Ghostly spectres at the stern of the ship.

Maurice · #1 31-01-2017, 07:26 PM

Hi all

Just starting a new image project.

Cometary globules CG30 (top right) and CG31 (centre) of this 6hr Ha image (in 20min subs) need a lot more imaging time. Surprised how faint they are in Ha. Hate to think how long its going to take in OIII.

Looks like an interesting region with HH120 in the 'head' of CG30. The whole complex is in the area of the 'stern' of the old constellation of Argo Navis... now in Puppis.

This might take a couple of years to complete..

GSO RC14 @2830mm fl QHY9 Baader Ha ASI120MM + OAG EQ8

cheers
Maurice

strongmanmike (Michael) · #2 31-01-2017, 07:36 PM

Wow Maurice spooky huh? it's a very cool object and you've made a great start...but be prepared to hit the exposure time though

Mike

Maurice · #3 31-01-2017, 08:07 PM

Cheers Mike.

Yeah...Its going to take while to get this one at f/8 from Melbourne.
I rekon it would be a great object with your rig at f/4 ish.

There aren't many shots of it around the 'net. Best I've seen is from Rolf Olsen a few years back... but it loses the the extension when only in RGB.

Might be one to consider....?

Paul Haese · #4 01-02-2017, 10:43 AM

Maurice I am looking forward to seeing the end result of this field. It's very intriguing.

Atmos (Colin) · #5 01-02-2017, 11:54 AM

That's an interesting region, looking forward to seeing what a LOT more exposure time will reveal

strongmanmike (Michael) · #6 01-02-2017, 12:43 PM

Quote:

Originally Posted by Maurice

Might be one to consider....?

Indeed.....

...too many objects not enough time, ah sigh.....

I think I will just sit back and enjoy your project, so keep posting

Mike

Placidus (Mike and Trish) · #7 01-02-2017, 05:43 PM

A worthy project proceeding nicely.

The gloomy mood reminds us of the Burghers of Calais by Rodin.

alpal · #8 01-02-2017, 06:44 PM

Hi Maurice,
we don't have to wait forever -
the giant Subaru 8.2m telescope got it.

https://apod.nasa.gov/apod/ap131012.html

Still it will be interesting to see what a more humble telescope
can pick up with this faint one!

cheers
Allan

Atmos (Colin) · #9 01-02-2017, 07:49 PM

Quote:

Originally Posted by alpal

Hi Maurice,
we don't have to wait forever -
the giant Subaru 8.2m telescope got it.

https://apod.nasa.gov/apod/ap131012.html

Still it will be interesting to see what a more humble telescope
can pick up with this faint one!

cheers
Allan

Maurice, not that you've started down this path we all EXPECT you to beat the Subaru!!

RickS (Rick) · #10 02-02-2017, 10:18 PM

A great start, Maurice!

Maurice · #11 04-02-2017, 06:13 PM

Quote:

Originally Posted by Paul Haese

Maurice I am looking forward to seeing the end result of this field. It's very intriguing.

Thanks Paul. We'll see how it goes, but there dosen't seem to be much there except for Ha... time will tell

Quote:

Originally Posted by strongmanmike

Indeed.....

...too many objects not enough time, ah sigh.....

I think I will just sit back and enjoy your project, so keep posting

Mike

I've managed another 6hrs over the past couple of nights (for a total of 12), but as you'd expect, its a case of diminishing returns. I'll take Ha out to 24hrs, but I'm not prepared to give it any more than that...

Quote:

Originally Posted by Placidus

A worthy project proceeding nicely.

The gloomy mood reminds us of the Burghers of Calais by Rodin.

A very apt comparison M&T... Might need an aperture like yours though to to collect enough photons in the end..

Quote:

Originally Posted by alpal

Hi Maurice,
we don't have to wait forever -
the giant Subaru 8.2m telescope got it.

https://apod.nasa.gov/apod/ap131012.html

Still it will be interesting to see what a more humble telescope
can pick up with this faint one!

cheers
Allan

Thanks Allan. I hadn't seen the Subaru image before. I really should have picked a more do-able object, I think..

Quote:

Originally Posted by Atmos

Maurice, not that you've started down this path we all EXPECT you to beat the Subaru!!

Not a chance Colin...but I'll give it a go anyway..

Quote:

Originally Posted by RickS

A great start, Maurice!

Thanks Rick..

Maurice · #12 04-02-2017, 06:15 PM

Added a second image with 12hrs total Ha...

Found I could push the stretch a bit more before excessive noise creeps in.

alpal · #13 04-02-2017, 10:58 PM

Quote:

Originally Posted by Maurice

Thanks Allan. I hadn't seen the Subaru image before. I really should have picked a more do-able object, I think..

Hi Maurice,
You sure do pick hard targets.

cheers
Allan

Maurice · #14 11-02-2017, 04:17 PM

Ha is up to 18hrs now and its changed very little from when I had 12hrs of data...

Might have to leave it at this..

The stack finished just over 2" FWHM, but there is only a 100ADU change from the darker to the brighter regions of the nebulosity.

That means that its only a signal difference of about 100/65000x22000(full well)=33e-

The read noise in the QHY9 is about 10e-, and the signal range that I'm interested in is only a change of 33e-.... I'm bound to have problems...

strongmanmike (Michael) · #15 14-02-2017, 12:13 PM

Nice comparison there Maurice, yes she is a faint one but looking good so far

Mike

Atmos (Colin) · #16 14-02-2017, 05:38 PM

The contrast has improved as you've increased the exposure but there is a point of diminishing returns.

Maurice · #17 16-02-2017, 10:28 PM

Quote:

Originally Posted by strongmanmike

Nice comparison there Maurice, yes she is a faint one but looking good so far

Mike

Thanks Mike.
Trying to rack up the hours with SII ATM...Not much there after 4hrs.

Quote:

Originally Posted by Atmos

The contrast has improved as you've increased the exposure but there is a point of diminishing returns.

Yep. Trying SII now. We'll see if there's anything there..