Close and reopen arm to fix EQ tracking

55u56qWD

I got my 2nd Seestar a few days ago - S30Pro. The first night in Alt/Az mode everything was fine. Two subsequent evenings I have set up in EQ mode (accurately on sturdy tripod with micrometer head) and had terrible problems starting the first target. The display showed images with long star trails and sometimes I got "Target offset detected. Recentering". As I have previously found this to help on S30: I closed the arm and reopened it. After that tracking was perfect. 20s exposures with no frames dropped, for hours.
I can see that others have reported similar problems. I recommend closing the arm and reopening it.

i-like

Tonight’s test shots with the S30 Pro in EQ mode showed terrible trailing. I remembered this post here and followed your recommendation to close and reopen the arm. After that, perfect tracking. No more trailing and/or dropped frames with 10, 20, 30 and 60sec subs in any direction in the sky. The closing of the arm seems to reset something in the firmware. Thank you for the hint!

3AC9bx99

Such a simple fix, worth a shot at.

55u56qWD

It seems to me that the software does not fully recognise EQ mode after doing polar alignment (I do it twice, to be accurate) unless I then close and reopen the arm.

55u56qWD

Another observation that I think may be related:
When I start the night by doing the polar alignment my Seestar S30 Pro goes the long way round to point to the zenith. It rotates by about 300 degrees instead of taking the shorter 60 degree route rotating the other way round. I get the alignment OK. Then, as described before, I close the arm and reopen it to get reliable tracking. The point is that the reopened arm then does the shorter rotation to get to targets near the zenith. Could this be significant?
(My ordinary S30 does the same thing.)

i-like

55u56qWD Yesterday, during another extensive test I noticed that closing the arm delivers perfect tracking only if NOT followed by ‘open arm’. The sequence close arm -> open arm and then ‘goto object’ caused inconsistent tracking with my device. It produced trailing and lots of ignored frames. I used goto object immediately after close arm, this worked fine.

The results so far, in EQ mode:
(1) polar alignment -> goto object -> tracking unreliable
(2) polar alignment -> close arm -> open arm -> goto object -> tracking unreliable
(3) polar alignment -> close arm -> goto object -> perfect tracking

Seestar_S50

Yet another Software / Firmware issue that should have been pick up during testing - Add that one to the ever growing list of problems with the latest release. My S30 Pro has been returned for a refund, haven't had a single night in the month I've had the S30 Pro of useable data, no images whether keeping due to star traling - out of focus - tracking issues.
Will support ever listen to the users and get it right, they need to concentrate on the core issues and stop trying to please everyone asking for this or that add-on for external apps. Fix the main issue first

SteveD

Seestar_S50 So my issues returned and I'm back to 95% + rejected frames (totally unusable). After the 5 week back and forth with ZWO customer service (I use that term lightly) they just told me today to get with the Vendor that I bought it from. So if anyone is planning on asking for an RMA. They will ask you for a copy of your receipt, hang weights off the end, check your compass cal, check your PA, check wind impact etc and check your EQ vs Alt/AZ. They will ask you one at a time to stretch the conversation across many days.

Nasa-HSIA

i-like Could you kindly tell me how do you define "perfect tracking"? Is the number rejected frame 0? What is the declination of your target? Thanks.

3AC9bx99

i-like Likewise need to know what the declination of the object is, what exposure time are you using and how many frames are being rejected as a percentage of total.

55u56qWD

I keep a record of the efficiency for each target, in terms of the percentage of elapsed time that the stacked exposures account for. Using my close/reopen arm procedure I have been consistently getting around 75% efficiency for 20s frames. That is quite reasonable if every 5th frame is a dark one.
I don't think the declination of the target is relevant at all. It makes no difference to the efficiency.

3AC9bx99

55u56qWD I don't follow your efficiency calculation. I was looking more at if you know the total number of frames taken how many were successfully stacked by the Seestar. I thought that after every 5th frame a dither took place not a dark frame. The declination drift can have a significant effect on the frame capture rate. The lower the declination of an object i.e the closer it is to the celestial horizon, the greater the rate of the drift, so you get more star trailing and therefore a higher frame rejection rate. This can be reduced by using lower exposure times.

55u56qWD

3AC9bx99
I see what you mean about declinations nearer the equator but I have not noticed any difference.
It does seem likely that offsets are done while dark frames are being taken.