eggy stars at 60secs, ok before on 900, why?

[tony]

I think I've been hit by a guiding or balance issue, but, baring in mind nothing has changed, nothing been touched or adjusted, no snagging cables, camera not loose, but I get eggy stars even at 60 secs, just like I've done a longer sub unguided. even put the finderguider back on in case it was an issue with the st80, a little better but still there when I get to about 300 secs.
really puzzling this.

its only a screengrab but this is 60 secs

this is 8 x 900 on ic410 before

and this is the result from the previous 2 sessions this past week on 7th and 9th where its been ok.

I am obsy based so its not like i'm setting up each night, as I've said above, nothing been touched or caught up, just really puzzled as to whats gone wrong.

I know the 60 sec sub is a different target but the monkey and tadpoles are roughly in the same area of sky and shouldn't make any difference, but it got worse on the monkey.

was thinking of a stripdown later and put it all back together again and doublecheck everything.

hoping that someone may have had the same problem and can point me in the right direction.

[tony]

donut, just realised i'm in the wrong section  if a mod could put it the right one please

[ollypenrice]

Unfortunately, having guiding that works one night and not the next, without apparent reason, is perfectly normal. I didn't say it wasn't infuriating, though!

The trails seem to go in almost the same direction, though not entirely. This means that polar alignment could be at the bottom of it but might not be. (Great!!) To test guiding, always have your camera aligned along RA and Dec so you can unravel which is which. In fact being aligned like this, in landscape or portrait, is a really good idea if your target allows it. Data can be added from other sessions far more easily. Just take a 5 sec sb while slewing slowly out and back to see how the trails align.

So do we know which axis is trailed in the problem image?

Olly

[tony]

Unfortunately, having guiding that works one night and not the next, without apparent reason, is perfectly normal. I didn't say it wasn't infuriating, though!

The trails seem to go in almost the same direction, though not entirely. This means that polar alignment could be at the bottom of it but might not be. (Great!!) To test guiding, always have your camera aligned along RA and Dec so you can unravel which is which. In fact being aligned like this, in landscape or portrait, is a really good idea if your target allows it. Data can be added from other sessions far more easily. Just take a 5 sec sb while slewing slowly out and back to see how the trails align.

So do we know which axis is trailed in the problem image?

Olly

thanks olly.

no we don't know which axis has trailed,, I will be taking everything down and putting back on so to check everything as I go, but I will check my polar alignment before I do that, just in case, you never know. I orientate my main cam but never bothered with the guidecam, just left it as it was when I put it on,something i'll do this time though, it makes sense.

one other thing I will mention is I used to guide with a finderguider, when we had that storm forecast last year I took the mount and scope indoors just in case, when I put it back in the obsy I then fitted my st80 which i'm using now. its been ok up until last night, so was going to put the finder back on and see how things go as it guided perfect before, if its ok then i'll put the st on and see what happens.