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View Full Version here: : Trifid Nebula .... without Hermentaria


DiscoDuck
25-06-2017, 09:51 AM
An attempt at the Trifid over two nights. 31x20 minute subs with a QHY8 and an RC8 on an EQ6.

During the first night I noticed a bizarre elongated "star" creeping across the nebula over subsequent exposures (at bottom right of attached crop of one sub). Turned out to be the asteroid Hermentaria, according to Cartes du Ciel. Largely disappeared in stacking thankfully, as it was quite bright (mag 10.8 apparently).

The perils of imaging near the ecliptic I guess - on the second night there was a similar fainter asteroid nearer the edge of the frame. Though I've never knowingly encountered that problem before!

Was hoping to get more detail of the neb than my last attempt a few years ago and also the jet. I think, with an optimistic eye, the jet may be just visible.

Comments appreciated. Full res (http://www.astrobin.com/full/300755/0/?real=&mod=)on Astrobin or more browser friendly here (http://www.astrobin.com/full/300755/0/).

Paul

traveller
25-06-2017, 09:57 AM
Very nice Paul,
Plenty of detail too.
Have you tried making an animation with the various subs with the asteroid? Should be an interesting project...
Bo

alpal
25-06-2017, 09:59 AM
Hi Paul,
nice image.
I want to do the Trifid but the weather has been bad in Melbourne.

cheers
Allan

Placidus
25-06-2017, 10:08 AM
The jet is definitely visible. The blue reflection nebulosity is well captured. (We tend not to see it in NB) A very fine shot.

We'd love to see a version without data rejection so that we could see the asteroid dotting its way across.

(The other day we did an asteroid in Virgo with an airbus or similar flying through the image about once an hour, and for some reason their flight path seemed to change with sidereal time, tracking the galaxy. You don't want to see that!)

DiscoDuck
25-06-2017, 10:36 AM
Thanks Bo. I've tried Mike n Trish's suggestion re a trail (see attached). An animation would be good too when I get a mo.



Thanks Allan. We had a few good - though cold - nights in Adelaide. Cloudy now again though. :(



Thanks. Hopefully was a Virgin plane in Virgo! :lol:

Nice thought re doing one without data rejection. I've just stacked the first night's images in the attached - half of which were not included in the other one as the FWHM was shoddy. You can see a couple of gaps in the trail where I've stopped to refocus! And the trail gets wider towards the SE (it was going NW to SE) as my FWHM deteriorated!

topheart
25-06-2017, 10:49 AM
Very nice Paul. Good colours!
Cheers,
Tim

Placidus
25-06-2017, 11:32 AM
That's great! The other asteroid is also clearly visible now.

strongmanmike
25-06-2017, 11:34 AM
An excellent Trifid Paul, all the main elements are well executed, it looks believable and natural, in fact my first impressions were of Marcus Davies award wining version (http://www.pbase.com/gailmarc/image/150932230/original) :)

My bits of feedback would be that it looks like it could do with some more selective sharpening, the jet is well revealed, in fact it is two jets, the long one angles back into the field while the smaller one angles out of the field and you can see this effect in your image nicely :thumbsup:

Mike

DiscoDuck
25-06-2017, 12:03 PM
Thanks Tim.



Aah. Hadn't seen that one! The other one I mentioned was from the second session - that data not in that stack. It's clearly a busy area for asteroids!



Thanks Mike. I tried to go easy on the processing (for once!) - e.g. no decon even. But will try some more sharpening selectively as you suggest.

Mind you to be fully honest I confess to attempting decon, but just couldn't find any settings where it did good things to the image without also doing bad things :sadeyes:

atalas
25-06-2017, 03:23 PM
A fine shot indeed Paul :thumbsup: some advice......back off on noise reduction and try and retain the dynamics of the central dust and core area.....colour looking good.

DiscoDuck
25-06-2017, 06:38 PM
Thanks Louie. Will take a look at noise reduction - though I don't think much at all was applied to that central area.

atalas
25-06-2017, 06:50 PM
Hi Paul

Sorry,I didn't explain very well....noise reduction around the neb and through the background.

The central region is looking a bit flat and I believe this is stopping the dust lanes from revealing their true nature.

Atmos
25-06-2017, 07:04 PM
Lovely M20 Paul. I think what Louie may be getting at is that if the dust lanes were a tad darker it would make them pop more :)

As for the asteroid moving through the Triffid, someone else spotted and captured this a few days ago, interesting animation too :)

Asteroid Animation (http://www.astrobin.com/300540/)

marc4darkskies
25-06-2017, 07:08 PM
Very good rendition Paul! Colours are spot on IMO. :thumbsup: I can just see the jets (usually the first thing I look for :) ) - excellent!. Now add some proper unsharp masking and the the dust lanes will pop.

DiscoDuck
25-06-2017, 07:09 PM
Aah. OK. Thanks.



Thanks Colin. Will take a look.

That animation is cool! :)

DiscoDuck
25-06-2017, 07:27 PM
Thanks Marcus and Louie and Colin.

What I tried was the dark structure enhancement script in PixInsight. Dialled back quite a bit from default settings.

Image updated on Astrobin (http://www.astrobin.com/300755/).

DiscoDuck
25-06-2017, 10:46 PM
Bo, thanks for the suggestion. Uploaded a quick process of the 15 relevant frames as an animated gif on Astrobin (http://www.astrobin.com/300848). Not great processing, but best I could do with the Process Container in PixInsight and my limited skills!

As well as Hermentaria, there is another asteroid that Placidus noted at the top of the frame, and a very faint one a bit ahead of Hermentaria.

cometcatcher
26-06-2017, 08:10 PM
That's a pretty cool shot with the asteroid actually.

DiscoDuck
27-06-2017, 06:09 PM
Thanks Kevin. Was a good idea from Bo to do a video.

Slawomir
28-06-2017, 09:50 AM
A splendid image Paul, really really good. This is one of the most charming DSO IMO, and you have captured its essence extremely well :thumbsup:

Retrograde
28-06-2017, 10:30 AM
Very nice Paul - wow 20 minute subs!

The multiple asteroids vid is very cool too. :thumbsup:

DiscoDuck
28-06-2017, 06:21 PM
Thanks Suavi.



Thanks Pete. I normally default to 20 min subs these days, though in this case wishing I'd gone a bit less to reduce the brightness of those centre stars.

Still, the 20 min subs helped with the video as each frame is just one sub and at 20 mins you can get a reasonable pic out of it.

SimmoW
28-06-2017, 10:01 PM
Seems its Trifid season again, heralded by your very impressive image Paul, considering the 'modest' equipment used

DiscoDuck
29-06-2017, 06:25 PM
Thanks Simon. Yes, my equipment sometimes feels a bit too "modest" aka cheap. I need to speak to my better half about that! :)

Andy01
30-06-2017, 03:10 PM
Nice rendition of a classic target :)

DiscoDuck
30-06-2017, 11:14 PM
Thanks Andy.

RickS
03-07-2017, 09:24 PM
Very nice, Paul!

DiscoDuck
04-07-2017, 08:48 PM
Thank you, Rick.