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09-21-2015, 11:18 AM   #31
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QuoteOriginally posted by sindbad1 Quote
Hi, I'm looking for a table with maximum tracking/expoure times for the astrotracer in pentax K-3 oder K-3 II. I couldn't find it on ricoh's website. Does anyone have a link?

Tom
On an APS-C sensor camera (K50, K3, etc) the recommended exposure time is 360 divided by the focal length of the lens. So for a 50mm lens, it would be 360/50 = 7.2 seconds. With the GPS attached and in astrotracer mode, you can go longer than the recommended time....around 20 seconds to about 4 minutes for some reports depending on focal length (exposure time inversely proportional to FL).

---------- Post added 09-21-15 at 02:22 PM ----------

QuoteOriginally posted by interested_observer Quote
Here is a paper that presents stacking images - without tracking.
Thanks. My last session was a bust. I don't think I aligned the mini-equatorial mount correctly (latitude setting as well as polar alignment). The small mount did not have a polar alignment scope and I had to eyeball it with the camera on the mount (note to self: not a good idea). Also, the latitude setting scale came off so I glued it back - I must not not done it correctly.

Sigh.

I'll be going back in a week or so lugging the larger equatorial mount AND the telescope (it has a polar alignment scope on it, and I just bought a dual-axis motor) with the T-mount adapter. Milky Way is essentially gone for the season (per your earlier posting) but I'll try to get some DSOs from the Messier catalog.


Last edited by realitarian; 09-21-2015 at 11:23 AM.
11-08-2015, 01:16 PM   #32
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Something is wrong, Im a little frustrated

Hey guys,

So I have been trying to do simple astrophotography and I cannot get clear pics. Every picture I get is blurry, not super blurry, but blurry. I have a tripod and remote control and its still not working and I just don't know what Im doing wrong! I don't have SR or NR on in any of my photos. They were all taken on a 24 mm lens, for about 8 seconds a piece. f2.4. PLEASE HELP!!!!
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11-08-2015, 01:23 PM   #33
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QuoteOriginally posted by photographerclare Quote
Hey guys,

So I have been trying to do simple astrophotography and I cannot get clear pics. Every picture I get is blurry, not super blurry, but blurry. I have a tripod and remote control and its still not working and I just don't know what Im doing wrong! I don't have SR or NR on in any of my photos. They were all taken on a 24 mm lens, for about 8 seconds a piece. f2.4. PLEASE HELP!!!!
First of all, your focus is way off. You may have to combine images if you plan to include a foreground. Your goal should be to get the stars sharp, which may involve a bit of trial and error if it's particularly dark.

It also looks like you tripod possibly isn't stable enough.

If/when you use the astrotracer, you have to make sure that it is properly calibrated. You shouldn't need to use it for exposures this short (I'm not sure if an 8s shutter speed would even be selectable).

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11-08-2015, 01:27 PM   #34
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Can anyone help me? Trying to figure out why my star picks are blurry. I don't have SR or NR on, my lens in 24mm, I have no idea if I actually am focusing to infinity or not, not really sure how to do that. I want to have sharp images in the foreground, but I don't know if that is possible without stacking. my ISO was 1600 and f/2.4. M exposure, I don't know why I get startrails (sort of, they just look like blurry stars) every time because I am not holding shutter open for very long. help please.

---------- Post added 11-08-15 at 01:35 PM ----------

QuoteOriginally posted by Adam Quote
First of all, your focus is way off. You may have to combine images if you plan to include a foreground. Your goal should be to get the stars sharp, which may involve a bit of trial and error if it's particularly dark.

It also looks like you tripod possibly isn't stable enough.

If/when you use the astrotracer, you have to make sure that it is properly calibrated. You shouldn't need to use it for exposures this short (I'm not sure if an 8s shutter speed would even be selectable).
Thanks for replying adam! How do you recommend that I get my focus "on". I don't quite understand how to set my focus to "infinity" or if my lens even has that option. Its definitely possible that my tripod is not sturdy enough. Is it possible that I need to turn another setting off in the camera so maybe it doesn't shake? I don't know if something besides NR and SR needs to be turned off. These look bad, but I just started doing this so they look better than they did in the beginning! Thanks again!

Clare

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11-08-2015, 01:42 PM   #35
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As Adam said, it looks like you are way out of focus and don't have a solid tripod. In the above image I can see 3-4 iterations of each star. It looks like the tripod head could be dipping as the exposure is going since the "trails" are moving down.

Also, I notice you said 24mm but your EXIF shows 35mm. Not that it matters that much but I was just curious. I believe you should be able to switch to manual focus mode and use the focus ring on the lens to focus to infinity. Be aware that it may not be exactly where it "stops" and could be slightly before that point. Just take some quicker, higher ISO photos to check for better focus. Once you have focus figured out, you can then address the tripod stabilization.

One other thing, this thread is about using Astrotracer but I don't know that I've seen you mention whether you are using Astrotracer or not. If you are, your foreground images will be blurry as the camera's sensor is moving to follow the stars. If you aren't using the Astrotracer, work on the focus and solid mounting and see where that gets you. It might be worth starting a different thread as well since again, this thread is more about using/troubleshooting Astrotracer.
11-08-2015, 08:27 PM   #36
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QuoteOriginally posted by photographerclare Quote
Can anyone help me? Trying to figure out why my star picks are blurry. I don't have SR or NR on, my lens in 24mm, I have no idea if I actually am focusing to infinity or not, not really sure how to do that. I want to have sharp images in the foreground, but I don't know if that is possible without stacking. my ISO was 1600 and f/2.4. M exposure, I don't know why I get startrails (sort of, they just look like blurry stars) every time because I am not holding shutter open for very long. help please.[COLOR="Silver"]
Good Evening,

Well let's start as simple as possible.
  • During the day, take your camera and lens out and since you are using a DA 35/f2.4 use auto focus to focus on something as far away as possible. Then, on the side of the camera flip the toggle switch to manual focusing and don't touch it again. It will help to put a piece of tape across the side of the lens taping down the focus ring. You camera is in focus. Just put it down until you are ready to shoot the stars.
  • So, if it is at night and you need to focus, you are going to need to manual focus. So flip the switch on the side of the camera to manual focusing. Go in to live view on the camera and focus on something. Well you are going to need some light - so take a flashlight and a couple of hundred feet away put the flashlight down and shine it on a tree or something as a target. Go back and focus on the lit target, and you should be in focus. You can zoom in with live view so that you can see what you are doing with the focus.
  • Put the camera on the tripod with the shutter remote. There is usually a hook on the bottom of the center column to hang a bag or something to add some weight to the tripos to make it more stable. Make sure that SR is off.
You should be ready to go....

11-09-2015, 08:32 AM   #37
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Once you get your focusing issues resolved, you also have camera movement during the exposures. All of the stars appear twice and the wires in the second image look like there are two of each wire. That is caused by the camera moving during the exposure. "I don't know why I get startrails (sort of, they just look like blurry stars) every time because I am not holding shutter open for very long." Are you holding the shutter release button during the exposure? If the camera is touched during the exposure, it will shake the camera. Set the camera for the desired exposure length (you mentioned 8 seconds) and trigger the shutter with a remote. If you don't have a remote release set the camera for a two second delay, press the shutter release button and don't touch the camera again until the exposure is complete. Be sure you aren't touching the tripod, either...feet, clothing, etc. Stabilizing the tripod might also help. (a breeze can shake the camera.) Simply fill an old milk jug with water and place it on the ground under the tripod and then use a bungee cord or some heavy string to tie the tripod to the milk jug.


11-12-2015, 02:08 AM   #38
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Thanks guys. I honestly don't know why my camera is moving. I tried again tonight and still no luck. I get two of each star. It is not my tripod (very sturdy and no wind) and I am using a remote. The only other reason I can think of as to why my camera is moving is because some weird setting is on that is not supposed to be. I have all NR and SR functions off, but when I want to focus on something via live mode, the picture on the live mode shakes, even when on the tripod (the tripod isn't moving). Also, my camera makes a clicking sound when it is taking long exposure shots, I don't know if this is normal. Here is my best attempt so far (I have not been able to recreate it).

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11-12-2015, 08:23 AM   #39
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How about taking some shots during the day and posting them. If they come out alright, focus on things you are doing differently at night that may be causing the issue.

Also, as I asked before, you never mentioned if you were truly using Astrotracer or just taking night photos.
11-12-2015, 03:35 PM   #40
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appears to be a focus issue.....are you turning off AF when shooting?
12-16-2015, 05:28 AM   #41
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So, here's my first attempt with my astrotracer, which did not turn out well. I was using a DA*300 set at f5.6 in a K5iis. ISO 100. Bulb mode of course, with 2-second delay. Manual focus. The astrotracer limited exposure to 90 seconds, so that is what I tried. Orion's Belt was perhaps at 45 degrees above the horizon, possibly slightly higher. Is this just too long an exposure for this long a lens?
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12-16-2015, 05:42 AM   #42
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QuoteOriginally posted by sholtzma Quote
So, here's my first attempt with my astrotracer, which did not turn out well. I was using a DA*300 set at f5.6 in a K5iis. ISO 100. Bulb mode of course, with 2-second delay. Manual focus. The astrotracer limited exposure to 90 seconds, so that is what I tried. Orion's Belt was perhaps at 45 degrees above the horizon, possibly slightly higher. Is this just too long an exposure for this long a lens?
Given the obvious curves in your star's "trails" it is quite clear that your camera moved during the exposure. Please don't tell me you were attempting this with a ball head...

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12-16-2015, 06:46 AM   #43
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QuoteOriginally posted by sholtzma Quote
So, here's my first attempt with my astrotracer, which did not turn out well. I was using a DA*300 set at f5.6 in a K5iis. ISO 100. Bulb mode of course, with 2-second delay. Manual focus. The astrotracer limited exposure to 90 seconds, so that is what I tried. Orion's Belt was perhaps at 45 degrees above the horizon, possibly slightly higher. Is this just too long an exposure for this long a lens?
The camera moved. You need to make sure the tripod is solid and that the camera is attached solid. Also boost the ISO.
12-16-2015, 07:09 AM   #44
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QuoteOriginally posted by sholtzma Quote
So, here's my first attempt with my astrotracer, which did not turn out well. I was using a DA*300 set at f5.6 in a K5iis. ISO 100. Bulb mode of course, with 2-second delay. Manual focus. The astrotracer limited exposure to 90 seconds, so that is what I tried. Orion's Belt was perhaps at 45 degrees above the horizon, possibly slightly higher. Is this just too long an exposure for this long a lens?
I'm agreeing with the others, that somehow the setup was bumped. It does not take much to bump or brush up against things, especially at 300mm. I would suggest using f4 to get more light in, along with bumping up (at least initially) to ISO 1600 (I would not really go above 1600). In this way you will capture 5x more light. The other aspect is, that since you are trying to capture a star field, take multiple shots - all in a row. Say 10 to 20. In this way you can stack them using some free software. The 90 second exposure should be fine.

Also, there a number of excellent discussions in the Astropotography group at....
12-16-2015, 09:19 AM   #45
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Harumph! I was using a gimbal head on a steady tripod. Perhaps I didn't lock down the gimbal's axes enough. I'll try it again tonight.
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