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Lester
15-01-2012, 01:45 PM
Hi all,

In my images of the LMC region I noticed a long faint line that passes in front of Comet Lovejoy from top to bottom. I was wanting to find similar images of this region that show this also, but without any success. Where does one find very deep widefield images on the net. I have done numerous google searches, but nothing that I am looking for.

Here is my image from last night that shows what I am talking about.
http://i638.photobucket.com/albums/uu109/Lester_045/Comet%20images/dc10a80c.jpg

Lester
15-01-2012, 03:15 PM
Hi all,

Rob has helped me out here with a link to Wikisky. Although I don't know how to use it to its full potential, some practice will help.

http://server3.wikisky.org/?locale=EN

renormalised
15-01-2012, 03:19 PM
Looks like a patch of integrated flux....hard to tell. Then again, it could just be artifact.

Lester
15-01-2012, 05:11 PM
Hi Carl, yes I agree.

naskies
15-01-2012, 06:12 PM
Hi Lester,

First of all, Nick Risinger's Photopic Sky Survey (http://skysurvey.org) is one of my favourite sources for deep wide field images free from light pollution gradients, etc.

As for your long faint line... with some drastic stretching it looks like that long dark line is present in the Sky Survey photos (pic #1). I dug up one of my recent deep wide field exposures (http://www.iceinspace.com.au/forum/showthread.php?t=85318) and found the same thing even stronger (pic #2). Both pics are inverted RGB and rotated to have a similar orientation to the one you posted.

The line appears to pass through the Reticulum constellation so I had a look at the region in WikiSky's infrared data... and ta-da! (see pic #3). It looks like it might be some sort of dark nebula?

I remember that there were a few posts in Deep Space a couple of years ago trying to image the bridge between the LMC/SMC and the Milky Way - with some links to really, really deep exposures. They may be worth a look too?

Lester
15-01-2012, 06:31 PM
Fantastic Dave, that is exactly what I was after, so it isn't an artifact. Also the first and second images show the faint stream that fooled me to think Comet Lovejoy had a fork in its tail. With the faint extention passing over Canopus.

Thanks.

Liz
15-01-2012, 06:58 PM
Interesting stuff Lester. :thumbsup: Wonder if it has a name .... The LeRob Dark Nebula .... BarnKauf Dark Nebula .... Robles dark Nebula :D

Lester
15-01-2012, 07:05 PM
LOL Liz. Celestine, likes the third one.

renormalised
15-01-2012, 07:40 PM
Still looks more like IF to me. The Magellanic Stream is a lot more elongated than that and very faint. You'd have to expose for many hours to even detect it!!!.

Lester
15-01-2012, 07:50 PM
Unfortunately my image was hindered by cloud on the right side last night. Hoping for a deeper image tonight, if it stays clear.

By my understanding Carl, artifacts are not likely to show up in the same place when using different gear, even reflections will not look the same. But these are not reflections from bright stars in this region.

All the best.

renormalised
15-01-2012, 08:09 PM
That's true Lester.......given what Dave posted, this is not an artifact. I think it's IF.

naskies
15-01-2012, 08:23 PM
Thanks Carl, IF sounds perfectly plausible to me... though I've only had a 10 min crash course reading about it online!

I didn't think this was the Magellanic Stream - rather, since those photos are very deep exposures then this object would show up more clearly.

For the record, my image - the middle, blue one - was a fairly deep exposure for a DSLR - 300 sec @ f/2.8, ISO 1600.

Lester
15-01-2012, 08:32 PM
Dave, was that with the unmodded 5D MK ll? If so, I cannot wait for mine to turn up.

naskies
15-01-2012, 08:41 PM
Lester, it was indeed. It's a bit frustrating not getting the H-alpha signal, but I mainly use the camera for family portraits so I won't be modding it. Check out this image (http://www.iceinspace.com.au/forum/showthread.php?t=84871) for an example of the 5DmkII's native ISO 6400 performance... I think you're going to enjoy it!

If the weather behaves this weekend, I might try to intentionally image this dark thingo (lack of a better name for now).

Lester
15-01-2012, 08:49 PM
Outstanding Dave, I had just seen that link earlier and was amazed. The image is very smooth for such a fast ISO setting.

All the best.