This is another reprocess of old data, this time of IC405 and IC420 along with the bright stars 16, 17, 18 & 19 Auriga between the nebulae.
The original post was here. Using Pixinsight, with final levels and saturation boost in Photoshop this is the new result.
Halfway between Perseus and Cassiopia and embedded in the Milky Way is this double nebula. This is the result of 4.5 hours of exposure gathered over two nights on my Astrotrac. Individual exposures are 10 minutes each through a Canon 75-300 lens at 135mm.
Processing was done in Maxim DL and Pixinsight. The image suffers quite badly from chromatic aberration and the stars have red halos that I’ve not been able to fully supress.
On Friday night the skies were actually clear for a while so I set the Astrotrac up for some images to test my Baader IR block filter under a sky with no Moon. The session was cut short by cloud but I did manage some images, pictures to follow.
Looking at the Society website I noticed that I’d imaged M83 using a Global-Rent-A-Scope system (now iTelescope) some time ago. A quick search of my hard disk turned up the original frames so I restacked then in Maxim DL and processed the L & RGB images in PixInsight.
Telescope: RCOS RC-10
Camera: SBIG ST-10
Luminance: 20x 2 minutes
RGB: 6x 2 minutes binned 2×2 (each colour)
I came across a folder on my computer hard disk called ‘Pending’. This contained 16 images (each of 5 minutes) I’d acquired in November 2011 of M33 and never got around to processing past the initial stacking. Several attempts at trying out some PixInsight processes later and this is the final result. I’m particularly pleased as the Ha regions (NGC 604 & NGC 595) are well defined even with just the OSC camera frames.
Telescope: WO Zenithstar 70
Camera: QHY9-C
Mount: Astrotrac
All the poor weather has given me a chance to look again at some of my older data to see if it’s presentation can be improved. As always, the answer is yes. There’s always something new to learn and I’m grateful to those individuals out there who are not only prepared to learn how to do this stuff, but also to share those techniques with others.
I’ve now removed the misaligned frames from my M31 image, there were also some 3 minute frames in the mix as well which have also been removed. I’ve probably pushed this data as far as I can take it and further improvements will require a few more hours worth of exposure to push the noise levels down.
Telescope: Zenithstar 70 with WO 0.8x focal reducer
Camera: QHY9C
Mount: Astrotrac
Exposures: 14x 5 minutes
It’s always interesting revisiting old data to see if you’ve learnt anything about image processing in the intervening period. Different techniques produce different results and this time I’ve added PixInsight into the mix. PixInsight has a reputation for being impenetrable but there are some good video tutorials out there to help and I’ve started to climb the curve. The good news is; it’s worth the effort.
My previous attempt at processing some M31 images from the 70mm Zenithstar was here:http://andrewluck.me.uk/?p=14 and was one of the first images I took with the QHY9C.
Reprocessed using PixInsight (and a little Photoshop to finish):
This is still a work in progress. It looks like a misaligned frame has made it into the image stack so I’ll have to go back to the beginning and remove it.
While waiting for Orion to rise last week I took a few images of Cygnus which was setting in the west. As with M42, the moon was rather a problem being almost full. Car headlights are a particular problem when looking in this direction and the road is busier than ever. 33 of the 30 second frames (bin 2×2) were useable and I stacked them in Maxim and then processed in PixInsight with a final curves adjustment and sharpen in Photoshop.
Monochrome only I’m afraid. A colour version may well have to wait until next year as Cygnus is getting rather low in the sky after sunset.
Friday evening was mostly clear albeit with a very bright moon. The original objective was to image the Sculptor galaxy (NGC253) which reaches 11 degrees above the southern horizon at this time of year. Unfortunately, there was a bank of cloud to the south which ruled this out. Plan b was the Orion Nebula.
The 20″ was tracking nicely and the Trapezium group of stars in the centre of the nebula provides a good guider reference. I dispensed with the luminance frames and just took 30 second red, green and blue sub-frames (20 of each) binned 2×2. This cuts image acquisition time which is important with the Alt/Az 20″.
Image processing was with Maxim, PixInsight and Photoshop. I’m using the trial version of PixInsight at the moment trying to get to grips with the very different method of processing. The background extraction process is exceptional but for final sharpening, levels and colour balance I used Photoshop.
My recent widefield nebula pictures of The Heart & Soul, Veil & Mu Cepheus left me rather flat with a disappointing lack of saturation and definition in the Ha regions. Suspicion fell upon the IR block filter in the imaging train but my first attempt at a replacement failed when it was a little too thick to enable my 75-300mm lens to focus.
Suspicion was confirmed when I found the original datasheet for the filter set where it was described as ‘Einsteiger filtersatz’ or Beginners filterset. The spectral response diagram showed a decline in light transmission after about 600nm. As the Ha line is at 656.28nm the filter was removing most of this light.
The second replacement was a Baader IR/UV cut filter in a 1.25″ housing that fits within the Geoptik adapter. As well as passing 98% of light upto 680nm this filter has the additional advantage of cutting violet light below 400nm.
A near full moon restricted me to relatively bright targets on the other side of the sky and the Veil nebula met the requirements. Focal length was increased to 200mm and 12 five minute sub-frames were acquired. Despite the less than ideal conditions the result is a huge improvement on my earlier attempt here: http://andrewluck.me.uk/?p=673
Last night was forecast to be clear until midnight so I loaded my portable setup into the car for the short trip over to the observatory. After last week, when 2 of us turned up for the regular tuesday night meeting, the evening was very well attended by club members. As the observatory was full I setup on the telescope pad outside.
Target for the evening was IC 1805 & IC 1848 between Cassiopia and Perseus and before the cloud closed me down I got 9 ten minute exposures. The camera was my QHY9C with the Canon 75-300mm zoom lens. I seem to be spending a lot of time with this combination at the moment with it’s 10 degree diagonal FOV and I’m starting to feel the lure of the 135mm f/2 prime lens with it’s faster light gathering and better colour correction. Maybe next year.
