Customer Name:
Pierce Palmer
Product: Bray Tablet Mount
Date: 3 March 2004
|
Comment:
Well, I've just received my Bray Tablet Mount! I have a Borg 100mm Achro which was supplied with Borg's SWII fork mount. Whist very lightweight, it was hopelessly unstable at anything other than the very lowest powers and in anything other than absolute calm conditions. This was a shame as my dream was to have a lightweight portable set-up to compliment my 10" dobsonian and take advantage of the dark-skies and lovely countryside I have around me (Cumbria, UK).
I spent several weeks trying to decide upon the right replacement, and even tried out a Manfrotto (Bogen) 410 geared head. This was an improvement on the Borg in terms of stability, but there was no way to slew without releasing and keeping hold of release clamps, making it a pain to use.
I then happened across the Tablet Mount, and was intrigued. Chris Garvey at Bray was very patient as he explained the mount's operations and seemed very confident in its ability to provide a rock-steady platform for both my Borg and my 10", even at the same time. He also went into several other mounting options available to me, and was completely unbiased in his viewsI ordered one a few days later, with the recommended wooden tripod by Tele-Optic (I believe) and it arrived this morning.
Having only managed to use it during daylight hours, my first impressions are very good indeed. The quality of the machining and finish far exceeds anything I have ever owned before. There is no slack in any of the fittings and the finish is first class. I've only mounted my Borg on it so far, but even at moderately high powers (x190) and with a considerable breeze, there was no image-shake whatsoever, even when focusing. To get any shake at all, I had to really knock the tube, and even then the vibrations damped out within half a second. I've never used the Giro mounts, but this does seem much more substantial.
Once I balanced the tube correctly, movements were silky smooth, effortless and with zero-backlash. I can imagine being able to track at high powers with absolutely no problems at all. The tension is azimuth is apparently factory set, and allows smooth movement with the merest touch. You can lock the mount in azimuth by turning a knurled knob and this feels very secure. Moving the mount in altitude is equally smooth, and very simple. The mount can hold two telescopes, one on each side, by use of two arms, each of which appear to be bearings in their own rights, allowing movement of the telescopes independently of each other in altitude. However, you can also lock these two arms together, and then move both telescopes in altitude as together. Whichever setting you choose, you can adjust the tension to suit by use of hand levers, which again feel positive.
Whilst not very lightweight, I can imagine happily taking this set-up a mile or so into the hills to get to wonderful observing sites. Whilst my tolerance of lugging stuff may be higher than others, the thought of having a rock-steady mount which you can immediately forget is there at the end of it, is a very tempting proposition.
Well, luckily the clouds turned hazy enough last night for me to spend an hour or so looking at the moon, and trying to put the Bray through its paces.
During the afternoon, I had to go to the post office, so I took the mount along to be weighed, just out of interest. The mount weighs approx 7.5kg (16lb), and I'm guessing the tripod weighs about 4kg (9lb) and with my 2.5kg Borg scope onboard, the whole package weighs 14kg or 30lbs. Whilst this is not inconsiderable, the compact nature of the mount (or more accurately the absence of a counter-balance shaft and weight) and the strap on the surveyor's tripod meant I was easily able to walk for half a mile to leave the village's street lights behind.
I extended the tripod to its full height to really test it, and then popped in a low power 2" eyepiece to find the moon. I think I should say that I love Dobsonian mounts for their stability, lack of vibration and intuitiveness in movement, and I dislike equatorial mounts for their (in my view) unnecessarily complex movements and the frequent need to rotate the OTA to get comfortable viewing, so I'm biased towards alt-az mounts.
Getting the moon in the field of view was a breeze, with free movements in both axis at the same time; something I have found hard to do with my Dobs in the past. Once I had the moon in the field of view, I put in a Meade Ultra Wide 6.7mm eyepiece and a x2 Barlow giving a magnification of x191. I've read some people bemoaning the lack of driven alt-az mounts. When I had my Borg mount, I too prayed for one...anything to stop me having to touch the scope and wait for the image to calm down again. I can't say I felt the need for one last night, as tracking the moon was effortless and in time will become something I don't even have to think about. There was never any image shake, and there was no hint of loose play or backlash at all. Comparing to the Borg again for a moment, if my eye even brushed the eyepiece, I would have to wait 4 or 5 seconds for the image to calm down again. Last night I was drumming my fingers against the tripod's legs and could see no movement at all in the image.
When I moved the scope in altitude on the individual arm bearing, as opposed to the shaft running through the mount, I did find the movement perhaps too loose, especially compared to the azimuth movement. This was somewhat rectified by slightly tightening the locking bolt on the individual arm, but I still found it preferable to lock the two arms together and use the overall altitude bearing (does this make sense? Probably not). This meant that the movements in both axis felt the same. Incidentally, it does seem possible to truly adjust the friction of the movements by varying the degree of tightness. On mounts I've used in the past, it was either locked, or unlocked, with very little in-between. Also, when "playing" with the mount before it got dark, and without a scope mounted to it, I did experience some slight sticky patches in the azimuth movement when rotating the mount round and round. However, once my scope was on, I didn't notice this at all, but I'll still ask Bray about this. With my Borg fork mount, and with previous Dobsonian mounts, I found balancing the tube to be critical, but I found it less critical here. Once I had the tube roughly balanced, I found I could have my eyepiece turret holding 5 eyepieces, or just one, and no adjustment was necessary, yet movements remained smooth and effortless.
I've yet to get the necessary accessories to mount my 10" on the other arm, but hope to do so soon. It'll be interesting to see if it's confusing going from moving a refractor to moving a Newtonian on the same mount and whether there are any balance issues when both are mounted. My gut feeling is there won't be, as the tripod appears rock solid and large enough to cope and I imagine their is sufficient weight in the mount itself to cope with both. I will also be interested to see how close to the Zenith I can get with an 1250mm focal length Newtonian; I managed with little problem with my Borg, once I removed the extra eyepieces from the turret. I shall also check the stability with a heavier and longer scope mounted to it. Again, my gut feeling is that it will be just as solid.
What I wanted was a no-compromise mount; relatively portable, easy to set up, able to mount anything, effortless tracking and rock-solid stability. I have spent far more money than I ever though I would on a mount; it is a reasonably expensive option. I know some people will think it's very expensive for "just" an alt-az mount, but I can't personally see why spending twice as much on an EQ6 (or even more on a GP-DX for example) would be money better spent. Whilst you would then have motor drives, I personally wouldn't see the point when you can track by hand so easily. Admittedly, I haven't tried tracking at x300 or x400 (I will as soon as I can) but from my days of having a GP-DX mount, I found that time-consuming polar alignment was needed to get decent results, and I just can't be bothered! In the past few weeks, I've lost about £100 on buying and selling the Borg Fork mount, and about £50 on buying and selling a Manfrotto 410. I was fed up with throwing money away and wanted to get it right. As I say, it may be a lot of money but at the moment, I can't see why I'd need to ever buy another mount. So far I'm very happy. I'll keep you updated and put some photos on when I get a chance.
PS...I neither work for Bray Imaging or know anyone who does. I am being objective in writing this; I've slagged enough astronomical equipment off in my time, and having spent a reasonable amount of money with them, if I wasn't happy, I would say....but this really is good!
|
44 1525 219100
44 1525 852202
email us
Bray Telescopes and
Teleport 14.5" f/4.5
Teleport 7" f/5.6