Daystar filterS
SolaREDi
α
Telescope Operating Guide
Dedicated telescope for Hydrogen Alpha solar observing.
Wavelength: Hydrogen Alpha 6562.8 Å
Focal length 1375mm, F/23
Clear aperture: 60mm
Clear exit aperture: 32mm
2 element refractor.
Thank you for purchasing the DayStar Filters SolaREDi alpha tele-
scope. This telescope has an 80mm F/4.0 doublet and a TeleVue 4X
powermate to accomplish a focal length of 1375mm. It has a
reduced clear aperture of 60mm in order to accomplish the F/23 nec-
essary for proper operation. The diffraction limited resolution of this tel-
escope at Hydrogen Alpha is approximately 2.8 arc seconds.
WARNING: POINTING TELESCOPES AT THE SUN CAN BE VERY DANGEROUS
WITHOUT THE PROPER EQUIPMENT AND CONFIGURATION. NEVER POINT AN
ORDINARY TELESCOPE AT THE SUN WITHOUT A SPECIAL, COMMERCIALLY
MANUFACTURED SOLAR FILTER AFFIXED TO THE TELESCOPE. WHEN USING A
DEDICATED SOLAR TELESCOPE SUCH AS THE SOLAREDi, REGULARLY CHECK
THE TELESCOPE CONDITION TO BE SURE THAT NO PARTS HAVE BEEN ADJUSTED
OR TAMPERED WITH IN A WAY THAT THE TELESCOPE COULD COME APART.
WHEN FINDING THE SUN USING THE "Sol-Searcher", DO NOT LOOK THROUGH
THE HOLE. MERELY OBSERVE THE POSITION OF THE DOT PROJECTED THROUGH
THE HOLE ONTO THE VIEWING SCREEN. IF YOU SUSPECT THE SOLAREDi TELE-
SCOPE MAY NOT BE FUNCTIONING OR ASSEMBLED PROPERLY, DO NOT
ATTEMPT USE. ANY UNFILTERED LIGHT PASSING THROUGH A TELESCOPE CAN
CAUSE INSTANT AND PERMANENT EYE DAMAGE.
KEEP THIS OPERATING GUIDE WITH THE SolaREDi AT ALL TIMES.
The recent availability of CCD cameras and DSLR cameras has offered a
simple opportunity for solar observers to image the Sun in Hydrogen Alpha
with a Digital SLR camera. Please be advised, however, that due to the
nature of monochromatic light and its effects on a CCD camera, certain
effects usually occur.
The DSLR imager must be aware that most camera manufacturers (Canon
and Nikon) use an IR blocking filter which greatly reduces the transmission
of Hydrogen Alpha light. DSLR cameras without this IR blocking filter will
have better sensitivity imaging in Hydrogen Alpha.
The imager should also appreciate that the COLOR CCD chip is construct-
ed in a way that only 1:4 sensors detect red light. The other 3 sensors only
detect blue and green. So a color CCD chip (in a
DSLR or a CCD camera) will only offer 1/4 the sensitivity
and 1/2 the resolution of a monochrome chip.
Another effect present in CCD imaging of monochrome
light is the interference pattern - or Newton's Rings. The effect is similar to
interference testing of an optical surface between two flat surfaces. The
sensor and cover slip cause a small interferometer inside the camera and
cause a Newton's Ring moire' pattern. The CCD chip must be tilted to a
minor degree to prevent this pattern. Recent advances in aftermarket
adapters offer a simplified solution for the issue. This effect is a concern for
both color and monochrome sensors. An optional accessory is available
from DayStar (MG-0408) which can be used between the DSLR and
SolaREDi to adjust the light angle and extinct the interference pattern.
Fortunately, short exposures mean imagers can sort from hundreds of
frames over a span of time to select from superior seeing cells which occur
regularly. High speed imaging and sorting from hundreds of frames greatly
reduces the need for stacking.
o The Best Digital imaging success in Hydrogen Alpha comes with a MONO-
CHROME SENSOR.
o Digital imagers should consider a way to tilt their chip through adapters or
configuration.
o Digital imagers should consider high speed imaging to image-sort for
superior seeing cells.
Daystar recommends MONOCHROME CCD and high
speed imaging cameras with image-sort technique to
overcome seeing limitations. When Newtons’ rings
are present, we recommend the MG-0408
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