A conversation at the club about the problems caused by bright stars in photographs of faint objects led to a couple of sessions imaging IC443, the Jellyfish, in Gemini. Eta Gemini is a magnitude 3.3 star alongside the supernova remnant. Photo opportunities for this object this year are closing fast as it’s culminating as it gets dark. I’ve managed two sessions during this New Moon period for a total of 3hrs 20 minutes in my usual 10 minute subs.
Early attempts at processing were rather heavy handed with noise reduction so I’ve toned that down in this version and applied most of it when the image was still in it’s linear form. This has left more of the finer nebula structure intact.
A lot of the images of this nebula on the Internet are done with narrow band filters which suppress Eta Gemini but when using a One Shot Colour camera the star rather dominates. I’ve toned it down using the StarhaloReducer script in Pixinsight but I could probably be rather more aggressive with this.
Somewhat fortuitously, after my last post of M81 & M82 a type 1a supernova has erupted in M82. After large amounts of rain, the clouds parted last night and I was able to take some additional pictures showing the event. All of the stars in this image, except for the additional one within the outline of the galaxy are local stars in our own Milky Way. The supernova is 12 million light years away which gives some idea of the power of this explosion.
I’ve had less practice processing images of galaxies so this picture has been on my hard disk whilst I tried different processes to see what worked and what didn’t. The increase in focal length from 330 to 450mm switching from the Zenithstar 70 has made a big improvement in image scale but, with the exception of M31 & M33, groups of galaxies work better to fill the frame.
I’ve imaged this pair before but this is the first time I’ve managed to capture the Ha streamers from M82. This is 3 hours of data in 10 minute sub-frames.
This is a test image checking operation of my new imaging setup based upon the Takahashi FSQ85-ED ‘Baby-Q’. After running several V curves in FocusMax I took 12x 5 minute exposures of M45. This is a good test of the optics as the stars are very bright and are a useful check for spurious reflections.
I’ve built a new flat panel using a larger EL panel and some translucent polycarbonate. The panel is still a little bright and I’ll need add a little more attenuation to enable me to use somewhat longer exposures to eliminate shutter artifacts.
I’ve finally got around to combining the remaining data into a mosaic of this area. Using a different technique to merge the images in Pixinsight I’ve removed the visible join that was due to a light pollution gradient in the original.
Sh2-155 is a region of Ha emission overlaid with dust in our galaxy, some of it thick enough to block the more distant stars completely and appear black.
This is a total of 10 hours 20 minutes of 10 minute subframes.
I’ve been meaning to capture a new version of this nebula as the previous one, done on the Astrotrac exhibited quite pronounced trailing. This will be one of my final images done with the WO Zenithstar 70 as I’ve purchased an ex-demo Takahashi Baby-Q (FSQ85-ED). I’ve enjoyed working with the Zenithstar and I’ve learnt a lot in the years of using it but the time has come to upgrade to something with rather better colour correction and a flatter field.
Fifteen 10 minute subframes using my QHY9C.
While at Kelling Heath in October I took advantage of the darker skies to leave the scope collecting data until dawn of this area just to the west of Rigel in Orion. The Witch Head is very faint and being low in the southern sky is swamped by light pollution at home. This is a re-processed version of the image that appeared on the club Facebook page some time ago and I was planning to add more data over the course of the winter. However, having just purchased a new refractor this isn’t going to happen and I’ll start over with the new telescope.
Even from Kelling there were severe light pollution gradients on these images which I removed using Pixinsight. The club’s dark skies site at Haw Wood on the Suffolk coast will probably be the location of choice for any new attempt.
I came upon this object whilst looking at my copy of Sue French’s book Deep Sky Wonders. I was looking for a suitable photography target and this appealed due to it’s large apparent size, high altitude and relative obscurity. Located on the Cassiopeia / Andromeda border it also features a subject that engages me; dust.
Dust can be tricky to photograph as it doesn’t emit any light of it’s own. All you get are reflections from nearby starlight or absorption of light from more distant stars. This means that it’s often dark and usually very faint so you need a reasonable sky quality and long exposures to capture it.
With a rural UK sky and only 150 minutes total exposure (in 10 minute subframes), faint detail is still elusive in this image. This is definitely one to revisit from a darker sky and a lot more exposure.
This is another image from the beginning of last week and I’ve reprocessed this from the version that I posted on the Breckland Facebook page. The background stars are a little less harsh, I’ve increased the contrast in the nebula and it’s a slightly closer crop. This is nine 10 minute subframes.
NGC 1499 in Perseus is a large, bright emission nebula created by the bright blue star Xi Persei irradiating a hydrogen gas cloud with UV. The brightest part of the nebula spans 5 degrees on the sky and just fits on the sensor of my QHY9 when used with my Zenithstar 70 and 0.8x reducer.
This is 110 minutes of 10 minute frames captured on Tuesday evening, processed with Pixinsight.