NGC281 - Pacman Nebula in Narrowband

Simon,

Great image interestingly on 8″ F4 Newtonian as well. About 12hrs of data do you mind me asking from what location you took them? Under arctic melt stratus cloud canopy for most of the time in Dublin that's a real challenge. I'm toying with an Autumn project on a narrowband target and hauling out my SCT 8" to gather data on a single target over a couple of months but not decided yet. I see the exposure lengths were 600s and wonder would subs of 1800s provide different result. I use an EQ8 only recently taming my setup to give 1800s I'm told for narrowband the longer and the more data the better. Regarding the tone mapping link I gave earlier I wonder does Pixinsight allow for star removal prior to processing the nebula ...but... lots to think about from your image there thanks.

Colm

Hey Colm

I didn't get a chance to look at that link yet, on your SCT you are going to need longer exposures as it is an F10 right?

I went from an F7.5 to an F4, which means my 10 min expsoure on my F4 is the same as a 35min exposure on F7.5, hence why I am abale to get a much more level of detail within a shorter exposure time, with F10 it is going to be a struggle, especially at a higher focal length too, this is one of the issues I had when I had my Ritchey Chretien, it was an F8, however the Focal length of 1600mm gave me some trouble, I had to increase the exposure time, and could never get the stars as pinpoint. Although I have learnt a hell of a lot more about guiding now

With longer focal length you yield a bigger resolution, but longer focal length also means longer exposure times, especially for narrowband.

All of my recent images post 2014 have been done in the UK, past couple of years from my home built observatory

Regards
Simon

Simon,

You'll be surprised its an Omni XLT Celestron refractor f5 with 3 matchsticks to stiffen focuser. Pacman above taken with it. Logic don't need a triplet for chromatic aberration for narrowbandpass but could do with a field flattener still looking at alternatives. I did make the mistake of going initially for long FL SCT 11" the weight ruining the Neq6 mount needed a Vimech wedge. Bloated stars are a problem along with too narrow FOV should make SCT long FL a nono for deepsky learned the hard way. No observatory but permanent pier.Recently got polemaster camera has made huge difference to alignment PA as I need to setup new most sessions. Re exposure lengths probably need to experiment more for local optimisation your 10m subs perhaps a better choice than my 1800s www.qdigital-astro.com/calculator

Clear skies,

Colm