Collimation: An article on collimating a Newtonian telecope"
Since completing my science degree with the Open University I have not managed to develop my observing skills as much as I would have liked. However, I am just starting to make the transition from "sightseer" to being a more dedicated observer and enjoy observing binary (or more) star systems and variable stars. I have developed an observation log sheet; please feel free to download a copy for your own use and / or modification here (needs MS Excel)- Astronomy observing form v1.0.xls).
To help plan my observations I have developed a computer program to calculate the azimuth and altitude of selected objects (according to their RA-DEC), at the same time of day, for a user-selected number of days. If you are interested please feel free to download a copy of Alt-Az here.
In 1999 I went to Amiens to view the total solar eclipse. This link will take you to the results of my light-level observations during the eclipse: Results of observations from August 11 1999 Total Solar Eclipse.doc
- These results were published in both the British Astronomical Association's official CD-Rom on the event and Eclipse, Vol 28 No. 3 (The journal of the South East Kent Astronomical Society)
If you are interested in taking your own pictures of a lunar eclipse, the exposure details given on this table ( Jan 9th 2001 lunar eclipse photo schedule.doc) might be of use. I used them to photograph the eclipse of 9/1/2001.
I have been observing with a 6" Newtonian reflector(Europa 150 from Orion Optics) since 1998 ; it looks something like this one.
The tube has a focal length of 750mm, making it reasonably "fast" at f5. The telescope has a motor drive on the RA axis and I have added a 10x50 right-angled finder scope. My only criticism of this telescope is that it was supplied with the main mirror lacking a centre spot, which made collimation difficult. However, adding a centre-spot was simple and collimation is now an easy task.
I use 25mm, 9mm and 2.5mm eyepieces in combination with a 2x Barlow, which yield the following magnifications and fields of view :
25mm Plossl - x30 magnification, 84 arc mins field of view
25mm Plossl + 2x Barlow - x60 magnification, 39 arc mins f.o.v.
9mm Kellner - x 83 magnification, 30 arc mins f.o.v.
9mm Kellner + 2x Barlow - x167 magnification, 13.5 arc mins f.o.v.
2.5mm Lanthanum - x300 magnification, 8.0 arc mins f.o.v.
Whenever possible I try to supplement my observations with measurements of how dark the sky was. I achieve this by using a "Pitch Black Meter" as described by Gote Flodqvist in her February 2001 Sky & Telescope article. The parts for this instrument were easy to find and it was simple to construct. The electronic components and enclosing box cost GBP38.00 from Maplin Electronics, and the green objective filter was an extra GBP6.00 from a camera shop. Anyone wanting to build a PBM can get hold of the design from a back-issue available from the S&T website here.
I am slowly working on a guide to Pegwell Bay (Ramsgate, Kent). As well as being my local "beach", Pegwell Bay is the
'type location' for the sub-eocene unconformity; a break in the geological record
between the underlying chalk (dating from the Cretaceous Period, about 100 million years ago) and the overlying Thanet Beds
(dating from about 70 million years ago). The unconformity itself is marked by a bed of unworn, green-coated flints (called the
The first step to producing this guide was achieved in 2005 when my paper on the Geology of Pegwell bay was published in the Open University Geological Society Journal (Spring edition 2005, Volume 26(1)) – a copy of the paper can be found here: The Geology of Pegwell Bay.
When completed, the guide will discuss the origin and evolution of the structures present, as well as the wider historical and natural scientific background of the site.
Attached here is my small write up of a visit to the fossiliferous beach at Portishead.
All Geology content on this page is © Lee Russell