Elongated Stars?

[EzyStyles]

Hi Guys,

First night testing the new scope with the DSI 2. Although the sky wasn't clear but i was able to shoot through the thin clouds. I've noticed the stars are elongated now?

I was thinking is it because:

1) Bad polar alignment
2) Bad collimation (using a laser)
3) Something got to do with the 2" focuser?

However at the start, I thought it might be tracking error but it seems the stars are staying dead centre on the screen. I have attached a live screenshot so you guys know what im talking about :P

thanks.

[ving]

your stars seem to be doubled up... what causes that? doesnt a hartmans mask do that?

[JohnG]

Hi Eric

My

[EzyStyles]

yep thats it. the stars are doubling up. i have no idea why they are. the hartman mask was removed from the live image.

[JohnG]

Hi Eric

My first guess would be polar

[JohnG]

Hi Eric

My first guess would be polar alignment, did you do a Drift

[EzyStyles]

thanks john. it was just a visual alignment from the polar scope matching the Octan's region. but would bad polar alignment causes the stars to double up?

[JohnG]

Hi Eric

My first guess would be polar alignment, did you do a Drift Align first? second guess would be possibly that your tracking rate has been changed, not on Solar or Lunar is it?

Cheers

JohnG

[Dennis]

I've had a similar (double star) effect from the ker-klunk of the mirror on my DSLR flipping up, as I do not have a mirror lock, but I see you were using the DSI - hmm?

Cheers

Dennis

[JohnG]

Gee don't know what happened there, strange.

JohnG

[ving]

thats the strangest thing i've seen today john! :confuse3:

[janoskiss]

Eric, if you get bored while the camera is collecting data, go and make yourself a nice hot cup of tea or coffee, but please refrain from kicking the tripod! :P :D

[EzyStyles]

lol Steve. no no its not wind or tripod movement, although the screenshot i have attached is in capture mode, the stars doubles up on live mode as well. I have another go with it tonight (finally some clear melb weather) , redo polar alignment (not drift as there are trees near the horizon) but will pop into this post to see what else might be. Another thing forgot to mention, scope is balanced on EQ6.

thanks.

[ving]

you are a strange fella steve! ;)

[rmcpb]

Eric, I seem to remember reading somewhere about that problem being generated by the tracking gears not being perfect and it effectively jumps periodically. I have no experience in imaging while tracking so take this suggestion as naive but I remember it somewhere.

Cheers

[mick pinner]

hi Eric, going on past experience it will be a bump in the gear drive, not meshing properly or incorrectly balanced and not loading up the gears.
l had exactly the same problem about a month ago, reweighted the left fork arm and no more double stars.

[Striker]

Make sure the balance is little over weight on the east side.

Whilst imaging to the east of the meridian....have a little more weight balance towards your counter weight set.

Whilst imaging to the West of the meridian...have a little more weight balanced to the scope..making the scope itselff a bit top heavy....if it is too well balanced you will get a rock between gears causing double stars with a skinny line between them both.

Hope it works Eric.

[etscumbag]

G'day Eric and Group,
I don't know the drive your using however with some drives if you have 3 or 4 drive speeds you use for slewing and and forget to go back to tracking speed the motors will run a little faster.Possibly similar to idling in 4th gear in your car instead of 1st gear.
ET:hi:

[EzyStyles]

thanks for your help guys. @ mike, just rechecked the live image tonight, they are not doubling up but elongated.
@ tony: thanks ive tried adjusting the counter weights sliding up and down still no go :(

thanks for your help anyway guys. I figure it out somehow. much appreciated.