back from a mount upgrade with the RASA now remounted in rings

[pyrasanth]

I've been out of action for nearly 3 weeks. The telescope mount had to go back to the USA to have a cabling fault during assembly fixed. That caused an 8 working day delay. I decided not to put the telescope back together until the Parallax rings arrived from the USA. These spent a further week stuck in customs but they cleared on Friday so I collected the rings on Saturday morning & put the telescope back together whilst dodging the rain storms.

The Parallax rings are fantastic. I removed the rails from both top & bottom on the RASA which shaved off nearly 12 LBS in weight. The rings were then bolted to the Paramount & the tube slides into the open crescent of the rings. This is a revelation. I've always used the Vixen type mounting with Celestron rails and it's always been a pain in the bum. The rails fit badly and they don't grip very tight in the clamp and are a pain to balance as the rail fits slightly off center in the clamp & jams when being moved- very frustrating. The rings are fabulous- drop the OTA between them & tighten just enough to slide the OTA between the felt linings inside the rings and balance. Then lock the rings tight. The quality is very good & the rings grip the tube rock solid when correctly tightened. I was dubious initially that the tube could slide but I've seen no motion at all even when exercising the mount 30 times at top speed. I had the sides of the rings milled out so I've been able to fit 2 very light steel rails between the rings on each side to hold the USB Hub, cable tidy & the wireless focus hub.

I've fitted the 80 mm guide refractor to an ADM 15" rail mounted on the top of the rings in a Skywatcher adjustable mount so I can easily move the guide scope if required to a suitable star.

The balancing in RA & DEC is now far easier as the rails fitted to the RASA seemed to do funny things with the balance but these have now been removed and the balance feels so much better.

When the sky clears I will polar align & see what sort of results I get. I'm looking forward to being back in action with what I hope is an improved mount. I'm really happy with the new way of mounting the OTA.

Clear skies to you all!

[laser_jock99]

Got a before-n-after picture?

[pyrasanth]

I will grab you a picture or 2 when I've charged my camera battery- always flat when needed-lol

[pyrasanth]

Weather is clear tonight. I've aligned on the refractive pole. I'm now running a 400 point super model to refine the pointing accuracy using T-point so all systems will be go when that is done. I will then used a closed slew to refine where the optical center of my finder-scope is & align the finder. Then I'm done!

[pyrasanth]

I finished the model last night & was anxious to test the guiding. The image below is taken last night & is very raw but it gives you an idea as to how much the guiding has improved. If anybody has any software to look at the image you might be able to tell me how round the stars are- but it looks good so far.

[appyaardvark]

The stars look round to me, right to the corners. What equipment have you used for this image? What was the exposure time? Is this on the Paramount MX+? Do you really need guiding with that mount?

[pyrasanth]

The image was taken with an Atik 460 mono with no filter other than the LPR filter on the Celestron RASA which is made by Astrodon. The image is 77 60 second subs stacked with CCDStack2 &  guided with PHD. Whilst in theory I might not need guiding at this focal length (620mm) it is doing no harm looking at the frame. The mount is a Paramount MX+ with a 400 term t-point model, pro-trac, PEC enabled.

The field with the Celestron RASA is sensational & now that the Paramount MX+ Dec axis has been re routed (the cause of it's return) the guiding is sesational.

[appyaardvark]

I've been doing some research on the MX+ and I am suprised that you would need any guiding on a 620mm focal length. I would expect this mount to achieve 5 minutes subs, unguided.

[pyrasanth]

I've been doing some research on the MX+ and I am suprised that you would need any guiding on a 620mm focal length. I would expect this mount to achieve 5 minutes subs, unguided.

I'm not saying that it can't or won't do this- I simply have not tested it. It is so simple to auto-guide with the MX+ that I have not really tested it without guiding. It only takes me mostly a couple of minutes with PHD or 30 seconds with the SkyX to be guiding.

[appyaardvark]

I'd be interested to know how you get on with the mount in that case :-)

I'm considering an upgrade and the MX+ is one that I have been considering. A major benefit is having a software package that not only controls the scope, but peripehrals and image acquisition.

[pyrasanth]

I'd be interested to know how you get on with the mount in that case :-)

I'm considering an upgrade and the MX+ is one that I have been considering. A major benefit is having a software package that not only controls the scope, but peripehrals and image acquisition.

I have never regretted purchasing the MX+, it is simply a fantastic mount. The software has been a revelation-especially for the winter. All my astronomy is by CCD camera & I RDP to a computer which is connected to the mount & I have full automation. I control everything from camera, focusing, guiding & slewing with the SkyX doing the bulk of the work. This is much better than freezing

[appyaardvark]

I have never regretted purchasing the MX+, it is simply a fantastic mount. The software has been a revelation-especially for the winter. All my astronomy is by CCD camera & I RDP to a computer which is connected to the mount & I have full automation. I control everything from camera, focusing, guiding & slewing with the SkyX doing the bulk of the work. This is much better than freezing 

That's what I do with the G11, I have an ITX PC located next to the mount and RDP to it from indoors, once I've set it up. Now I want to minimise set up time and not have to worry about the mount, so I can concentrate on imaging.

[pyrasanth]

Here is a picture of the mount before the upgrade:

And after:

The balance is much improved & no longer requires a counter weight on the front of the OTA although the Edge HD has been replaced with the RASA OTA. I removed the counter weight extension bar & added another weight. The balance is such that the motion on both axis is now finger light despite a combined weight of over 100 lbs. The USB hub is carried on a rail parallel to the one shown on the other side of the mount and all cabling goes through the mount via the polar scope hole.

[laser_jock99]

Thanks a picture is worth a thousand words. So basically the top/bottom rails have been replaced by tube rings + more substantial top & bottom rails.

It is certainly a good way to add stabilty to a rig and takes the strain off the tube itself.

Something I advocate is longer, stronger dovetail bars top & bottom. On my 12" Newt the main dovetail is 0.5m long and an inch thick.

.....and as wide a piece of decking. More rigid that the monkey metal casting it shipped with!

[pyrasanth]

I agree with the fact that most OTA's are shipped with inadequate mountings. What makes the matter worse is that the Celestron Vixen type rails are not standard size so their fit into most mount clamps is hit & miss. The top rail is a 15" ADM and it is rock solid & needs to be as it carries the guide scope. I've now switched to direct guide which works really well so I now don't need the cable between the lodestar & the mount which eliminates another possible source of failure.