RASA 8 arrived today

[fwm891]

I purchased an 8 inch f2.0 RASA (Rowe-Ackermann Schmidt Astrograph) from FLO. It arrived via DPD this afternoon along with an IDAS NB-1 filter.

The OTA was double boxed in heavy weight cardboard with ridged foam inserts to provide support and cushioning. All OK removing the scope from the box.

I have a Celestron motor focuser  from another scope so I spent some time fitting that and calibrating. No problems (yet), I decided to tinker around in doors rather than in the observatory as I have more room in the kitchen.

I connected everything up via a Pegasus Pocket power box to the lappy. Downloaded the latest drivers for the motor focuser from Celestron.

I run SG Pro as my pointing/tracking/capture software, it recognised the focus motor, the Pegasus power box, the asi120mm (on the 9 x50 guide scope) and the ASI 294MC Pro on the RASA. Great stuff.

Then I hit a snag. I needed to take the glass filter out of the RASA as I intend to use filters with this OTA and Celestron don't recommend using multiple glass filters due to focus shift and the sweet plane is quite critical with the 8 inch RASA. There are 2 little notches either side of the glass window but it was screwed in too tight to remove unaided - I ended up getting a short engineers rule, engaging that in the notches and un screwing it that way.

I'm using a Baader universal filter drawer with a 2" insert allowing me to swap filters as needed although at present it will be either a UV/IR cut filter for straight OSC recording or the IDAS NB-1 to capture Ha and OIII/Hb.

So I positioned it on a worktop and pointed it outside at a distant tree. All connected through SGPro and the focuser refused to work. Ran on the Celestron calibration software but refused to run through SGPro. After a great deal of faffing about I found the problem: Both the Pegasus Pocket Power box and the focuser were trying to communicate through the same comm port. Why is it I never go for the simple stuff first....

Anyway with that sorted it was easy to focus on the tree then align the finder/guider scope up with the RASA.

Once I get round to seeing some stars I'll do a first light review

TBC

 

 

 

Edited October 23, 2019 by fwm891

[sloz1664]

Hi Francis, and WOW. This should be interesting..... Awaiting first trial and photos..........Don't forget the photos, with bated breath.

Steve

[Z3roCool]

Ahh man! Would love this setup. My dream is to have an obsy in my garden and setup so I can just start imaging every night without having to go through PA etc. And to image at F2!  Really looking forward to what you get , a lot of people using the RASA seem to get some stunning results with fairly short subs, 2-3 mins.  Look forward to your FL

Edited October 24, 2019 by Z3roCool

[tooth_dr]

Yes imaging at F2! With 8” apeture 🤘🤘

[fwm891]

Frightening when your new scope throws a wobbly on it's first outing.

Thankfully the causes have been found (hopefully). First was cables from the camera didn't have enough slack and when I pushed the dew shield on it tightened them further pulling the camera to one side. Next which only aided the former was that the Baader filter draw wasn't fully tightened against the RASA T thread so there was a little play. It felt tight enough when I set up, but only after having to shut down pronto because there was wet stuff falling I found it turned about an eighth of a turn further...

So you can see on the images that the focus is a vertical area approximately central with focus falling off each side due to camera tilt. I found that the threads between the filter drawer and the RASA T thread mounting plate were binding which is why I thought they were tight. A little touch of candle wax on the thread has stopped the binding and the two parts fit together easily.

The images: The white light was 5 x 120s subs - Gain 120 offset 30. The NB image (using an IDAS NB-1 filter) was 5 x 180s.

Sadly rain cut short this first light. Interestingly though these were processed in PI but I had no calibration subs so these are light frames only and the dreaded amp-glow isn't there. ABE cured the illumination across the frame. Must try this again with more subs...

[andrew s]

"It's full of stars."

Great start. 

Regards Andrew 

 

[fwm891]

Well an improvement but I think I still have a spacing issue....

Shot through cloud (it was there when I set-up) just disappeared as soon as I started the sequence run. Captured the smiley face anyway 🙂

1 minute sub on ngc6995. RASA 8 ASI 2994 MC Pro. Processed in PI.

 

[Froeng]

Is it Christmas yet? 😉. Looking good. Incredible what 1min exposure can capture at f2... Have fun with your new toy!

Frank