John Hothersall
28-06-2012, 07:32 PM
SPX350 F9.1, Mintron (GStarEx),2xPowermate, Baader RGB+Astronomik UHC filters.
The UHC filter needed an IR block to lift contrast and gave much better structure to the PN even though they were faint compared with the brighter Luminance filter which gave a very soft image.
Menzel 3 mag 13.8 (The Ant Nebula - 85" wide) in Norma was tricky to find even though it was near to Gamma Normae and its brightest parts looked like 10th mag. It took 2hours of the maximum exposure of the sensitive Mintron at 3.2 meters FL with the UHC filter to get the wispy legs of the Ant to show strongly.
Minkowski 2-9 (The Butterfly Planetary - 75" wide) was the faintest at mag 14.7 but looked more like 11th mag once I managed to find the pesky little devil somewhere North of star Eta Oph. The Bipolar rays coming out of either side of the central star where faintly seen in the UHC filter. These strange rays are thought to eminate from a binary at the centre, an animation in professional scopes (http://en.wikipedia.org/wiki/File:M2-9motivo_corradi.gif) shows its development over 18 years.
The Retina nebula IC4406 95" wide in Lupus west of Eta Lupi was the brightest at mag 10.2 but that was in the central part while the outer parts could not be glimped in the single exposures.
Thanks, John.
The UHC filter needed an IR block to lift contrast and gave much better structure to the PN even though they were faint compared with the brighter Luminance filter which gave a very soft image.
Menzel 3 mag 13.8 (The Ant Nebula - 85" wide) in Norma was tricky to find even though it was near to Gamma Normae and its brightest parts looked like 10th mag. It took 2hours of the maximum exposure of the sensitive Mintron at 3.2 meters FL with the UHC filter to get the wispy legs of the Ant to show strongly.
Minkowski 2-9 (The Butterfly Planetary - 75" wide) was the faintest at mag 14.7 but looked more like 11th mag once I managed to find the pesky little devil somewhere North of star Eta Oph. The Bipolar rays coming out of either side of the central star where faintly seen in the UHC filter. These strange rays are thought to eminate from a binary at the centre, an animation in professional scopes (http://en.wikipedia.org/wiki/File:M2-9motivo_corradi.gif) shows its development over 18 years.
The Retina nebula IC4406 95" wide in Lupus west of Eta Lupi was the brightest at mag 10.2 but that was in the central part while the outer parts could not be glimped in the single exposures.
Thanks, John.