Rowan Belt mod for HEQ5

[MattJenko]

This is not a question as such, in fact, not at all, it is a post to extoll the virtues of the Rowan belt modification I have recently done to my HEQ5.

I was finding that my HEQ5 was doing ok in terms of image results (to be honest I am astounded by the images that it can help produce), although the tracking seemed particularly wild. I thought that was a result of my slapdash setup routine (levelling/balance/PA/alignment all done with minimum effort - I think the purists amongst you would tut - a lot). I then got the chance to try an NEQ6, and found that with my same setup process, the tracking results were significantly better, by a seriously long way. This pointed at my mount being out of whack to where it could or should be. I had no intention of doing a strip down, as I am known for making a mess of things like that, but after living with the knowledge that my mount was sub-optimal for a few months, I finally bought the belt mod kit, thinking that if I was going to open it up, I may as well go for it, and I have always cringed a bit at the grinding noise the mount makes when it slews.

The kit arrived promptly and the instructions were so good and the bits arranged so nicely, that I managed to do it easily. There was all manner of nasty grease everywhere, so I tidied it all up and screwed in the last screw on the now fatter mount and awaited a chance to test it out. It certainly sounded much better and did not appear to have any obvious backlash. I also now have lost the fear of my mount's internals, which is a good thing.

My first light was a resounding success. The mount just seemed better behaved. Starting and stopping slewing didn't involve the fabric of space-time tearing noise that it used to make and it just seemed more responsive. On to tracking. Oh my. Doing nothing different from previous sessions, PHD indicated that each successive guiding frame was actually within the 2" target, which previously it was not. Before, I was getting guide graphs of well over 3" in either direction which was resulting in noticeable single pixel random movements, which was affecting my star sizes (but not their shapes, as the movement was all over the place). This was a major improvement. I was down well between the 2" levels, mostly between the 1" level and the corrections being sent to the mount were both fewer, and less aggressive. I even had some guide frames where there was no correction at all, which never happened before. My wife got heartily sick of my pointing and coo-ing at the guide graph.

As to results. I did a run on M71, the hidden away little globular cluster in the hidden away constellation of Sagitta. I chose a globular as these are not very forgiving for tracking problems, as I have found in the past. The results far surpassed what I have achieved on these kinds of targets before. I have also subsequently done longer runs on different targets (20 min Ha guides on fainter nebula with similar excellent results)

They are still not as good as some of the epic images I see here, but I can only compare to my own work and try and improve where I can, and this simple mod has moved me a great step forward, so thanks to the Rown Engineering team - one rather happy and enthused customer

Scope : Skywatcher ED80, Camera Atik 414ex. 20 x 2 mins L, 8 x 2 mins RGB.

[JamesF]

Can't argue with that image.  The belt drive conversion for my HEQ5 has been on my list of things to do for some time.

As a complete aside, I notice in the image that there are two bright stars in the bottom right (and a few others actually) that have diffraction spikes.  I wonder where they have come from?  Spacers in the objective intruding into the light path?

James

[MattJenko]

Hi James,

After a good few attempts to work out where the spikes came from, my conclusion was the same as your rather good guess and that they are from the clips on the objective. This is a conclusion based on elimination of all other causes rather than direct proof, and I never bothered doing a little stop down test to make sure. This is down to laziness on my part, and the fact that I decided they didn't bother me and that I rather liked them, in their own false way.

As for the belt mod, I should have done it sooner, although then I wouldn't have the pleasure of seeing the improvements now

Cheers

Matt

[Thalestris24]

Hi Matt

I did the belt mod too but my guiding hasn't really improved. It's still +/-4" p-p (with a finder guider + qhy5l-ii mono) and gets worse with increasing alt above about 35-40 deg. I'm not sure if it isn't a balance or flex issue. Also I get pretty much the same guiding error with the AVX. However, I've only been using the heq5 for widefield (200mm) for a while so the errors aren't so important. Glad you are pleased with yours!

Louise

[MattJenko]

Sorry to hear that Louise. I did see your thread of woe, which did make me a little reluctant to tinker with mine. I have a feeling that in doing the mod I also cleaned up as it was very messy and ensured everything was nice and tidy inside which might have helped irrespective of the mod itself.

[Thalestris24]

Sorry to hear that Louise. I did see your thread of woe, which did make me a little reluctant to tinker with mine. I have a feeling that in doing the mod I also cleaned up as it was very messy and ensured everything was nice and tidy inside which might have helped irrespective of the mod itself.

That's ok. I'm mostly using the AVX + 130pds anyway. There could be several reasons for the not-so-good guiding with both scopes. I'm working to improve things with the AVX. Mind you, it's been cloudy up here for weeks! I've also just got a Star Adventurer kit and hope to get to have a go with that soon. Waiting for a ball head, some other bits - and clear skies!

Louise

[MattJenko]

Good luck with the Star Adventurer. I have one and think it is excellent. Took it on holiday and it worked a treat.

[kookoo_gr]

Sorry for hijacking this thread but i would like to place my positive opinion for this mod. For the heq5 pro this mod gives a new life to the specific mount. I did mine and although i had tuned my mount and wasn't that noisy now it is stealthy quiet. As for the guiding i can confirm Matt's post, the guiding has improved tenfold, I used my RC 8'' and after the tuning of the mod i had my phd graph at 0.8'', my limiting factor is seeing which gives me an average of 1.0''ish at phd and i need to play with the adjustments at phd to find the sweet spot for my guiding. I have logged the periodic error of my mount and entered it at eqmod in order to see my mount's behaviour the next time, but initial tests show that it tracks much better than before. The "but" in all of these is that you need reduce any flexure at the system. Here is a pic of M20 with 25 frames at each channel, before this mod i would have trhown half of the frames due to bad guiding. http://www.astrobin.com/196469/

[Gonzo]

This is something I'm planning to do on my HEQ5, didn't have the time before I went to Germany to install the mount.

After seeing the videos on youTube about it, it looks like a sound mod to do.