What about fogging up somewhere in the optical train; the humidity would have been pretty high wouldn't it?
raymo
Don't think so, humidity this time of year is low, the night was cool and dry for this time of year, this is a crop from my eta redone, the last image posted
I tried with a different camera, a modded dslr , and the artifacts are still there.
Thanks Jorge, will do a thorough clean and see what happens.
Any recommendations as to who can clean the lenses on a WO Flt 110, from what i 've read it is a no-no to do it yourself.
George
It's really hard to tell George. The DSLR pic doesn't have the foggy appearance of the CCD, but the stars are still quite fat. I think there may be a couple of different problems going on at the same time.
If you have more pics of different objects that may help too. Cropped and not cropped as well.
It's really hard to tell George. The DSLR pic doesn't have the foggy appearance of the CCD, but the stars are still quite fat. I think there may be a couple of different problems going on at the same time.
If you have more pics of different objects that may help too. Cropped and not cropped as well.
Kevin , i know my polar alignment wasn't perfect but it was the closest i've ever been. Without guiding there was some movement in the images, with PHD there was about 2 arc seconds corrections at a setting of 2 secs, could this do this?
I have a couple of images on this forum, ie centaurus a and omega centauri, check my threads
When guiding, the P.A. doesn't have to be perfect, the guider can overcome some inaccuracy. I have to have mine down to a few arc seconds in order to get the longest possible unguided exposures.
raymo
Was the object fairly low to the horizon? looks like some kind of chromatic aberration? could be atmospheric or optical. I can't remember what your telescope is? you could try and selecting the blue channel and shifting it to the right?
Was the object fairly low to the horizon? looks like some kind of chromatic aberration? could be atmospheric or optical. I can't remember what your telescope is? you could try and selecting the blue channel and shifting it to the right?
Russ
Hi Russ , yeah it was pretty low on the horizon, remember i am at 12 deg south and it was past the meridian when i commenced the sequence.
I thought of that myself and am going to try something higher to see if i get the same effect. I processed the 1st image and had the same effect, i don't know if this means anything but the blue colour is to the left of the stars and when i zoom in to a yellow star the red/yellow is off to the right.
I have a TMB WO FLT 110, one of the early ones.
Moving the blue channel to the right did not improve anything.
George,
Funnily enough, I had something similar happen in my last image (M20) only it was more of a cyan in colour. Now that image was processed with Pixinsight, and I found that changing the reference frame to a another image totally got rid of it. So,in my case at least, it seems to have been an alignment/combination issue. Bear in mind this was with 3 seperate colour channels from a mono CCD. I'm not willing to say that this is the issue, but maybe worth a play with the registration parameters?
George,
Funnily enough, I had something similar happen in my last image (M20) only it was more of a cyan in colour. Now that image was processed with Pixinsight, and I found that changing the reference frame to a another image totally got rid of it. So,in my case at least, it seems to have been an alignment/combination issue. Bear in mind this was with 3 seperate colour channels from a mono CCD. I'm not willing to say that this is the issue, but maybe worth a play with the registration parameters?
Goran.
Thanks Goran, i am now back from a few days camping so i will try your suggestions
That looks very much like chromatic aberration to me.
What exactly does your imaging train look like? Are you using any sorts of filters or focal reducers?
Not sure about the fact that it was low on the horizon. I sometimes image low as well and never seen such aberrations in either case.
Just my two cents, hope you can work it out.
Quote:
Originally Posted by vlazg
Hi Russ , yeah it was pretty low on the horizon, remember i am at 12 deg south and it was past the meridian when i commenced the sequence.
I thought of that myself and am going to try something higher to see if i get the same effect. I processed the 1st image and had the same effect, i don't know if this means anything but the blue colour is to the left of the stars and when i zoom in to a yellow star the red/yellow is off to the right.
I have a TMB WO FLT 110, one of the early ones.
Moving the blue channel to the right did not improve anything.
This is an image taken with a saxon ed 120 using the same camera, the stars are now much better.
Could the problem with the WO FLT 110 be a collimation issue somewhere in the image train, either the lenses or the focuser or both? If so is there somewhere to send it, i don't have the confidence or the knowhow to do it myself. George
yeah it was pretty low on the horizon, remember i am at 12 deg south and it was past the meridian when i commenced the sequence.
