SADR - too far wiith red?

[bobro]

It's difficult trying to work out how far to go with red processing for nebulosity - possibly a bit too far this time? Anyway, here is SADR and surroundings : 31 subs @ 240 secs with my 'new' CG5 setup with dithering on both axes working for the first time.

 

[stevewanstall]

I was interested to see you use a Celestron CGT mount.  I use one as well and have jsut swapped a too heavy 8 inch reflector for a 80mmrefractor (ED80). The tracking with autoguiding is much improved. What is your 'set uo routine with the mount? I am interested to see if you do anything different to me. 

[Paul M]

Interesting subject.

I've never given Sadr much thought but your image had me Googling. Quite an impressive star and only 12m years old!

[bobro]

10 hours ago, stevewanstall said:

What is your 'set uo routine with the mount?

The CG5 is very new to me - until now I've been using an EQ2 with DIY autoguiding but decided to try a CG5 in order to have goto.

A SkyWatcher motor is on the RA axis with a more powerful stepper motor with pulleys and belt drive on the DEC in order to eliminate motor backlash. The SkyWatcher motor had considerable backlash so I wanted to reduce this in order to take advantage of dual axis dithering (as used with my EQ2).

For setup I just plonk the whole setup (setup is kept assembled) onto marks on the patio which means close polar alignment. SharpCap then gives very accurate polar alignment which means DEC guiding corrections are typically not issued when an exposure is made.

Following polar alignment, I use Cartes du Ciel to direct the mount (via EQMod/AstroEQ) to a bright star, using a red dot finder to ensure the scope is pointing to the star when slewing stops. APT then makes use of camera Liveview to show how close the star is compared to the centre of the image, with EQMod manual slewing controls used to make final adjustments. Cartes du Ciel sync is then used to move the CdC cursor back to the star to ensure everything is finally synchronised.

That's it for setup, except for ensuring scope focus is good by either taking a test exposure or using Liveview on a bright star with a Bahtinov mask.

Making the RA axis east heavy cuts down on gear chatter but doesn't seem to make much difference to guiding.

HTH