SBIG AO units - do they work with other cameras?

[gregbradley]

I am wondering if SBIG AO units can be used with other cameras or do they only work with SBIG cameras?

Greg.

[rally]

Only SBIG !

[Poita]

Damn, I'd been wondering that as well...

[gregbradley]

Thanks Rally.

That's a shame. It'd be good for them as well if they did as not many other companies sell an AO unit.

Greg.

[DavidTrap]

Starlight Express make one that works with the QSI cameras and others.

Link (http://www.starlight-xpress.co.uk/SXV-AO.htm)

DT

[RickS]

In theory, the only issue with using the SX AO-LF with non SX cameras is getting the spacing for the guide camera right.

Cheers,
Rick.

[bert]

What rally said!

But... you can drive it via an OAG with a sbig camera for instance with an other camera imaging.

So you could have an oag behind the ao unit, with an sbig camera (with an i2c port, some st402s have them, and my st8300 and st4k has) in the oag, as the AO guider and have another imaging camera.

Greg: Even if you got an Sbig AOL (shich is the larger of the sbig AO units) I don't think it would cover the 16803 sensor, I have an AOL on a stl6303 without issue, but I do remember someone telling me that they had to crop slightly with the 11002 sensor because of artifacts with the oag pick off prism. Essentially, if you went down the path of driving the AOL with an sbig camera would have to crop the 16083 heavily or just your ML8300.

Brett

[cventer]

Any views on sx ao vs Orion one?

[bert]

The sx works, so the does the orion... sometimes. The orions optic gets stuck sometimes.

[gregbradley]

Thanks for the replies and work around Brett.

So an SX one would work on say an 8300 chip but not a large chip either I take it.

The SX one does look interesting. I wonder if it would make my 8300 work better with the CDK17 or is it not worth pursuing?

Greg.

[RickS]

Greg,

The SX AO-LF deviator plate is 60mm diameter, but the prism is in the optical path, so I think you'd get significant vignetting with a really big sensor.

I have an AO-LF sitting here waiting for my Atlas to arrive. I'll be putting them both on the GSO RC10. Without the Atlas I don't have enough back focus to make everything fit.

Cheers,
Rick.

[Peter Ward]

The SBIG AO can use SBIG's external guide head or the internal guide CCD (in dual chip models) for its operation, hence can not be used with third party cameras.

In the latter configuration it looks at a very tight iso-planic patch of sky that can deliver superb FWHM's as a result. (translation: the further you go off axis the less accurate adaptive corrections become)

[originaltrilogy]

So these have lens inside that bends the light before it gets to CCD instead of moving the mount for little fixes yes?
Does image degrade with extra glass in path?

[telemarker]

Hi Greg,
I use a SX-AO (not the LF version) with my SBIG ST-8300 with no problems, but only at 1650mm FL with a GSO-RC8 on an EQ6pro. I guess at the FL I'm using I don't really see the benefits of beating the seeing. What it does do though is allow me to do longer exposures than I could without it and still get round stars. I've gone as long as 1 hour subs with round stars - not bad eh!!
Guiding really becomes easier using AO, becomes hard when you have to go back to using just a guide cam.:P

[cventer]

Rick do mean back focus or inwards focus ? With the extension rings for the gso I am surprised back focus is an issue? I would have thou go inward focus travel may be with sx ao, plus filter wheel plus camera etc...

[Terry B]

I use an AO8 and find it very useful on my EQ6. I am imaging at 1800mm fl and it made guiding much better especially in dec as it compensates for the backlash very well.
I have very recently changed to a lovely tak NJP mount and I think that the benefit will be less as its trackiing is significantly better than the EQ6.
I have an AO7 for sale and it worked just as well as the AO8 but took up more back focus hence the change.
The AO7 is a mirror that moves rather than a lens. Neither seem to cause image degredation although the AO8 in theory has more potential to do so.

[RickS]

It's a flat plate rather than a lens, but it does lose a small amount of light (claimed to be about 2% for the SX unit).



I mean that I don't have enough back focus distance on the RC10 to fit my intended imaging train (focuser, focal reducer, AO-LF, FW, camera) so, yes, this could also be described as not having enough inward focus travel. I'm currently using a Feathertouch focuser which chews up a lot of distance.

Cheers,
Rick.

[gregbradley]

Thanks for that.

How is that lovely Tak NJP Mount? I miss it already!

Greg.

[gregbradley]

Thanks for the replies.

I am wondering how much improvement the SX AO unit would produce for my setup.

A CDK17 and FLI ML8300. 2932mm focal length.

It is very subject to seeing. Poor seeing, forget it, images will be way too soft.

I have taken a few images though with it and they were good. If the seeing is OK it works allright but I know I will get comments about the images looking a bit soft.

5.4 micron pixels and nearly 3 metres focal length is not a good mix. But its such a good camera it would be worth making it work.

Greg.

[RickS]

I'll let you know how I go with mine, Greg, although I'll only be imaging at 1600 to 2000mm. In theory it is possible to make guide corrections several times a second, so I'm hoping it will result in significantly better images.

Cheers,
Rick.

[Terry B]

Greg
Thanks
I have only installed it last weekend due to needing a Losmandy bar to put my side by side adaptor on it.
As expected it has been 90% cloudy since then. The short time I have used it have shown very smooth movement. The only hassle has been the clunky ascom software compared to EQMOD.
I will get use to it but it will take time.

[gregbradley]

I'll be interested in your results.



Right. That's the Chuck Faranda driver? I used the Sky and the Chuck Faranda driver which boots up once you connect the mount.

Its got the handy park mount feature which means if you don't move the mount the next day you don't need to do an alignment. Also I used the timer every time as a fail safe. Plus the ability to adjust the guide rate on the fly was good for fine tuning the guiding. Plus its free!

Greg.

[telemarker]

If you go with the SX, you'll also need a lodestar and more than likely an extension tube for the OAG. More $.

[gregbradley]

I have a Lodestar. Crappy little thing it is. It has defects in the image.
This is the 2nd one and its worse than the original. A white horizontal line and a bright vertical left edge confuse the guiding software.

I have programmed in a dark subtract but that makes the image go whitish in CCDsoft.

Terry Platt's response is to use darks.

I think I'll ask for a refund and get an SBIG STi.

Greg.

[cventer]

Interesting info greg

By all accounts you read its supposed to be the bees knees of the autoguider world. My understanding was they are supposed to come with class 1 chips in them. Sounds like qualitity control is very poor.

The Atik 16IC gets a decent write up in Graig Starks guider review. I think it was 2nd place behind the lodestar.

His review did not however include the Sbig STi so be interesting to see how that compares. I think you should buy one then tell us all what you think ;)

[bert]

Not that I will tell you what to do......

But if you bought a st402 with the i2c port then you can use Sbig ao as well.

And the 402 is far more sensitive than the sony based guiders.

Brett

[bmitchell82]

I use the 402-me for guiding, though it is a absolute power chewer!!!!! without the cooler it will draw .5-1 amp alone which is far more than my laptop.... Put the cooler on and it jumps to 1.5 2 amps. This isn't a issue when your in a cosy little obs but out in the field its a killer! I have seen a few Lode stars and each one of them have been flawless and very very sensitive! I feel for you Greg with getting duds and a bit of dud service but I think they are very good for field use with no external power req and for the size they are spot on!

I measured the sbigs consumption over the weekend, without it hooked up my whole astrophotography kit with the qhy9 running at 60% cooling power (-25degC) mount tracking, eeepc with full screen brightness it was sitting just on 2.5 amp hours, turn the sbig on it went straight to 3.5 ah turned the cooler it went over 4. so its using twice the amount of power :( Lucky i had a 105ah deep cycle! but for those long winter nights ide be pushing the friendship!

[gregbradley]

Yes I am using an ST402ME already and it works very well. Its a little heavy perhaps and also the power jack is a bit unstable but there is never a problem getting a guide star and no defects in the image. It is also not very USB hub friendly.

So I could use an AO unit with the ST402 eh?

Sounds interesting.

Greg


Martin Pugh has one and told me it was fine.



Power consumption isn't an issue for me as I use mains power at home and a powerful generator at my dark site. But yes if you are using a 12V battery you want to make it last throughout the night.

Thanks for the responses.

Greg.

[Grahame]

Greg, you must have pretty unlucky with the lodestar - Using one myself for 2 years now and apart from mastering a new set of darks as the seasons change its been a godsend! I know of at least two others with them and no such problems have reared their heads - I really do hope these units are going to keep with the standard expected from Starlight Xpress.

[gregbradley]

Hi Grahame,

Did you find you have a white horiztonal line at the top of the image or a white left edge or similar defects?

Greg.

[RickS]

Greg,

I get the white edge on my Lodestar, but Maxim dark subtracts it nicely for me. I'm quite happy with mine...

Cheers,
Rick.

[DavidTrap]

Touch wood - I have no issues with my Lodestar. Very sensitive - haven't had to go hunting for a guidestar using an OAG at 1800mm on 1 sec subs tonight.

Sorry to hear you've had a bad experience Greg. I've certainly come to expect more as I've moved up through the price-range of astrogear.

DT

[gregbradley]

I had a bright idea tonight about the Lodestar. I got a long USB cable with the PMX with mini USB plug. So I plugged it into the Lodestar and connected direct to the computer rather than through the FLI Proline's USB hub which is what I usually do as these small plugged USB cables are usually only really short. I'll have to find another long one from somewhere.

The defects were far far less and these then seem to dark subtract out much more cleanly at 2x2 and at 1x1 it is a really clean dark subtract.

I think Terry was right in the first place when he mentioned it sounded like a USB issue.

I have been finding out recently how sensitive USB 2 cables are. They don't like extensions and they don't like hubs too much.

Hopefully next clear night it'll work like a charm.

Greg.

[marki]

SBIG Sti is not available right now due to a problem with shutter mechanisms. I have been waiting for one for more then 3 months. Dont get rid of the lodster too quickly Greg.

Mark

[gregbradley]

Thanks for the heads up.

Greg.

[Grahame]

Hi Greg,

similar to Rick i have seen the line you speak of but it does subtract out nicely with maxim - again with OAG i never have issues with it (odd hot pixel here and there) but maxim's "remove bad pixels" function sorts them out.

good luck with the testing - just for reference i only ever use the lodestar on a 5 meter active usb2 extension - never through a hub of any sort.

Grahame.

[gregbradley]

Thanks Grahame. What do you use for an active 5 metre USB cable?

Do you know where you can get a 3 or 5 metre USB cable with the mini plug on the camera end?

Greg.

[Poita]

Yes, USB2 cables are very buggy, it is worth investing in a really high quality one. I have in the past had one specially made to provide the 5V separately from a standalone power source, or use the 'twin' usb cables that provide the combined power from two ports, and a lot of problems go away.
I've had luck with these:
http://www.soundlabsgroup.com.au/p/CL-USB2-AmB-cable/Premium+USB+2.0+Cable+Type+A+to+Min i-B
and these:
http://www.4cabling.com.au/products/3M-USB-2.0-Certified-AM%252dBM-CABLE.html

Anything over 5m also tends to cause trouble because of USB expecting certain response times, which is nearly impossible over 5m.

http://en.wikipedia.org/wiki/USB_cable#Maximum_Cable_Length

Though I have had a surprising amount of success using USB -> CAT6 converters and running CAT6 ethernet cable for really long runs.

[DavidTrap]

My Lodestar is working fine (so far) using the supplied cable (3m I think) into a Belkin powered 4 port hub.

I have a 5 metre cable between my hub and pc.

Are you using a quality hub or a no-name one?

DT

[gregbradley]

Thanks for the cable info.

I have been using the supplied very short USB cable into either a hub or the Proline's built in hub.

Hopefully the change of cable has resolved the problem as when it works the Lodestar is handy so light and easy to mount and no extra power cable.

Greg.