I seem to manage about one deep sky image per year so I don't barge in here too often. However, I posted my latest image yesterday on the ASV AP group and it generated some interest and I thought maybe I should put it on wider display here as not too many APs seem to know about the faint structures around and in-between the LMC and SMC.
This in a 3 panel mosaic captured with an old 50mm Pentax SLR lens and QHY8 camera. About one hour exposure for each panel. It was hard work to remove the gradients and the skyglow.
A higher resolution version is in my ASV gallery: http://asv.org.au/images/gallery/Ste...ours_small.jpg
Excellent project Stefan and an intriguing result, something different and interesting and indeed something I have aaalways wanted to do myself since way back in the day, so thank you for doing it for me ... I wonder if any of that faint stuff is part of the Magellanic steam?
Out of interest, when you are removing the described gradients in an image like this with such mega faint tenuous features spread everywhere, how do you ensure you don't remove or add structures or information..?
That's really good Stefan, you've managed to go very deep there. I may have to give it a shot the next time I am up at my dark site. You've got me intrigued
Michael,
Very good question. I spent hours hand selecting reference points in IRIS to generate a polynomial background to be subtracted from each panel and I had to do two passes as well. Maybe there are easier ways with other software but I like the numerical approach and the total control that IRIS provides.
If you follow the links from this site, https://arxiver.wordpress.com/2016/0...-periphery-ga/, you will be able to download a PDF paper, that I only found yesterday, with information on these faint structures.
Also Phil Hart showed me his unfinished version of the same field and his image shows exactly the same structures.
Ok, that all makes sense and a great paper. In case I wasn't clear, I wasn't questioning whether what you had recorded was real or not, just how accurate the structures were given the indicated heavy gradient removal required, that's all. Looking at the images and figures in the Martinez-Dalgado et al paper I'd say you are pretty close
Ok, that all makes sense and a great paper. In case I wasn't clear, I wasn't questioning whether what you had recorded was real or not, just how accurate the structures were given the indicated heavy gradient removal required, that's all. Looking at the images and figures in the Martinez-Dalgado et al paper I'd say you are pretty close
Mike
Mike you were very clear, but I had the same doubts about the integrity of those structures after the heavy processing, until I found the above paper.
This is excellent Stefan. Sub-zero cool. I'm really impressed how you brought up all this faint stuff on such a wide area of sky having to contend with sky glow and uneven light. Quite extraordinary.
I had a go years ago at the Eridanus loop from Coona which is pretty dark. It was in Ha and even that, it was just almost impossible to process.
Thanks Marc,
Yes, it was not easy and I had so many attempts at processing it that I'm not sure I can remember the whole sequence that worked in the end.
Other than IRIS the other main software I used was StarTools.
Cool productive image. Whilst I had read about the streams both these galaxies have following them, this is the first amateur image I have seen that looks to have captured the streams. If nothing else the halo about the LMC is larger than that I have seen captured before. Well done Stefan. Certainly an interesting image.
... I wonder if any of that faint stuff is part of the Magellanic steam?
