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05-11-2013, 11:03 AM   #376
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Leo Trio M65, M66, NGC 3628

Taken through Celestron C8 and f6.3 focal reducer. Stack of 12 5-minute guided exposures. (I think the distorted stars are because of too much distance between camera and reducer. There's always something new to improve.)



05-14-2013, 05:27 PM   #377
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QuoteOriginally posted by DRabbit Quote
In some of my own research on this topic, the big key is avoiding star trails (unless you want them). The wider the lens the better. There's a formula...

600 focal length = exposure time (in seconds) to avoid star trails.

So for example... I shot some with the Samyang 14mm f/2.8 lens. It's effective focal length is 21mm on the Kx (the camera I was using at the time).

600 21mm = 28.5 seconds.

So I shot at 30 seconds, wide open, ISO 1600 or 3200.

These aren't the most beautiful results, but it was my first attempt!









I'm looking forward to trying this again with the K-5... once I get a nice wide lens again
What aperture did you use?
05-21-2013, 09:38 PM   #378
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My frist shot of moon,K5 with takumar200/f4+APS 2X,20 exposures stacked.

05-24-2013, 04:15 PM   #379
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Very beautiful! Why stacked?

05-24-2013, 04:53 PM   #380
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QuoteOriginally posted by tonypysm Quote
My frist shot of moon,K5 with takumar200/f4+APS 2X,20 exposures stacked.
I'm stunned by the details and colors. Puts my attempts to capture the colors to shame.
05-25-2013, 10:35 PM   #381
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OK, I'm new here, and cannot locate where to make a new post.. Eeks!
I'm new to astro-photography. I own a K5 with only the basic, kit lens. I also own an Apertura AD10 10" DOB with nice EP's [Explore Scientific 82deg. 30mm and 11mm, and others]. I would like to explore the possibilities of both using my DOB with an EQ dual-axis platform, and trying the O-GPS1 unit.
My initial questions are:
1) What Pentax [or 'better'?] telephoto lens is best for deep-sky imaging using the O-GPS1?
2) Is the O-GPS1 really worth buying - I've read various complaints...
3) Can the O-GPS1 be used with my DOB, or is it not suitable, considering the algorithms in the camera?
-- I'll await answers before asking more..
Thank you! -- Marc
05-26-2013, 04:11 AM   #382
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QuoteOriginally posted by Tecnozac Quote
Very beautiful! Why stacked?
There are several good reasons to stack astro photographs - including lunar such:

http://keithwiley.com/astroPhotography/imageStacking.shtml

Astrophotography: Star Photo Stacking

But it really all boils down to the fact that stackning levels the statistical "random" noice and thus increases the signal-to-noise-ratio. That again is a pre-requisite for successful enhancements in repect of clarity/detail, contrast, colour, dynamic range.......
05-26-2013, 04:25 AM   #383
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QuoteOriginally posted by Suhndog Quote
OK, I'm new here, and cannot locate where to make a new post.. Eeks!
I'm new to astro-photography. I own a K5 with only the basic, kit lens. I also own an Apertura AD10 10" DOB with nice EP's [Explore Scientific 82deg. 30mm and 11mm, and others]. I would like to explore the possibilities of both using my DOB with an EQ dual-axis platform, and trying the O-GPS1 unit.
My initial questions are:
1) What Pentax [or 'better'?] telephoto lens is best for deep-sky imaging using the O-GPS1?
2) Is the O-GPS1 really worth buying - I've read various complaints...
3) Can the O-GPS1 be used with my DOB, or is it not suitable, considering the algorithms in the camera?
-- I'll await answers before asking more..
Thank you! -- Marc
1) It really depends on what deep-sky objects you what to photograph. Many objects are very small and dim indeed. But used together with the O-GPS1 you should restrict yourself to about 200mm and downwards. And, obviously, you should go for as fast optics as you can afford. Personally, I go up to some 350mm to 400mm and f/5.6. but then I am also willing to accept that tracking errors will occur (much) more frequently.

2) We are many happy users of the O-GPS1 - see all the images posted in this forum and elsewhere - but "worth buying" will eventually be a personal assessment. The O-GPS1 is not a full subsitute for a good equatorial mount, but it is an extremely handy and quick grab-and-go assitant in a great many instances.

3) No, the sensors in the camera will believe that your optics is pointing at a right angle to what it acrtually is. And most dobsonians will have a far too long focal length to be sensibly used with the O-GPS1 Astrotracer function.

05-26-2013, 06:23 AM   #384
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Thanks, Stone G. ...
Being on a limited budget, I wasn't/am not sure whether to invest in a dual-axis EQ plat. approach or the O-GPS1 approach. I would like to image the 'M' catalog, at least. When I bought my K5, I never expected it to be so versatile in the areas of astro-imaging. Then yesterday is when I discovered this thread and read about the O-GPS1 for the first time. Then when I saw all the amazing images folks are getting with it, I almost thought my 10" DOB was going to be superfluous - LOL!
Nonetheless, I'm even more excited now! I'm using an Orion StarShoot 4 Color Planetary Camera presently, but it is a lot of work to use [mainly trying to aim at an object [the sensor is so tiny].. Marc

Here's an example: it's my very 1st.-ever image [of Jupiter]..
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05-26-2013, 10:40 AM   #385
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QuoteOriginally posted by Suhndog Quote
Here's an example: it's my very 1st.-ever image [of Jupiter]..
Now, there's a first-ever image that makes me quite jealous. Well done!

Anyway, if your ambition is to photograph the entire Messier catalogue, my advice is that you look for a decent EQ Platform to begin with. Personally, I have had reasonable success with a used Meade LXD75 that I got at a very decent price.



It may not be the most portable solution, but quite reliable and sturdy.
05-26-2013, 01:11 PM   #386
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Thanks, Stone G.

Frankly, I was so gung-ho about firstly going with making an EQ DOB platform.. until I saw Stephane's amazing O-GPS1 images on his website! Even a shot of the Horse Head Nebula! All with only a 200mm lens, and his K5! Now, I'm really excited to do the same! I eventually will get the platform.. but I can't resist getting the O-GPS1 first. I do so much appreciate your suggestions!

BTW; I've noticed that folks here seem to favor the Deep Sky Stacker program.. How does that compare to Autostakkert 2? I used Autostakkert 2 for my Jupiter prog. - the results you can see [above post].. ?

I never would have dreamed that some visionary, forward thinking person[s] came up with the idea of the O-GPS1 ! I know that some folks have had problems with it.. but I feel compelled to maybe contact Stephane, and learn what his 'tricks' are... Also, if anyone else knows the best way to take advantage of it, in a concise manner.. I'd like to know... Marc
05-26-2013, 01:16 PM   #387
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Here are the pictures I was referring to on Stephane's website - simply stunning!!

Accueil / Albums / Astrophoto / Ciel Profond | PhotosSteph
05-27-2013, 03:10 AM   #388
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QuoteOriginally posted by Suhndog Quote
BTW; I've noticed that folks here seem to favor the Deep Sky Stacker program.. How does that compare to Autostakkert 2? I used Autostakkert 2 for my Jupiter prog. - the results you can see [above post].. ?
Deep Sky Stacker is dedicated for stacking of star field photographs - and it does a fine job of de-rotating and aligning such images. It is NOT suited for stacking of solar/lunar/planetary photograhs as it is designed to identify stars (pointlike sources of light) and use those for alignement in an automated process.

I am not familiar with Autostakkert 2, (thanks for the hint), but took a brief glance at the tutorials: This is software dedicated for solar, lunar and planetary photography with its "surface" and "planet" features. Perhaps you could use the "surface" feature for (some?) Deep Sky Objects, but I doubt that it was intended for that purpose.
05-27-2013, 03:54 AM   #389
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My first attempt at photographing Saturn.. The seeing was not good at all last night. This is a single image, where I reduced noise in the post processing and increased sharpness. Still, the K-5 is not a great camera for planetary photography. Still I haven't looked at Saturn in 30 years and I was good to see it again. A better way to photograph planets is to take a video of the planets with a camera with a smaller chip dedicated for doing astro-photography. Using stacking software, one can increase the quality of the image significantly.
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05-27-2013, 05:08 AM   #390
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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 .


QuoteOriginally posted by Suhndog Quote
Also, if anyone else knows the best way to take advantage of it, in a concise manner.. I'd like to know... Marc
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.

Last edited by valy; 05-27-2013 at 05:13 AM.
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