New and improved NGC3576 in HST pallet

[telemarker]

Here is my latest narrowband image: emission nebula NGC 3576 and NGC 3603 to the left of the loops of ionised gas. Located between the Running Chicken nebula (IC2948) around Lambda Carina and the much larger Eta Carina nebula (NGC3372), these nebulae appear close together but are separated by 11000 light years. NGC3576 is in the Sagittarius arm of our galaxy at a distance of 9,000 light years. NGC3603, considered to be the largest nebula in our galaxy, is also located in the Sagittarius arm but is estimated to be about 20,000 light years distant.

Scope: 127ED
Camera: ST8300 with Baader Ha, OIII and SII filters
15 and 30 minute subs
Guiding: SX-AO at 4Hz

Roughly 2 hours per filter over 2 nights. Calibrated and stacked in DSS, combined in Nebulosity, post processed in PS and finished in Pixelmator.
Also included is the Ha image showing the extent of Ha emission surrounding the loops.

C&C most welcome. Thanks for looking.
Keith

[strongmanmike]

The Ha only shot looks great Keith, and yes you have brought out plenty of nebulosity.

The combined data image looks ok but the cyan in the bright parts is overexposed and looks wrong. I don't have a diffinitive suggested fix as NB imaging is so much like ..?..cooking a bolognese sauce, bit o this bit o that.. :D just have another go mate :thumbsup:

How would you quantify the guiding quality of the SX AO? Is it easy to use?

Mike

[multiweb]

Looks real great Keith. Superb data. You've clipped one of the channels in your composite though. Other than that top stuff. :thumbsup:

[iceman]

I agree with Mike about the coloured version but the Ha is very nice!

[telemarker]

Thanks for the comments Mike, Marc and Mike.



Yeah, the colour is problematic, its soooo.. much easier working with single strong monochrome data. I need to find a suitable workflow for the colour data but that's what forums are for, right? :D



The Ha data came out nice. The others, not so much.... a much weaker signal. I often wonder whether I should bin the SII and OIII (something to try in the future). However, the biggest problem lies in combining the data, most of the tutorials I've seen are based around DSLR and OSC. I think I need to rethink the earlier workflow. The registering and stacking of each data set seems to be OK the later stuff is a bit of a mystery. Any suggestions are more than welcome. :D



Thanks Mike,
In the crystal ball, I see a (dare I say it....) Sidornio is in my immediate future! This is the first time I tried normalising the intensity of each stacked SII, OIII and Ha data set before combining. Is this the accepted protocol? Also, do you start stretching the data for each filter before combining or stretch the image after combining? Probably pretty basic questions but....

The cyan areas would be the OIII data overcooked, but also the Ha being too bright as well. I'll have to take it right back I think and see whether the normalising is doing something untoward.

As for the SX-AO, I really like it now (bloody expensive guide cam :P). A couple of things annoy me but I think there are fixes around. An its getting easier to use as I become more familiar with it. With a good strong guide star it performs :thumbsup: and the lodestar has binning to help in this regard. It does seem rather cloud sensitive though. The HEQ5pro is too light for my latest acquisition (RC8 - which is why I bought the AO in the first place) but performs well with the 127ED. The crystal ball is predicting a new mount :eyepop: and probably a trip to the Gold Coast too;).
This an expensive hobby.

[telemarker]

Tried a repro with the 2x2 binned colour NB data with the 1x1 Ha as aluminance layer. I realised what was causing the highlights to blow out in the previous version (the conversion from 32bit tiff to 16 bit step). Anyway, a Sidonio......