Ngc104

[Paul Haese]

So what do you image during full moon? Well if you have tight narrow band filters you can image nebulosity or you can just have a crack at doing short subs on a favourite globular cluster. That does come with its own issues like very extreme gradients, but it was fun all the same.

A massive :P 44 minutes of data went into this image. Luminance subs were 2 minutes and colour was 60 seconds; with core subs being 20 seconds each.

There are still issues with either the secondary cage or actual secondary moving just very tiny amounts, but I can get enough data to construct images. My suspicion is that the actual secondary is rotating a little and that it is being caused from the spider not having enough stiffness. Further stiffening needs to be installed onto the secondary cage in the form of diagonal braces, which will eliminate the cage being the cause of the star movement.

Click here (http://paulhaese.net/NGC104.html) for larger resolution image.

[Geoff45]

Nice rendition of a popular object Paul.
Geoff

[Placidus]

Beautiful!

Your colour rendition is excellent. We're going to have to revisit our attempt and shamelessly see if we can make it more like yours. :D

Lovely balance between simultaneously showing core detail and faint halo stars while preserving the overall feel.

[gregbradley]

That looks great. Your efforts are paying off.

Greg.

[RickS]

44 minutes put to good use, Paul :)

[Paul Haese]

Thanks guys for the comments. It's a plain target but a really good target to test star shapes.



Thanks MnT, really appreciate your enthusiasm.

[Regulus]

That looks excellent Paul. Beaut star colours!
Why is the secondary rotating at all? Even if the spider isn't 'stiff', where is the force that moves it coming from? Is the tube flexing?
Sorry, just curious, and I hope it is an easy to fix proble.

Trevor

[Paul Haese]

Trevor, there is no tube flex (truss system) but the secondary is very large on this scope. Any scope with this from f5 down has a large secondary. Quite a few people who have used Newtonians a lot have advised that the secondary assembly can twist slightly under gravity (rotates) at certain angles in the sky. That very slight twist is totally unnoticeable when viewing through such a telescope but is clearly evident when you are imaging. Stability of the secondary in the alignment is paramount. I think I have stopped the cage from moving, but not the secondary itself. So I either need to extend the spider veins to a higher angle or provide a counter weight extending out from the assembly forward of the secondary opening. Most agree this is the best method to fix the problem. In any event I will report this to GSO as a suggested fix for this scope.