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05-27-2013, 07:41 AM   #391
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QuoteOriginally posted by valy Quote
Saturn is a difficult task, you can take several shots and crop&stack them, but it is a waste of time, usually you need a lot of frames to get better results, filming is not good unless Pentax provide 100% crop movie, still pictures consume the shutter. Anyway it is nice to see the Saturn .


Mee too. I think I made some mistakes, but don't know where, after several shoots I get various results, none being close to a normal EQ mount tracking platform.
After about a year of ownership and very frequent use of the O-GPS1 (as frequent as the lousy Danish weather permits), I should say that I get fairly consistent results. So, my experience is that as long as you have the most recent firmware update and get confirmation on 'Precise Calibaration OK' there is little more you can actually do and to my experiences there are only the following three issues to observe:

1. The magnetic sensor seems to be by far the largest source of inaccuarcy. By all means do the Precice Calibration and use the astrotracer safely away from very localized magnetic disturbances, be they man-made or geological.

2. As GPS satellites change their positions the quality and number of signals received may change. A short break followed by a renewed Precise Calibration may be required from time to time during a night's session.

3. There remains a certain element of "black magic" to the operation of the Astrotracer function. On any night do try to use it at different azimuth and altitudes. Chances are that on any night, some directions will work better for you than others. On those nights where everything seems to conspire against you, try using your widest lenses only.

If problems persit, I would suspect that errors would most likely, though not exclusively, be found in the camera body sensors and/or actuators. I know of no other way of checking that than trying out your O-GPS1 unit on another K-5 body.

05-27-2013, 08:41 AM   #392
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Thanks, Stone G.

I appreciate your information. Also, not remembering exactly where I saw the images, but some folks produce a Saturn image not only with planetary banding, and the Cassini Division, but sharp as well. I'm assuming they were made with much better cameras? Using my Orrery program, Saturn is relatively close to us.. as such, I would've thought it would've looked much better through my 'scope.. instead, it looks small as in my image.. Marc

Last edited by Suhndog; 05-27-2013 at 08:46 AM.
05-27-2013, 08:41 AM   #393
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Thank you. So first: precise calibration. Didn't manage to get one except the first time when trying to do it, I must find the magic movement to do the calibration.

Suhndog, in order to get nice Saturn, with details, colors & so on, you need longer focal length, ~5000mm f/20-f/30 scope, and some camera capable of shooting ~10-100 fps, then stacking to remove the noise and bring some details. Here some guys playing with planets: http://www.cloudynights.com/ubbthreads/postlist.php/Cat/0/Board/Imaging

Last edited by valy; 05-27-2013 at 08:53 AM.
05-27-2013, 10:01 AM   #394
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Thanks, valy..

Since I'm not good with math or math-related physics, I have trouble dealing with some aspects of astronomy. If things are explained in a more 'right-brain' [show me..] manner, then I get it. I will check out your link.. I did a good job in imaging Jupiter, so I just figured that Saturn would do well, also..?

05-27-2013, 10:14 AM   #395
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What great stuff to learn! Thanks for the link, valy.. I get so excited learning about 'all of this'.. space is so awesome! I can't wait to make more images! I just wish I also had friends around here who share the same interests as I do.. No one that I know in my town share the same passion and enthusiasm as I do.. Some nights I just get the blahs, because I like to share my 'journeys' in space.. Marc
05-27-2013, 11:27 AM   #396
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There is no much math or physics, just fun. If you managed the Jupiter, then Saturn is not much different, but still there is a difference in light.
05-27-2013, 11:52 AM   #397
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True.. I'll keep at trying to image Saturn [weather permitting here]. The Orion StarShoot 4 camera is difficult to work with since it has such a very small sensor. That is what takes most of my time getting an image. The slightest adjustment of my 'scope throws the image off a lot... not to mention trying go make my initial focus. Nonetheless, it's rewarding to make images! - Marc
05-27-2013, 01:23 PM   #398
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Motorized tracking is mandatory for such focal lengths.

05-27-2013, 01:41 PM   #399
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I understand. With that in mind, I will forgo doing planetary imaging until I can afford an EQ platform... unless I'm feeling feisty, and a 'glutton-for-punishment' some night. In the meantime, I will read a lot here and elsewhere on doing imaging with a DSLR [both with O-GPS1 and on the 'scope]..
05-28-2013, 08:13 AM   #400
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QuoteOriginally posted by Suhndog Quote
Thanks, Stone G. I appreciate your information. Also, not remembering exactly where I saw the images, but some folks produce a Saturn image not only with planetary banding, and the Cassini Division, but sharp as well. I'm assuming they were made with much better cameras? Using my Orrery program, Saturn is relatively close to us.. as such, I would've thought it would've looked much better through my 'scope.. instead, it looks small as in my image.. Marc
Not "better" cameras, but cameras better suited to the job. Video processing is the usual method for Saturn. Basically, you take a video, select the best individual frames, then stack the best frames to reduce noise and improve contrast. Registax and Autostakkert are 2 software packages made for planetary video stacking.

The K5's limitation with respect to planetary imaging is that the video mode combines multiple physical pixels into a large virtual pixel; the image of Saturn fills a few pixels in the center of K5 video and the rest of the sensor is wasted. You would need an enormous amount of magnification (approx 10000mm focal length) to get a good-sized image with an APS-C video.

Webcams and modified webcams are the most common way to collect planetary video. Some Canon DSLRs support a 1:1 video crop mode that only uses the pixels in the center of the sensor. The Pentax Q's video mode also has potential because of the small sensor; if I knew someone who owned one I would give it a test.

Google Damian Peach for some outstanding planetary imaging.
05-28-2013, 08:31 AM   #401
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Shot of Saturn

Took this with a K-5 IIs and a 12" Homebuilt Dobson Telescope I converted to be able to use prime focus with (no lens, direct connect to scope with a k mount to t-mount adapter). Soooo....I effectively now have a 2000mm F/5 lens! This is a single shot at 400 iso and 1/80th of a sec. I was a first try. No shake reduction and its about a 100% crop. No other post processing and was only about an hour after sunset and in light polluted skies.

Had to weight the thing down pretty good though to make it stable enough to avoid it shaking. Can get down to a 50th of a sec before i started getting movement. I could get Titan to show up at 1600 iso and got usable shots all the way down to 256000 iso.

Can't wait for a dark sky again!
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05-28-2013, 08:38 AM   #402
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Interesting how surprisingly well the Pentax Q + Kenko 1.5x PZAF + Pentax DA* 300mm F4 setup holds up against many telescope setups. Though your telescope setups can do much more.

05-28-2013, 09:19 AM   #403
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Thanks all! I still plan to use my DOB for imaging, but until then, I want to explore what the O-GPS1 can do.. after seeing Stephane's work.
Nice shots of Saturn, guys! I'm so glad I bought the K5! I just learned from a friend that our gov. in special, important areas of endeavor - use Pentax exclusively.. I've always favored Pentax. -- Marc
05-28-2013, 09:21 AM   #404
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I believe the Q is good for Sun/Moon shots, but for planets we still need many frames and don't need so much pixels. This is what I get using a small refractor and a dedicated small chip planetary CCD, stacking from ~5000 frames:


Last edited by valy; 05-28-2013 at 09:31 AM.
05-28-2013, 09:44 AM   #405
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That's great valy!
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