Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: JohnP on Apr 10, 2007, 22:04:09

Title: m81 - tough object...!
Post by: JohnP on Apr 10, 2007, 22:04:09
This is a tough object from a light polluted location - the spiral arms are just starting to show.. would probably be loads better from Tuesnoad. Any way details are SC3 through ZS66 (it's a big galaxy) with CLS filter - sum of 140 X 30 secs..

Cheers,  John

(http://homepage.ntlworld.com/john.punnett/graphics/oas/m81_rev2_filtered.jpg)
Title: m81 - tough object...!
Post by: Ian on Apr 10, 2007, 23:21:28
Looking fine to me John. I had a frustrating night a couple of evening ago, my SC3 is waaay too noisy to be any use. It's now back on the bench, in bits :(

I think if it were my image I'd stretch the histogram a little more and blacken the star field. It has a "lumpy" appearance, is detail or processing do you think?
Title: m81 - tough object...!
Post by: JohnP on Apr 11, 2007, 07:51:58
Thanks Ian - I know what you mean about background - I had to process quite hard to get to this stage & I think blottchy background is result of artifacts etc. I'll give it another try & see if I can improve. I can stretch histogram more but the noise really increases...

I didn't know that you had an SC3 - have you had this long...? Did you do the mod yourself....? It's a great camera for the price although, with mine I'm starting to think 8-bit & lack of cooling is becoming a problem...

Cheers,  John
Title: m81 - tough object...!
Post by: Ian on Apr 11, 2007, 10:20:20
I built my SC3 way back when, in fact not long after Steve Chambers published the method. It also coincided with the arrival of my youngest Rhys who I'm blaming entirely for my lack of imaging and general observing...

It started out being mounted in a baked bean tin and worked very well. Only my lack of skill and time stopped me from getting good pics. However, I felt a little while ago that the camera could do with being cooled and putting into a decent enclosure so I rebuilt it. Having taken it apart I thought I'd do the amp off mod at the same time. Trouble is, I've now introduced so much noise the camera is unusable. Hence a pile of SC3 bits on my workbench. I think I'll try one more time before I buy an Atik or something.
Title: m81 - tough object...!
Post by: JohnP on Apr 11, 2007, 18:58:14
Yeah - I'm severly tempted with the Atik.... I think I will probably get one...

John