Eta in the eyes of a RedCat

[h0ughy (David)]

taken tonight before the clouds moved in its only a short 2 hours worth of this most imaged region of stars and gas, just waiting for the day it goes boom. Taken with a puddy cat, i thought i saw Eta through the eyes of a 51mm objective with a canon eos Ra, iso 800 with a multi spectrum filter. its sampling what could be a great field of view.

stacked in DSS and processed in pixinsight then PS.

[RB (Andrew)]

Nice and sharp.
Good colours.
Can't wait for you to get more on this one.

[xelasnave]

Excellent David I would love to see a high res but I get the idea..I have been trying to talk myself out of buying a Red cat all week ( and goto Startracker) and your photos are not helping me avoiding a purchase.

It seems to be a very flat field.

They seem like a very good unit.

Alex

[JA]

Originally Posted by h0ughy

taken tonight before the clouds moved in its only a short 2 hours worth of this most imaged region of stars and gas,

It looks great in detail and colour.
I'm always curious: Can I ask what sort of subexposure duration you used?

Best
JA

[h0ughy (David)]

Originally Posted by JA

It looks great in detail and colour.
I'm always curious: Can I ask what sort of subexposure duration you used?

Best
JA

I start with 1 second, 5 second, 10 second 30 seconds, 60 seconds 120 seconds and 180 seconds with 20 images of each then stack it all in deep sky stacker and the process in pixinsight then maybe Photoshop for a tweak if needed but that's mainly for resizing after pixinsight.

I use a multispectrum filter on the Canon Eos Ra . My light pollution is hideous and only use iso 800 or 400 if the moon is up

[h0ughy (David)]

Originally Posted by xelasnave

Excellent David I would love to see a high res but I get the idea..I have been trying to talk myself out of buying a Red cat all week ( and goto Startracker) and your photos are not helping me avoiding a purchase.

It seems to be a very flat field.

They seem like a very good unit.

Alex

That Redcat would be ferral at your place

[h0ughy (David)]

Originally Posted by RB

Nice and sharp.
Good colours.
Can't wait for you to get more on this one.

Thanks RB

[JA]

Thanks for the info H. It's useful as a reference for DSLR based imaging of how much H-Alpha is picked up given that your Ra is Canon factory manufactured/"modified" for extended H-Alpha.

Best
JA

[h0ughy (David)]

Originally Posted by JA

Thanks for the info H. It's useful as a reference for DSLR based imaging of how much H-Alpha is picked up given that your Ra is Canon factory manufactured/"modified" for extended H-Alpha.

Best
JA

Well my theory is that the shorter shots get the star colours and the longer ones the nebulae and dust if you go long enough

[multiweb (Marc)]

Really nice fov. Looks like you'll have a lot of fun with that rig.

[h0ughy (David)]

Originally Posted by multiweb

Really nice fov. Looks like you'll have a lot of fun with that rig.

Well I hope so

[peter_4059 (Peter)]

Dave, how do you combine the different exposures? Are you layering in ps?

[h0ughy (David)]

Originally Posted by peter_4059

Dave, how do you combine the different exposures? Are you layering in ps?

Being a lazy astronomer a just shove it all in deepsky stacker and let it stack everything . The save the TIFF file somewhere and run pixinsight. I clip rotate etc with screen transfer, then perform a sin by working on the histogram to align the channels. Then after that boost the colour saturation maybe noise reduction then a few other things and save

[peter_4059 (Peter)]

Which DSS rejection algorithm are you using?

[h0ughy (David)]

Originally Posted by peter_4059

Which DSS rejection algorithm are you using?

Good question, will have to find out.

[RB (Andrew)]

Originally Posted by h0ughy

Good question, will have to find out.

You’re using Kappa-Sigma Clipping Dave.

[peter_4059 (Peter)]

Originally Posted by RB

You’re using Kappa-Sigma Clipping Dave.

Just wondering if that rejection algo ends up clipping the longest and shortest exposures such that they do not get included in the stack? Shame to spend time capturing subs just to have the software dump them.

[h0ughy (David)]

Originally Posted by peter_4059

Just wondering if that rejection algo ends up clipping the longest and shortest exposures such that they do not get included in the stack? Shame to spend time capturing subs just to have the software dump them.

I thought it was on image quality?

[RB (Andrew)]

Originally Posted by peter_4059

Just wondering if that rejection algo ends up clipping the longest and shortest exposures such that they do not get included in the stack? Shame to spend time capturing subs just to have the software dump them.

Originally Posted by h0ughy

I thought it was on image quality?

Pete, I’m no expert by any stretch of the imagination, but I think David is right.
I’ve used Kappa-Sigma at times and it’s given me the better result.
Other times I’ve used Median Kappa Sigma and it’s given me the better result.
I’ve even gone Average or Median.
I find it depends on the data you’re working with.

It’s been such a long time since I’ve done AP though, so that’s the best I can advise you on.

Sometimes you get a better result, rejecting some of the data.
Well, letting the software reject it for you, actually.

RB

[peter_4059 (Peter)]

Worth reading the manual....
http://deepskystacker.free.fr/english/technical.htm