shockwave of this star exploding is travelling at 20,000 km/s - thats almost 12,500 miles per second - pretty quick.

Type 1a supernovae are special because they allow astronomers to accurately gauge the distance from the Earth of the galaxy that spawned it.  Each one that is identified gives astronomers much more accurate data about the Universe around us.

I managed to gather a quick snap of Messier 82 tonight before the clouds rolled in.  This animation shows the difference between some Messier 82 images I took last year in February versus the 2 exposures I managed to capture tonight.

 

Last Updated on Wednesday, 22 January 2014 21:45
 

Latest Images

 

 

Solar System Viewer

 

 


 

Creative Commons License
All images on this website are owned by Richie Jarvis or Emily Jarvis unless otherwise noted
They are licensed under a Creative Commons Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales License.
Permissions beyond the scope of this license are be available at here