[Rturbett]

I've learned to turn the gps on first
Then I tun astrotracker on, and do a calibration (i do find humor in tumbling - in the dark-the most expensive camera I have ever owned. I believe this was designed to thin the herd)

Then attach to the tripod (Yay for the LED feature)

I'm shooting with my zoom lens set at 28 mm ( hope for a smaller fixed lens in the near future)

bulb setting

f 13 3 minute exposure iso 800

still getting star trails.


Do the settings look right? There is a green dot next to the astrotracker icon in the lower right, the icon also says "off" but it is not highlighted. Any hints on what Im missing? I don't think it is camera shake, as they all look consistant. Would love any advice, as this feature is one of the main attractions to this camera for me. (ok, it really is awesome all around, but I really want to get good at this.)

Thanks,
Rob

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[disasterfilm]

Can I ask why you're shooting at f/13? You want to go the other way... open that lens up as much as you can. At f/13 and ISO800 you're about 5-6 stops underexposed for getting usable images of stars.

The other thing is, the astrotracer isn't 100% magic. The wider you shoot, the less benefit you'll see to reduce star trailing. Any time you're reducing a spherical shape (the actual view of space) to a 2D rectangular plane, simply moving the sensor plane can't correct of for that equally across the frame. It corrects well when it only makes up a small portion of the radius of the sphere, if that makes sense.

[jbinpg]

Hi. Give this thread a read. It explains what you need to know to do Astrotracer properly on the K-1:

Astrotracer's giving me problems, help! - PentaxForums.com

- Jack

[DrawsACircle]

Try two minutes instead, check the result if ok, add 20-30sec of exposure time.
I have my own rule of thumb based on achieved results.
Exposure time: (300/focal length)*10, that's on an K-70 (APS-C), that would be (500/focal length)*10 on a K-1 (FF).
3minutes/180 sec is within the above, but apparently over the edge.

[Auzzie-Phoenix]

As stated by another member, your aperture is too narrow to start. The other problem is that you're doing a 3 min exposure with a 28mm focal length... this is too long of a shutter time. Even using an ultrawide, you'd have trailing with an exposure that long. You want to open the aperture up to at least f/4 (3.5 or 2.8 is better if possible), the maximum amount of time to keep the shutter open at 28mm will probably be somewhere around 1 minute to 1 min 30 sec. possibly even less. Calibration of the gps isn't as important as one would think (I frequently forego calibration on my K-3II with no issues). Hope this helps, kind of in a rush to get to bed but figured I'd post real quick.

[slartibartfast01]

If there is a precise calibration for the K-1 astrotracer you should do that as well as the standard calibration.

[Gimbal]

As already stated, 3 minutes is way too optimistic to start with. Begin with 30sec and increase time in steps until limit.

Important is to have the LCD tucked in in its home position when calibrating. Then use the LCD for setting up your shot. THEN tuck the LCD back in its homeposition again. Now shoot.

If you thought that you wanted large DOF using f/13 you really do not need that since the foreground will be blurred due to the sensor moving. Open up and let the light in so you can lower the ISO.

If you can read swedish I have a manual for this...

[Jeffvan]

Rturbett I think you missed one special dance that still needs to be completed.

Here is what I was able to get at 2 minutes:
Andromeda Galaxy

I used f/4.0 because this lens is at its sharpest at f/4.0 corner to corner at 200mm.

There are still star trails but for 2 minutes it isn't much. Even at 60 seconds there were some star trails.

Here is what I found to work best. You need to turn on the GPS before even turning on the Astrotracer (As you pointed out). Make sure the lens you are going to use is mounted on the camera. Next make sure the GPS gets a signal with the icon changing. Next mount your camera to your tripod and make sure it is VERY WELL secured to the tripod. Next stand exactly where you are going to place the tripod and as far away as possible to other metal objects. Now turn the mode to Bulb (B) mode and turn Astrotracer on. Press the +/- to calibrate and proceed to spin the camera and tripod together to calibrate the rig. The reason for this is that the camera has an internal compass and by changing the proximity of metal to the camera will change the calibration of the compass.

Two things will affect how much star trails you will get. The higher you point in the sky the more trails you will get. This is another picture I took which was much lower in the sky and pointing almost West North West about 40 degrees up from the Horizon:


The other is the wider your camera lens angle, the less of an effect the trails will appear to have in your picture.

The trails will always be worse towards the edge of the picture.

Bulb mode has two versions with Astrotracer turned on. One is regular bulb mode, where you keep the shutter depressed while you want to shutter open. The second mode is a timer mode. You can cycle between the two modes using the green button in the back. While not in live view and in Timer mode there will be a block displaying the maximum shutter time possible for the tracking sensor with the lens combo you have (I have firmware 1.41). As long as you don't exceed this, you should be good.

Also invest in a remote (I have an IR one) and stand back when you start the shot and keep away. You can watch the GPS light come back on when it is done processing.

I hope this helps.

Edit: oh, if you are using a telescoping lens, have it set to the focal length you are planning to use before calibrating the astrotracer. Always envision how metal parts moving in proximity of the camera would affect the compass.

[Rturbett]

Wow- thanks for the great info- I'm pretty sure I did not press the green button to engage. I'll report back if that was it.

My impression was that the astrotracker would move the sensor for up to 5 minutes? but I have wondered how focal length would effect that.

I was using the long exposure at f13 , relatively low iso- just to check the astro tracker function. I have gotten a few good shots without astrotracker using different settings and keeping the exposure at 25 seconds.

Will try again tonight- looks pretty clear out, even if the moon is up... good to practice.

Thanks for all the help-
Rob

[Rturbett]

Green button did it- but I now will see if the bulb mode can be set to a timer- better yet,will order a handheld shutter release tonight. Birthday is coming, will ask for a real tripod.

The moon- nearly full, was behind this- ignore the exposure- about 1min 20 I will work on focus, but no star trails compared to what I was seeing before.

Thanks for making this happen for me- I'm very excited.

Rob

[Jeffvan]

Green button did it- but I now will see if the bulb mode can be set to a timer- better yet,will order a handheld shutter release tonight. Birthday is coming, will ask for a real tripod.

The moon- nearly full, was behind this- ignore the exposure- about 1min 20 I will work on focus, but no star trails compared to what I was seeing before.

Thanks for making this happen for me- I'm very excited.

Rob

Good to hear!

Just to clarify:

While in Bulb mode: Use the green button to toggle between regular bulb mode and timer mode. You can then use the index dial to increase the time on the timer.

Bulb mode with Astrotracer turned on, adds this additional feature of the timer. You can use Astrotracer with regular bulb mode or the additional timer feature (in bulb mode).

Both Bulb mode and Bulb Timer Mode can exceed the maximum sensor time, but once you do the star trails will suddenly be introduced as the sensor hits its maximum travel.

The reason to step away from the camera and tripod is to avoid any additional shake to the system. It won't do much to the compass as long as you don't have a lot of metal on you.

I use this $10 remote shutter. This remote works best with the timer mode. I found that if you use bulb mode (with one shutter press starting bulb open and one shutter press stopping bulb mode - Found in C Menu) you will be in a perpetual shutter release. The remote emits a long signal when the button is pressed. Pressing the remote button once will start the shutter open event. When pressed again, the shutter will close, and since the remote releases a long signal, trigger another shutter open even. You then have to turn the camera off to get things to stop. Which means calibrating everything from start again. But in timer mode (which can go up to 10 minutes) everything works great and it lasts long enough for most capabilities of the Astrotracer tracking.

For focusing:
First set your F-stop to what you would like it to be. I like using the sharpest setting that the lens can operate at with the lowest F-stop value. For that look at this website:
Lense Sharpness
Find your lens and then look for the focal length you are going to use, and locate the F-stop column that has all dark blue or mostly dark blue. This comes down to your preference here.

Now onto focusing: I go into Live View, then hit the OK button to go into zoom mode. Love the tilt screen here!!! I use the Thumb dial to zoom out and try to find a bright star (play with the thumb dial here so you are not too zoomed out to start with). You might have to play with the focus here to locate something. I then zoom in (thumb dial) a bit and then start playing with the focus. Your aim is to get the star to appear as small as possible. This is one of those other dancing parts, playing with the thumb dial to locate a star and the focus ring to get the focus. The smaller the star is the more in focus it is. Once you have this sorted, you most likely won't have to touch the focus again. Just to make sure I don't touch the focus, I flip the switch on the side of the camera to Manual Focus. You can now look into any direction in the sky and all the stars will be in focus. This is the true infinity focus point of your lens at that temperature. You will note the lens can go far beyond what the infinity focus is. This is to accommodate adapter rings (and such items) as well as accommodate temperature changes. If the temperature changes dramatically, while you are outside with the camera, you might have to refocus. This is why it helps to let your camera sit outside for a few minutes before you begin the whole process. Pro Astro-Photographers will do this between 30 minutes to 60 minutes, for their gear, but this is to avoid heat waves coming off their system and distorting the optics.

Locating what you want to shoot:
I use the Sky Map app (Android Google Play Store) to look around for where objects are in the sky. I then target that area as close as I can with the setup and take a short 15 second exposure. I then can look at my picture and see if the object is actually there. I then re-adjust the position until I have the object in sight and then I increase my exposure time.

Yeah, a solid tripod is a good investment!

What to do after Astrotracer has hit its limit:
It is good to know what is involved as you go beyond the K-1's capabilities. Including the cost of items. Lots and lots of costs!
I found the information in these videos below useful even for my K-1 Astrotracer. It helped me understand the importance of a solid tripod, and the issues related to tracking.
If you get more interested in Astrophotography then look at these three videos, they give a good insight into what is involved, as you step up your game:

You Tube

You Tube

You Tube

You Tube

You Tube

You Tube

[Rturbett]

Great write up-
I was able to set the timer in bulb mode, but it seemed to ignore the time set- going to 5 minutes when I just wanted two. Will play with it some more. It's likely that I switched the bulb mode to press once for start, once for stop.

Also, when everything is set and using live view to focus, I can't zoom the live view. I would love to do that to ensure best focus like I do when in manual mode. any hints?

Good to hear!

Just to clarify:

Bulb mode with Astrotracer turned on, adds this additional feature of the timer. You can use Astrotracer with regular bulb mode or the additional timer feature (in bulb mode).

Both Bulb mode and Bulb Timer Mode can exceed the maximum sensor time, but once you do the star trails will suddenly be introduced as the sensor hits its maximum travel.




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To use Astrotracer with just bulb was new to me but testing without any stars I see that it actually turns. I thought that the Astrotracer timer was necessary. Maybe a glitch in the FW. Is it the same on the K-3II?

Great write up-
I was able to set the timer in bulb mode, but it seemed to ignore the time set- going to 5 minutes when I just wanted two. Will play with it some more. It's likely that I switched the bulb mode to press once for start, once for stop.

Also, when everything is set and using live view to focus, I can't zoom the live view. I would love to do that to ensure best focus like I do when in manual mode. any hints?

Zooming in Live view is done when pressing the OK button.

Also, do not use Bulb for this. Go to bulb, make sure Astrotracer symbol is visible in the upper left corner. Make sure you have green GPS symbol. Press exposure comp button and calibrate. Press Green button to toggle between Bulb and Astrotracer timer. Use the timer and set the time. Press the shutter with 2s delay and a cable release or infrared. Preferably in Live view so that you won't get the mirror slap. With this you will not have to stop the exposure, it will end when the timer ends. If not you have the wrong settings.

I attach my Astrotracer manual. It is in swedish but the images may help...