Balance or Alignment Problems? Astrophotos

[Lonnie]

Had a litlle bit of a fiddle again last night I had to add 3kg of weights to counterbalance scope. Unfortunately I dont think the mount likes this much weight as occasionally in certain angles it was making very light tapping noise, but once I removed 1 1/4 kg noise went away but then wasnt balanced correctly was top heavy. I took a couple unguided and guided photos
attached M42 was 1 minute 400 iso guided and the star was 800iso 1 minute
unguided. Andromeda was iso 800 3 minutes guided . I notice the outer edge stars are sort of aiming semi circular , thats probably another problem but hey gives me more things to work on.
Also did drift alignment again in 10 minute increments didnt get any drift I must say I dont use reticle eyepiece I am using live view on back of camera and have star dead centre in small focus square of Nikons live view.
Checked guide camera by using PHD goto tools section and manually moved guiding and I could here it doing its small adjustment.
Might try stacking 10 1 minute shots see if that changes anything.

[Ian Robinson]

Originally Posted by Lonnie

Hi Barry
When I am using the scope visually and I touch the scope it does vibrate for
about 5 to 10 seconds before it settles down steady again.
So what I do when taking photos is get it guiding using PHD (maybe I should try a different guide program) I get everything setup and then step outside my Observatory and trigger the camera via a cordless remote which lifts the mirror up and delays exposure for further 2 seconds to stop any additional vibration this is a function of the Nikon D300.
My balance is bad I know when I have scope horizontal and release clutch it sits still , but If I raise OTA straight up to meridian or really any higher than say 60 degrees its swings over itself. I am not sure if I should be adjusting weight everytime I move to new object I am photographing or just get scope reasonably balanced overall?
Below are some more photos of setup maybe someone has a better idea by seeing it.

Do yourself a favour and get rid of the guidescope altogether and buy a good offaxis guider .

This will sort any flexure problems and make your outfit easy to control.

[Lonnie]

Ian
I am going to try my clubs off axis guider tonight on my setup.
Should have borrowed it a few months ago when they told me to give
it a go.
I figure I have nothing to lose and probably save on counterweight's
and flexure.
Will post picture hope it stays clear tonight.

Originally Posted by Ian Robinson

Do yourself a favour and get rid of the guidescope altogether and buy a good offaxis guider .

This will sort any flexure problems and make your outfit easy to control.

[Lonnie]

No luck with the off axis guider.
Couldnt get focus on the guide camera. I was presuming the guide camera would fit in top of off axis guider and main nikon camera worked like normal thru
the main part of the off axis guider.
The guide camera needed to get in closer for focus but was impossible.
I did take one unguided 1 min 400 iso exposures of m42 attached.

Originally Posted by Lonnie

Ian
I am going to try my clubs off axis guider tonight on my setup.
Should have borrowed it a few months ago when they told me to give
it a go.
I figure I have nothing to lose and probably save on counterweight's
and flexure.
Will post picture hope it stays clear tonight.

[OzRob (Rob)]

Originally Posted by bmitchell82

i wouldn't run the PEC, it will be battling the guide. 1 second iterations is fine. you have to find what is causing phd to loose your star. have a good read of craig starks user guide for phd (stark labs) that should give you some insight.

Brendan, maybe this is a stupid question but how would PEC cause a problem with guiding? Surely PEC increases the accuracy of tracking so that there will be less work for the guiding software to do and less corrections.

[bmitchell82 (Brendan)]

not a stupid question. think of it this way, if your pec says slow down the mount by x amount and the guider at the same time says speed up by 3x. your guider is fighting the pec. i may be wrong but yeah thats how logic directs me in that area. if your guide iterations are in the order of 5 - 10 seconds pec will be benificial. but why would you do that when 1 second makes sure the star is bang on

[OzRob (Rob)]

Originally Posted by bmitchell82

not a stupid question. think of it this way, if your pec says slow down the mount by x amount and the guider at the same time says speed up by 3x. your guider is fighting the pec. i may be wrong but yeah thats how logic directs me in that area. if your guide iterations are in the order of 5 - 10 seconds pec will be benificial. but why would you do that when 1 second makes sure the star is bang on

If your thinking is correct I would like to know why experienced imagers (eg Jase uses PEMPro) use PEC software. The reason that I ask is that I am going to give PEMPro a go. Sorry for going off topic a little.

[bmitchell82 (Brendan)]

i cant vouch for jase, but if your mount is polar aligned well. then guiding will kill 95% of your errors out and paying good money for a good mount will capture the 4.9% your guiding doesn't! it also depends on which port is accepting the guide movements. mine uses pulse guiding though eqmod which clashes with PEC.

Good mount + Guiding = round stars

insane mount + PEC = round stars

the differnece in price is big.!