Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: MarkS on Oct 11, 2013, 00:06:04

Title: Double Cluster in Perseus
Post by: MarkS on Oct 11, 2013, 00:06:04
Taken from High Halden on Sunday night.

Canon 350D on Takahashi Epsilon 180ED with IDAS LP2 filter. 
Exposures: 30 x 5min at ISO 800 plus 8 x 1min at ISO 800.

(http://www.markshelley.co.uk/Astronomy/2013/doublecluster06102013_small.jpg)

See the larger version to do it justice:
http://www.markshelley.co.uk/Astronomy/2013/doublecluster06102013.jpg
Title: Re: Double Cluster in Perseus
Post by: mickw on Oct 11, 2013, 08:29:05
Nice one Mark
Title: Re: Double Cluster in Perseus
Post by: MarkS on Oct 11, 2013, 08:49:20
It was surprisingly difficult to process to make it "look right".  I think it lacks visual impact overall but if I make it any brighter then many of the stars merge into blobs, which does give an immediate impact but ends up looking rather ugly on close examination.  So I've erred somewhat on the side of caution where each star can be individually resolved but it does a bit toned down.  I prefer toned down!
Title: Re: Double Cluster in Perseus
Post by: RobertM on Oct 13, 2013, 21:03:27
Nice one Mark but being picky I think the processing has made the red stars appear a bit square.
Title: Re: Double Cluster in Perseus
Post by: MarkS on Oct 13, 2013, 21:36:20
Quote from: RobertM
Nice one Mark but being picky I think the processing has made the red stars appear a bit square.

Yes, It's the same old "square stars" feature of the Tak. I don't know why it's so pronounced on the red ones, though.
Title: Re: Double Cluster in Perseus
Post by: RobertM on Oct 14, 2013, 10:39:49
It's about time you got the Hyperstar out :)
Title: Re: Double Cluster in Perseus
Post by: MarkS on Oct 14, 2013, 11:35:59
Quote from: RobertM
It's about time you got the Hyperstar out :)

I know!  It'll happen soon.  Trouble is, at the moment I'm still fiddle faddling with the guiding on the EQ6 mount - I really want to be able to do some long focal length stuff this Winter.

Then I'll do a few Hyperstar vs Tak side by side comparisons.  I think that'll be very interesting.

The square stars is a processing issue - they're not obviously square on the RAW frames - it's the log stretch that causes it.  Actually I perform an asinh stretch but that more or less amounts to the same thing on those brighter stars.