It was clear last night, the first truly clear night in a long time, but very cold. Ambient temperature was -18c. I opened the dome and started things up, to have a series of mount problems. Guiding was very ragged, jumping around a lot.
Here is a test RGB image of NGC6888 just to see how the partially-collected data might look together. No Red collected yet, so this uses Green and Blue in their proper roles, with Hydrogen-Alpha as the Red channel. 160 minutes Ha (as Red) 120 minutes Green 180 minutes Blue Calibrated & stacked in CCDStack, post-processed and colour-combined in Photoshop.
The moon was quite bright - between 1st quarter and full - and washing out the sky a little. However, NGC6888 is an emission nebula, so produces a fair amount of H-Alpha light, and this is much less affected by moonlight.
The first night I managed 70 minutes in 10-minute subs. The next night, 90 minutes more in 15-minute subs. So, for the start of this project, this is 160 minutes of H-Alpha in 10-minute and 15-minute subs.
|I was able to capture an hour of Red data for M13 under good steady skies. I thought it might be interesting to share the colour channels data for such projects as they are collected, in case others might like to use them to experiment with processing, colour combination, etc. (I found few such examples to play with when doing my own searching some years ago.)|
Now, in mid-autumn, the sky has rotated to the point where M13 is well-located from my observing spot - and it's dark earlier too. So I started an M13 data collection project tonight with 2 hours of luminance data, in 5-minute subs. Colour will follow over the next few available nights.
I re-did the blue channel in 3-minute subs, getting 27 of them before the target sank below my hedge. This larger number of subs reduced the noise in the channel quite a lot (although it is still a bit noisy).
I have gathered at least some data now for 3 colour channels and luminance, and did a first combination tonight. It needs more colour data to improve the signal-to-noise ratio, especially in the Blue channel which was taken through light cloud and is very noisy. However, it's still quite pretty and I'm pleased with the result so far.
July 30: I was working on M51 data, but it eventually rotated below my hedge. I have a little time left, so decided to also start an M101 project, since it is well-positioned in my sky at this time of year.
This is the first set of Luminance, total of 1.5 hours in 10-minute sub-frames.
I've started a multi-night project for M51. July 28 was the first chance to catch Luminance data, 1.5 hours so far (in 5-minute subs). Sky-glow is fairly bad in this part of the sky (removed manually in the attached shot), and will require some careful processing as I get more data.