[Kendigitize]

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.

Are you using a remote control? That's a must.

[sholtzma]

2-second delay instead of a remote. 90 second shot on Bulb, governed by the astrotracer.

I'll try the same setup tonight, as well as shorter times (with higher ISOs), and I'll try some shorter lenses.

[Gimbal]

In my experience you can forget about the maximum time the astrotracer tells you should be possible.
With a 300mm lens I doubt you will have any success over 30seconds, perhaps one now and then, but in reality it's better to aim for perhaps 15seconds and take multiple shoots and stack them.
The probability for four 15s exposures being good is a lot higher then one 60s being perfect. And if one of the 15s fails you have only lost 15s and can take another one in just 15s.

[Grey Area]

Hope questions about built-in Astrotracer on the K3-II are allowed...

Using the stock 18-55 that came with the camera. Getting noticeable trails over 15s exposures when filming Andromeda. Elevation quite high. Does anyone know if setting camera "portrait" instead of "landscape" will improve or worsen?

Someone indicated a ball mount is a problem...why? Yes I'm very new...

Should I still polar align? I love the way I said that as if I know what it means...!

I read that the external unit has advanced compass functions. Anyone know if the built-in unit has the same? Still trawling through my camera manual...

Edit...more q's

Lenses...Someone mentioned DA*? Won't astrotracer work with others?

How well does it work with longer lenses? I inherited a 200mm lens but it's old and need to set to use f-stop ring.

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Last edited by Grey Area; 12-27-2015 at 11:03 PM.

[Sagitta]

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?

Its doable. Maybe not at 90 seconds, but I was able to pull off 60 easily with an old Sears 300mm.

EDIT: The weird haloing was (probably) from my camera sensor itself - I was rocking a heavily damaged sensor when I shot this.



One trick is to check your tripod itself - I have always had my best luck by foregoing using a tripod altogether and supporting the camera in other ways (bean bag, propped on a rock, etc). I suspect this is because I always used mine with cheap pan and tilt Walmart-bought tripods (I havent really had a chance to play with the new one I picked up last Spring yet to see if I have any real differences going on).

One thing to note (at least with the newer cameras) is that high ISOs are fine to use. Don't be afraid f ISO 1600/3200 or even 6400 in a pinch. This is especially true if you intend to stack (though I have yet to fiddle much with stacking myself).

[Grey Area]

Not relevant to this thread but related to it; when I type "200mm lens" or "300mm lens" the forum formats them as links to an adorama webpage. Is this a forum setting or have I picked up some adware somewhere?

[UncleVanya]

Not relevant to this thread but related to it; when I type "200mm lens" or "300mm lens" the forum formats them as links to an adorama webpage. Is this a forum setting or have I picked up some adware somewhere?

I see it too.

Code:

http://adorama.evyy.net/c/60093/51926/1036?sharedid=al&u=http%3A%2F%2Fwww.adorama.com%2Fsearchsite%2Fdefault.aspx%3Fsearchinfo%3Dpentax+200mm+lens

[sholtzma]

So, I was finally able to get out tonight: not too cold, moonless, clear. Tried the astrotracer on a much sturdier tripod and much sturdier gimbal head tightly locked down. That should have eliminated most user-caused movement. I stayed with the DA* 300 but went up to f8 and ISO 400, moving from 30 seconds to 20 seconds to 10 seconds. While the results were much better than the first time, they were not as sharp as I would have liked, and there is still some trailing. I was again shooting the Orion Nebula, which is in the East at roughly 45 degrees above the horizon. Am I supposed to be shooting due South? I tried portrait and landscape orientation.... Naturally, my manual focus might be a bit off, and that would explain the sharpness issue, but what explains the trailing at even 10 seconds? Then, on top of everything, I tried to calibrate again, thinking that perhaps my precise calibration could stand redoing. I was able to do the first rough calibration but never again the second precise calibration. Aaargh! Can't figure out what I might be doing wrong there....

[colonel00]

It's hard to tell from your photo as posted but instead of trails, could that actually be from slight movement of the setup? Perhaps from the mirror? Perhaps use a different lens and no astrotracer and just try for some crisp shots of stars to make sure everything else is good. Basically removing variables to help pinpoint the root cause of the issue(s). I guess another good question would be to ask if you were getting similar "trails" in the 30, 20 and 10 second images of if the trails were definitely longer on the longer exposures as you might expect.

[Aaron28]

yep certainly trails..but looks like a stable set up...the o-gps is a mysterious device for sure.....I have had my share of frustrations with it......how fresh is the battery? it not wanting to give ya a precise calibration is prolly a contributor......focus seems pretty good.....the one thing that really stands out is f8.......open that lens up!

[Grippy]

I've been playing round with mine a bit lately, I've had excellent results with the 300mm up to 50 seconds. I usually just shoot 30 seconds though as it makes it easier to blast away at the darks afterwards in manual 30 second exposure.
My first shot at it I used the 2 second delay and had similar results as yours, a little blurry, you would be surprised at how much the tip of the 300mm amplifies even the slightest bit of movement. Since then I have used a wireless remote and ran a few test shots to ensure focus is tack sharp, using live view zoomed in on a single star. Also the precise calibration is key I think, mine didn't want to play ball with the normal calibration and has given fantastic results with the precise, sometimes it takes about a minute of twisting and turning to get it but it eventually works.
Open up the aperture, f/8 is too small for these faint little things in the sky.
Here is my most recent attempt, a couple of nights shooting all stacked together, exposures mainly around the 30 second mark.

[sholtzma]

I'll see if replacing the battery works. But it allowed me one precise calibration earlier in the evening, just not later when I tried to recalibrate to try to improve my results.

Can I calibrate it inside (where warm) and then move quickly outside to set it up? At least then I won't care as much if it takes 20 tries to get calibration to work....

I can certainly use a remote. No problem there.

[Grippy]

I'll see if replacing the battery works. But it allowed me one precise calibration earlier in the evening, just not later when I tried to recalibrate to try to improve my results.

Can I calibrate it inside (where warm) and then move quickly outside to set it up? At least then I won't care as much if it takes 20 tries to get calibration to work....

I can certainly use a remote. No problem there.

I've found with the precise calibration I have to be very quick with the moves and do almost full revolution s. Last night I nailed it after 1 of each turn. Takes a bit of hand juggling but it seems to help

[Aaron28]

Can I calibrate it inside

not recommended!! but would be nice as nights are rather chilly now a days!!
however if the 3d lights up green inside that means it has a lock!
if I do not turn the unit off 1 precise calibration seems all that is necessary......
also if i'm only using the astrotracer mode I do not bother with the general calibration

[Sagitta]

I'll see if replacing the battery works. But it allowed me one precise calibration earlier in the evening, just not later when I tried to recalibrate to try to improve my results.

Can I calibrate it inside (where warm) and then move quickly outside to set it up? At least then I won't care as much if it takes 20 tries to get calibration to work....

I can certainly use a remote. No problem there.

One other issue worth considering is where it is you're shooting from. If your location has an unusually high iron content, believe it or not it CAN throw the tracker off.

In my case I can shoot inside from out the apartment window (nice wide 3 foot sills), or out in the boonies, but not down by the riverside. The riverside used to have houses and factories, so the ground is utterly saturated with old pipes, iron slag and who knows what else. I have yet to get a decent shot down there that doesn't show trailing. I even get better results in the parking lot next door to here.

By that same token, don't set up right next to your car (similar reasons). You have to remember that part of what makes the tracker tick is being able to lock on to the magnetic pole - if anything interferes in that, then you won't get decent results as things won't track true.