NGC6164 Bicolour NB

[peter_4059]

More narrow band bi-colour processing this morning. Again this was data from Astrofest and I've had a number of tries to come up with a result I was happy with. This one is 71x5min Ha and OIII subs through the SN10/QSI683.

Large version is here: http://astrob.in/full/224791/0/

Advice welcome.

Thansk for looking!

[RickS]

Nice & deep, Peter. I'd add some RGB stars (to replace the pink ones!)

[Slawomir]

IMO this is a tough object to process and you have done very well.

Subtle processing artefacts can be seen when fully zoomed in, but otherwise a nice image Peter :thumbsup:

[RobF]

Really like this one Peter. Agree those outer curtains or quite hard to get data and demonstrate in final pic. Think you've a great job on tough target.
Resolution and detail impressive also.

[strongmanmike]

Really good result Peter, you have all the halo as far as I can see and some good detail in the main PN. I think your scope benefits well from using NB filters.

Purely from an aesthetic point of view, I agree with Rick about the stars but looks like you only gathered Ha and OIII so coloured stars were out of the question. Looks like the stretching has upped the noise but overall I'd rather see the faint bits at the expense of a bit more noise anyway :thumbsup:

Nice job...Astrofest just keeps on delivering :)

Mike

[gregbradley]

Very nice Peter. A slight crop would also help as there is a stacking edge at the bottom of the image.

More importantly, the neb and shockwave are nicely presented.

Greg.

[Flugel88]

That looks fantastic Peter!
Come along way from your ngc 6164 version with the GSO newt.
Nice colour and detail in the oxygen/hydrogen shells.

[batema]

Peter that is a fantastic image. The detail in the outer shell is amazing.

Mark

[Paul Haese]

This object is one hell of a tough mother to image and process. Your detail levels are very good and I like your colour palette too. I spent over 50 hours collecting data on this and in the end only used 34 hours. You have got a good result for 6 hours of data. RGB stars really make this target and I encourage you to get them if you can.

[Placidus]

Good result. Nice to see.

[troypiggo]

Agree - think the nebulosity colour balance is great. The image scale just suits this object.

[ozstronomer]

Great Image Peter, nice colour and detail in the PN

Geoff

[peter_4059]

Thanks Rick. It will have to wait for Astrofest next year as my horizon to the north at home is non existent.



Thanks Slawomir, it would be nice to have 70 hours on this!



Thanks Rob. I was surprised at how tweaking the blue and cyan selective colour sliders made the outer nebulosity stand out.



Cheers Mike. I'll probably come back to this next Astrofest and get some RGB as well as some more Ha and OIII.



Thanks Greg. I should have spent more time tidying up some of the aesthetic items however I was really focused on how to get the colours to look good. I might have another try with some better processing steps.



Cheers Michael. I suspect the Newt image was suffering from dew on the primary as this tends to be a midnight target at Astrofest.



Thanks Mark.



Cheers Paul. It would be nice to have a fixed setup where I could get more data but in our current location that is unlikely to happen.



Thanks Mike n Trish.



Cheers Troy. I think around 1m f/l is the sweet spot for amateur astrophotography.



Thanks Geoff.

[Slawomir]

Yes, it would be very nice! But 21 hrs is okay..ish too :)

http://www.astrobin.com/full/195481/E/

[peter_4059]

Nice, was that done from Brisbane? I wonder how the maths works out with 84x900 secs through a 4" f7 system vs 71x300 secs through a 10" f4 system?

Looks like your mount is performing well if you are able to consistently do 15min subs.

Peter

[RickS]

Suavi has a 102mm f/7 with 0.8x reducer and ICX-814 sensor, IIRC. Compared with that, your system will be about 2.8 times faster at Ha wavelength. I have a simple spreadsheet model that takes into account aperture, % obstruction, focal length, optical efficiency, pixel size and QE.

Cheers,
Rick.

[peter_4059]

Thanks Rick - so his image had a total integration time of 75600 secs and mine had 21300 secs so a factor of 3.5 difference. Interesting how much smoother Suavi's image looks.

[RickS]

The speed comparison assumes that subs are sky limited. That's not the case here and I probably should have mentioned it. Your camera has higher read noise and you're doing pretty short subs for narrow band. You'd get much cleaner results in the same time with longer subs.

Cheers,
Rick.

[peter_4059]

Rick, I had a look at the PI calculator and assuming I'm using it properly, here's what it shows for my gear with a single sub taken at Duckadang. Not sure how to interpret the results?

[RickS]

Peter,

I did read some stuff about the Anstey limit calculations but it was a while ago and I don't remember the details.

I've been happy using the method described by Ray (Shiraz) here:
http://www.iceinspace.com.au/forum/showthread.php?t=117010
I was able to derive the same result from the basic noise equation and convince myself that it works.

Cheers,
Rick.

[Slawomir]

Yes, from Brisbane near the city (Paddington- 10 hours Ha, 11 hours O3).
The mount is doing okay at 1.33 arcsec/pixel, I usually need to throw away about 20% of subs due to poorer tracking in RA. Need to experiment with balancing the mount, because at some telescope orientations subs are very good, maybe need to make it a tad more east-heavy?