Saturn 6th April - Advice Please

[Uplooker]

Hi,

Here is my latest effort at imaging Saturn using the following:-

Celestron 8 inch SCT

NEQ6

Phillips SPC900

Orion Shorty Plus X2 barlow

I captued 3000 frames and limited to 600 best in Registax 6. The image you see has only had basic wavelet adjustments in Registax. I did have a brief play in PS CS5 but was not able to improve the image.

I would be greatful for advice people can provide on how to improve upon this. I am particularly frustrated by the sharpness on the rings.

I am pretty confident on the collimation of the scope as i have spent the last few nights collimating it using AlsCollimationAid, and i get really nice even rings when either side of focused.

I have found it difficult to get focus correct as there is so little margin for error when adjusting. I feel I need to turn the focus knob a smidgen more to get a sharp image, and the focus then goes way off - is that why people purchase a new focuser with dual speed for SCTs?

I must add that i am still trying to get to grips with the SCT since buying it second hand - primarily for planetary use.

All advice and critique welcomed.

Regards,

Ian

[Frogpills]

Going from a single speed focuser to a dual speed focuser or auto focuser is a game changer. It's so much better.

[Kokatha man]

Hi Ian - if you're using the primary mirror adjuster knob for focus you're making a rod for your own back to be sure.....and another aspect to using it is it can quite easily affect collimation due to any play/slop/ineven grease distribution between the primary sleeve and baffle.

Before going really up-market with a digital readout Moonlite hi-res unit (almost mandatory with mono imaging to get accurate repeatability) I had great success with a (cheapish) Chinese dual-speed Crayford-style focuser fitted to the C11.....I bought a "Skywatcher" electric focuser (about $90 AUS) that attached to the dual-speed Chinese focuser and it was very easyt to get very fine focus.....they are powered by a little handpiece using a couple of AA batteries that last forever.

There is literally a "quantum shift" in focusing abilities when you go to something like this if you're using the primary mirror adjustment knob at present....!:)