| Image exposure per tile: 2 x 8.5 min; 1 x 7.8 min | Image size: 3.22º x 2.09º | Image date: 2022-10-02 |
The Small Magellanic Cloud (SMC) is a nearby dwarf galaxy, about 200,000 light years away, well known to inhabitants of the Southern Hemisphere. Well, perhaps it is well known to astronomers and others who look up at the stars.
It is one of the largest objects, with an apparent size of 5º x 3º, while at best my telescope can only image about 2º x 1.3º.
So, the plan was to stitch together several tiles of a mosaic from images of adjoining regions of the sky, centred on the SMC but trying to capture all of it – and maybe some of its surrounding context as well.
I ended up with this funny shaped image. It was my first foray into astro-mosaics, so no surprise that it is comprised of a mix of both failure and success.
- Failure: because the clouds ended my session after shooting only three tiles; a satellite wrecked the first tile; and I misjudged the positioning of the third tile.
- Success: because I captured a good chunk of the SMC in those three tiles; and I learnt how to successfully stitch them together.
I’m not normally someone who likes publishing a partially completed project but I’ll make another attempt at this when the next opportunity arises and hopefully post a finished job.
In the meantime, here’s a single wider image of the same region, which I took seven years ago with my Canon 60D DSLR camera on a tripod:
Image size: 11.5º x 11.5º
Image R. Powell
◽ Skywatcher Esprit 120 Refractor telescope. ◽ With 0.77 reducer = 644 mm focal length @ f/5.4 ◽ Skywatcher EQ6-R Pro mount. ◽ ZWO ASI 071 MC cooled imaging camera. ◽ Images © Roger Powell |
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Cosmic Focus
ABOVE US ONLY SKY : amateur astronomy in australia
Cosmic Focus 
I feel your mosaic was a success. I realize it was unfinished according to you. I would never have suspected it. I hope you get an opportunity to do the whole project soon.
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Thanks. It was a dodgy night and after capturing these frames, it clouded right over. I waited two hours hoping for the clouds to clear.
I finally realised that I was wasting my time and gave up at 11 pm. It took me fifteen minutes to pack the gear away. Looked up and the sky was clear!
☹️
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So frustrating! I had hoped to offer views of the Moon Saturn and Jupiter to the neighbors this week. No luck due to clouds. I know some clear skies will be here next week.
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Jupiter is certainly dazzling at the moment. I hope you get to spend time showing it to your neighbours.
I know it is one of the best views of Jupiter for years at 50 arc-sec diameter but with the predicted poor run of weather here I want to keep my current wide field set up primed for any opportunity which may arise, so I’m giving Jupiter a miss until next year.
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When stitching together photos, I sometimes leave the jagged edges, and sometimes I crop to clean them up.
Photoshop has a ‘fill’ feature that would likely do a good job on a starfield, but — because it’s a starfield — would be inaccurate in a way that an empty sky filled in at the edges isn’t (meaning, the end result wouldn’t match the actual area of the night sky).
But, I agree with Jim R . . . you might know it’s ‘wrong’ but to me, it looks great.
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You’re quite right, I couldn’t fill in an artificial star field. That would place me in the same class as photographers who copy and paste the Moon into their landscape or cityscape images, oversizing it or displaying the wrong phase in the wrong location.
I’m not so bothered about the jagged edges,I think that is legitimate but who knows what I will decide as I progress with other mosaics. If I get enough mosaic tiles I will be able to crop to a suitable field.
I could have filtered out the satellite though.
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Thank you for sharing the partially-completed image. I am sure you will leverage the experience in future projects.
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Hi Paul, thanks for that.
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