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02-04-2014, 12:45 PM - 1 Like   #586
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Hi dqniel and welcome to the fascinating world of astrophotography.

You have many, fully understandable questions -and there will be more than one "correct" answer to each of those.

To begin with your gear: You have ALL you need to get started, so do rush out under your light polluted sky and try out your gear with fixed tripod astrophotography. Get acquinted with your gear well in advance of your trip to Mexico. We all have our personal limits as to when star trails become objectionable; my limits are: Some 20 seconds max exposure with a 14mm lens; 8 seconds with a 35mm lens; 4 seconds with a 70mm lens. Try our your lenses at full aperture and stop downonly, if aberrations are very annoying at wide open apertures. Also, start out with high iSO - don't be afraid of ISO 3200 with a K-5 II.

Next comes post-processing: Don't expect to see an awfull lot with your images straight out of the camera. So, if you don't have it already, your next purchase should be a decent imaging software, where you can work with curves, levels and, preferrably also layers. Such software could be of the type PhotoShop Elelements or PaintShop. And then you will soon need a stacking program such as Deep sky Stacker, which can be downloaded for free.

Regarding tracking platforms: Now it becomes difficult to give solid advice! I have the O-GPS1, and I wouldn't be without it. It's portability and quick set-up procedure means an awful lot to me. Still, I consider the O-GPS1 a supplement and not a substitute for a more 'robust' tracking platform that will allow the use of longer lenses for significantly longer exposure times. The platforms that you mention all require accurate polar alignment to work properly, which can be quite time consuming and even frustrating for the beginner, but you will have to master it sooner or later anyway.

I hope, others may join and tell how the Polarie and the Skytracker compares.

02-04-2014, 02:01 PM   #587
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Thank you very much for your help Stone. The advice is much appreciated. To clarify, I have done some fixed tripod AP on both my old Sony system and also on Pentax. I'm familiar with adjusting curves in Photoshop and am also familiar with a few plugins for Photoshop from my past experiences with terrestrial photography, but I expect to learn new processing techniques once I get into tracked AP. I have no experience with stacking images, but plan on learning to do so with Deep Sky Stacker and then processing the final image in Photoshop.

And yes, I definitely plan on being frustrated with polar alignment until I get used to it. Once my equipment is ordered and comes in, which I hope to do by next week, I plan on doing many practice runs to become familiar with the process.

As for your experience with the O-GPS1- what kind of exposure times, and at what focal lengths, have you been able to achieve without trailing?


Thanks again for your input, and hopefully some Polarie and Skytracker users will chime in.
02-04-2014, 03:08 PM - 2 Likes   #588
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QuoteOriginally posted by dqniel Quote
As for your experience with the O-GPS1- what kind of exposure times, and at what focal lengths, have you been able to achieve without trailing?
Thank you dqniel,

I believe that my best answer will be to direct you to my page with Astrotracer sample images:

DSLR Astophotography: Astrotracer Images with Pentax GPS Unit O-GPS1

On the more general level, I also have this page on camera settings to refer to:

Camera Settings for Astrophotography

Good luck - and have fun!
02-04-2014, 04:47 PM   #589
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QuoteOriginally posted by Stone G. Quote
Thank you dqniel,

I believe that my best answer will be to direct you to my page with Astrotracer sample images:

DSLR Astophotography: Astrotracer Images with Pentax GPS Unit O-GPS1

On the more general level, I also have this page on camera settings to refer to:

Camera Settings for Astrophotography

Good luck - and have fun!
Wow. Some impressive photos on your site. To bad that many lenses have so much coma wide open. I have tried some with a Pentax M 50/2, but I have to close it to f5.6 to get rid of that coma. Now, I just wait for some good nights to test a Sigma EX 50/1.4.

About the tracking platform, I will choose the iOptron. One reason can be found in a detailed review made by one of the must trusted Sky & Telescope authors, Dennis Di Cicco, review you can find on the iOptron page

https://www.ioptron.com/index.cfm?select=productdetails&phid=febb7d36-d904-4...0-41a6103fae86

The other one, is that sooner or latter you will need longer exposure than those which can be offered by the Pentax O'GPS, which, by the way, is good, and cheap, but has his limits.

02-05-2014, 05:20 AM - 1 Like   #590
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M42, The Great Nebula of Orion.

Taken by Pentax K5IIs on Refractor with 2min x 10shots at ISO1600.
Attached Images
 
02-05-2014, 05:27 AM   #591
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QuoteOriginally posted by kamayok3 Quote
Taken by Pentax K5IIs on Refractor with 2min x 10shots at ISO1600.
Beautiful!
02-05-2014, 09:03 AM   #592
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QuoteOriginally posted by Stone G. Quote
Thank you dqniel,

I believe that my best answer will be to direct you to my page with Astrotracer sample images:

DSLR Astophotography: Astrotracer Images with Pentax GPS Unit O-GPS1

On the more general level, I also have this page on camera settings to refer to:

Camera Settings for Astrophotography

Good luck - and have fun!
Thanks again. Your site has a ton of useful information. I'll have to read it from top to bottom when I get a chance later today.
02-05-2014, 03:06 PM   #593
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QuoteOriginally posted by kamayok3 Quote
Taken by Pentax K5IIs on Refractor with 2min x 10shots at ISO1600.
Which refractor? You simulated diffraction spikes during processing?

02-05-2014, 04:46 PM   #594
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QuoteOriginally posted by DeadJohn Quote
Which refractor? You simulated diffraction spikes during processing?
I am using Takahashi 85ED and simulate the spike using photoshop plugin. Thanks.
02-05-2014, 05:28 PM   #595
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Very nice shot.
Not sure why one would simulate a defect in optical path.
02-06-2014, 02:22 PM   #596
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QuoteOriginally posted by Ex Finn. Quote
...why one would simulate a defect in optical path.
Because you don't have it
The same as the case when you close the aperture in the 15mm LTD to get those beautiful star effects.
02-06-2014, 03:08 PM   #597
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QuoteOriginally posted by valy Quote
Because you don't have it
The same as the case when you close the aperture in the 15mm LTD to get those beautiful star effects.
The 15 ltd. star-bursts are not a defect
02-07-2014, 09:51 AM   #598
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starbursts

Starburst alias star spikes occurs when taking photos through reflector style scope due to the spider legs that hold the secondary mirror and are not useful for accurate Astros photos. They are added only for the eye of the beholder. I do not like seeing them in quality pictures because the spikes hide other information. The spikes also appear when taking photos with various lenses. Although not a defect the affect is not usually sought after.
Hank
02-07-2014, 07:06 PM   #599
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Beautiful shot. The processing is impeccable. I understand that adding the star spikes is user choice and that you do lose information by doing this. For example, Iota Orionis below the nebula has an easy double at about 140 degrees from its O-class primary that is easily split by your scope but is hidden by the spikes. Not to worry... since this is added in post you can just as easily take it out!

Jack
02-07-2014, 09:27 PM   #600
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QuoteOriginally posted by Chris A. Quote
Hello everybody,

Here my last shots with my K5 + O-GPS1 + 50 mm f/1.4, near Toulouse (France) :

Pleiades - M45 & NGC 1499


27/11/2013
Stack: 3 images ISO 400 F2.8 (2 x 120 sec + 1 x 300 sec)

Andromeda Galaxy - M31


28/11/2013
Stack: 6 images
- 3 images ISO 800 F2.0 (3 x 60 sec)
- 3 images ISO 3200 F2.0 (3 x 30 sec)

Orion - M42


28/11/2013
Stack: 3 images
- 2 ISO 400 F2.0 (2 x 60 sec)
- 1 ISO 200 F2.4 (1 x 60 sec)

All the best for 2014!

Chris A.
Absolute beautiful images! and all with a 50mm F/1.4. Good job and keep posting the wonderful shots.
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