Guiding Needed?

[hatflyer]

I have a Nikon D5500, a Nikon f/4.5 400mm lens, and the AZ-GTi mount.

My first subs at 30 seconds looked pretty good. Then they deteriorated a bit, before a big jump in star trails. Not sure if the mount jerked or what. Things got better, but still noticeable trails, even at 15 seconds.

I PA'ed again, and things were better, but not to what they were at the start. Not sure if something shifted and stayed that way or what.
But every thing was locked in tightly, tho I am not a fan of the Sky Watcher wedge.

The lens is attached via the collar. My counterweight is only 1 pound for this 3 1/2 pound camera/lens combo.

Do I have to auto-guide?

Thanks.

[davesellars]

Are you using the AZ-GTi with an equatorial wedge? If not, you will be restricted to short exposures only because of rotation (guiding won't help).

[hatflyer]

Are you using the AZ-GTi with an equatorial wedge? If not, you will be restricted to short exposures only because of rotation (guiding won't help).

Yes, I have a wedge, tho I don't like it. The Sky Watcher wedge.

Btw, my PA error was about 2'. Is that too much?

[davesellars]

Sorry, I missed in your original post you did mention the wedge... :p

I can't see that a PAE of 2' would cause that much of an issue at 400mm FL so it's likely to be something else that's the problem. Is the tripod you're using the one that comes with the AZ-GTi? For me, this looks to be the weakest part as the weight of the setup is not massive however 400mm focal length is starting to get to the point where you are going to need pretty good stability. Watch out for cables from the camera particularly that may be causing some flexure.

[hatflyer]

Sorry, I missed in your original post you did mention the wedge... :p

I can't see that a PAE of 2' would cause that much of an issue at 400mm FL so it's likely to be something else that's the problem. Is the tripod you're using the one that comes with the AZ-GTi? For me, this looks to be the weakest part as the weight of the setup is not massive however 400mm focal length is starting to get to the point where you are going to need pretty good stability. Watch out for cables from the camera particularly that may be causing some flexure.

Tripod is steady, tho it is light-weight. Didn't notice any movement, but it being 2 lbs I guess may make a difference.

[davesellars]

It may be worth to try hanging a heavy(ish) weight off the centre of the tripod which would just give it some extra stability. Take many 30 seconds exposures and then judge how many have star trails. Also are you using a delay after opening the shutter before taking the exposure? the vibration from the shutter could be causing an initial problem in movement especially in a lightweight setup.

[hatflyer]

It may be worth to try hanging a heavy(ish) weight off the centre of the tripod which would just give it some extra stability. Take many 30 seconds exposures and then judge how many have star trails. Also are you using a delay after opening the shutter before taking the exposure? the vibration from the shutter could be causing an initial problem in movement especially in a lightweight setup.

I'm using NINA to control the shutter. Not sure if a delay between images occurs or not.

[JayTee]

If you were to use a different lens and possibly drop the fl down to 200 mm, it would be interesting to see what that change causes in your images.

I have a Canon 50-350 mm FL zoom lens. I keep increasing the zoom amount until I find the level where star trails are annoying, then I back the FL down a bit to manage the star images.