Hi , here is a couple of shots from this last week taken of the moon in its waning phases .The last was 3am this morning after work ISO 400 1/4 second .
I hear all the time that the lowely old Achromat is no good for AP , well I disagree as these shots show .
Zero CA , super sharp , very dark background .
Taken prime focus with my Istar 127mm f8 Achromat , sony alpha 200 DSLR , zero work on these just straight out of my camera into my computer and posted here .
Replies welcome .
Brian.
Time to buy a decient screen then , the edges are white in my Compaq Q2009 .
Here come the doomsayers , but please keep it coming ,,,,,
You kinda forgot that this shot is raw , it would be easy to cheat and process any defects out but that's sort of cheating .
Brian.
Quote:
Originally Posted by naskies
Nice shots, but the edges of the moon are clearly green?
Last edited by brian nordstrom; 28-07-2013 at 01:42 PM.
Thanks for posting these Brian. It's important to encourage people to try it for themselves, and pictures like this helps.
We see some truly stunning images here from IIS members, and we see the sophisticated and expensive equipment they use to achieve their results. The equipment used often puts it outside many peoples budgets (time as well as money)
Ur photo's are encouraging proof that amateurs can get satisfying results with the basics. Certainly good enough to make there own attempts worthwhile, and give them a whole new reason to get the telescope out. And it must be satisfying to have photos from your hobby to show friends and workmates.
I'd like to see people posting some of their solar system pictures taken with standard viewing equipment+camera just for this reason.
Nice pics Brian! My iMac does show a thin rim of green but I think overall too many people worry too much about CA instead of what is actually in the image.
(It was so much simpler when all anyone had was an achro, none of this apo v achro banter existed.)
To my untrained and old eyes they look very nice but if you want some perhaps more discerning evaluation post some of these pics in the Solar System Imaging section and see what some of the dedicated AP folks have to say.
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Nice shot Brian. If you filter an achro, say with a red filter, you'll get rid of any CA. That's how they did it in the old days. These days, you can just pull the red channel out of the digital image. Do that and the fringe disappears.
One thing about your pic confuses me. You say it's prime focus of your 5"f8 refractor and 1/4s ISO 400. Intuitively, that seems much too long an exposure for that optical train and ISO. Are you sure it wasn't 1/400s?
OOPs yes 1/400th , on the CA it does now bother me at all , its so slight when looking at the moon any way , nice lense that Istar .
Brian
Quote:
Originally Posted by OzEclipse
Nice shot Brian. If you filter an achro, say with a red filter, you'll get rid of any CA. That's how they did it in the old days. These days, you can just pull the red channel out of the digital image. Do that and the fringe disappears.
One thing about your pic confuses me. You say it's prime focus of your 5"f8 refractor and 1/4s ISO 400. Intuitively, that seems much too long an exposure for that optical train and ISO. Are you sure it wasn't 1/400s?
Thanks everyone ,
Trevor , I will do some Jupiter , Saturn and mars shots next year when they are all back at a reasonable hour .
And yes I will post in the solar system imaging section and see what comes out .
Brian.
Time to buy a decient screen then , the edges are white in my Compaq Q2009 .
Here come the doomsayers , but please keep it coming ,,,,,
You kinda forgot that this shot is raw , it would be easy to cheat and process any defects out but that's sort of cheating .
Brian.
Impressive shots Brian. You're too honest ! You can cheat you know !
GET EM OF YOUR BACK !
Seriously these big achros get hammered by some, yet you have had all kinds of
scopes and can vouch for them for crisp visual, and AP general use.
At about 20X - X40 prime focus magnification with an Achro - which these shots represent, CA will not be noticeable . At X400, using eyepiece projection for a descent close up shot the CA in these Achro refractors will be absolutely objectionable in the pictures - even for visual observing pretty useless....
I am not sure exactly what you are proving in these photos - the subtext being that somehow CA in achros is an overrated criticism ?
Have attached a picture of Copernicus using frame stacking , by Anthony Wesley using a basic 10" F6 reflector in 2005 - just to put some perspective on this !
.
Time to buy a decient screen then , the edges are white in my Compaq Q2009 .
OOPs yes 1/400th , on the CA it does now bother me at all , its so slight when looking at the moon any way , nice lense that Istar .
