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M51 With a C5

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#1 brlasy1

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Posted 14 May 2021 - 10:02 AM

Trying out my new to me white tube C5 as an AP lens.  

 

84 X 25" lights, ISO 1600, LENR on.  Unguided AS-GT, Nikon D5100 unmodded.  Siril and Mac Photos.  Waiting on my AT-branded f6.3 focal reducer to ship to speed up the light gathering.

 

Clouds and wind curtailed the number of subs.

 

 

 

 

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#2 vidrazor

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Posted 14 May 2021 - 10:14 AM

Nice. You can probably open that up further. You may need to make a separate stretch for the core if you're blowing it out opening the edges, then composite them in Photoshop/GIMP/Affinity Photo.
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#3 jgraham

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Posted 14 May 2021 - 10:32 AM

Excellent! Nicely done!


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#4 vidrazor

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Posted 15 May 2021 - 12:02 AM

I messed with the file you posted here a bit. You certainly have some more data you can extract, and you'll have much better data to work with than the highly compressed file here. You'll probably need a second stretch to preserve the core and star color. Your overall color balance was a bit blue also. You might want to try a bit more extraction, it should look pretty decent. :-)

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Edited by vidrazor, 15 May 2021 - 12:14 AM.

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#5 boxcorner

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Posted 15 May 2021 - 07:55 AM

Trying out my new to me white tube C5 as an AP lens.  

 

84 X 25" lights, ISO 1600, LENR on.  Unguided AS-GT, Nikon D5100 unmodded.  Siril and Mac Photos.  Waiting on my AT-branded f6.3 focal reducer to ship to speed up the light gathering.

 

Clouds and wind curtailed the number of subs.

Very interesting, as I too have a C5 and use a Nikon DSLR. Could you please tell me more about the focal reducer that you have ordered? What specifically you ordered & from whom. I would like to know how you get on with it & to see any results. Hence I am following this topic. Thanks.



#6 brlasy1

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Posted 15 May 2021 - 12:54 PM

I messed with the file you posted here a bit. You certainly have some more data you can extract, and you'll have much better data to work with than the highly compressed file here. You'll probably need a second stretch to preserve the core and star color. Your overall color balance was a bit blue also. You might want to try a bit more extraction, it should look pretty decent. :-)

I welcome any and all tweaking, and thank you all in advance.

https://drive.google...iew?usp=sharing


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#7 brlasy1

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Posted 15 May 2021 - 12:58 PM

Very interesting, as I too have a C5 and use a Nikon DSLR. Could you please tell me more about the focal reducer that you have ordered? What specifically you ordered & from whom. I would like to know how you get on with it & to see any results. Hence I am following this topic. Thanks.

This is the one I ordered from Astronomics.  Don't know if it will work, but it seems like a generic option for Celestron tubes.  I'll let you know once I get it.

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#8 vidrazor

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Posted 15 May 2021 - 09:33 PM

I welcome any and all tweaking, and thank you all in advance.

https://drive.google...iew?usp=sharing

Well here's what I wound up with, hope you like it. :-) Although it's not that great really, for 35 minutes' worth of time, I don't think it's too bad. I figured you had some more info in there, and here's probably most of it, although time and ISO were not on your side. I did my best to wrangle color and luminosity noise. Are you able to autoguide? If so, I would drop the ISO to 400 and see if you can track for around 1.5-2 minutes, and grab about 4 hours or so of time. That should give you a pretty decent amount of data to play with. I would kill the LENR unless you want to shoot multiple nights, and shoot around 30-50 darks and BIAS. If you can't autoguide then I would kill LENR and shoot as many subs as you can with the same settings and just shoot some darks and BIAS. Are you shooting flats? If not I would put them in there too. Just try and get as many subs as you can. Enjoy. smile.gif
 

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Edited by vidrazor, 15 May 2021 - 09:35 PM.

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#9 BQ Octantis

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Posted 16 May 2021 - 05:12 AM

This was one of the first DSOs I shot, also through a C5: my vintage 1974 black tube C5/750 f/6. So kind of like coming across a version of myself in the past. Like old man Biff in Back to the Future II.

 

So what would I tell my younger self? You need way more subs, mate. In the future, I have a target integration metric for high quality data at 100-170% sensor scale on galaxies and DSOs: 2-4 hours at f/2.8 with 4.3µm pixels. So for a Nikon D5100 with 4.77µm pixels and an f/10 scope? That's 20-40 hours. With an f/6.3 aperture? That's 8-16 hours.

 

Here's a crack at processing the data at 100% scale:

 

(Click for full size.)

gallery_273658_12412_286921.jpg

 

With enough integration, all the holes turn into data.

 

Cheers,

 

BQ (from the bleeding edge of tomorrow)


Edited by BQ Octantis, 16 May 2021 - 05:15 AM.


#10 boxcorner

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Posted 16 May 2021 - 05:14 AM

This is the one I ordered from Astronomics.  Don't know if it will work, but it seems like a generic option for Celestron tubes.  I'll let you know once I get it.

Thank you kindly.



#11 brlasy1

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Posted 16 May 2021 - 03:18 PM

Well here's what I wound up with, hope you like it. :-) Although it's not that great really, for 35 minutes' worth of time, I don't think it's too bad. I figured you had some more info in there, and here's probably most of it, although time and ISO were not on your side. I did my best to wrangle color and luminosity noise. Are you able to autoguide? If so, I would drop the ISO to 400 and see if you can track for around 1.5-2 minutes, and grab about 4 hours or so of time. That should give you a pretty decent amount of data to play with. I would kill the LENR unless you want to shoot multiple nights, and shoot around 30-50 darks and BIAS. If you can't autoguide then I would kill LENR and shoot as many subs as you can with the same settings and just shoot some darks and BIAS. Are you shooting flats? If not I would put them in there too. Just try and get as many subs as you can. Enjoy. smile.gif
 

It looks very nice, thank you!  Much better color, given my lack of subs.  To answer your question, I'm going to start guiding when the weather clears here; we're in the Spring rainy season.  I like the LENR, even though it eats up outside time, but I'll add bias and flat frames to the processing next time. I cut the session short for weather and old age reasons, but I hear what you are saying about collecting more photons.  Can't process what you don't collect.  Thanks again!



#12 brlasy1

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Posted 16 May 2021 - 03:27 PM

This was one of the first DSOs I shot, also through a C5: my vintage 1974 black tube C5/750 f/6. So kind of like coming across a version of myself in the past. Like old man Biff in Back to the Future II.

 

So what would I tell my younger self? You need way more subs, mate. In the future, I have a target integration metric for high quality data at 100-170% sensor scale on galaxies and DSOs: 2-4 hours at f/2.8 with 4.3µm pixels. So for a Nikon D5100 with 4.77µm pixels and an f/10 scope? That's 20-40 hours. With an f/6.3 aperture? That's 8-16 hours.

 

Here's a crack at processing the data at 100% scale:

 

(Click for full size.)

gallery_273658_12412_286921.jpg

 

With enough integration, all the holes turn into data.

 

Cheers,

 

BQ (from the bleeding edge of tomorrow)

Thanks!  I've been lagging on developing my equipment skills.  I've got guiding gear but haven't started learning the process, and my data processing procedures are basic at best.  With summer coming on here, I suppose it's time to up my game.

 

As an aside, where is Red Center?  Western Sydney?  I used to travel to Sydney on business every fall for several years.  Did the tourist thing with my better half at the end of one of my trips but never got west of the Blue Mountains.  Good people and great outdoors-reminds me of Texas!



#13 BQ Octantis

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Posted 17 May 2021 - 02:37 AM

The Red Centre is a loosely-defined area of central Australia along the Tropic of Capricorn that encompasses the southern tip of the Northern Territory and the northern edge of South Australia. It encompasses all the possible geographic centers of Australia (through multiple geographic methods), the highest point along the Stuart Highway, the East and West MacDonnell Ranges, Uluru, and several meteor crater sites along the Red Centre Way. It's home to incomprehensibly vast open spaces with zero infrastructure, inhospitable wilderness, the sparsest possible population density in the world, and Bortle 0 skies (which I define as Bortle 1 + not a single light dome on the entirety of an expansive horizon).

 

red-centre-map.gif

[Source]

 

The Tropic of Capricorn is also quite unique. Jupiter, Saturn and Mars have all been winter planets for the last several years, so I've gotten to observe and image them near zenith. And at midnight on the June winter solstice, the Galactic Center of the Milky Way passes through zenith at midnight. If there is no moon, the majesty of the spectacle induces vertigo in all but the strongest of constitutions. cool.gif

 

BQ


Edited by BQ Octantis, 17 May 2021 - 02:39 AM.

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#14 brlasy1

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Posted 17 May 2021 - 11:00 AM

The Red Centre is a loosely-defined area of central Australia along the Tropic of Capricorn that encompasses the southern tip of the Northern Territory and the northern edge of South Australia. It encompasses all the possible geographic centers of Australia (through multiple geographic methods), the highest point along the Stuart Highway, the East and West MacDonnell Ranges, Uluru, and several meteor crater sites along the Red Centre Way. It's home to incomprehensibly vast open spaces with zero infrastructure, inhospitable wilderness, the sparsest possible population density in the world, and Bortle 0 skies (which I define as Bortle 1 + not a single light dome on the entirety of an expansive horizon).

 

red-centre-map.gif

[Source]

 

The Tropic of Capricorn is also quite unique. Jupiter, Saturn and Mars have all been winter planets for the last several years, so I've gotten to observe and image them near zenith. And at midnight on the June winter solstice, the Galactic Center of the Milky Way passes through zenith at midnight. If there is no moon, the majesty of the spectacle induces vertigo in all but the strongest of constitutions. cool.gif

 

BQ

Amazing!  What a great location to view the heavens in all their awesomeness.  I spent a couple of nights on Midway Island in the 80s and remember the stars being bright enough to see objects on the ground clearly.  Must be a lot like that.

 

Uluru's on my bucket list, but that flight from Dallas to Sydney (not to mention multimode travel from Sydney to Uluru)-ouch! 

 

Thanks.  



#15 BQ Octantis

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Posted 18 May 2021 - 01:03 AM

Yep, it is. I waxed on about it back in '19 when we did a Red Centre Way trek. But truth be told, I first saw the Milky Way in its full glory at zenith from Henbury—the one Red Centre Bortle 0 site I would recommend to anyone for both its sky and its context. We camped there to watch the Eta Aquarids right before dawn, and I stepped out of my tent with fully adjusted night vision and looked up. I almost passed out from the sight.

 

Back in the old days (when we used to shake hands and fly in aeroplanes), there were daily flights from all the major cities to Uluru (AYQ). Jetstar seems to still offer such a service. So only 1 connection in SYD from DFW…easy as! If only the Australian border would open up. They're saying 2022… fingerscrossed.gif

 

BQ


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