RE: [ap-gto] Re: 29 hours of m27 at 3366mm


Aug 4, 2007

 


----------------------------

#18792 Aug 4, 2007

I began this over the July 4th holiday and took my most recent data

last night, Aug 3



This is 12 hours of [SII], 10 hours of [OIII] and 7 hours of Halpha



It was shot using the TK1024 powered FLI Dream Machine camera (1kx1k

@24x24 micron pixels at about 85% QE) using 4.5nm Cust Sci emission

line filters on the Stinger 450 classical cassegrain/AP1200GTO using

a Lumicon Giant Easy Guider with focal reducer for a focal length of

3366mm (~f/7.1). You just can't beat those TK1024 chips and other

such similar chips for going really deep. The combination of the high

QE, the deep wells and the big pixels really makes for a fast camera

that is just wonderful for deep emission line imaging with tight

filters.



I am intrigued by the sulfur channel data (red in this palette). I am

seeing detail I've not seen previously in shallower exposures.



I may take some more exposures, but am getting a bit tired of this

object after shooting it for the past month.



www.narrowbandimaging.com/m27_mk1sn2_dm_geg_cs4_s2hao3_page.htm



----------------------------

#18796 Aug 4, 2007

You just can't beat those TK1024 chips and other

> such similar chips for going really deep. The combination of the high

> QE, the deep wells and the big pixels really makes for a fast camera

> that is just wonderful for deep emission line imaging with tight

> filters.

> www.narrowbandimaging.com/m27_mk1sn2_dm_geg_cs4_s2hao3_page.htm



Hmmm... it doesn't seem THAT deep for 29 hours.



As a comparison here's my Halpha shot from New Mexico Skies. This shot is only 2

hours total of HAlpha with my 160EDF (1/3rd the aperture of your 18") and an

"inferior" STL-11000M. I think it shows the same faint shell structure that your

29 hour image shows.



And maybe the seeing was soft or the focus was drifting with temperature a

little too?? The refractor seems to show tighter stars and more detail in M27. I

would expect an 18" to be the sharper of the two??



www.gralak.com/Astro/M27-AP160-HA-120mins-Cropped-100.jpg



-Ray Gralak



----------------------------

#18799 Aug 5, 2007

Hi Richard,

I was gonna add similar comment to Ray's on depth of the image for

the hours spent.



www.backyardastronomer.com/ccd-images/m27/M27-SII-Ha-OIII.jpg

3 hours, taken in July 2005. (same palette as yours)

here's with the RCOS16" @f/6.7 on trusty old ST10xme, with Astrodon

6nm SII, Ha, OIII filters, combined using the hubble palette. 3hr

total, 1hr per channel (3x20min). This was a second light image

getting the system up and working in its new backyard in light

polluted (mag 3.5 at best) skies. ST10 though has much smaller

pixels (6.8u) versus the TK1024, and still nicely has 85% QE in Ha.



a little more stretching revealed the outer halo in the shot. Though

not the intent of the "pretty picture" image above, the detail was

there in the 60min Ha.

www.backyardastronomer.com/ccd-images/m27/M27-SII-Ha-OIII-test2.jpg



so what "detail" are you seeing. The majority of detail in this

target is in Ha. There's strong component in OIII but very minor in SII.

www.backyardastronomer.com/ccd-images/Sum%20M27-SII-1-ddps-test.jpg SII

www.backyardastronomer.com/ccd-images/Sum%20m27-ha3x-1-ddps1.jpg Ha

www.backyardastronomer.com/ccd-images/Sum%20M27-OIII-2-ddps-test.jpg

OIII



5hrs of Ha for fun last summer under a full moon and hot humid

conditions not perfect for serious imaging. ie camera running at -10C

www.backyardastronomer.com/ccd-images/m27-5hrs-web1.jpg

clearly shows the extent of the halo, but again H-alpha data.



of course having fun with other palettes.

www.backyardastronomer.com/ccd-images/m27/M27-OIII-Ha-SII.jpg

fun palette

www.backyardastronomer.com/ccd-images/m27/M27-Ha-OIII-SII.jpg

CFHT palette.



cheers,

...paul.



----------------------------

#18802 Aug 5, 2007

Hey Paul,



We don't see many images from you, but your M27 blew me out of my seat this morning. I think some of us who have moved to those big arrays have forgotten just how good the ST10 is!



Cheers,



jg

-----Original Message----- >From: Paul Mortfield paul@...>

>Sent: Aug 6, 2007 1:49 AM

>To: ap-gto@yahoogroups.com

>Subject: [ap-gto] Re: 29 hours of m27 at 3366mm

>

>Hi Richard,

>I was gonna add similar comment to Ray's on depth of the image for

>the hours spent.

>

>www.backyardastronomer.com/ccd-images/m27/M27-SII-Ha-OIII.jpg

>3 hours, taken in July 2005. (same palette as yours)

>here's with the RCOS16" @f/6.7 on trusty old ST10xme, with Astrodon

>6nm SII, Ha, OIII filters, combined using the hubble palette. 3hr

>total, 1hr per channel (3x20min). This was a second light image

>getting the system up and working in its new backyard in light

>polluted (mag 3.5 at best) skies. ST10 though has much smaller

>pixels (6.8u) versus the TK1024, and still nicely has 85% QE in Ha.

>

>a little more stretching revealed the outer halo in the shot. Though

>not the intent of the "pretty picture" image above, the detail was

>there in the 60min Ha.

>www.backyardastronomer.com/ccd-images/m27/M27-SII-Ha-OIII-test2.jpg

>

>so what "detail" are you seeing. The majority of detail in this

>target is in Ha. There's strong component in OIII but very minor in SII.

>www.backyardastronomer.com/ccd-images/Sum%20M27-SII-1-ddps-test.jpg SII

>www.backyardastronomer.com/ccd-images/Sum%20m27-ha3x-1-ddps1.jpg Ha

>www.backyardastronomer.com/ccd-images/Sum%20M27-OIII-2-ddps-test.jpg

>OIII

>

>5hrs of Ha for fun last summer under a full moon and hot humid

>conditions not perfect for serious imaging. ie camera running at -10C

>www.backyardastronomer.com/ccd-images/m27-5hrs-web1.jpg

>clearly shows the extent of the halo, but again H-alpha data.

>

>of course having fun with other palettes.

>www.backyardastronomer.com/ccd-images/m27/M27-OIII-Ha-SII.jpg

>fun palette

>www.backyardastronomer.com/ccd-images/m27/M27-Ha-OIII-SII.jpg

>CFHT palette.

>

>cheers,

>...paul.

>







----------------------------

#18804 Aug 5, 2007

Paul,



I would also like to echo my sentiments surrounding those wonderful

images. Good stuff!



Anthony.

--- In ap-gto@yahoogroups.com, "Ray Gralak" rgr@...> wrote:

>

> Paul those images are all very nice. I think they reinforce that

something must

> be wrong with Richard's setup if it took 29 hours of exposure to get

the image

> he posted. Hopefully this will prompt him to find the problem.

>

> -Ray



----------------------------

#18809 Aug 5, 2007

Hi Paul,

--- In ap-gto@yahoogroups.com, Paul Mortfield paul@...> wrote:

... The majority of detail in this

> target is in Ha. There's strong component in OIII but very minor in SII.

...



I am uncertain if the SII is actually from sulfur atoms present in the

target. We all know that the universe is Hydrogen and Helium and the

OIII comes from the CNO process in stellar fusion. But is there enough

sulfur from stellar evolution to feed that spectral line to a

noteworthy intensity? Could there be continuum light picked up by the

SII filter? Or a 'leak' from the nearby very intense HII?? Too tough

to call for me right now. Somebody has more data?



Clear Skies,



Gert



----------------------------

#18810 Aug 5, 2007

the custom scientific 4.5nm filters show emission at 673.4nm which corresponds to the stronger of the [SII] doublet.



----- Original Message -----

From: drgert1

To: ap-gto@yahoogroups.com

Sent: Sunday, August 05, 2007 6:42 PM

Subject: [ap-gto] Re: 29 hours of m27 at 3366mm





Hi Paul,



--- In ap-gto@yahoogroups.com, Paul Mortfield paul@...> wrote:

... The majority of detail in this

> target is in Ha. There's strong component in OIII but very minor in SII.

...



I am uncertain if the SII is actually from sulfur atoms present in the

target. We all know that the universe is Hydrogen and Helium and the

OIII comes from the CNO process in stellar fusion. But is there enough

sulfur from stellar evolution to feed that spectral line to a

noteworthy intensity? Could there be continuum light picked up by the

SII filter? Or a 'leak' from the nearby very intense HII?? Too tough

to call for me right now. Somebody has more data?



Clear Skies,



Gert











[Non-text portions of this message have been removed]



----------------------------

#18814 Aug 6, 2007

thanks John, Ray, Anthony et al.

that "old" camera is such a workhorse especially in light polluted

environments doing narrowband. And with the NIR sensitivity, its fun

for projects like I showed at AIC last year.



As for the M27 shot, I'm more of the monochrome B&W guy, so I must

give all the color credits to Stef Cancelli. He's the photoshop

wizard that took my narrowband master frames and did the final color

combine, tweaking and photoshop magic. We've collaborated on a bunch

of images that turned out really well.



cheers,

...paul.



----------------------------

#18815 Aug 6, 2007

Here's another M27 for comparison. It was taken with a different

scope than Richard's or Ray's but it shows what I came up with as far

as detail in the outer HII shell(and of course this is HaRGB not

purely narrowband so the comparison may be mute). Taken on an AP

mount.



www.tvdavisastropics.com/astroimages-1_000038.htm



Tom











--- In ap-gto@yahoogroups.com, "Richard Crisp" rdcrisp@...> wrote:

>

> I began this over the July 4th holiday and took my most recent data

> last night, Aug 3

>

> This is 12 hours of [SII], 10 hours of [OIII] and 7 hours of Halpha

>

> It was shot using the TK1024 powered FLI Dream Machine camera

(1kx1k

> @24x24 micron pixels at about 85% QE) using 4.5nm Cust Sci emission

> line filters on the Stinger 450 classical cassegrain/AP1200GTO

using

> a Lumicon Giant Easy Guider with focal reducer for a focal length

of

> 3366mm (~f/7.1). You just can't beat those TK1024 chips and other

> such similar chips for going really deep. The combination of the

high

> QE, the deep wells and the big pixels really makes for a fast

camera

> that is just wonderful for deep emission line imaging with tight

> filters.

>

> I am intrigued by the sulfur channel data (red in this palette). I

am

> seeing detail I've not seen previously in shallower exposures.

>

> I may take some more exposures, but am getting a bit tired of this

> object after shooting it for the past month.

>

>

www.narrowbandimaging.com/m27_mk1sn2_dm_geg_cs4_s2hao3_page.htm

>



----------------------------

#18824 Aug 7, 2007

Hi Bill,

> My understanding is that the length of the subframe determines how

> deep you go, while the noise is reduced by the total number of

> subframes. So it seems to me that Richard's image should have less

> noise to it than the others--which of course enables you do draw out

> more detail in processing.

>

> What I think I see in Richard's shots that I don't seen as much in

> the others, is the depth in the non-ha images. You see multiple

> colors in the halo of Richard's image, but in Paul's the halo is

> basically monochromatic. If I understand this right, it means that

> Richards goes deeper in SII and OIII?



I think the main question is why isn't it a LOT deeper? I think he wrote the HA

component of his image is 7 hours. Given that the 18" aperture is 3x (9x the

area) of a 6" refractor and the QE is 2x in HA that means that he accumulated

the _equivalent_ of 126 hours (9 x 2 x 7 hours) exposure on a 6 inch refractor.



But I think that the 2 hour exposure from the refractor at least matches the

depth of the HA component of the 18" + FLI. Some of this is probably because I

imaged from a very dark site and he from the Bay Area, But a factor of 63x (126

hours/ 2 hours) seems like too much unless there was some equipment malfunction

(e.g. I have had a filter bandpass either shift or was set at the wrong

frequency once with a Custom Scientific filter).



-Ray







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