Would Drizzle help in my case

[lensman57]

Hi,

Right now I am imaging @ 3.35 arcsec/pix, would a 2X drizzle at the stacking stage improve the scale?

Regards,

A.G

[andrewluck]

This isn't too encouraging: http://deepskystacker.wikispaces.com/should+I+use+Drizzle+stacking%3F

You could always try it though and see if it works.

Cheers

Andrew

[JamesF]

In theory, drizzle can't do anything to help if you're oversampling already.  That is, if the resolution of your camera exceeds the resolution of your telescope.  Craig Stark has a paper explaining drizzle and why this should be so.  I believe Emil Kraaikamp, author of AS!2, also says there's no point using drizzle if you're oversampling.

However...

Quite a few people seem to feel that using drizzle on planetary images brings something more out of the image.  I wonder if this is because it effectively causes a "smart resize" that makes small detail more readily visible, but I really have no idea.

As you've not said whether you're talking about DSO imaging or planetary imaging I'd guess from your image scale that you're talking about DSO imaging in which case I'd go with Craig Stark's opinion and ignore the planetary stuff.

I think, though I'm far from certain, that if your guiding is really hot then you may need to dither guide to get any real benefit from drizzle.

James

[JamesF]

Oh, Craig Stark's article is the first 2006 one here: http://www.stark-labs.com/craig/articles/articles.html

James

[lensman57]

Oh, Craig Stark's article is the first 2006 one here: http://www.stark-labs.com/craig/articles/articles.html

James

Hi James,

Many thanks for your reply, yes I was talking about DSO and the at time I was using a QHY8 on a 80mm Apo triplet. the guiding was great with 900s subs, The FF was not at optimal distance though and I have been dithering ( high dither ) with both DSLR and CCD. I will read Craig Stark's article as suggested.

Regards,

A.G

[Physicist13]

Without knowing ur scope details it's hard to know if you under or over sampling. But at 3 arc sec thts likely to be under sampling in which case drizzle would help. Drizzle should be done during tracking however, post capture drizzle is somewhat different and not as good, but easy to see if using it mks things better or worse! Ie just try!!

[JamesF]

Without knowing ur scope details it's hard to know if you under or over sampling. But at 3 arc sec thts likely to be under sampling in which case drizzle would help. Drizzle should be done during tracking however, post capture drizzle is somewhat different and not as good, but easy to see if using it mks things better or worse! Ie just try!!

You don't mean dither whilst guiding?

James

[Physicist13]

Sry, yes dither then drizzle in the stacking!

[lensman57]

Thank you all for yout kind comments and posts. At the moment the question has become hypothetical as for some reason the stack produced by DSS is unusable , PI does a much better job but can not drizzle. Perhaps at some point I would try Nebulasity.

Regards,

A.G

[Physicist13]

drizzle in PI soon )

[lensman57]

drizzle in PI soon )

Hopeful for it to be very  soon too, this was the first time that the stack of 14X900s subs in DSS was totally unusable as if a heavy stretch was applied during stacking, most peculiar situation.

A.G

[Physicist13]

sounds bizarre??...want to post a sub and the stack? or link to??

P

PS Juan says by Summer....it will have pix rejection inc which will make it more powerful than just drizzle.