Hello Folks,
With advice from this forum I captured the Eta Carinae nebula last night.
A stack of four 6.5 minute ISO 800 pictures with Canon 60DA at prime focus of my Mewlon 210,off axis guiding with Orion thin off axis guider and PHD2.
A hot day and even with 3 hours to cool to ambient the focus was hard to keep as the evening cooled and the scope shrank. Refocusing the Mewlon is a pain with image shift. This means that PHD has to be stopped and restarted after focusing. I still did not get it right, more practice required.
Would people tell me what else is wrong, apart from coma from the uncorrected Mewlon.
I like it but, I'm very new at this & imaging via a long focal length SCT..
I am curious though, I see you and others getting that (I'm not sure how to describe it or what it's called) IMHO elongated star effect on your bright stars,
How do you achieve this, I like it so much more than just a bright round dot...
Nice detail there Chris. A little noisey but I'm sure you know that and the heat wouldn't have helped. And framing, there's some interesting shapes at the end of the pointy end of this one where the dark neb cuts in. All in all a good effort though.
Hi Carlton,
They are called diffraction spikes, and all reflecting telescopes that have a secondary mirror supported at the front of the open tube by what is known as a spider produce them. Most reflectors have two, three, or four struts that come from the inside of the tube to the secondary mirror located in the centre of the open end of the tube. The struts cause the spikes.
raymo
Last edited by raymo; 31-01-2019 at 11:44 PM.
Reason: more text
