guiding log from last session

[Bottletopburly]

So finally the other week guiding seemed to be heading in the right direction but what does the log tell me ,anything i need to watch and alter ?

 

 

Edited November 30, 2018 by Bottletopburly

[Tweedledee]

Whoa!!! This is going to be a daunting learning curve for me. ?

 

Might that possibly be a periodic error or am I talking complete rubbish?

 

Interesting stuff. ?

[Bottletopburly]

5 minutes ago, Tweedledee said:

Whoa!!! This is going to be a daunting learning curve for me. ?

 

Might that possibly be a periodic error or am I talking complete rubbish?

 

Interesting stuff. ?

the spikes are Dithers pete that i do know 

[Tweedledee]

Yep, I'm talking complete rubbish!

 

Dithering is a bad habit of mine. ?

 

Will have to consult google about that. ?

[red dwalf]

nothing wrong with dithering, you should dither if you can, to be honest i never look at these logs, get good polar alignment, set the guide scope and guide camera details properly into PHD brain and let it do it`s thin when you calibrate before starting an imaging run, seeing conditions make a difference to the graph, cable drag can affect it too so make sure these are as good as you can get them, if the stars look round you have done it all correctly. 

[+Bino-viewer]

Error : mods please remove this bit.

Edited December 1, 2018 by Bino-viewer

[+Bino-viewer]

14 hours ago, Tweedledee said:

Whoa!!! This is going to be a daunting learning curve for me. ?

 

 

And me as well.

My wife accuses me of dithering from time to time ?

I'm making slow progress putting my own imaging rig together and hope to try it out fairly soon

once this comet puts in an appearance.

There won't be any dithering happening though. Nor Polar alignment.

But they may be plenty of binning.....via the delete button.

[Tweedledee]

2 minutes ago, Bino-viewer said:

And me as well.

My wife accuses me of dithering from time to time ?

I'm making slow progress putting my own imaging rig together and hope to try it out fairly soon

once this comet puts in an appearance.

There won't be any dithering happening though. Nor Polar alignment.

But they may be plenty of binning.....via the delete button.

Just like me Rob. Trying to find an easy way, just to get some sort of image. Can I do it in altaz? Can I do very short subs without guiding? Can't I just point and shoot?? ?

 

It is probably going to be a lot of hard work! 

 

[+Bino-viewer]

I intend to start with around 30 x 30 second subs, and then attempt some sort of stacking with them.

350mm focal length. 200mm if its a better option.

[Bottletopburly]

44 minutes ago, Tweedledee said:

Just like me Rob. Trying to find an easy way, just to get some sort of image. Can I do it in altaz? Can I do very short subs without guiding? Can't I just point and shoot?? ?

 

It is probably going to be a lot of hard work! 

 

Yes you don’t need to guide, under a minute and near PA should be fine , guiding just allows longer subs , dithering saves time taking darks ? 

[Tweedledee]

6 hours ago, Bottletopburly said:

Yes you don’t need to guide, under a minute and near PA should be fine , guiding just allows longer subs , dithering saves time taking darks ? 

I like the idea of dithering. I'm pretty good at it already in principle. ?

[Bottletopburly]

1 minute ago, Tweedledee said:

I like the idea of dithering. I'm pretty good at it already in principle. ?

on my uranus sub you can see a white border on two sides thats the dithering distance 

[Tweedledee]

Hmmm, been googling. Floyd–Steinberg dithering. Seen what it does to a cat, but still trying to get my head around what it does on the stars. Looking at your white border, is the distance different horizontally and vertically? Any info gratefully received. ?

[Bottletopburly]

2 minutes ago, Tweedledee said:

Hmmm, been googling. Floyd–Steinberg dithering. Seen what it does to a cat, but still trying to get my head around what it does on the stars. Looking at your white border, is the distance different horizontally and vertically? Any info gratefully received. ?

your mount moves a couple of pixels ,after each image sort of smudges the noise out  ,more info here pete   https://www.skyandtelescope.com/astronomy-blogs/astrophotography-jerry-lodriguss/why-how-dither-astro-images/

[Tweedledee]

13 minutes ago, Bottletopburly said:

your mount moves a couple of pixels ,after each image sort of smudges the noise out  ,more info here pete   https://www.skyandtelescope.com/astronomy-blogs/astrophotography-jerry-lodriguss/why-how-dither-astro-images/

Wow! Light bulb moment!! ? ?

 

That certainly explains it nicely, thanks very much David. ?

 

Got that bookmarked for future revision.

 

This dithering certainly seems like a magic bullet. I like algorithms and don't like hot pixels and artefacts.

 

Brilliant, cheers. ?

[Bottletopburly]

2 minutes ago, Tweedledee said:

Wow! Light bulb moment!! ? ?

 

That certainly explains it nicely, thanks very much David. ?

 

Got that bookmarked for future revision.

 

This dithering certainly seems like a magic bullet. I like algorithms and don't like hot pixels and artefacts.

 

Brilliant, cheers. ?

? that just leaves flats and bias frames to do which are quick to do at end of session

[Tweedledee]

Yep, flats and bias frames - need to do some more studying. ?

[Bottletopburly]

10 minutes ago, Tweedledee said:

Yep, flats and bias frames - need to do some more studying. ?

flats take out the dust bunnies , Bias frames are used to remove the readout signal from you camera sensor,  though when dithering, general consensus is to load bias frames as darks in DSS.

http://www.rawastrodata.com/pages/typesofimages.html

Edited December 1, 2018 by Bottletopburly

[Tweedledee]

3 minutes ago, Bottletopburly said:

flats take out the dust bunnies , Bias frames are used to remove the readout signal from you camera sensor,  though when dithering, general consensus is to load bias frames as darks in DSS.

http://www.rawastrodata.com/pages/typesofimages.html

Excellent stuff thanks David. Another new lesson bookmarked in my AP file. Exactly how I like it on a Saturday night, interspersed with whisky and ginger and the X Factor final. ? ?

[Bottletopburly]

@Tweedledee more homework Pete http://www.stark-labs.com/craig/resources/Articles-&-Reviews/ImprovedGuiding_RTMC.pdf pretty much explains guiding from the creator of phd 

[Tweedledee]

37 minutes ago, Bottletopburly said:

@Tweedledee more homework Pete http://www.stark-labs.com/craig/resources/Articles-&-Reviews/ImprovedGuiding_RTMC.pdf pretty much explains guiding from the creator of phd 

Thanks for that David, your help is really appreciated, keep these coming please and I will devour and digest everything with interest. ?

Had a quick 10 minute run through and found a lot of useful stuff in that pdf. Will have a longer study later. The bullet point method is great up to a point, but in some areas, I feel the images, screenshots and diagrams especially could do with a bit more explanatory text. But maybe that is the real homework bit, I'll have to do some extra googling/reading to fill in those blanks.

Good stuff, thanks. I know there are a few others on EMS that like me are at the kindergarten stage of AP who will be learning from this as well ?

Edited December 3, 2018 by Tweedledee

[8472]

I'm totally inexperienced with PHD2, but looking at your log, have you made a dark library, David? Apparently this will deal with hot pixels and the like, and make guide star detection easier.

 

We seem to have the same guide camera, and your exposure length looks good (not too short and not "chasing the seeing").

 

Also I've no idea if you did beforehand, but running the Guiding Assistant will generally point you in the right direction, setup-wise.

 

On my last guided run (a botched Flaming Star Nebula attempt), my Log viewer tells me my Star Adventurer had a RA drift of +6.16"/min and a Dec drift of +0.12"/min. For some reason, this was only good enough for 180s subs (I didn't run the Guiding Assistant), so I'm guessing my Aggression (0.700), Hysteresis (0.100) and MinMo (0.190) values were not optimised, as my Dec, and indeed Polar alignment seemed pretty good. YMMV.

 

As i say, I'm brand new to this so please feel free to disregard everything I said. ?

 

Kev

[Bottletopburly]

4 hours ago, 8472 said:

I'm totally inexperienced with PHD2, but looking at your log, have you made a dark library, David? Apparently this will deal with hot pixels and the like, and make guide star detection easier.

 

We seem to have the same guide camera, and your exposure length looks good (not too short and not "chasing the seeing").

 

Also I've no idea if you did beforehand, but running the Guiding Assistant will generally point you in the right direction, setup-wise.

 

On my last guided run (a botched Flaming Star Nebula attempt), my Log viewer tells me my Star Adventurer had a RA drift of +6.16"/min and a Dec drift of +0.12"/min. For some reason, this was only good enough for 180s subs (I didn't run the Guiding Assistant), so I'm guessing my Aggression (0.700), Hysteresis (0.100) and MinMo (0.190) values were not optimised, as my Dec, and indeed Polar alignment seemed pretty good. YMMV.

 

As i say, I'm brand new to this so please feel free to disregard everything I said. ?

 

Kev

Guiding assistant ran , darks library done too ? I seem to be on the right path few tweaks here and there maybe  , it’s all  a learning curve ?. 

[Bottletopburly]

6 hours ago, 8472 said:

I'm totally inexperienced with PHD2, but looking at your log, have you made a dark library, David? Apparently this will deal with hot pixels and the like, and make guide star detection easier.

 

We seem to have the same guide camera, and your exposure length looks good (not too short and not "chasing the seeing").

 

Also I've no idea if you did beforehand, but running the Guiding Assistant will generally point you in the right direction, setup-wise.

 

On my last guided run (a botched Flaming Star Nebula attempt), my Log viewer tells me my Star Adventurer had a RA drift of +6.16"/min and a Dec drift of +0.12"/min. For some reason, this was only good enough for 180s subs (I didn't run the Guiding Assistant), so I'm guessing my Aggression (0.700), Hysteresis (0.100) and MinMo (0.190) values were not optimised, as my Dec, and indeed Polar alignment seemed pretty good. YMMV.

 

As i say, I'm brand new to this so please feel free to disregard everything I said. ?

 

Kev

ah i stand corrected seems i did'nt load darks library ,DOH

[Bottletopburly]

I did find an interesting comment on cloudy nights , if you have star mass ticked it gives you a yellow line at top of graph in log viewer can’t see the option in phd2, chap says he has it enabled and uses it as a guide for transparency,  spike in good transparency usually precedes incoming cloud ☁️  He found.