Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: Fay on May 27, 2014, 13:04:12

Title: Milky Way with Ioptron
Post by: Fay on May 27, 2014, 13:04:12
19x220secs, Ioptron, cls, Canon 600D, dks and flats, Sigma @ F3.5 10mm

light pollution at bottom and a tree

(https://farm4.staticflickr.com/3724/14284068922_bcae74127f_b.jpg)
Title: Re: Milky Way with Ioptron
Post by: MarkS on May 27, 2014, 20:11:51
The Ioptron Skytracker has certainly done its work well.

The image scale is really good.  You've done a good job of removing the light pollution but it might be a bit difficult to remove the remaining greenish background.

Did you take flats?

Mark
Title: Re: Milky Way with Ioptron
Post by: Fay on May 27, 2014, 20:15:23
Yes. It is not amazing but glad I tried the ioptron
Title: Re: Milky Way with Ioptron
Post by: RobertM on May 27, 2014, 20:15:55
That's certainly a wide field and a tricky one to process with that greenish hue.

Robert
Title: Re: Milky Way with Ioptron
Post by: Fay on May 27, 2014, 20:24:32
Well I was trying to tame the red and probably went too far
Title: Re: Milky Way with Ioptron
Post by: RobertM on May 28, 2014, 07:49:24
I blame the CLS but then I tend to do that.
Title: Re: Milky Way with Ioptron
Post by: Fay on May 28, 2014, 08:14:35
i need a lesson on star colour, yours are nice and blue
Title: Re: Milky Way with Ioptron
Post by: RobertM on May 28, 2014, 14:03:56
I didn't use a CLS 8)
Title: Re: Milky Way with Ioptron
Post by: Fay on May 28, 2014, 14:53:52
so is that definitely the problem?
Title: Re: Milky Way with Ioptron
Post by: MarkS on May 28, 2014, 19:43:44
In my experience a CLS filter will always ruin the colour balance of a Milky Way or constellation shot.
Title: Re: Milky Way with Ioptron
Post by: Fay on May 28, 2014, 19:50:56
It is ok not to use one with the shorter exposures. But difficult with the long ones. Will try without next time
Title: Re: Milky Way with Ioptron
Post by: RobertM on May 28, 2014, 21:19:34
The exposures on mine were 180s at ISO 1600 and f/4 so not much different and I didn't use any filter.

I also had a CLS clip filter and found I lost so much signal that I sold it.
Title: Re: Milky Way with Ioptron
Post by: Fay on May 29, 2014, 08:10:43
so why would the milky way shot look so different to this one, which looks ok? i think this was taken with 50mm lens, normal tripod, cls and a single image.

the milky way was taken with 10-20 sigma, on Ioptron,  and does have a lot of edge problems at 10mm.
I thought colours etc were corrected during stacking


(https://farm4.staticflickr.com/3737/14109584969_9e062b09f5_b.jpg)
Title: Re: Milky Way with Ioptron
Post by: MarkS on May 29, 2014, 22:24:25
Quote from: Fay
so why would the milky way shot look so different to this one, which looks ok? i think this was taken with 50mm lens, normal tripod, cls and a single image.

There's no Milky Way in your Orion shot so you can colour balance it without worrying about the Milky Way looking odd.  The problem with the CLS filter is that it literally chops out half the wavelengths in the spectrum. This means it causes problems with the subtle colour variations in the "cloudy" parts of the Milky Way.

The IDAS LPS-P2 gives a better colour balance and the IDAS LPS-D1 which I now use is even better.  But for the Milky Way I would still use no filter at all.  Without a filter there will be big problems with gradients but the end result is better.  I hope to show you an example later tonight  ;)
Title: Re: Milky Way with Ioptron
Post by: The Thing on May 30, 2014, 09:27:54
That's very nice Fay and no 'greenish hue' visible on my laptop.