The QH5Y Guide Camera v The DSI-C

[centroid]

Further to my recent 'thread' regarding the QH5Y and guide cameras in general, I was very fortunate to be able to make a direct comparison between the DSI-C (my current guide cam), and the QH5Y.

Roger (celescope) was up at his Holiday Home here in Suffolk this weekend, and came round to spend the evening in the obsy with me, in order to comapare the two cameras. Rog has recently acquired a QH5Y BTW.

The comparison test was purely subjective, so there are no actual performance figures that I can quote. However, the tests were quite conclusive.

Firstly, I was interested to see how the QH5Y worked with AA4, and the simple answer to this is, very well, and as there are also Maxim drivers available for this camera, I'm confident it would work equally well with this software.

For the purpose of this test, and to mimic what Roger uses, I downloaded the free version of PHD, and this was then used throughout the tests.

With my main scope/mount (LX200R) 'talking' to TheSky 6 software, we set about locating a dim star, and settled on one at mag 9.83.

The QH5Y was attached to my ED80 guide scope, at it's natural f/7.5 and 600mm Focal length. With the exposure time at 1 second, the star was just about visible on the screen, but PHD managed to 'grab' hold of it, complete a Cal sequence, and guide the LX Mount.

Without moving the scope, we swapped the QH5Y for the DSI-C. Instead of seeing the one dim star, several stars now appeared on the screen, and the test star, was significantly brighter.

From this, is was very apparent that the CCD in the DSI, albeit a colour one, is significantly more sensitive than the CMOS sensor of the QH5Y.

Having said that, the DSI-C is something like twice the price of the QH5Y, and in practical terms, the QH5Y is, IMO, a very useable guide camera, for not a lot of money.

Roger has been using the QH5Y/PHD combination very successfully recently, and achieved some excellent guiding with it.

So, from my own point of view, and wanting a more sensitive guide camera than the DSI-C, the QH5Y would be a retrograde step for me, and as such is now off my list of 'possibles'.

I should also comment on the PHD software, which I had not used before. There was no question that it did guide very well indeed, and I was quite surprised and impressed with how accurate it did guide, throughout and hour of 5 min subs.

From a 'user' point of view, I found it had quite a few annoying 'quirks', such at that it wanted to run through a very time consuming calibration procedure every time after it was 'stopped', by default it kept resetting the exposure time to 0.2s, and it couldn't remember which camera it had been told to use, once 'stopped'. Also on several occasions, it needed to be closed and re-opened to get it to talk to the 'mount' again.

Being used to guiding with AA4, and having tried Maxim, I found that I couldn't control various parameters, that I used to being able to.

However, it is free, and it does guide very well indeed, so my criticism may be somewhat unjust.

I'm lead to believe, that there is a version of PHD that has be purchased, and I suspect this version would be a lot more sophisticated than it's 'freebie' sibling.

For me, I'm no further forward in deciding which camera with which to replace my DSI-C guide cam, in order to get increased sensitivity. However, it was a very interesting and productive evening, spent in good company.

Hope this mini-review is of interest to other forum members, who like me, may be thinking about guide cameras and guiding software.

Dave

[coatesg]

Great review there Dave - thanks for the useful info about these cameras.

More to chew over now on the guide cam front...

Cheers,

[barkis]

That was a very informative report Dave, and I am sure it will help decision making for others too.

As far as your own dilemma, have you not considered a sxv guide head, I understand the later ones had a more sensitive chip modification, so there must be an improvement on the performance. I know they are fairly expensive, so I guess a used one would be desirable should you decide on going for one.

Ron.

[centroid]

The SX guide head is on my list of options Ron, but I've yet to read any reports/reviews on it.

The SX Lodestar is just what I'm looking for, as it uses the Sony ICX429AL 'chip', and I've used this 'chip' before, and know what it can do.

However, like most SX 'gear' its expensive (£400) for just a guide cam.

Dave

[MartinB]

£400 eh. Well the advantage of the lodestar (whenever it is finally available) is that it has a bigger chip than the current SXV guide head. I find the SXV guidehead to be fine with an ED80 but the Lodestar will be worth considering for use with the SXV AO unit. It's no fun finding a guide star in an off axis set up with a f/l of 2000 at F10!

[centroid]

In my initial 'post' under this 'thread', I said:

I'm lead to believe, that there is a version of PHD that has be purchased, and I suspect this version would be a lot more sophisticated than it's 'freebie' sibling.

Disappointingly, this appears not to be the case. I checked on Stark-Labs web-site, and only the basic 'freebie' version seems to be available. Unless someone know different of course?

Dave

[daz]

Dave

From an EQ6 owners POV, the QHY5 also plugs straight into the autoguiding port - being ST4 - and this means less hassle I think with other conversion hardware.

But a great comparison experiment none the less.

[SteveL]

Can I ask how this direct connection ST4 works? Do you still have to select a guidestar on a connected PC, or does it do it all "automagically"? Just curious

[Milamber]

Steve - you still have to connect the USB lead to your PC/laptop and do the Guidemaster/PHD/Guidedog thing... but going direct from the camera to the mount means there are two less leads - one from the camera to the PC and one from the PC to the mount. Less chance for interference too.

Arthur

[SteveL]

Thanks Arthur, just wasnt sure how it worked... thats cleared that one up for me