Dark Tower - work in progress

marc4darkskies (Marcus) · #1 28-05-2011, 01:31 PM

A few clear nights in Sydney and what happens? A mad rush to image before the clouds return (sorry - a bit pessimistic).

I haven't finished this one yet but I thought I'd post anyway as a work in progress. So far so good - only preliminary processing has been done so still a way to go!

This is a faint one for sure - especially through a 5.9" and with Ha filter!!

Most of the signal you see is the Ha component. The Lum is just filling in the stellar profiles a bit and exposing the few small bits of reflection near in top in the dark part.

Hopefully RGB will follow in the next few days!

Small:
http://www.pbase.com/gailmarc/image/135068508/large

Large:
http://www.pbase.com/gailmarc/image/135068508/original

Cheers, Marcus

strongmanmike (Michael) · #2 28-05-2011, 01:48 PM

Looks exactly as I would expect it to look Marcus ie excellent

Some good exposure time there and the addition of the Lum has brought out lots of stars, which in this field actually looks good.

The colour version will look fantastic, ahhh I can see it already

Mike

renormalised (Carl) · #3 28-05-2011, 01:53 PM

Looking good, Marcus. Will be a top shot when it's finished

gregbradley · #4 28-05-2011, 04:37 PM

Looking good Marcus.

A bit of fuzziness on lots of the stars though. Its from overflow from the pixel wells.
Was that in the Luminance or the Ha or both?

30 minutes for Ha or 20 minutes for Lum may be too long for the 60,000 electron
wells of the 11002 chip. Length of exposure has too much noise with too short on one side versus
oversaturation with long exposures on the other side. It depends on the well depth and noise levels of the camera
and the cooling ability.

Greg.

multiweb (Marc) · #5 28-05-2011, 04:48 PM

That's a great shot Marcus. An excellent sharp base to do colors from.

Peter Ward · #6 28-05-2011, 05:15 PM

To quote H. Simpson..... Huumm Doughnuts

Drool....

marc4darkskies (Marcus) · #7 28-05-2011, 06:11 PM

Quote:

Originally Posted by strongmanmike

Looks exactly as I would expect it to look Marcus ie excellent

Some good exposure time there and the addition of the Lum has brought out lots of stars, which in this field actually looks good.

The colour version will look fantastic, ahhh I can see it already

Mike

Thanks Mike - appreciate that!

Yeah can't wait to get the colour but wouldn't you know it .... cloudy tonight, same with showers tomorrow, rain on Monday and showers all next week!!!

Quote:

Originally Posted by renormalised

Looking good, Marcus. Will be a top shot when it's finished

Thanks Carl! I was pleasantly surprised at the resolution although seeing wasn't the best. It wasn't bad though.

Quote:

Originally Posted by gregbradley

Looking good Marcus.

A bit of fuzziness on lots of the stars though. Its from overflow from the pixel wells.
Was that in the Luminance or the Ha or both?

30 minutes for Ha or 20 minutes for Lum may be too long for the 60,000 electron
wells of the 11002 chip. Length of exposure has too much noise with too short on one side versus
oversaturation with long exposures on the other side. It depends on the well depth and noise levels of the camera
and the cooling ability.

Greg.

Hehehe ... methinks you're too used to 17 inches of aperture. 5.9" at F11.7 requires long subs - especially on a faint object like this! Max ADU is 51,000 odd for the brightest of stars in Lum (at the bottom of the frame) and 59,000 in Ha. Yep, they're pretty well saturated but the sub length is aimed at revealing the subject so I'm happy to sacrifice a few stars for that. Really, any overly fuzzy stars you see (?) are because this is a work in progress.

Cheers mate!

Quote:

Originally Posted by multiweb

That's a great shot Marcus. An excellent sharp base to do colors from.

Thanks Marc - still hopeful I can gather some RGB before the moon comes back!

Quote:

Originally Posted by Peter Ward

To quote H. Simpson..... Huumm Doughnuts

Drool....

Thanks Peter! I trust you mean Krispy Kreme doughnuts? ... With lots of icing .... and 100s and 1000s? ... Mmmmmmm

troypiggo (Troy) · #8 28-05-2011, 08:06 PM

Wow. Appetite whet, looking forward to the next installments.

gregbradley · #9 29-05-2011, 01:00 AM

Hehehe ... methinks you're too used to 17 inches of aperture. 5.9" at F11.7 requires long subs - especially on a faint object like this! Max ADU is 51,000 odd for the brightest of stars in Lum (at the bottom of the frame) and 59,000 in Ha. Yep, they're pretty well saturated but the sub length is aimed at revealing the subject so I'm happy to sacrifice a few stars for that. Really, any overly fuzzy stars you see (?) are because this is a work in progress.

Cheers mate!

Yes that is true. It is a spectacular image and very nicely framed. It is impressive that you can get such round stars for so long a period at F11.7.

Greg.

marc4darkskies (Marcus) · #10 29-05-2011, 06:21 PM

Quote:

Originally Posted by troypiggo

Wow. Appetite whet, looking forward to the next installments.

Cheers Troy. Dying to finish it - I just need the cloud gods to blink.

Quote:

Originally Posted by gregbradley

Yes that is true. It is a spectacular image and very nicely framed. It is impressive that you can get such round stars for so long a period at F11.7.

Greg.

PME = round stars

I think framing / composition is often underated as an essential ingredient of a striking image. I always devote some thought to what I want the final frame to look like and often crop just to make it right. I haven't decided this is the final composition yet, it may change when the colour is added.

Thanks again!

Phil Hart · #11 29-05-2011, 08:57 PM

very impressive marcus.. that seems very deep to me.. 7 hours sure but f11.7.. and you're not even in really dark skies? i'm amazed at what you can do..

marc4darkskies (Marcus) · #12 29-05-2011, 11:35 PM

Quote:

Originally Posted by philiphart

very impressive marcus.. that seems very deep to me.. 7 hours sure but f11.7.. and you're not even in really dark skies? i'm amazed at what you can do..

Thanks Phil! You're too kind!

Yes it's quite deep but Ha is good for piercing the sky glow if you have the patience to gather the data. My SE sky is pretty well blotted out from the light dome over Sydney so I may have to wait till after transit for the G and B data. Everywhere else is reasonably dark though.

TrevorW · #13 30-05-2011, 12:45 PM

Very nicely captured plenty of detail

Hagar (Doug) · #14 30-05-2011, 07:15 PM

I Love the detail in this one Marcus. Should be a contender for the pool room once you add some colour. Very nice.

marc4darkskies (Marcus) · #15 30-05-2011, 09:57 PM

Quote:

Originally Posted by TrevorW

Very nicely captured plenty of detail

Cheers Trev!

Quote:

Originally Posted by Hagar

I Love the detail in this one Marcus. Should be a contender for the pool room once you add some colour. Very nice.

Thanks Doug! I might just have to build that pool room too - I'm running out of wall space in the study!

Doesn't look like colour is comining any time soon ... the cloud and rain is back

gregbradley · #16 31-05-2011, 07:47 AM

Quote:

Originally Posted by marc4darkskies

Cheers Trev!

Thanks Doug! I might just have to build that pool room too - I'm running out of wall space in the study!

Doesn't look like colour is comining any time soon ... the cloud and rain is back

Ah doubter! Friday is supposed to be partly cloudy! You never know your luck.

Why is it for the last 2 years that the full moon weeks are often far clearer than the no moon weeks?
Have a look at the pattern its almost 100% of the time. Is it like a tide thing with moisture in the air
dragged to other areas in the full moon week?

Greg.

Leonardo70 (Leonardo Orazi) · #17 31-05-2011, 05:57 PM

WOW ....
Fantastic resolution....

Ciao,
Leo

Bassnut (Fred) · #18 31-05-2011, 06:24 PM

Excellent Marcus, atmospheric in B/W.

marc4darkskies (Marcus) · #19 31-05-2011, 08:50 PM

Quote:

Originally Posted by gregbradley

Ah doubter! Friday is supposed to be partly cloudy! You never know you're luck....

Yeah but I hate it when I have to stop in the middle of a project! Grrrrr ...

I guess "Partly Cloudy" will have to do. I'd prefer to see "Fine" for the next week though! And I think you're right about the coincidence of full moon with clear skies. Hey! Maybe we should consult an astrologer to see when the next best imaging nights will be!?

Quote:

Originally Posted by Leonardo70

WOW ....
Fantastic resolution....

Ciao,
Leo

Thanks a lot Leo. Yes, the 1.6 Extender on the TOA works a treat in good seeing and really shows off the top quality of Tak optics!

Quote:

Originally Posted by Bassnut

Excellent Marcus, atmospheric in B/W.

Cheers Fred! Hopefully I can maintain and/or enhance that atmosphere with the colour.