* Astronomy

Members Login
Post Info TOPIC: Hydrogen Alpha Filter


L

Posts: 131433
Date:
RE: Hydrogen Alpha Filter
Permalink  
 


SOLARMAX II 40 FILTER WITH RICHVIEW TUNING AND BF10

Coronado by Meade SolarMax II 40mm Solar Filter set with RichView tuning system. Includes 40mm diameter primary H-Alpha etalon filter with sub 0.7 angstrom bandwidth and 10mm Blocking Filter. Recommended for telescopes with a focal length of 1000mm or less to provide a fully illuminated image on the solar disc.
USD $ 1,099.00

Source



__________________


L

Posts: 131433
Date:
Permalink  
 

The sun has two prominent element spectral lines: Hydrogen Alpha and the Calcium K-line (at 3933 Angstroms). A hydrogen-alpha filter, or H-Alpha filter, blocks all parts of the solar spectrum except the alpha spectral line of Hydrogen at 656.281nm (6562.8 Angstroms), and allows you to see fine detail on the solar surface or prominences.

A hydrogen-alpha filter is an optical filter designed to transmit a narrow bandwidth of light generally centred on the H-alpha wavelength. They are characterised by a bandpass width that measures the width of the wavelength band that is transmitted. These filters are manufactured by multiple (~50) layers of vacuum-deposited layers. These layers are selected to produce interference effects that filter out any wavelengths except at the requisite band
Read more


Credit rockinho131

H-Alpha filters are sophisticated and thus expensive.  

2 Angstrom (±0.5 Angstrom) H-alpha-Filter 1'/4"

£662.40

Read more  


H-Alpha filters are sophisticated and thus expensive. The quality of the filter is denoted by the bandwidth of the H-Alpha part of the spectrum which the filter passes - a narrower bandpass means less visual "noise" and more detail. The bandpass is measured in Angstroms (one ten-millionth of a millimetre) and traditionally the less expensive H-Alpha filters have been 1.5 Angstrom filters while the most expensive have been 0 .8 or 0.7 Angstrom filters. However, there is a difference in what you can best see, between these two types.
Read more

Venus Transit 2004


Credit BaaderPlanetarium

Note: an emission line H-Alpha filter used for viewing or imaging nebulae or deep sky objects should NOT be used for solar observation. These filters have a too wide bandwidth (15-7nm, and therefore not contrasty enough) compared with a 'proper' solar H-Alpha filter (with a narrow ~0.7nm bandwith. 

An Angstrom is 1/10th of a nanometer; and a nanometer is 1 billionth of a metre.



__________________
Page 1 of 1  sorted by
Quick Reply

Please log in to post quick replies.



Create your own FREE Forum
Report Abuse
Powered by ActiveBoard