Another Deep Helix - Ha and O3

[alistairsam]

hi,

This is still a work in progress but thought I'd post what I've collected so far.

These are roughly processed Ha and O3 stacks.
17.5 hrs of Ha and 6.3hrs of O3.
Sub lengths between 20mins and 60mins depending on the moon

90% was taken from my light polluted backyard so yep gradients galore, need to re-process from scratch, but I like the faint stuff that i've picked up so far. The fainter areas are noisy and need more data for sure.
Planning to stick with this till I get most of the faint stuff.

still a WIP and I keep thinking of how I'm going to combine these.
the spokes of the O3 with the extensions of Ha...

Larger versions here

Ha
http://www.astrobin.com/full/208437/B/

O3
http://www.astrobin.com/full/216674/B/


Equipment
STF8300m Mono
Astrodon 5nm Ha and 3nm O3
Home built 10inchF4,
Paramount MyT
Startools

comments welcome

Cheers
Alistair

[Placidus]

Already very good, and given the short time and urban circumstances, quite remarkable. A sensible image scale for the Helix.

[RickS]

Quite deep, Al. Look forward to the combo!

[Slawomir]

Very impressive Alistair :thumbsup:

[Paul Haese]

Looks good Alistair. Loads of detail already.

[alistairsam]

Thanks, I did have to crop it though as I don't have a rotator and the various sessions ended up in different angles



Thanks Rick. I'm aiming high, trying to get how Martin got the O3 details so beautifully combined.



Thanks Slawomir



Thanks Paul, hope to get another 20 hrs or so and I'll be done.

Cheers
Alistair

[Fabiomax]

A great job! Deep and details. ..no mystery more for the helix nebula !
Cheers
Fabiomax

[gregbradley]

Looking fabulous there Alistair. I can see some fixed pattern noise showing through.

Best to check you have an up to date and high quality bias for that. I was getting some fixed pattern noise with the Trius recently and that's what seemed to make the difference - a good bias.

Greg.

[alistairsam]

Thanks Fabio



Thanks Greg,

yes I did take a new set of Bias frames for this but it might be my flats as I recall seeing the pattern in them. not sure how.

There are 2 or 3 clear nights this week, so hope to get the hrs I need and complete it.

Cheers
Alistair

[gregbradley]

Thanks Greg,

yes I did take a new set of Bias frames for this but it might be my flats as I recall seeing the pattern in them. not sure how.

There are 2 or 3 clear nights this week, so hope to get the hrs I need and complete it.

Cheers
Alistair[/QUOTE]


I play around with calibration these days and see how it works. Sometimes I see better results with a bias subtracted from the flats when making the master flat and on some setups (CDK) it seems to work better to subtract the bias when the flats are being applied.

The fixed pattern noise may go also if you bias subtract from your flats when making the master flat. Not sure if darks remove it.

Greg.

[Shiraz]

nice work Alistair - looking forward to the final result.

[dylan_odonnell]

What a beauty! I couldn't help take a quick peek at combining as a bicolour .. looks amazing. That oxygen really turned out great.

[strongmanmike]

Nice work Alistair, them's about as deep as they come :thumbsup: The OIII structure on this one always fascinates too. I look forward to seeing the finished colour version/s :D

Mike