Telescope Reviews: M16 Eagle - Ha

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Astrophotography and Sketching >> Beginning and Intermediate Imaging

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SL63 AMG
professor emeritus

Reged: 12/21/09

Loc: Williamson, Arizona

M16 Eagle - Ha
#5284405 - 06/22/12 08:12 PM

Last night I imaged M20, but my collimation was off causing poor focus, but I did take a momment to see what the eagle and pillars of creation would look like at 1575mm FL f/6.3. This is a single 5 minute 3nm Ha sub, calibrated then applied levels and curves in Photoshop.

Now I need to decide for tonight, M16 or the Crescent Nebula.

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CounterWeight
Postmaster

Reged: 10/05/08

Loc: Cloudyopolis, OR.

Re: M16 Eagle - Ha new

new

[Re: SL63 AMG]
#5284442 - 06/22/12 08:54 PM

I'd say that looks very nice! Dark filaments and the usual suspects all come out very nicely.

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SL63 AMG
professor emeritus

Reged: 12/21/09

Loc: Williamson, Arizona

Re: M16 Eagle - Ha new

new

[Re: CounterWeight]
#5284483 - 06/22/12 09:46 PM

Jim,

Your narrowband images on your website are phenominal.

I'll share my skies with you if you'll come down here and teach me how to process images using the hubble pallette!

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CounterWeight
Postmaster

Reged: 10/05/08

Loc: Cloudyopolis, OR.

Re: M16 Eagle - Ha new

new

[Re: SL63 AMG]
#5284537 - 06/22/12 10:24 PM

Dave,

Thanks for the kind words, much appreciated. The way my weather has been here, there is more possibility of that weekly! Send a PM and I'll answer anything I can - you are way ahead in the game getting such good data to start with, and so much of it. You, Mark, and a few others here have me thinking very seriously about a large inventory revision wrt imaging scopes... maybe I'll be putting off that XX14g for a while longer and get something that can haul the frieght you fast imagers are pulling in, it's really impressive!

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rigel123
Postmaster

Reged: 06/29/09

Loc: SW Ohio

Re: M16 Eagle - Ha new

new

[Re: SL63 AMG]
#5284597 - 06/22/12 11:27 PM

Looks great Dave! I'm hoping to go after this one close up tonight!

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NorthBoundTrain
Carpal Tunnel

Reged: 11/23/11

Re: M16 Eagle - Ha new

new

[Re: rigel123]
#5284630 - 06/22/12 11:50 PM

Wow, that's amazing for a single 300" sub!

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Hilmi
Carpal Tunnel

Reged: 03/07/10

Loc: Muscat, Sultanate of Oman

Re: M16 Eagle - Ha new

new

[Re: NorthBoundTrain]
#5284903 - 06/23/12 08:38 AM

I envy your skies, you got more in Narrow band 5 minutes than what I got in 73 minutes using LRGB. You must have excellent skies. And my camera is supposed to be more sensitive than yours too

That's a pretty shot, I wonder how good it will be once you stack enough of them together. Here is mine for comparison.

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5281177/page/2/view/collapsed/sb/5/o/all/fpart/1

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terry59
Carpal Tunnel

Reged: 07/18/11

Loc: Colorado, USA

Re: M16 Eagle - Ha new

new

[Re: SL63 AMG]
#5285022 - 06/23/12 10:32 AM

Dave, that is very nice. It has helped me decide to get an Ha filter to start working with.

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SL63 AMG
professor emeritus

Reged: 12/21/09

Loc: Williamson, Arizona

Re: M16 Eagle - Ha new

new

[Re: Hilmi]
#5285026 - 06/23/12 10:34 AM

Hilmi,

Thank you for the reply.

I looked at your image. It's really nice.

With regard to capturing more data, I believe there are several factors.

1) My single exposure time was 5 minutes, your exposure time was 60 seconds, then each stacked. You cannot capture more data through stacking. Stacking only provides a better representation of the data captured relative to each pixel location on your chip. Is the SBIG ST402me that much more sensitive than the FLI ML8300? I haven't looked at the specs side by side.

2) Faster scope. Isn't your LX200r an f/10? I captured this data at f/6.3 which means I will gather more light faster.

4) More aperature. Your scope is 8" and mine is 10" thus I have a "bigger eye" looking at the same object.

5) Skies. This is quite important to capturing good data and acheiving good focus. The seeing here at my new Arizona home is spectacular. On good nights, there is very little twinkle in the stars down to about 20°. The scintillation is minimal.

Sky conditions at my home

I did a lot of research before buying the ASA system, but in general, I learned there is no substitute for a fast Newtonian astrograph with large aperature.

The tradeoff here is collimation. It can be quite painstaking getting one properly collimated.

I suspect flexure could be another issue if the Newtonian astrograph isn't built well. I have a lot of weight hanging off the side of mine. The ASA OK3 focuser and Wynne corrector system is quite rigid.

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Hilmi
Carpal Tunnel

Reged: 03/07/10

Loc: Muscat, Sultanate of Oman

Re: M16 Eagle - Ha new

new

[Re: SL63 AMG]
#5285112 - 06/23/12 11:26 AM

Dave,

Thanks for the feedback, with regards to your comments.

1) Sky tools 3 had recommended 60 seconds as the optimal sub-exposure. I will try 5 minutes next time. The ST402me has more than 20% higher QE.

2) My scope was at F6.3 using a reducer

3) Don't tempt me

4) Skies, ahh, what can I say... magnitude 3 with 70% to 80% humidity. I don't call em murky skies for nothing you know.

Regardless, I love your work in general. And your equipment list

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CounterWeight
Postmaster

Reged: 10/05/08

Loc: Cloudyopolis, OR.

Re: M16 Eagle - Ha new

new

[Re: Hilmi]
#5285396 - 06/23/12 02:44 PM Attachment (11 downloads)

Hi- Don't meant to go OT but this more to Hilmi, I always input min and max values in the exposure time and then use the resulting SNR/Q suggestions as a guide, seems most of the time it will always suggest shorter sub exposures[my assumtion is it does this to increase SNR? only], but from experience I know I get better images with longer sub's.

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DaemonGPF
Redonkulous

Reged: 03/22/08

Loc: Rio Rancho, New Mexico

Re: M16 Eagle - Ha new

new

[Re: SL63 AMG]
#5285766 - 06/23/12 06:45 PM

Quote:

Hilmi,
I did a lot of research before buying the ASA system, but in general, I learned there is no substitute for a fast Newtonian astrograph with large aperature.

Ah, but there is! It's called Hyperstar.

F/2 with a C14, C11, C9.25, or C8 is just devastating. Even with a C8 Hyperstar in the right hands should be able to just blow away most conventional astrographs out there in respect to depth vs exposure and total integration.

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CounterWeight
Postmaster

Reged: 10/05/08

Loc: Cloudyopolis, OR.

Re: M16 Eagle - Ha new

new

[Re: DaemonGPF]
#5285832 - 06/23/12 07:58 PM

Josh,

I agree, but it does restrict choice of mono CCD with filter wheel more than the Newt's?

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DaemonGPF
Redonkulous

Reged: 03/22/08

Loc: Rio Rancho, New Mexico

Re: M16 Eagle - Ha new

new

[Re: CounterWeight]
#5285872 - 06/23/12 08:27 PM

The filter wheel aspect, yes. You'd have to remove the camera. That's the trade off. I started working on a solution for mine before I sold it. I'll probably pick it back up after I build my new one shortly and see if I can finish solving the problem.

Unfortunately being the nature of AP, there's just not the "one perfect instrument" that I've found yet. Would seem to be why so many people have a large variety of OTAs in their signatures/inventory.

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psu_13
sage

Reged: 05/30/10

Re: M16 Eagle - Ha new

new

[Re: DaemonGPF]
#5285935 - 06/23/12 09:21 PM

I don't quite understand how skytools decides what to recommend as a good exposure time, but with my set up it's consistently way too short (i.e. in the *seconds* not minutes).

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theskyhound
Vendor (Skyhound)

Reged: 03/10/06

Loc: Cloudcroft, New Mexico

Re: M16 Eagle - Ha new

new

[Re: psu_13]
#5289494 - 06/26/12 02:19 AM

Quote:

I don't quite understand how skytools decides what to recommend as a good exposure time, but with my set up it's consistently way too short (i.e. in the *seconds* not minutes).

Have a look at the documentation here that may help:

http://skyhound.com/sub_exposure_guide.html

There are a lot of factors at play and it is important to have all the inputs as accurate as possible. Also, for some imaging systems the sub-exposure time makes little practical difference. SkyTools will sometimes suggest short exposure times in these cases. A little experimenting with the Exposure Calculator tool, as described in the docs above, will help you determine how sensitive the sub-exposure is. If it makes little difference, use whatever sub-exposure that is practical.

It is important to keep in mind, however, that changing conditions, such as moonlight, twilight, and the altitude of your object, may affect this sensitivity.

Also, people should note that SkyTools does not claim to work with emission line filters! This would require a comprehensive catalog of emission line strengths, and sadly, as far as I know that data is not available.

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CounterWeight
Postmaster

Reged: 10/05/08

Loc: Cloudyopolis, OR.

Re: M16 Eagle - Ha new

new

[Re: theskyhound]
#5290095 - 06/26/12 12:53 PM

Greg,

Thank you so much for posting in here

!! Your software is absolutely fantastic in my book, even that falls short. Thank you sir!

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