GUIDE STARS CLOUDS AND MEMORIES

[MarkH]

Not reminiscing in the title but more of a solution to a problem that I can foresee. I'm just getting set up with guiding stuff, using orion solar system imager through my finder scope. Now, I need to use my finder scope synchronised with the main scope to align the wedge with the celestial pole so it would be nice to keep it synchronised. Next I want to use the finder scope as a guider, now with the guiding software connected can I still use goto facilities to find my target if so that may be a solution to the next issue. So there i am sitting taking a set of subs when a nice big cloud comes along and blots out my guide star, (can you see where this is going). when the cloud passes I've lost my guide star and my target. What techniques do people use to reacquire the guide star? Is the goto option possible and if so is it accurate enough? or is it a case of memorising the viewfinder and estimating the required shift ? or a star map and torch? You can see how new to all this i am can't you. Oh and any tips for cleaning optics Do's and don'ts. Thank you people.

[Mac]

I wouldnt worry,
you will find once the cloud rolls in, its in for good. 

Seriously, there should not be too much displacement of the guide star
unless your talking ages for the cloud to pass,
most software should be able to repick up the guide star,

If not, then you can move the mount untill the guide star is back in view,
but if its off by that amount after such a short time, then your alignment is out.

Mac.

[The Thing]

If using PHD2 set Star Mass Tolerance to On and set a figure that is less than 100(%). This means that if the guide stars' notional 'mass' changes outside the tolerance, PHD stops trying to guide - if it continues it will move the mount around in a bit of a random dance. When the cloud clears and the star 'mass' goes above the threshold  guiding restarts. I use 90% in London.

If you have the Search Region set to a size big enough to accommodate the likely drift and mechanical movement likely to occur given the accuracy of your polar alignment and quality of your mount PHD can pick up the star and resume guiding. Note the big if! It is best to choose guide stars without close companions to make this more likely!

I don't remember how Metaguide handles this scenario but I know it's quite clever...

[MarkH]

If using PHD2 set Star Mass Tolerance to On and set a figure that is less than 100(%). This means that if the guide stars' notional 'mass' changes outside the tolerance, PHD stops trying to guide - if it continues it will move the mount around in a bit of a random dance. When the cloud clears and the star 'mass' goes above the threshold  guiding restarts. I use 90% in London.

If you have the Search Region set to a size big enough to accommodate the likely drift and mechanical movement likely to occur given the accuracy of your polar alignment and quality of your mount PHD can pick up the star and resume guiding. Note the big if! It is best to choose guide stars without close companions to make this more likely!

I don't remember how Metaguide handles this scenario but I know it's quite clever...

Where do I find that button on my stylophone then ? Sorry been on  the vino

[doug]

 

[MarkH]

I'm quite scared of attempting this I'm sure I'm going to be sitting there for hours pulling my hair out, oops I don't have any