This is my first pic I have posted here. I have not any clean-ups in PS or other but would like any advise the group has.
Image taken with FLT132 / STL11k Mono Camera.
4x5 minute guided exposures with each RGB in Melbourne Skies
Dark subtracted / stacked / aligned / colour overlayed in CCDsoft.
Big Dave, off to a good start indeed. You've got the gear, just need to spend more time in processing the data. Its a little hard to critic a small image, but from a distance the data acquisition looks on track. NGC2070 is a little burnt out. You need to get comfortable with PS levels and curves. While these are relatively simple tools of the trade, they play a major role. You can always try to get fancy with DDP, log stretches etc, but you'll probably find you will come back to levels and curves as they provide the most flexibility in what you are trying to convey in your image. Gutsy effort to start out with an RGB image. I stuck with luminance data for some time until I learnt the ropes (and I'm still learning). Look forward to seeing more of your work. Well done.
I have only had the 'gear' for a few months now, luckly just before the dollar crashed! Weather has not been kind lately so practice has been at a minimum. I get fustrated playing with the levels sometime when the target object looks ok, the stars around it go crappy. I think I need a little more practice!!!
I have been really working on focus, until now my focusing has needed improvment. I thought these par-focal colour filters (SBIG) should be right if I focus on luminance, but I have been finding a small tweek is sometimes needed on each colour.
Thanks for the comments - I will have to get photoshop I think,
Big Dave.
Quote:
Originally Posted by jase
Big Dave, off to a good start indeed. You've got the gear, just need to spend more time in processing the data. Its a little hard to critic a small image, but from a distance the data acquisition looks on track. NGC2070 is a little burnt out. You need to get comfortable with PS levels and curves. While these are relatively simple tools of the trade, they play a major role. You can always try to get fancy with DDP, log stretches etc, but you'll probably find you will come back to levels and curves as they provide the most flexibility in what you are trying to convey in your image. Gutsy effort to start out with an RGB image. I stuck with luminance data for some time until I learnt the ropes (and I'm still learning). Look forward to seeing more of your work. Well done.
Photoshop is pretty much a necessity when using CCD cams.
Also plan on 90 minutes total exposure as a kind of minimum unless an extremely bright object like Omega Centauri and even then... Several hours are the way to go once you are used to processing the images.
Wodaski's 2 books are great to learn the ropes with and have pretty much all you need to know in them.
Hi Dave, Nice first RGB. I can only reiterate the other comments. Get comfortable with PS levels and curves. Wodaskis book "zone system is a great one for getting going with these.
The core is a bit overcooked but with practice you can fix these problems.
Slightly embarising, I had the FITS on my memory stick. I thought I copied them from my laptop but it turns out when I looked tonight I must have cut them. Gone, they would have totalled 60 Megs anyway, zipping al three would have still been large.
Tonight looks to be clearing so I will have another shot.
I ordered Photoshop 11 today, lucky I found the old student card at them prices!
I think the raw data must have been ok, just the CCDsoft is very limiting in the colour stacking.
- Dave.
Quote:
Originally Posted by Omaroo
A great start there Dave
Can you give us access to the original files some place?
Well met Big Dave, as others have said good sart. This is a great place to learn, take the comments good and bad.
I should say snap as well as we have the same scope and camera, though I've got a G11. I even had a VLC200 years ago.
Cool, I am a real fan of my WO scopes.
The one good thing about astronomy is there is plenty of time to try different scopes, image targets and to hone in on techniques. Just when you master something - the goal posts seem to move with technology!
These posts are great for constructive comments, expecially when you work alone on imaging and start to run out of ideas!
P.S. I was considering a G11 - nearly bought it, but as I had a SXW mount and was use to the starbook, I stuck with Vixen.
- Dave.
Quote:
Originally Posted by KenGee
Well met Big Dave, as others have said good sart. This is a great place to learn, take the comments good and bad.
I should say snap as well as we have the same scope and camera, though I've got a G11. I even had a VLC200 years ago.
This has 4 FITS in it.
Each colour is 4 x 5 Minutes aligned & stacked (Dark Subtracted first)
The Luminance is 2 x 5 Minutes aligned & stacked, however I did not use this.
The CCD was at -20 deg.
My Photoshop is due tommorow, can't wait to improve it!
I am keen to find out from anyone if the RAW data is any good?
Clear Skies & bugger off moon,
- Dave.
Quote:
Originally Posted by Big Dave
Slightly embarising, I had the FITS on my memory stick. I thought I copied them from my laptop but it turns out when I looked tonight I must have cut them. Gone, they would have totalled 60 Megs anyway, zipping al three would have still been large.
Tonight looks to be clearing so I will have another shot.
I ordered Photoshop 11 today, lucky I found the old student card at them prices!
I think the raw data must have been ok, just the CCDsoft is very limiting in the colour stacking.
............ I thought these par-focal colour filters (SBIG) should be right if I focus on luminance, but I have been finding a small tweek is sometimes needed on each colour............
Big Dave.
Good start Dave. The filters are par focal, it's just the telescope isn't.
PAR focal filters are simply equal thickness filters, and will not change the focus of a converging light cone from one filter to the next.
With reflective optics the focal plane remains unchanged across the spectrum.
With refractors however, even APO's, there is a subtle variance in red, green and blue focal planes.
While it would be possible for a refractor manufacturer to design a variable thickness RGB filter set that would correct the focal plane variation in a specific instrument, I am not aware of any....plus a variable thickness filter set would not kind toward reflective or different spec refractive systems.
There is also a secondary effect of having to change focus for RG&B filters. The image scale will change and you may see subtle rainbow fringes around stars after the 3 planes have been colour stacked.
(Hope that wasn't seen as an exercise in "how to suck eggs" )
Last edited by Peter Ward; 14-11-2008 at 10:49 AM.
Reason: clarification
