Hampshire Astronomical Group
Celebrating 50 years (1960 - 2010)
Astro-Physics 7-inch 'Starfire' F9 Apochromatic Refractor
The 7 inch Starfire refracting telescope is one of the most modern refractors housed in any of the domes at the Clanfield Observatory. This telescope is computer driven and also has the ability to be electronically guided during long imaging exposures of the night sky. This effectively means that images taken through this telescope offer pin point stars and the images can be of high quality.
This telescope was originally owned by one of our members, the late Douglas Arnold. Douglas was an author as well as an astro-photographer of high regard. Many of his images adorned his and other’s books and were frequently shown for many years by Patrick Moore on the BBC’s Sky at Night program.
Upon his death in 2006, Douglas 's widow Audrey, very graciously donated his pride and joy that stood so proudly in the garden of their home, complete with the dome in which it was housed, to the Group. The dome and telescope were dismantled, brought to the observatory and in 2006 ground preparations were made so we could to re-erect this observatory. Following the re-assembly the observatory was officially opened by his widow, Audrey, in May of 2007.
The lens in this telescope is of modern design is known as an Apochromat as opposed to the lens design in the older telescopes on site.
If Achromatic means "no colour" then Apochromatic might be ‘defined’ as "really, really no colour". While an Achromat brings two wavelengths of light at opposite ends of the spectrum to a common focus, it still leaves some residual chromatic aberration along the optical axis.
‘Apos’, as they are affectionately known by astronomers, eliminate residual chromatic aberration almost completely by using two, three or four- element objective lenses using special glass type (often Fluorite) SD' Special-Dispersion or 'ED' short for extra-low-dispersion glass. Apochromats minimize dispersion of light by bringing all wavelengths to just about the same focus.
For either visual or photographic use, ASTRO-PHYSICS Apochromatic Refractors are regarded as some of the best refractors. Consequently, the view through this telescope is of very high quality. We are extremely fortunate indeed to have such a fine telesocpe housed in one of our Observatories.