Horsehead and Flame from last night

[RobertM]

It wasn't very good last night as others have commented so dont harp on about any noise.  I also couldn't get a decent guide star to guide on so this was unguided.   15 x 10 mins Sky90@f/4.5 with SXV-H9/13nm Astronomik Ha filter dithered via mount in maximdl.

Bite sized:


Full size:

http://farm4.static.flickr.com/3410/3245041566_aa2226ba89_o.jpg

Robert

[Fay]

What are you on about, Robert, that is great!! Lots of nice contrast

[JohnP]

Robert - you are taking the piss....! looks tremendous to me.. maybe a tad oversharpened.... John

[RobertM]

I should also have said sharpening.  It's been well overprocessed with noise reduction and the over sharpening was in part to counteract the smoothing of the NR.  I don't like pushing images this far as it results in noticable artifacts in the image - well spotted John.

[JohnP]

Still looks great to me though... 10mins unguided - very impressive... John

[Daniel]

Yep, have to say that's phenomenal, way better than anything i've been able to get even on perfect nights!

Daniel
:O)

[JohnP]

Robert, I'm curious when you do 15-20min subs with your H9 & Ha filter how much of the well depth do you fill? Do you start to saturate stars or is there still headroom?

Cheers,  John

[RobertM]

John,  normally stars are saturated all over the place but not by too much.  In the raw 10 minute subs for this image Alnitak fully saturated 5 pixels but was over 60k ADU over a 13 pixel area, there weren't any other saturated pixels.  I think the sensor in the H9 is very non linear (it flattens off sharply) over the last 5k of adu, probably due to the anti blooming gate and this helps to reduce saturation.  I don't usually worry about stars saturating pixels unless they are very bright (Mag 3-5 or brighter) but there is quite a difference between 10 and 20 min subs.  Ha tends to suppress stars, especially those that are hot and luminous - that is a big win when imaging especially in LP environments where contrast is a real problem.

[Rocket Pooch]

i'm with john your taking the piss, my heart bleeds for you not finding a guide star

how smug can this society get with astro imaging, if only we were in arizona....

[RobertM]

Sorry, you're right.  I look at what's around and think it's no good but then we don't live in New Mexico or even outside the M25.  It's very frustrating though when you get a clear night and the limiting magnitude is just 3.5 or less ! Thank goodness we have narrowband.

[Mike]

That is superb Robert. I'd be well chuffed with that.

[MarkS]

Very good Robert.  Conditions were not good that night so I'm impressed at the detail you've managed to get with narrowband
I'm so jealous of 10min unguided!!!

Mark