How do you do drizzle in PixInsight?

[gregbradley]

I am wanting to try some drizzle integration for my undersampled Proline 16803 with the Honders.

Does it assume the subs were dithered first?

Is there a tutorial from PI about how to do it?

Greg.

[multiweb (Marc)]

This is one way to do it. You'll have to dither your data and shoot a lot of subs for it to work. The guys at Astrofest showed me how to do it but I need to practice a lot more before I'm efficient at it. It did wonders for my QHY8/FSQ combo that gives a shocking 3 arc sec per pixel image scale.

[gregbradley]

Thanks Marc.

I'll have to get the dither tool in PHD 2 working.

Greg.

[multiweb (Marc)]

Originally Posted by gregbradley

Thanks Marc.

I'll have to get the dither tool in PHD 2 working.

Greg.

Nebulosity works hand in hand with the PHD server. You can pause, then dither by X pixels and guide again when the threshold set is reached.

[Geoff45 (Geoff)]

Originally Posted by gregbradley

I am wanting to try some drizzle integration for my undersampled Proline 16803 with the Honders.

Does it assume the subs were dithered first?

Is there a tutorial from PI about how to do it?

Greg.

http://pixinsight.com/forum/index.php?topic=7151.0

[gregbradley]

Thanks Geoff.

Originally Posted by multiweb

Nebulosity works hand in hand with the PHD server. You can pause, then dither by X pixels and guide again when the threshold set is reached.

Marc do you use PHD2? Do you find it loses the guide star relatively easily? And then does not reacquire them (say when a small cloud goes overhead).


Greg.

[Garbz (Chris)]

It should only lose the guide star if the duration of the clouds or movement of the scope cause the guide star to drift outside the search radius. That radius I believe is adjustable but I don't have a computer with PHD2 in front of me so I can't confirm that right now. Accurate polar alignment should resolve that problem.

[RobF (Rob)]

Doing PI drizzle is 3 step and not immediately intuitive (of course!)
You have to do star alignment with option to produce data data.
Then integrate, again with update of drizzle data selected.
THEN using the drizzle integration to generate the final file.

Would be interested to hear how/if it benefits?
(With the FSQ/QHY9 around 2 arcsec/pixel seems very marginal benefit until super-zoomed in)

[Octane (Humayun)]

Rob,

I have had incredible results with my FSQ/STL at 3.51"/pixel.

I dither very, very heavily. To the tune of 15 steps per frame (automated by CCD Commander). I have to do this to get around the crack on the coverslip of my sensor.

H

[Rod771 (Rod)]

Originally Posted by gregbradley

Thanks Geoff.
Marc do you use PHD2? Do you find it loses the guide star relatively easily? And then does not reacquire them (say when a small cloud goes overhead).


Greg.

Hi Greg.

I use PHD 2. Not so long ago, I had troubles with it losing the guide star. In fact, it would lose it after every dither (and I had even enlarged the search field). I uninstalled the version that I had , then updated to the latest version. I haven't lost a star after a dither since.

[RobF (Rob)]

Originally Posted by Rod771

Hi Greg.

I use PHD 2. Not so long ago, I had troubles with it losing the guide star. In fact, it would lose it after every dither (and I had even enlarged the search fied). I uninstalled the version that I had , then updated to the latest version. I haven't lost a star after a dither since.

Yes, losing a guidestar from dither hasn't been a problem here either.

[RobF (Rob)]

Originally Posted by Octane

Rob,

I have had incredible results with my FSQ/STL at 3.51"/pixel.

I dither very, very heavily. To the tune of 15 steps per frame (automated by CCD Commander). I have to do this to get around the crack on the coverslip of my sensor.

H

Thanks for restoring my faith in drizzle Humayun! This makes perfect sense of course. All those gobsmacking FSQ/11000 images already out there can't be wrong. Effectively you're ending up with a perceived resolution only slightly larger than my QHY9/FSQ combo but with pretty much 4 times the field dammit!!

[multiweb (Marc)]

Originally Posted by gregbradley

Thanks Geoff.



Marc do you use PHD2? Do you find it loses the guide star relatively easily? And then does not reacquire them (say when a small cloud goes overhead).


Greg.

No I still use the old PHD, 1.14 I think. If you lose the star make the detection box bigger so it has less chances of drifting out of it. It defaults to 15px but you can increase it to 20/25px.