CCD imaging activity as it happens
I finished processing the NGC 281 image this evening. This is a HaRGB image (300:120:180:120), total exposure time 12 hours
I used Robert Gendler's technique of blending the hydrogen alpha data with the red filtered data to use for the RGB image, then layering in the main hydrogen alpha data. It results in less washed-out reds in the nebula
A busy couple of nights
Yesterday I managed to get two hours of blue data for NGC 281 and then once it had crossed the meridian I switched to M45 and captured nearly two hours of blue data.
This evening with it being cloudy, the camera has been taking dark frames
Progress update:
NGC 281
Hydrogen alpha - 5.5 hours
Red - still to shoot - aim for 2 hours
Green - 3 hours
Blue - 2 hours
M45 Pleiades
Luminance - 1.5 hours
Red - still to shoot - aim for 1.5 hours
Green - still to shoot - aim for 1.5 hours
Blue - 1.75 hours
Unexpected clear skies this evening so decided to gather some more NGC 281 data. I acquired 3 hours through the green filter before the scope cables hit the mount. I then decided to capture some luminance data for M45 The Pleiades; another target I'm interested in.
As I have been using 5 minute subframes I will need some 5 minute darks at -22 degrees
RGB and Hydrogen alpha flats captures at twilight this evening.
Guiding performance was good, especially in declination due to the better polar alignment
Last night I managed another 2.5 hours of NGC-281 in hydrogen alpha. I spent a little longer than usual setting up as I'm still getting to grips with PHD2 and the need to optimise the polar alignment for best results.
Autoguiding performance was very good, with good RMS values for both RA and Dec. Sub-pixel guiding was achieved ensuring round stars in all 15 minute subframes.
This evening the CCD is busy capturing dark frames and I'll run the Bias frames later.
After some disappointing weather over the last 12 months, I've taken my first proper deep sky image again in 2016. NGC 281, The Pac-Man Nebula is a nice easy target in Cassiopeia. This latest image is simply 2.5 hours of hydrogen alpha data, no darks, flats or bias frames. Naturally the image will be reprocessed when these calibration frames are available. I also want to add another evening's worth of data when the weather allows it.
NGC 281 will be my project focus over the nest few sessions. Firstly I will create a HaRGB image, then shoot O-III and S-II data to create a Hubble Palette image. The narrowband data will need to be several hours per filter to achieve a good image. I will be aiming for at least 5-6 hours per channel.
I am now using PHD2 autoguiding software with its added features. In order to improve guiding performance I have started using the polar align assistant which allows even greater polar alignment accuracy than the Takahashi EM-200 polar alignment scope does. Given the declination backlash which unfortunately plagues the EM-200, a very accurate polar alignment will reduce much of the declination drift and any necessary corrections. Guiding performance was very good last night despite the wind. Polar alignment was accurate and declination guiding corrections kept to a minimum. Sub-pixel guiding was still achieved with round stars in each of the subframes.