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NGC3718 in Ursa Major with 8" f/4 astrograph

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#1 Dan_I

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Posted 21 March 2023 - 02:32 AM

  Hi,

 

NGC3718 is a barred spiral galaxy in Ursa Major (distance 57 millions l.y.), well-known for its distorted shape due to its gravitational interaction with nearby NGC3729. The galaxy group Hickson 56 at its feet is much further away (about 400 millions l.y.)

 

I had a small window of clear weather on Monday night to shoot about 5h30min of luminance in good seeing conditions (1.83" median FWHM after stacking), that I combined with RGB data from last year. This is a rather difficult object from my light-polluted backyard.

 

Image25_cn.jpg

 

Link to the full-resolution: https://www.webastro...25f0d7472db.jpg

 

Link to the annotated luminance: https://www.webastro...04e12850d83.jpg

 

One can see a quasar at z=4.8 which is my new record!

 

Thanks for looking and clear skies,

 

Dan

 

Technical details

200/800 custom Newtonian astrograph with Romano Zen optics and carbon fiber tube
AP900 CP4 mount on Losmandy HD tripod

ASI183mm (0.66"/pix)
TS 2.5" Riccardi-Wynne corrector
ZWO LRGB filters
Guiding : ZWO OAG + ASI120mm mini + AsiairV1
Luminance : 330 *60sec
Chrominance : 80*60sec for R and G filter, 150*60sec for B filter
Conditions : Bortle 7/8 skies in Paris' suburbs (20km from the Eiffel tower), rather good seeing, average transparency
Processing with Pixinsight


Edited by Dan_I, 21 March 2023 - 11:09 AM.

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#2 Dynan

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Posted 21 March 2023 - 04:20 AM

Very nicely done! 

 

(But it's NGC3718. [Trois-mille-sept-cent-dix-huit] Those darned numbers make a difference. smile.png)


Edited by Dynan, 21 March 2023 - 04:23 AM.

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#3 Dan_I

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Posted 21 March 2023 - 04:28 AM

Very nicely done! 

 

(But it's NGC3718. [Trois-mille-sept-cent-dix-huit] Those darned numbers make a difference. smile.png)

Thanks! Corrected waytogo.gif


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#4 Dynan

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Posted 21 March 2023 - 04:46 AM

Can't seem to find the quasar. Can you point it out please?



#5 Dan_I

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Posted 21 March 2023 - 05:03 AM

Can't seem to find the quasar. Can you point it out please?

It is near NGC 3729. Here's an inverted annotated image

 

quasar.jpg



#6 Dynan

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Posted 21 March 2023 - 05:10 AM

Thanks waytogo.gif

 

What program/site did you use for the annotation?


Edited by Dynan, 21 March 2023 - 05:12 AM.


#7 Steve OK

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Posted 21 March 2023 - 11:44 AM

A very beautiful image of a tough target!

 

Steve



#8 Dan_I

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Posted 21 March 2023 - 05:27 PM

Thanks waytogo.gif

 

What program/site did you use for the annotation?

I used the AnnotateImage script in Pixinsight. You need to select the Milliquas catalog to display the quasars.


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#9 Dan_I

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Posted 21 March 2023 - 05:28 PM

A very beautiful image of a tough target!

 

Steve

Thanks a lot Steve!



#10 Dynan

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Posted 21 March 2023 - 08:13 PM

Thanks, Dan. This'll be very handy to see what crept into our images.



#11 Mert

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Posted 23 March 2023 - 07:18 AM

That's a great image of a difficult galaxy!
What is the total amount of integration time?
I did an attempt of the same field with 24h total but under strong LP ( Bortle 8+ ) balcony skies :shrug:

Edited by Mert, 23 March 2023 - 07:19 AM.


#12 dhkaiser

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Posted 23 March 2023 - 11:54 AM

Z=4.8, how many light years is that?



#13 Dan_I

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Posted 23 March 2023 - 05:21 PM

That's a great image of a difficult galaxy!
What is the total amount of integration time?
I did an attempt of the same field with 24h total but under strong LP ( Bortle 8+ ) balcony skies shrug.gif

 

Thanks Mert ! The total integration time with the L filter was 5h30min. The conditions were rather good (not in absolute terms, but for my place).

 

Z=4.8, how many light years is that?

 

The photons that hit the sensor were emitted 12,6 billions years ago.....


Edited by Dan_I, 23 March 2023 - 05:22 PM.

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#14 PeteM

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Posted 23 March 2023 - 09:06 PM

Nicely done Dan! Tons of galaxy scattered throughout. It was fun to explore that high-res.



#15 Dan_I

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Posted 28 March 2023 - 05:51 AM

Thanks a lot Pete!

 

clear skies,

 

Dan



#16 Startex

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Posted 29 March 2023 - 03:44 AM

Absolutely nuts!!



#17 Dan_I

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Posted 29 March 2023 - 05:09 PM

Absolutely nuts!!

 

Thanks!

 

clear skies,

 

Dan



#18 Jim Thommes

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Posted 30 March 2023 - 08:30 PM

Excellent image! Well done.



#19 Dan_I

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Posted 02 April 2023 - 06:49 AM

Thanks a lot Jim!

 

Clear skies,

 

Dan




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