Testing Changes last night

[Startrek (Martin)]

Last night Sydney had a rare clear night ( 90% waning moon ) so took the opportunity to test a few changes to my rig

New USB3 Hub
To minimise cable drag , I eliminated 2 cables going from laptop to mount / scope by fitting a new USB3 hub to the underside of the Losmandy dovetail plate. Bought a Startech Industrial USB3 4 port powered hub and connected imaging camera , guide camera and mount via Startech USB3 and USB2 1m cables.I use a 5m Startech Active USB3 main cable from Hub to laptop.
Worked perfectly all night with all software programs , APT , Stellarium, EQMOD, PHD2. With USB3 set ups you have to find quality cables that are USB3 performance certified ( there’s so much junk out there claiming USB3 conformance ) and keep your distribution cables from hub to equipment on the mount no longer than 1m (the Startech USB3 cables have not let me down, so far after 3 years )

Re Orientation of OTA and rebalance
Down south at my Obs , I reorientated my 8” Newt with camera facing down at 6 o’clock in lieu of at 2pm, re balanced it and this proved to have a significant improvement in tracking and guiding.
I did the same re orientation last night on my 6” newt and again the guiding numbers were a marked improvement from previous
Previous 0.70 to 0.80 arc sec error ( over 3 years )
Last night 0.52 to 0.60 arc sec error ( in 4 different locations in the sky ) I’ve had this mount ( EQ6-R pro ) over 3 years and never had the guiding so tight. Ra and Dec were well behaved using the PPEC algorithm in PHD2 ( with dithering) and only noticed one or two small excursions all night.

Tilt evident in image
After reviewing some 5 minute subs , I did notice some evidence of tilt in the smaller fainter stars across the image, nothing too alarming but it’s there . I’m confident it’s due to the re orientation of the OTA with camera facing down as now the camera is exhibiting more torque on the focuser than ever before in most positions.The 2600MC with adapters and Baader MPCC is a lot of weight hanging out from that little 6” newt. May need to use some ring spacers and tighten up the whole assembly a bit better ( a works in progress)

Heavy dew set in around 1am , it was a productive night and tested and proved a few changes which went well

Cheers

[Drac0 (Mark)]

Glad you had a productive night Martin. Was good to get a few hours of clear sky on the coast.


Tested a few mount adjustments myself last night - though according to PHD2 things haven't really improved with it reporting huge DEC backlash. But it calibrated just fine & the guiding was pretty good. Sadly on my small mount, to adjust the DEC you need to remove the motor and didn't really feel up to it again last night. Now I need to adjust it & wait for another few hours of clear sky (next month maybe?) to test it again.


Was only using a DSLR last night but ASTAP showed some pretty severe tilt (30%+), but never got around to trying to determine whether it is the camera, reducer/flattener or the scope. Something else for the next time.


In the end just decided to grab a couple of hours on Centaurus A. Not even sure yet how it came out with the moon around...


Cheers

[AdamJL]

Good to hear, Martin.

I just setup at my parents house and practised. A lot went wrong especially around autofocus. Might upgrade my focuser but it’s not cheap

Also forgot to add the temperature sensor so when I woke up, the scope was covered in dew because the dew heaters didn’t trigger

All in all not a bad night as I got a few images but it was good to clear out the cobwebs and practise

[Startrek (Martin)]

Thanks Mark and Adam
Pretty happy about the USB3 cabling system , I can now adopt the same set up with my new rig down south in the Dome ( EQ8-R pro and 10” f5 CF newt ) when it finally arrives in June

The new re orientation and balance has been a game changer as far as tight guiding goes. Admittedly I did spend some time on the mount tuning the backlash out of the worm gear / main axis and motor drives which did help.

Cheers
Martin