Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: JohnP on Sep 15, 2008, 12:19:49

Title: Another Pacman..
Post by: JohnP on Sep 15, 2008, 12:19:49
No where near as good as Robert's but was chuffed to be able to do 10min subs for the first time. Seeing was terrible - Full moon, moisture & loads of high cloud. Image represents approx 10X10min subs with atik 16ic through WO ZS66 + 13nm Ha filter.

(http://gallery.orpington-astronomy.org.uk/albums/userpics/10007/ngc281_test.jpg)


Cheers,  John
Title: Re: Another Pacman..
Post by: Daniel on Sep 15, 2008, 12:53:09
Excellent image considering the conditions, I tried a new heart nebula image a couple of days ago under the same conditions and it was a compete washout. also the fact you did 10 min subs under those conditions is amazing, not only was it a pain to guide that night, but I could only manage 3 mins before my images became too saturated with light polution.

Daniel
:O)
Title: Re: Another Pacman..
Post by: MarkS on Sep 15, 2008, 12:59:57
Well done John.  Incredible image for the conditions.   Can't believe you managed 10min subs.

I'm ashamed to say that I got my stuff half set up last night then decided the conditions were too bad even to do a full moon.

Or maybe you have the same cloud buster that Daniel uses?

Title: Re: Another Pacman..
Post by: RobertM on Sep 15, 2008, 13:36:27
Hi John,

That's pretty good considering the conditions.

As a suggestion, try doubling the size of each sub then stacking.  I find this helps in most situations and you end up with better detail in the final image.  I managed to get another 30mins of Ha but then the clouds rolled in, as they do then things are going well :(

Robert

Title: Re: Another Pacman..
Post by: JohnP on Sep 15, 2008, 14:05:07
Thks Daniel - I used a 13nm Ha filter which makes a lot of difference to exposure length even with a full moon - I just checked a raw & even with a 600sec exposure the ADU of brghtest star was approx 50,000 - which means I could have gone longer....

Thks Mark - forgot to say I took this on Saturday evening... It was a bit of a weird experience actually. I just bought myself a new tent for DSC's & tried it out in the garden on Saturday. It was such a nice afternoon that we lit the bbq & ended up sitting outside drinking red wine till it got a bit too cold. It was only then that I realized it was quite clear so I thought what the heck I'll get the astro kit it. All in all it felt like I was down at DSC... :-)

Thks Robert - I will try that - In fact I just noticed that AIP4Win has a X2 upsample button that you can press - it does it all automatically for me. Out of interest do you process the whole image at X2 & then sample back down for final display... or do you upsample - stack & then downsample before processing...?


Thks again,  John
Title: Re: Another Pacman..
Post by: RobertM on Sep 15, 2008, 15:26:31
I generally flatten, upsample, stack using SD Mask then apply DDP.  If you need a smaller picture then resample down but you may not need to.  I leave most of mine x2 now and process in PS.
Title: Re: Another Pacman..
Post by: MarkS on Sep 15, 2008, 16:22:26
Quote from: JohnPI took this on Saturday evening

Ah, Saturday.  I remember.  I had just finished a one day 570 mile round trip in a van taking both children plus most of their wordly possessions to their respective Universities.  Too tired to begin imaging ...
Title: Re: Another Pacman..
Post by: Fay on Sep 15, 2008, 17:07:53
Nice, John, looks like you are on course again!