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09-03-2016, 08:19 AM   #1006
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Excellent links on wonderful and useful articles -- thanks very much for posting them.

09-08-2016, 04:45 AM - 1 Like   #1007
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You guys have inspired me to buy the O-GPS1. I'm still waiting for it but when I was looking for a longer lens, I stumbled on Celestron Nexstars for sale. I couldn't resist. Now I'm the proud owner of Nexstar 5se :-)

Now if it would just stop raining! :-P
09-11-2016, 06:08 AM   #1008
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Hi,
When I see these excellent pictures made with a K-5 I wonder how you get it so well in focus.
I have now a setup with a mount, a telescope and a dedicated astro-camera mainly for guiding.
With the KStars application under Linux on a very small Raspberry Pi 2, I am able to focus the astro-cam.
The main tool is the viewer of the pictures taken together with the focussing module of EKOS (part of KStars).
When guiding, I take pictures with my K-5 mounted on my guiderscope.

Pentax does not provide software to at least download a picture to a PC on which you can zoom and run a protocol for focussing.
The Pentax LV screen cannot be rotated in a position that you can easyly adjust focus (k-5 is mounted high on telescope).
I use a 90degree prisma to look through the viewfinder, but you can hardly see even the brightest star to focus on.

My colleagues of the observatory all use Canon or Nikon with software such as BackYardEOS, and they focus the camera on the PC with very good results.
I get hopeless when suffering with this K-5, unless someone could explain the method used.
I am seriously thinking about selling my K-5 for a Canon, knowing that I will not get better quality for a higher price.

Does someone have some hints? If I could get the pics already via usb on my computer for checking that would already be something.
Thanks in advance!!!
Stefan
09-11-2016, 09:40 AM   #1009
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QuoteOriginally posted by noste99 Quote
Hi,
When I see these excellent pictures made with a K-5 I wonder how you get it so well in focus.

-----------

I get hopeless when suffering with this Kj-5, unless someone could explain the method used.
I am seriously thinking about selling my K-5 for a Canon, knowing that I will not get better quality for a higher price.

Does someone have some hints? If I could get the pics already via usb on my computer for checking that would already be something.
Thanks in advance!!!
Stefan
For me, this has never been a real problem, neither with my K-5 nor with my K-3. I just find a bright star in a convenient wieving angle, use liveview and 8-10 x magnification for critical focusing. Once I have nailed focus, I can then confidently go to my targets elsewhere in the sky. You may use tape, if you want to fix that focus position and you can further do the focusing during the day-time on remote objects.

You can also try to autofocus on such brighter stars. You might get a surprise when you see how efficient Pentax low-light autofocus really is. OK, here K-3 AF excels over that of the K-5, but I do use AF on both cameras with my faster telephoto lenses.

Finally, you could try pktether - works fine with the K-5. Again, lt's a matter of nailing focus first and keeping it there before you go hunting for your targets.

09-11-2016, 10:32 AM   #1010
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Focusing on a star with Pentax

Focusing on a point of light in the sky can be very difficult,.maintaining that focus is even more frustrating.especially if your are focusing through a telescope. Don't always blame the camera, many amateur telescopes have very poor focusing devices. and require upgrades that costing several hundred dollars (moonlight, and feathertouch focusers are an example), The scope itself might not come to focus and of course you have atmospheric conditions that are constantly changing making small adjustments in focus always necessary and as temperature changes focus also changes.. You are correct Pentax should be able to make it easier with software to live view on a computer monitor in bulb mode and allow you to make and see your focus adjustments results. I bought a used 14" LED monitor from Shopgoodwill,com for $20 Dollars. Make sure it has an HDMI connector.
Connecting it to my camera (K5-K3 or KS2). with an HDMI cable, that makes it easy to monitor and adjust what I am imaging. The Ks-2 makes a very good astro DSLR. The pentax software works fairly well (to many restrictions) with the KS_2.
Whichever camera you use there are many variables that should also be considered if you want achieve sharp astro- pictures. That what makes the hobby so very interesting and satisfying
Hank
09-11-2016, 12:30 PM   #1011
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Thanks a lot for the advice.
Stone G. I was trying out pkTriggerCord on a linux box, and yes it works but easily blocks the whole camera in a way you need to take out the battery or it does not want to restart. I thought that pkTriggerCord was the more recent version of pkTheter. For you pkTheter works without blocking??? I am immediately going to try this out and keep you informed.

oneeyedhawk, my setup is mobile and car-battery powered. I do not want to add a 12V-220V converter and therefore I use now a Samsung tablet wifi connected to my telescope gear. Samsung sells a micro-usb -> HDMI converter and I took the MHL 3 version. This version seems to allow HDMI in both directions, hoping that my K-5 could work as source and my tablet as screen. Unfortunately this idea does not work out.

Many of my colleagues use now Bahtinov screens to focus, and that seems to work fine, but they watch their pictures on a PC monitor screen.

---------- Post added 09-11-16 at 08:39 PM ----------

Sone G. I just saw why I did not tried before with pkTether, it seems not to be available for linux.
Same problem with other good-working tools under Windows. I am using linux because it runs on a credit card size quad-core machine. Unfortunately these machines do not run windows.

I have never thought to use the Pentax low-light autofocus. Will try this out during the next cloudyless night. My refernce star is Vega, so this should work well.

Thanks again for the excellent hints.

Stefan
09-11-2016, 04:30 PM   #1012
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I have a K3. It's my understanding that the PK Tether does not work with the K3 camera. Is this correct? Has anyone used the K3's "movie" function to capture "video images" through a telescope and then "stacked" them? If so, how did you do it? I have a Celestron Schmidt Cassegrain telescope with which I would like to try that technique out on the brighter planets and brighter deep space objects. If I remember correctly, I believe that Jerry Lodriguss alludes to that technique. although quite briefly, in his book on astrophotography and the DSLR. Somewhere I have that e-book on a cd-rom -- I'll have to look for it.
09-13-2016, 02:08 AM   #1013
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QuoteOriginally posted by XLXW Quote
I have a K3. It's my understanding that the PK Tether does not work with the K3 camera. Is this correct? Has anyone used the K3's "movie" function to capture "video images" through a telescope and then "stacked" them? If so, how did you do it? I have a Celestron Schmidt Cassegrain telescope with which I would like to try that technique out on the brighter planets and brighter deep space objects. If I remember correctly, I believe that Jerry Lodriguss alludes to that technique. although quite briefly, in his book on astrophotography and the DSLR. Somewhere I have that e-book on a cd-rom -- I'll have to look for it.
I tried filming with a 400 mm F5.6 Pentax lens ( moon craters and a moon pano stiched from several pictures) but used an Olympus OM-D instead of the K3 II because it has a "lossless" 2xdigital zoom that works with a crop on the sensor. I filmed 1 minute clips and stacked them with the free Autostakkert2 software without any problems. The results were very good in my eyes.

09-13-2016, 10:04 AM   #1014
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Thanks, Pete. I took some handheld pictures of the Moon the other night using a 500 mm mirrorless lens and the K3. A couple turned out well. I did it to try to figure out how to use the camera with a Schmidt Cassegrain telescope since that mirrorless lens is essentially the same as the Schmidt Cassegrain telescope. The difficulty is in the focusing and getting it right. I used the "live view" to try to focus the camera as it was impossible through the viewfinder nor could I do it with a Pentax reconverter attached to the viewfinder of the camera. I now am thinking that the best way to do it is to somehow connect the K3 to a laptop computer and focus the K3 via the image which would be presented on the computer's screen if that is possible to somehow manage. Does anyone have any suggestions as to how to accomplish this? I'd like to figure this out before the next New Moon as I would like to get out to the desert in Joshua Tree and try to do some astrophotography with the K3 through the Schmidt Cassegrain telescope. By the way, did you use a ND Filter on the Moon shot with your 400 mm lens? Perhaps, that may be the problem with the brightness of the Moon in "live view" mode? I could not even see the "Mare" of the Moon to even focus the camera due to the "brightness" of the Moon in "live view." By the way, there is an excellent article on using "Autostakkert" in the recent edition of either Sky and Telescope magazine or Astronomy magazine. I scanned it and made a Pdf of it and have it if anyone is interested in it. I'd attach the Pdf but I don't know how to do it. I'll look for it and post the citation to it in the magazine in case anyone is interested.
09-13-2016, 02:07 PM   #1015
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QuoteOriginally posted by XLXW Quote
Thanks, Pete. I took some handheld pictures of the Moon the other night using a 500 mm mirrorless lens and the K3.
--------- The difficulty is in the focusing and getting it right. I used the "live view" to try to focus the camera as it was impossible through the viewfinder nor could I do it with a Pentax reconverter attached to the viewfinder of the camera.
The difficulty with liveview focusing of the Moon is that (to me) annoying auto-gain of the LCD liveview image in all still image shooting modes. However, there is a work-around for that:


Set you camera to Manual Video Mode and adjust exposure time and aperture until you see the Moon properly exposed. Now, focusing using magnified liveview and Focus Peak is easy. Once you have established your shooting parameters, you can either do a video as set or return to single image shooting in Manual Mode using the settings you have found.
QuoteOriginally posted by XLXW Quote
I now am thinking that the best way to do it is to somehow connect the K3 to a laptop computer and focus the K3 via the image which would be presented on the computer's screen if that is possible to somehow manage.
Since you have the K-3: I have the Pentax FluCard and sometimes use that for quality control in the field. Transfer of jpg-images to a smart phone or a tablet with either Safari or Chrome browser is reasonably fast and efficient. However, the card is quite power hungry so I rarely use it for astrophotography purposes.

Last edited by Stone G.; 09-13-2016 at 02:12 PM.
09-13-2016, 02:40 PM   #1016
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Thanks. Interesting idea. The K3's box references an AC Adapter Kit (K-AC132) which is one of the few Pentax gizmos I don't have. That would probably solve that "power hungry" issue if that adapter is for the camera. I would assume that it could be hooked up to a Honda generator in the field for astrophotography purposes since the telescope's computerized mount is run off the generator. It's difficult to tell because the reference on the K3 box to that particular adapter is so vague. There are some expensive astro software programs out there which will control a DSLR camera but I am not aware of any which will work with Pentax -- just Canon and Nikon.
Will the new K1 Pentax camera link up and function with a laptop computer? If so, it may be time to upgrade the camera.
Will that FLU card transfer images to a laptop computer as well? I am asking because I not particularly computer literate.
09-13-2016, 04:04 PM   #1017
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Yes, the K-1 can be tethered to a laptop. You will have to purchase the appropriate software then if my understanding is correct.

And yes, the flucard will also work with a laptop. I have tried the following browsers wit success: Firefox and Chrome. I am sure a mac with Safari will work too.
09-13-2016, 06:25 PM   #1018
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Thanks. What astro software works with the K1, if you know? I have not found any which works with the K3 but then I haven't dutifully looked for the past year. There might be new software out there -- it changes pretty rapidly. I am just not aware of it.
09-14-2016, 11:39 AM   #1019
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Bahtinov Mask!!! I printed mine out, cut the holes out with an exacto knife, then taped it down for focusing. Works perfectly and GREATLY assists.
09-24-2016, 10:14 AM - 6 Likes   #1020
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I did my astrothings with my new K3 II in the passed year. Yesterday I put on the good old K5 once more to go for a dim nebula from my suburban light polluted balkony.

I did not do any comparison between K3 II and K5 until now but anyway the K5 is a great tool for faint DSOs I think.

This is the Heart Nebula (IC 1805) with its companions IC 1795 and NGC 896. 45 shots of 3 minutes exposure at ISO 800, F6.0 with a TS 480 mm telescope. Hope you like it....

IC 1805, IC 1795 und NGC 896 by pete_xl, auf Flickr

Last edited by Pete_XL; 09-24-2016 at 11:49 AM. Reason: misspelling
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