NGC 7380 - Wizard Nebula

[Kbramley]

Here is my attempt at NGC 7380, aka the Wizard nebula in narrowband (SII,Ha and OIII)

Details as follows

kit as per signature, guided with QHY5L-II mono via OAG

SII - 9x30mins

Ha - 6x30mins

OIII - 7x30mins

total 11 hours

The Sii was super faint, OIII not too bad but Ha really strong (as always), imaged over a period of about 1 month as clear nights have been elusive.

I blended them together SII (Red), Ha (Green) and OIII (Blue) with Ha used as a lum at the end which seemed to help bring up the overall brightness of the nebula without bloating the stars (the SII and OII had bloated stars due to having to push the data hard in stretching)

enjoy

Keith

Big version here http://astrob.in/120572/0/

[Epicycle]

Lovely wizard. You can try to control the star sizes when you stretch the oiii and sii. What software do you use?

In PIxinsight, one can do a masked stretch or decrease the size of stars aposteriori via a morphological transformation with a suitable star mask,

E.

[Kbramley]

Thanks for the advice, I just use PS and do levels and curves as I don't have Pixinsight unfortunately, I may give it another go if I get time

[lensman57]

Thanks for the advice, I just use PS and do levels and curves as I don't have Pixinsight unfortunately, I may give it another go if I get time

Hi,

You can do a starless copy of the final image, and use the stars from the Ha image. As this is an HST palette the star colors are meaningless anyway but atleast you end up with tight stars. The other way of doing it is to make a copy of the Oiii image, make a very mild stretch to keep the stars under control with the copy, do a proper stretch for the Oiii with the original, paste the low stretch on top of the proper stretch and make a layer mask , copy and paste the proper stretch on to the layer mask, apply a high Gaussian blur about 10 pix, use curves to just leave the bright stars in the mask and flatten , with a bit of luck you get tighter stars. If you got lost in all this one of the members Uranium 235 has posted a great tutorial for this star control, http://stargazerslounge.com/topic/223750-star-control-the-u235-method/, this should be easy to follow.

A.G

[PhotoGav]

That's a splendid result, really beautiful image. I found the stretching required to the OIII data was off the scale and I think you've kept it really well under control here! You have some lovely colours coming through too. Well done!

[Kbramley]

Thanks Gav, I find the colours are normally way off initially with the HST palette with the initial layering, all the stars are magenta and the nebulosity dominated by the green Ha. I generally have to play with the "selective colour" option and tune down the magenta and boost the blue, after a couple of iterations I get something I think looks right. I guess with narrowband images there is no real right answer as it's a totally false colour anyhow, although I'm a big fan of the blue OIII in images as it feels right somehow

[ollypenrice]

Good Wizard. Using a starmask in Ps would certainly help but you need to stretch very gently under it and ditch it once you start to see artefacts.

Ollyu

[AndyUK]

Very nice indeed Keith - You mentioned you "played around" with selective colour until it looked more or less right... and you've done a very good job .  As you say, it's false colour anyway, but I always used to use this as a the basis for putting an HST together - http://bf-astro.com/hubbleP.htm - It usually got me somewhere fairly close and then you can tweak again "to taste"

[Kbramley]

Very nice indeed Keith - You mentioned you "played around" with selective colour until it looked more or less right... and you've done a very good job .  As you say, it's false colour anyway, but I always used to use this as a the basis for putting an HST together - http://bf-astro.com/hubbleP.htm - It usually got me somewhere fairly close and then you can tweak again "to taste"

Great link, quite handy the example they use is the Wizard nebula