New camera, new hub...

[Hallingskies]

During the “close season” I decided to upgrade the camera and peripherals on my venerable Vixen ED114SS.  Whilst the scope itself has some minor faults, I am rather attached to it and decided I could live with the slightly halated stars at the blue end of the spectrum, and reckoned that the addition of a focus motor might help reduce the considerable image shift I was getting when trying to manually tweak the rather hefty rack and pinion focuser after swapping between filters.

The first stage was replacing my old and equally venerable SXV-H9 for a wider field camera with set-point cooling.  I had ruled out shuttered cameras and big chip jobs, partly on cost, partly because I wanted to stick with my existing 1.25 inch Astronomik LRGB filters, and partly because I wasn’t too sure the ED114 could give me a flat field over too big an imaging area (although DLSR frames had always seemed reasonable). 

After much agonising I went for the ATIK 460EX, rather than the Starlight Xpress equivalent, the SX674.  My SXV-H9 has been absolutely brilliant for the last 15 years and the SX674 (with its excellent cooling capability and nifty inbuilt USB hub) was therefore very tempting.  What put me off was that I have never had much luck when it comes to Starlight Xpress software.  I have yet to successfully install the SXV-H9 on any of the computers I have owned over the years first time, without an endless series of error messages and “missing driver” warnings every time I changed computer.  I had a similar nightmare when I bought a Lodestar last year.  Although I cannot fault the support I got from SX’s Terry Platt, who helped me get it all going in the end on my obbo PC (though even he couldn't make the Lodestar work on either my XP laptop or desktop), I would rather just have something that works out of the box first time, without the need for a subsequent series of e-mails and additional software downloads. 

My old ATIK manual filter wheel was also overdue for replacement.  This has always leaked light and I had to resort to wrapping it up in tin foil, like the turkey it was.  The act of manually changing over filters also seemed to cause a tiny bit more image shift. 

As I had plumped for the ATIK 460, I thought I may as well push the boat out and get the EFW2 electronic filter wheel to go with it.  And a new set of narrow band filters while I was at it.  My existing H alpha filter was a 12nm bandwidth, and my Astronomik OIII filter was utterly useless for imaging, giving horrendous halos around stars.  As the EFW2 is a nine-place job, I also went for a full stack of Baader narrow band filters (SII, Ha, OIII and Hb), which, when combined with my LRGBs and a CLS, filled it up nicely.  I have never used SII or Hb filters and it will be interesting to see what they add.

So eventually, I gave many, many of my pounds to local astro dealer Ian King who, in return, promptly sent me my shiny new toys. 

It was with some trepidation that I downloaded ATIK’s software on to my observatory Windows 7 PC.  It took a nerve-wracking few minutes for it all to squirt over the airwaves and down the wires, hanging for disconcertingly long periods during which it seemed to be doing nothing.

And then finally…

…it all connected and it all worked, first time.  It was the same story when I loaded it all on to an old Vista laptop.  No drama, no fuss.  I was a little disappointed that I couldn’t get the camera to talk to Astroart, which I had been using for image acquisition, despite downloading and installing the Astroart plug-in.  However, ATIK’s Artemis capture software seems to be, in many respects, a better way of working and I soon got used to it.

The EFW2 is a beast of a unit.  It is very solidly built and makes a satisfying little hum to let you know it is doing its thing when you ask it to.  Its size meant it needed to be mounted “upwards” on the back of the scope to avoid hitting the telescope pier when the scope was pointing at targets overhead.  Fitting the filters is easy, and having nine places makes that a one-off job.

With the image train sorted, I decided to look at the focuser.  I also now had a veritable rat’s nest of USB, power and dew heater cables hanging down from the scope that meant a snagging disaster would be inevitable.  Whilst I was wary of introducing a USB hub into the mix given the many and varied horror stories I have read about them on this forum, I thought a hub would be preferable to the alternative of four five meter USB cables (mount, filter wheel, camera, guide camera) and a similar run of 12v power cables trailing from the scope, down the pillar and along the floor to the PC/power supply, the former of which was already USB’d-up with the dome controller, keyboard, mouse and radio dongle for the internet connection.

So yet more of my pounds went to Altair Astro for a Pegasus Ultimate Hub and associated focus stepper motor.  The hub mounted easily to a dovetail bar on the top of the scope and a set of quality Lindy 1m USB cable connected everything up, with a single 5m Lindy going back to the PC.  As a bonus, the Pegasus hub allows you to plug in and control your dew heaters (one for the main scope and one for the guide scope), saving yet another run of cables.

I had a few minor niggles with the Pegasus kit.

The mounting brackets are optional and rather expensive extra for what they are.  For the price they charge for the hub, you’d think they’d include them.  Similarly, they provide a nice diagram telling you how to wire up a cable for the focus motor (which I did), but I’d much rather they just supply the cable!  Maybe I am being unreasonable as I suppose some users will not require either.

The hub comes with a full set of 12v supply cables which fitted the ATIK camera and filter wheel, but the input 1.8m 12v cable with a 2.5mm pin (the outputs are 2.1mm) isn’t really long enough.  I couldn’t find a suitable plug on the web to make up my own power lead, and so I just cut the cigar lighter plug off of the supplied lead and extended it (my power supply output is fused so no worries there).  Given that everything runs off this one input, I was a bit disappointed that it’s just a push-fit plug with no locking screw collar.  Other than that, the hub build quality feels excellent, with (all six) USB and (all four) 12v power outlet sockets firmly gripping their respective plug-ins.

The focus motor comes with a somewhat bendy bracket that nevertheless fitted readily onto the end of the scope dovetail bar and enabled a straightforward coupling of the motor to the shaft of the rack and pinion of my scope.  I had to drill the flexible aluminium coupling boss out a bit as it was too small for my focuser, but other than that, it was a cinch to install.

The control software for the hub downloaded and installed easily.  I would have appreciated some detailed instructions for using it, although to be fair it is fairly basic in nature.  I had an initial puzzling couple of minutes before I realised that the “connect” icon for the hub is a tiny squiggle tucked away in the top left hand corner of the main control screen.  Once I worked that out, everything connected up just fine. 

Although my scope rack and pinion is a direct drive with no geared reduction, the Pegasus focuser allows really tiny adjustments to be made.  There seems to be a capability to manually put a backlash figure in to compensate for the inevitable lag in the rack and pinion, but it doesn’t seem to store the figure.  I guess the design intent is for it to run with an autofocus set-up, but I have still found it quite easy to use in “manumatic” mode, in conjunction with the ATIK Artemis focus screen.  It has greatly reduced the amount of image shift I get on refocusing, and allows me to make much finer focus adjustments than I could ever achieve manually.

One outstanding minor aggravation is that the Pegasus software seems to “hog” the USB ports on my PC.  I have not (yet) routed my NEQ6 EQDIR USB connection via the hub, preferring at the moment to send that back to the PC separately.

However, if I turn on the mount before I try and connect the hub via its command screen, the hub sulks and simply refuses to connect.  It connects just fine if the mount power is off, and then stays connected when the mount is turned on.  However, the hub seems to then “block” the EQDIR connection to EQASCOM from the mount.  The EQDIR connection shows up on the PC device manager, but I get the dreaded ASCOM “time out screen” when I try to run the planetarium programme.  I have to then unplug the EQDIR cable from the PC and then plug it back it in.  This seems to “force” the connection, and I can then open the EQMOD telescope control and connect my planetarium software to it.

I now also need to make sure I connect the guide camera and mount to PHD before I connect to the planetarium software, otherwise connecting PHD after I have pointed the scope freezes the EQMOD control, stops all tracking and locks up the planetarium software, requiring a re-set from the Windows task manager.

I’m not yet entirely sure that this is 100% down to the Pegasus software, but I had none of this aggravation before using the Pegasus hub.  I do wonder if my EQDIR cable is on the blink instead, but provided I start everything up in the right order, it all seems to work – touch wood.

I may try and send the EQDIR output from the mount through the hub to see if this improves connectivity, but at the moment I’m inclined to leave things alone.

The Pegasus hub offers temperature and humidity monitoring that has already proved invaluable as I live by a river, so that even inside an observatory, dew heaters are an absolute essential to keep the optics clear and dew-free.  There is an automatic option that allegedly adjusts the power sent to the dew heaters based on the temperature/humidity readings, but so far, it just seems to be full on/full off from what I’ve seen - not that this is a problem or necessarily even wrong.  It definitely runs the heaters once the dew point catches up with the temperature, so that's one less thing to think about.

As for the ATIK 460EX, initial images seem very promising.  Although its cooling capability is a bit pathetic to be honest, running it at -5 degrees seems to give quieter and far more reproducible dark frame stacks than I could achieve with the SXV-H9.  And the image field offers twice the area, which I look forward to exploiting in the coming months.

Although I am fairly pleased with them, my first images with the new set-up do show slightly eggy stars at the corners, with the axes of the eggs directed towards the centre of the frame.  This is almost certainly a camera spacing issue.  I have e-mailed Vixen UK to see if they know what the right corrector-to-focal plane distance for the ED114 is, but it may well be a case of trial and error to fix things on that front.

One small thing with the EFW2 software is that although the filter wheel connects and goes through its initial start-up rotation as soon as I power it up via the Pegasus hub, attempting to subsequently select a filter position gives you a choice of a hundred filter positions, none of which work!  Disconnecting and reconnecting via the Artemis software brings up the usual nine positions, and the wheel works fine after that.

So whilst not a clean win on the software front, I am reasonably happy with the upgrade exercise as it stands.  The ATIK camera and filter wheel work well and the Artemis control software seems hassle free and reasonably intuitive.  The Pegasus hub really cuts out the cable tangle, allowing me to easily de-mount the whole scope/hardware bundle and bring it all indoors for security purposes if I know I won’t be imaging for a while.  And I'm pleased with the simplicity of the stepper motor focus control and the delicate touch it provides.

Early days I know, but the hardware all seems to work fine.  I think the software is going to be the immediate ongoing issue (as ever) but fingers crossed…

Edited September 5, 2018 by Hallingskies
typo, URL added

[hughgilhespie]

15 hours ago, Hallingskies said:

One outstanding minor aggravation is that the Pegasus software seems to “hog” the USB ports on my PC.  I have not (yet) routed my NEQ6 EQDIR USB connection via the hub, preferring at the moment to send that back to the PC separately.

Hi,

Really good write up - thanks!

I had a similar experience with my Pegasus UPB in that when I connected it to my mount computer, the computer wouldn't accept other USB inputs. At that time I was using an old EQDir cable with the Prolific chipset. I replaced this with a new FTDI based adaptor and as far as I can tell everything now works as it should. However, I do use the Pegasus USB hub in preference to the mount computer so my EQDir does come from the Pegasus hub. 

As everything seems to work, I haven't really done any more testing so this is far from definitive but I suspect the problem was more to do with the old EQDir cable rather than the Pegasus.

HTH

Regards, Hugh

Edited September 6, 2018 by hughgilhespie
Added comment

[Hallingskies]

1 hour ago, hughgilhespie said:

At that time I was using an old EQDir cable with the Prolific chipset. I replaced this with a new FTDI based adaptor and as far as I can tell everything now works as it should.

Thanks for your reply, Hugh, it’s good to know it’s not just me!  The EQDIR cable I use is of the FTDI variety, but I do have a shorter Lynx-made FTDI cable that I could connect the mount to the hub with.  If I get any more problems that’ll be the first thing I try.

[assouptro]

Brilliant report with loads of useful info

i had the hitch Astro mount hub pro until it recently developed a fault and I also had a “start up” routine that made everything work but if I deviated I would sometimes have to restart my windows 7 laptop to reconnect everything.

in particular the Atik efw2, I would start this second after the camera and then count to 20 before starting anything else, this gave enough time for the efw2 to complete a full revolution and “calibrate”

thanks again for taking the time to communicate your experience.

Bryan