NGC 1760 - The Tasmanian Devil (UPDATED)

[Andy01]

Work in progress on this relatively unpopular target in the LMC.

This bizarre shaped little nebula reminds me of the Tasmanian Devil from Looney Tunes. :P

Fred & Paul have previously posted their own stunning versions, and inspired by them I attempted it last year - but now 12 months later I hope to do it more justice this time around.

Just 5 hrs Ha in 20min subs so far, the Ha is still only 1/3 of the data required as I'm hoping for a full 30Hr+ NB workup on this one :)

•UPDATED High res version now with 12Hrs Ha data here, much clearer - http://www.astrobin.com/full/222206/B/

cheers
Andy

--- --- ---

(UPDATE) Finished image, now in Colour - High Res here - http://www.astrobin.com/222206/C/

11.5 hrs 5nm Ha 1200 sec subs
6.5 hrs 5nm S2 Binx2 900 sec subs
4 Hrs 5nm O3 900 sec subs

15x60sec ea RGB stars

C & C welcome

cheers
Andy

[Ryderscope]

Coming along nicely Andy. Good catch with that little globular in the foreground as well.

[Paul Haese]

I was looking at the image I did of this earlier this evening and assessing if I would do it with the RC. I decided against it this year, but it is an interesting object. I look forward to seeing your image of this object. It is an unusual framing but seems to work. Is this your full frame or is it a crop?

[Andy01]

Thanks Ryderscope - lots of cool stuff to see in this area of space, amazing to think that we can photograph nebs in another galaxy from our backyards!



Thanks Paul, you guys set the bar pretty high for the rest of us! Yes, it's a square crop - original full frame version below.

[Placidus]

A very nice framing, Andy. Definitely a Tasmanian devil - probably Mrs Devil, near as I can see. Your title goes well with the busy, extroverted star-forming activity. Lovely work.

[topheart]

A great subject - portrayed extremely well!

Thanks,
Tim

[RickS]

It's an interesting object. Should be a cool image, Andy!

[Andy01]

Thanks Mike - There's plenty of obscure targets in the LMC, which is a good thing as there's not many other nebulae elsewhere at this time of year. ;)



Thanks Tim - never ceases to amaze me what else is out there.:thumbsup:




Yes it sure is Rick, hope to do it justice this time around.

Forecast is clear tonight, and it's a full moon - might as well have a crack at getting more data - should be an interesting challenge for the 5nm Astrodon Ha.
At least the moon's mainly in the North and this is object in the South, so hopefully the gradients are not too bad :)

[strongmanmike]

He, he, Tassie Devil indeed :thumbsup:...well, at least you know if you need to tame this image at any time during processing, just play some nice music :D

Mike

[codemonkey]

That's a really cool target, Andy. Looking forward to seeing the final result!

[Andy01]

He He, Maybe I'll play him some Neil Diamond records :)



Cheers Codemonkey, I've added 6 hrs Ha = 11hrs+ new updated version here http://www.astrobin.com/full/222206/B/

[vlazg]

Looks great Andy, lots of detail , i also am looking forward to the end result.
Tassie devil ?? Looks like a bucktoothed chicken.

Rorschach rules

[Ryderscope]

Gee Whiz! The extra data has certainly made a (great) difference.
R

[rustigsmed]

great work Andy looking forward to seeing the finished version.
interesting neb shapes in the LMC/SMC

cheers

russ

[gregbradley]

The extra data has made a lot of difference to the contrast and detail. Nice.

I often wonder if I should go for 3nm Ha and O111 filters. I thought you were using 3nm until I saw this thread. The 5 is good. Have you considered the 3nm? I wonder what the advantages/disadvantages are? Longer exposure time is the disadvantage but how much more detail, if any, does the 3nm achieve?

Greg.

[Atmos]

The most important difference between the 3&5nm Ha filters is the NII emission line. A 3nm Ha has only the Ha emission while 5nm+ will also contain the NII emission. With the extra emission it will bring make some objects brighter but it isn't a "true" Ha filter.

[Placidus]

I like the new one because it's brighter and more contrasty without having lost anything at all, even, and much kudos to you, the cluster stars in the very brightest patches of nebulosity.

[gregbradley]

Thanks for that. Yes I knew that and its why I decided for my Honders not to switch to 3nm at my dark site on the advice of Don Goldman. But my home site, whilst fairly dark, does have some easterly pollution and I wonder how much of a gain you get from the 3nm. They are very expensive.

3nm narrowband filters seem to be used on this site often with the QSI683 as 30mm filters are far less expensive than the 50mm square ones.

Greg.

[Atmos]

I've just started using Astrodon 3nm Ha filters, not sure how other passband ones compare as I've never used them but I have a sky limit of ~12-13 minutes with a full moon in the light polluted burbs of Melbourne.

[LucasB]

Really nice Andy. The extra data has sure been worth it. The depth is great!
Lucas

[condebob]

Andy, thanks for sharing! A really wonderful image, with exceptional detail.

Something to aspire to.

bob/

[Andy01]

Lol :) Cheers George - hoping the Victorian skies clear again soon!



Yea Ryderscope, I was amazed - there's just no substitute for more data as Paul Haese and Fred (Bassnut) have repeatedly demonstrated with their exceptional images.
With my 5.6 rig and the 5nm filters, 10 hrs per filter = 30Hrs+ total seems to be the minimum requirement for a nice image on these little feint nebs in the LMC.



Thanks Russ, plenty of interesting targets in that region - blows me away that we can photograph nebs in another galaxy from our backyards!



Thanks Mike - Learning Startools has really helped with my image processing. It's a pretty awesome program, and for a visual learner/user like me, very simple to use. This was taken under an almost full moon so the gradient removal tool (wipe) has been very useful.



Thanks Lucas, I'm thinking it may benefit from even more data, when the weather permits.



Thats very kind of you to say so - thank you Bob. :thumbsup:

[Andy01]

I believe that Paul Haese uses 5nm Ha & S2, and 3nm O3 - Al Sam has just ordered the 3nm O3 as well (wasn't cheap!). Under full moon in Melbourne, I've found the 5nm O3 is most affected by gradients etc. Certainly considering the 3nm O3 in future for this reason alone.



Yes Colin, Bert (Avandonk) previously on this forum used the N2 filter extensively with great results. 656.3nm for Ha vs 658.4 nm for the N2 filter - they're pretty close together but certain objects appeared to respond very well to the N2. It would be creatively interesting to see colour images mapped RGB 3nm S2 Ha N2 or in combinations including the O3.



Greg, you've probably already seen this but for other reading, this post from Astrodon is interesting - http://www.astrodon.com/uploads/3/6/0/7/3607549/astrodonnarrowbandfaq.pdf

Slawomir uses 3nm filters with great results from his LP affected home base, and I think ultimately that's the way to go.
I made a financial compromise to get the 3 x 5nm filters at the time of my QSI purchase. Having used them extensively over the past year, I may well move to a full set of 4x 3nm filters in future as I expect more creative opportunities will result.
However, aside from the extra cost, the required exposure times will increase as well. I'm currently using 20min subs, but I expect 30mins to be the minimum with the 3nm filters. Having realised that 30hrs plus data is now the minimum for many targets with my backyard rig, I dread the fact that it will probably increase further with the 3nm filters!



Out of curiosity Colin, when you get a chance, could you perhaps post some examples of your results with various exposure times in the 15-30min range? I know you did post those amazing 1hr subs recently and it's probably a technical thing but I'm curious as to why you're limited to 12-13 mins here in Melbourne.

[Atmos]

The limit I am referring so is the sky limited exposure, not so much an actual limit. Using the SkyLimitedExposure script in PI it gives those numbers which refer to the point at which there is nothing more to be detected, the sky background has become the brighter than anything else that can be detected.

The read noise limited exposure is vastly different however, that is 1.5-2 hours exposure. Being read noise limited is a theoretical maximum exposure where going longer just isn't practical for the dimmest parts of your image.

[Shiraz]

great image Andy - nice resolution and low noise as well as an interesting subject.

[Andy01]

Thanks Ray, it's a surprisingly unpopular target, but it's really quite intriguing.
Was hoping for clear skies over Snake Valley to finish it in colour this weekend but seems it's not to be, c'est la vie! Cheers :)

[Stevec35]

Very nice detail and contrast Andy. Should be a cracker when finished. Of course the weather might have something to say about that.

Cheers

Steve

[Andy01]

(UPDATE) Now in Colour - http://www.astrobin.com/222206/C/

The Melbourne finally relented and I managed to gather some O3 & S2 data.
Probably not enough as there's still some noise there but now some 20+ hrs later I think it's time to move on from this one!

11.5 hrs 5nm Ha 1200 sec subs
6.5 hrs 5nm S2 Binx2 900 sec subs
4 Hrs 5nm O3 900 sec subs

15x60sec ea RGB stars

Tried several different colour maps but settled on this rather patriotic one in Aussie Green & gold. Very similar to HST palatte. Tone Mapped using JP Metsavainio's Astro Anarchy methods. (thanks J-P!)

Footnote: I was amazed how much more colour I got out of the RGB stars by trying 15 x 1 min subs instead of my usual 4x1min subs.

Taken from my light polluted backyard in suburban Melbourne, Australia.

C&C welcome :)

[Atmos]

I am loving the colour! What is the pallet?

[Placidus]

Hi, Andy,

Missed this update. It's gorgeous. Well done. And of course we totally approve of the palette.

Best,
M & T

[gregbradley]

That's a great image Andy. You are very good at these narrowband images and they are always well framed and thoughtfully presented.

Greg.

[Paul Haese]

Nice image Andy, but I am not a fan of the colour myself, I have never really like that colour palette. It sort of looks wrong to me, but I respect that people can like this too. Just letting you know that is the only thing I don't like about the image.

I do like the composition though, and the star colours look good. Though I found I did not need to use RGB stars on this object because the stars were easily pushed to show natural colour. Your blue stars are better though and that comes with the RGB star addition.

[Andy01]

Hi Colin, Recipe is start with basic HST Palatte: Ha - Green, O3 - Blue, S2 - Red, then add selective colour http://bf-astro.com/hubbleP.htm and colour balance adjustments to taste :)



Thanks M&T, appreciate the feedback and nice comment :D



Cheers Greg, those are very kind words indeed, it takes forever to do these images but it's a labour of love :thumbsup:



Cheers Paul, the stars were even more "pure" before I added a final Luminance layer to it, I used three in all, including one in "darken" blend mode that worked a treat.

As to colours? I knew that would be contentious but honestly it just looked the best with the data I had, and I tried a zillion combinations and looked at yours, Fred's and others versions before settling on this one. However, I appreciate that it's subjective and as you once said, dealer's choice ;)

[Andy01]

(UPDATE) Finished image, now in Colour - High Res here - http://www.astrobin.com/222206/C/

11.5 hrs 5nm Ha 1200 sec subs
6.5 hrs 5nm S2 Binx2 900 sec subs
4 Hrs 5nm O3 900 sec subs

15x60sec ea RGB stars

C & C welcome :)

[Slawomir]

VERY nice composition Andy, a pleasing result of your persistence and solid effort :thumbsup:

[Andy01]

Thanks Slawomir, very kind of you to say so. :)

Spending a week or two on raw data capture and a couple of days processing one's images is made even more worthwhile knowing that others in this community find these images pleasing and interesting as well. :thumbsup: