Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Astrophotography and Sketching >> DSLR & Digital Camera Astro Imaging & Processing

Pages: 1 | 2 | (show all)
Jerry Lodriguss
Vendor


Reged: 07/19/08

Loc: Voorhees, NJ
NGC 891 20121116
      #5554899 - 12/05/12 12:18 AM Attachment (57 downloads)

Galaxy NGC 891 is a beautiful fall astrophotographic target.

http://www.astropix.com/HTML/SHOW_DIG/NGC891.HTM

Click on the link to see a larger version of the image with more information.

This image is a composite of six 10-minute exposures at ISO 800 taken with a Celestron C11 Edge at f/10 and an unmodified Canon T3i (600D).


Post Extras: Print Post   Remind Me!   Notify Moderator  
srosenfraz
Post Laureate
*****

Reged: 03/06/11

Loc: United States
Re: NGC 891 20121116 new [Re: Jerry Lodriguss]
      #5554920 - 12/05/12 12:34 AM

Superb NGC 891, Jerry. Great dust lane details, some really nice background galaxies, and the slight blue color to the galaxy is perfect!

Post Extras: Print Post   Remind Me!   Notify Moderator  
nikao
member


Reged: 06/14/12

Re: NGC 891 20121116 new [Re: srosenfraz]
      #5555124 - 12/05/12 05:06 AM

Nice result! .. Love the detail in the galaxy, but I think this deserves a bit more exposures

Post Extras: Print Post   Remind Me!   Notify Moderator  
fco_star
Carpal Tunnel
*****

Reged: 12/13/10

Loc: Texas, Midland
Re: NGC 891 20121116 new [Re: nikao]
      #5555196 - 12/05/12 07:04 AM

beautiful picture Jerry

Post Extras: Print Post   Remind Me!   Notify Moderator  
jambroseus
professor emeritus


Reged: 04/05/07

Loc: Mount Laurel, New Jersey
Re: NGC 891 20121116 new [Re: fco_star]
      #5555248 - 12/05/12 08:09 AM

Beautiful Jerry! Is the noise profile of the T3i any different from the 2; any improvements over the T2 that you see so far? Do you plan to mod it?

Great resolution with that C11 at f/10.

Congrats on 1st light!

John

Edited by jambroseus (12/05/12 08:13 AM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Eyegasms
sage


Reged: 08/08/11

Loc: ON Canada
Re: NGC 891 20121116 new [Re: jambroseus]
      #5555263 - 12/05/12 08:26 AM

Excellent detail.

Post Extras: Print Post   Remind Me!   Notify Moderator  
JoeR
Pooh-Bah
*****

Reged: 03/07/10

Loc: Columbus, OH
Re: NGC 891 20121116 new [Re: Eyegasms]
      #5555325 - 12/05/12 09:08 AM

That is an amazing amount of detail at f/10 and only six subs too. Well done!

Post Extras: Print Post   Remind Me!   Notify Moderator  
zambonikane
super member


Reged: 01/14/11

Loc: West Chester PA
Re: NGC 891 20121116 new [Re: JoeR]
      #5555509 - 12/05/12 11:16 AM

This is a great shot. I think I have found a new target when my camera gets back. I probably know the answer to this question, but could I get a similar results with my f/4.9 and a 2x barlow? I know barlows are usually frowned upon unless it is for planetary or lunar, so I am guessing no.

Post Extras: Print Post   Remind Me!   Notify Moderator  
jgraham
Postmaster
*****

Reged: 12/02/04

Loc: Miami Valley Astronomical Soci...
Re: NGC 891 20121116 new [Re: zambonikane]
      #5555628 - 12/05/12 12:51 PM

Wonderful detail and color. This is one of my favorite challenge objects as its tough to pull out from behind my sky glow. Not bad if I get a night of exceptional transparency.

Beautifully done!


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jerry Lodriguss
Vendor


Reged: 07/19/08

Loc: Voorhees, NJ
Re: NGC 891 20121116 new [Re: jambroseus]
      #5555859 - 12/05/12 03:27 PM

Thanks everyone for your kind words and for taking the time to take a look at the pic.

John, It's the same sensor in the 600D as the 550D, the only difference is the articulated LCD screen on the back, which is wonderful.

I do plan to mod it.

Jerry


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jerry Lodriguss
Vendor


Reged: 07/19/08

Loc: Voorhees, NJ
Re: NGC 891 20121116 new [Re: zambonikane]
      #5555870 - 12/05/12 03:34 PM

Quote:

This is a great shot. I think I have found a new target when my camera gets back. I probably know the answer to this question, but could I get a similar results with my f/4.9 and a 2x barlow? I know barlows are usually frowned upon unless it is for planetary or lunar, so I am guessing no.




Thank you!

There are a ton of other variables that might affect your ultimate results, such as how dark your skies are, and the fact that my shot was done with an 11 inch scope and you would be using an 8 inch scope.

But if your sub exposures are long enough to get you up out of the readout noise of the camera, using a good-quality 2-inch Barlow in this instance to get you to f/10 should be ok.

Just be careful because depending on the spacing, a nominally marked 2x Barlow can be a lot more magnification than 2x because the sensor in the camera is a lot further away from the Barlow elements than an eyepiece, so you might end up working at f/15 or f/20 instead of f/10, and then your exposures would get extremely long.

But give it a try!

Jerry


Post Extras: Print Post   Remind Me!   Notify Moderator  
Mike B.
Carpal Tunnel
*****

Reged: 10/24/05

Loc: Louisiana
Re: NGC 891 20121116 new [Re: Jerry Lodriguss]
      #5556422 - 12/05/12 09:05 PM

That C11 works well for this one. It brings it in nice and close for a detailed view. Great work, Jerry!

Post Extras: Print Post   Remind Me!   Notify Moderator  
orlyandico
Postmaster
*****

Reged: 08/10/09

Loc: Singapore
Re: NGC 891 20121116 new [Re: Mike B.]
      #5556545 - 12/05/12 10:13 PM

Hi Jerry,

Is this with the EM200 or some other mount?


Post Extras: Print Post   Remind Me!   Notify Moderator  
David PavlichAdministrator
Transmographied
*****

Reged: 05/18/05

Loc: Mandeville, LA USA
Re: NGC 891 20121116 new [Re: Jerry Lodriguss]
      #5556573 - 12/05/12 10:30 PM

Great job, Jerry, on one of my favorite galaxies!!

David


Post Extras: Print Post   Remind Me!   Notify Moderator  
bilgebay
Post Laureate
*****

Reged: 11/06/08

Loc: Turkiye - Istanbul and Marmari...
Re: NGC 891 20121116 new [Re: David Pavlich]
      #5556761 - 12/06/12 01:12 AM

Lovely! It appears you tamed the mount to cope with the long focal length of C11 Jerry.

Very impressive indeed.

Cheers


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jerry Lodriguss
Vendor


Reged: 07/19/08

Loc: Voorhees, NJ
Re: NGC 891 20121116 new [Re: orlyandico]
      #5556797 - 12/06/12 02:02 AM

I used my Losmandy GM100EQ for this particular image.

Jerry


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jerry Lodriguss
Vendor


Reged: 07/19/08

Loc: Voorhees, NJ
Re: NGC 891 20121116 new [Re: bilgebay]
      #5556799 - 12/06/12 02:04 AM

Hi Sedat,

Thank you!

This was shot with the Losmandy mount, but I have come to the conclusion that most of the problems are with the C11 are seeing related.

If the seeing is not good to excellent, you basically can't do anything with that scope.

I was going to shoot another hour or two after a meridian flip, but the seeing went bad, and I couldn't even focus it!

Jerry


Post Extras: Print Post   Remind Me!   Notify Moderator  
bilgebay
Post Laureate
*****

Reged: 11/06/08

Loc: Turkiye - Istanbul and Marmari...
Re: NGC 891 20121116 new [Re: Jerry Lodriguss]
      #5557710 - 12/06/12 03:10 PM

Quote:

If the seeing is not good to excellent, you basically can't do anything with that scope.




Absolutely !

However, the Hyperstar configuration is quite forgiving even under bad conditions. But then, it is only 560mm FL

Clear skies


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jerry Lodriguss
Vendor


Reged: 07/19/08

Loc: Voorhees, NJ
Re: NGC 891 20121116 new [Re: bilgebay]
      #5557754 - 12/06/12 03:35 PM

True that!

:-)

Jerry


Post Extras: Print Post   Remind Me!   Notify Moderator  
Nils_Lars
Postmaster
*****

Reged: 01/04/08

Loc: Santa Cruz Mountains , CA
Re: NGC 891 20121116 new [Re: Jerry Lodriguss]
      #5560215 - 12/08/12 12:13 AM

Some outstanding details here Jerry , super sharp at this scale

Post Extras: Print Post   Remind Me!   Notify Moderator  
Jerry Lodriguss
Vendor


Reged: 07/19/08

Loc: Voorhees, NJ
Re: NGC 891 20121116 new [Re: Nils_Lars]
      #5560304 - 12/08/12 01:39 AM

Hi Erik,

Thank you,

Jerry


Post Extras: Print Post   Remind Me!   Notify Moderator  
Barry E.
super member


Reged: 12/27/08

Re: NGC 891 20121116 new [Re: Jerry Lodriguss]
      #5560660 - 12/08/12 10:44 AM

Quote:

But if your sub exposures are long enough to get you up out of the readout noise of the camera, using a good-quality 2-inch Barlow in this instance to get you to f/10 should be ok




Great image as usual, Jerry!

Regarding the use of a barlow for deepsky, I have done some thinking in that area:

Why are our stars bigger than the pros?

Keep up the great work.


Post Extras: Print Post   Remind Me!   Notify Moderator  
jimegger
Pooh-Bah
*****

Reged: 12/22/05

Loc: Palmer,Alaska
Re: NGC 891 20121116 new [Re: Barry E.]
      #5561277 - 12/08/12 05:58 PM

Jerry, you have done it once again - nice shot !!!

Post Extras: Print Post   Remind Me!   Notify Moderator  
petemumbower
Carpal Tunnel


Reged: 07/12/09

Loc: West Michigan
Re: NGC 891 20121116 new [Re: jimegger]
      #5561643 - 12/08/12 10:55 PM

Excellent work Jerry, you simply have the magic touch with astrophotography.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Jerry Lodriguss
Vendor


Reged: 07/19/08

Loc: Voorhees, NJ
Re: NGC 891 20121116 new [Re: petemumbower]
      #5561683 - 12/08/12 11:25 PM

Hi Barry, Jim and Pete,

Thank y'all very much!

Jerry


Post Extras: Print Post   Remind Me!   Notify Moderator  
LeCarl
super member


Reged: 03/16/11

Re: NGC 891 20121116 new [Re: Nils_Lars]
      #5561740 - 12/09/12 12:25 AM

Wow, I'm very impressed, tons of details, I will show this to my friend that think the c11 can't be used without focal reducer! haha!
I can't believe that!

So you mean it is better to use it without focal reducer at native focal? (a lot oversampled) for using longer exposure to reduce background noise,
but... it's not better to use lower iso at faster focal because lowering the iso keep background noise away too... For example:

f10 focal at iso800 for instance background value of X
Vs
F6.3 focal at iso400... maybe? near same exposure time background value 1/2X then the S/N will be higher

I guess that... I don't know the background value properties but I think it is proportional, so we can play with (an idea)

Edited by LeCarl (12/09/12 12:31 AM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Moonwalker1968
member


Reged: 10/19/09

Loc: Switzerland
Re: NGC 891 20121116 new [Re: LeCarl]
      #5561884 - 12/09/12 05:06 AM

Jerry,

I have been on your interesting website several times and have learnt a lot. Thanks! Your beautiful NGC 891 image caught my attention a few days ago. I also work with long focal lengths (2.1 m and 2.3 m) at f/5 and would have thought 18MP on DX format with 2 m of focal length is a strong oversampling. Does it still make sense to use a modified (or unmodified) Canon 600D over a Canon 20Da at 2 m focal length? Do you win anything with it?

Best wishes,
Markus


Post Extras: Print Post   Remind Me!   Notify Moderator  
Turf1
member


Reged: 12/02/12

Loc: SW Michigan USA
Re: NGC 891 20121116 new [Re: Nils_Lars]
      #5562659 - 12/09/12 03:36 PM

Jerry, WOW!!!! I just got a C11 on a Cgem mount. when the skies clear and I can use it for the first time, could I expect ANYTHING close to this with my Nikon D50? Any response would be much appreciated. Thank you for a wonderful picture.

Post Extras: Print Post   Remind Me!   Notify Moderator  
moxican
sage


Reged: 11/13/11

Loc: Toronto, ON
Re: NGC 891 20121116 new [Re: Nils_Lars]
      #5562701 - 12/09/12 04:00 PM

That is an awesome image. Maybe someday I'll get one just like it

Post Extras: Print Post   Remind Me!   Notify Moderator  
rainycityastro
professor emeritus
*****

Reged: 03/29/10

Loc: Seattle, WA
Re: NGC 891 20121116 new [Re: Jerry Lodriguss]
      #5563126 - 12/09/12 08:58 PM

Gorgeous image! Amazing result for only 60mins and F-10. With a DSLR! That too unmodded!

Post Extras: Print Post   Remind Me!   Notify Moderator  
JoseBorrero
Post Laureate
*****

Reged: 09/04/09

Loc: Puerto Rico Island
Re: NGC 891 20121116 new [Re: rainycityastro]
      #5563271 - 12/09/12 10:37 PM

Awesome picture as always, I noted the you changed from Tak mount to Losmandy. Wonderful change

Post Extras: Print Post   Remind Me!   Notify Moderator  
bluedandelion
Carpal Tunnel
*****

Reged: 08/17/07

Loc: Hazy Hollow, Western WA
Re: NGC 891 20121116 new [Re: JoseBorrero]
      #5563287 - 12/09/12 10:49 PM

That is a very cool image. Well done.

Ajay


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jerry Lodriguss
Vendor


Reged: 07/19/08

Loc: Voorhees, NJ
Re: NGC 891 20121116 new [Re: LeCarl]
      #5563399 - 12/10/12 12:21 AM

Hi LeCarl,

This is a complicated question. There has been a lot of contentious material written on this subject.

I am definitely oversampling at f/10 with 4.3 micron pixels at 2794mm of focal length, the sampling is about 0.3 arcseconds per pixel.

But at f/6 the sampling is 0.5 arcseconds per pixel. Not that much difference. It's still oversampled by a lot.

Signal-to-noise ratio goes down, but image scale goes up. If you reduce the image to the same image scale, I think you get the s/n back.

A lot depends on whether you want to consider it from the perspective of pixel s/n or object s/n.

See:

Steve Cannistra: The Relationship between f ratio, subexposure time, and pixe...

Stan Moore: The F-Ratio Myth

Craig Stark S/N Part 1

Craig Stark S/N Part 2

Craig Stark S/N Part 3

Craig Stark S/N Part 4

Craig Stark S/N Part 5

Emil Martinec: Noise, Dynamic Range and Bit Depth in Digital SLRs

Martinec seems to be saying that the same number of photons fall on the chip, regardless of pixel size, so the s/n should be about the same as long as you are shot noise limited.

I have found that a much bigger consideration is the seeing with long focal lengths. You really need good to excellent seeing to shoot at 3,000mm of focal length. If the seeing is not good, you are wasting your time.

Jerry


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jerry Lodriguss
Vendor


Reged: 07/19/08

Loc: Voorhees, NJ
Re: NGC 891 20121116 new [Re: Moonwalker1968]
      #5563403 - 12/10/12 12:25 AM

Quote:

I have been on your interesting website several times and have learnt a lot. Thanks! Your beautiful NGC 891 image caught my attention a few days ago. I also work with long focal lengths (2.1 m and 2.3 m) at f/5 and would have thought 18MP on DX format with 2 m of focal length is a strong oversampling. Does it still make sense to use a modified (or unmodified) Canon 600D over a Canon 20Da at 2 m focal length? Do you win anything with it?




Hi Marcus,

You are welcome!

18mp is on APS-C not DX, but it is still way oversampled.

What you gain by using a 600D vs a 20Da is the improved technology in the camera that produces less noise.

As far as the sampling, you're not going to resolve anything more spatially, but I think the s/n is about the same because the same number of photons fall on the chip, regardless of what size the pixels are (as long as you are shot-noise limited and not read noise limited).

Jerry


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jerry Lodriguss
Vendor


Reged: 07/19/08

Loc: Voorhees, NJ
Re: NGC 891 20121116 new [Re: Turf1]
      #5563408 - 12/10/12 12:29 AM

Quote:

Jerry, WOW!!!! I just got a C11 on a Cgem mount. when the skies clear and I can use it for the first time, could I expect ANYTHING close to this with my Nikon D50? Any response would be much appreciated. Thank you for a wonderful picture.




Hi Turf1,

Thank you!

If you have the same equipment, and the scope is thermally stabilized, and correctly collimated, and the seeing and guiding are the same quality as the night I shot, and the sky darkness is the same, and the exposure is the same, and the image calibration and processing are the same, then the results should be somewhere in the same ballpark.

The Nikon D50 is much older technology than the Canon T3i so the camera is going to probably have more noise, so you might need more total exposure to improve the signal-to-noise ratio.

Jerry


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jerry Lodriguss
Vendor


Reged: 07/19/08

Loc: Voorhees, NJ
Re: NGC 891 20121116 new [Re: moxican]
      #5563409 - 12/10/12 12:31 AM

Quote:

That is an awesome image. Maybe someday I'll get one just like it




Hi Moxican,

Thank you.

Jerry


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jerry Lodriguss
Vendor


Reged: 07/19/08

Loc: Voorhees, NJ
Re: NGC 891 20121116 new [Re: rainycityastro]
      #5563410 - 12/10/12 12:32 AM

Quote:

Gorgeous image! Amazing result for only 60mins and F-10. With a DSLR! That too unmodded!




Thank you!

Jerry


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jerry Lodriguss
Vendor


Reged: 07/19/08

Loc: Voorhees, NJ
Re: NGC 891 20121116 new [Re: JoseBorrero]
      #5563411 - 12/10/12 12:34 AM

Quote:

Awesome picture as always, I noted the you changed from Tak mount to Losmandy. Wonderful change




Hi Jose,

Thank you!

I'm only shooting with the Losmandy because the Tak mount is in for repair.

The GM100EQ is a great mount, but I can't live without goto anymore with 3,000mm of focal length!

Jerry


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jerry Lodriguss
Vendor


Reged: 07/19/08

Loc: Voorhees, NJ
Re: NGC 891 20121116 new [Re: bluedandelion]
      #5563413 - 12/10/12 12:34 AM

Quote:

That is a very cool image. Well done.




Hi Ajay,

Thank you,

Jerry


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | (show all)


Extra information
13 registered and 30 anonymous users are browsing this forum.

Moderator:  Dave M, WOBentley, tecmage 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 1236

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics