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Solar Imaging at SkyBadger.

solar imaging at Skybadger goes back a long way. One of the first attractions to the sun was due to the mentorship of Harold Hill, an amateur astronomer now celebrated in print by his lunar drawing book but also an avid and well known solar observer. Harold had an observatory ( well 3 actually ) in his backgarden. One for the Criterion Dynamax 8" with a Daystar H-Alpha filter, one contained a 3" prominence scope and the last contained his 10" Newtonian. Shortly after meeting Harold I turned towards Solar astronomy as part of meeting my Astronomy 'O' level practical requirement - three practicals were required, one of which was going to be measure the solar rotation period using sunspots. At that time I had an 8" homebuilt Newtonian reflector and access to a 6" refractor at school.

Following that I went on to an Astronomy degree learning Solar Physics at UCL. Now I was hooked. So much dynamics!

Insert 'Inappropriate observing of the the sun will damage your eyesight warning' here


Equipment

  1. Full-aperture Mylar filter

    This aluminium coated plastic filter attenuates the suns light by up to 5 orders of magnitude and is IR safe. ( I measured it on a Grubb-Elmer spectrometer while still at Pilkingtons Research Labs... ) The down side is that when stretched tight the microscopic holes in the aluminium layer get larger so it must be double side coated to minimise this leakage. The upside is that a slack filter has very little detectable effect on the resolution through the eyepiece. jump to the pictures

  2. Herschel Wedge solar Diagonal

    This uncoated diagonal reflector attentuates the suns rays by 4 orders or magnitude by a combination of initial reflectance of 98% of the suns light away from the eyepice and then by use of ND 2 filters and cross-polarisers to tune the final brightness. The wedge angle of the surface of the diagonal tapers so that most of the light is reflected out of the back surface of the diagonal and only a small internal reflection from unsilvered galss is reflected to the eyepiece. Mine was provided by Intes through Baader of Germany. I highly recommend it for visual viewing of sunspots at full working aperture. jump to the pictures

  3. Hydrogen Alpha Filters

    This filter consists of a stack of interference films that combine to allow only a very narrow passband of light through at the wavelength of the Alpha line in the Hydrogen Balmer series at 6563.6 Angstrom. The purpose for all this is to see the features at the bottom of the chromosphere which emit strongly at this wavelength. Other alternatives are Calcium K and H Beta. Use of this filter shows all the photospheric features across the disk which are hardly visible in integrated light due to the low contrast available. The filters show filaments, flares, plages and faculae in much greater relative contrast then before. this is where solar dynamics really comes in. Using this filter you can watch the ejection, growth and decay of huge prominences under the course of an hour. jump to the pictures

References

  • Foukal - Solar Astrophysics. Pub. John wiley and Sons.

  • Baxter - Introduction to the Sun


The pictures

Skywatcher ED80 and Herschel Wedge + nd3 filter & Nikon CP8700 on MaxView40 : 10755 & 10756

2005 May 01


The image above is that of the recent Transit of venus after third contact. The whole episode was imaged through a webcam and Herschel Wedge on an 80mm RFT mounted on the Visac/GPDX. Each image was captured on a timed basis by the DCAM webcam server application and then a WSH script served to copy and timestamp the image to preserve it from being overwritten. You can find the script here.
The set of images was assembled without further processing using Image Magick and the convert command into the animated gif above. The middleof the sequence loses the sun as the sun rotates behind the dome slot while I was at work. I had to ruing up and get the wife to move it!. Click on the image to download the animation.

Vixen SP102M and Herschel Wedge + nd3 : 10486, 10488 and lots of little children

2003 Nov 27

Vixen SP102M and H-Alpha filter : Composite of long and short exposures

2003 Oct 23

Vixen SP102M and H-Alpha filter : Monstrous sunspots AR 10486

2003 Oct 26

Vixen SP102M and Hershel wedge Monstrous sunspots AR 10486

2003 Nov 01

Vixen SP102M and OM1 Kodak Royal gold 125 ASA and 26mm eyepiece projn at F/40

2002 Jul 22

06/13/03 8:08:08 AM

More solar images here