Lagoon & Triffid

[Jasp05]

Last night's effort on the Lagoon and Triffid from my light polluted backyard.

Canon 1100d(not modded) on HEQ5Pro, 50-250mm lens @ 135mm F7.1
16x 3min subs 400iso. (No darks/ flats yet).


My only problem (apart from my editing skills) is the stars are never fully round. if you look closely they have a little tail that hangs off the bottom left. (Not sure if you can see it in the picture below? )

I've tried and tried to adjust focus, tried either side of what I thought was "in focus" and still no better. Is it possible this is an artifact of the lens? (Also focal length does not matter. only makes it more apparent). Also stopping the lens down doesn't help much either. Note the F7.1 when wide open is F5 on this lens.

Edit: I've added a closeup of the star tails / odd shape of my stars. (this problem exists in single exposures, so I don't believe its a stacking artifact).

[Mickoid]

Aaron, first of all, good on you for giving it a go with a standard camera lens. Your processing looks good too and you have disguised the light pollution well. The funny shaped stars can be any number of things from camera movement to aberrations of the lens. It's going to be a process of elimination to find the cause. Here's a few things to try. 1. Make sure your lens stabilization switch is turned off. 2. Use your self timer setting to allow the camera and mount time to settle before exposing. 3. Try a shot with mirror lock up enabled. 4. Make sure your connection from camera to telescope is secure. 5. Try another lens. You've already established that stopping down didn't help so you've eliminated that possibility.

Apart from that, just keep experimenting, maybe even shortening your exposures to 1 min and upping your ISO to 1600 and see if that helps.

[xelasnave]

Aaron
You did a fine job so please take the time to appreciate what you have achieved.

There will always be better unless you buy the Hubble.

Enjoy your achievement.

Here we offer advice to improve which sometimes takes away from all the good things each person has achieved.

I am so impressed with your effort I am now inspired to try the same...so your work can be called inspirational...and although scriptures tell us that pride is a sin when they wrote that they were never thinking about the pride in ones astro photos.☺

Keep the coming..

Alex

[Jasp05]

Thanks guys.

I have tried different lenses and the problem is not there.
It is my biggest lens im using (others are 50mm f1.8 and the stock 18-55mm). Neither of which have this problem.

I hope its not the camera wobbling. Its mounted to an heq5 and bolted on the dove tail so tight its not funny. (And very light breeze if any at all when i was imaging last night.) And its there on previous attempts as well to the same degree as far as i can tell. So i dont think weather is the issue.

And its connected to a laptop using apt to take the images. So should be minimal camera shake. And stabilisation is off.

I think ive covered most of the bases you mentioned already but just wanted a second opinion on what "could" be wrong.

[rcheshire]

A long shot. Is it possible that the tails are internal reflections/refractions among the numerous lens elements?