AstroArt v5 and Autoguiding

[samtheeagle]

Last night was my first clear night since getting the rather nifty AA5 for my birthday a couple of weeks back. So having been playing a load with the image processing aspects I was VERY keen to get out and try it for guiding and image acqusition I spent a good few hours tinkering, and with it being all new to me I wasn't expecting to achieve a lot. More of a getting to know you exercise really. And it's just as well, as I didn't get a single good sub! I managed to get everything all connected up, and the main capturing aspects went well. The real issue was autoguiding...

The manual explains things fairly well, but I can't help but think I've missed some crucial step, as it failed to guide correctly despite all of my efforts I had a few issues. Firstly the AA5 webcam plugin doesn't appear to offer any facility to adjust the webcams settings. I think this is why the HD Lifecam could only pick up the brightest stars. I've always found it sufficiently sensitive to detect guide stars when using it with PHD. The next bit of fun was the autocalibration routine, the first time I clicked the button it waited a few seconds and then complained that the scope didn't move enough. A second click right after that then seemed to work. Well, it didn't report the same error. Unfortunately I found that if I ran the autocalibration routine a couple of times in a row that it seemed to calculate quite widely varying value for the scope speed and camera angle. That can't be right surely? Then when I did try to guide it was all over the place, and I'm not quite sure how to read the AA5 interface to understand what was going on. Eventually both graphs were just solid blocks of colour, like the star had just drifted miles away from where it should be. And the trails in the subs I took certainly confirm that.

It also crashed on me LOADS, but I can almost forgive that, as I know how tricky it can be to interface with hardware... It just really didn't like my constant connecting and disconnecting of devices while I tried experimenting.

Don't get me wrong, I'm very happy with my purchase of AA5, it's a great bit of software, and once I get the wrinkles sorted out I'm sure it's going to make my imaging workflow a lot cleaner. But if there are people out there who use AA5 for guiding I'd love to hear your thoughts on what the heck is wrong with my AA5 -> EQMOD guiding setup.

[samtheeagle]

I've just got around to looking at the test subs from my first AA5 imaging session, you can quite clearly see that there's some interesting trailing going on.

That's a 100% crop from a 120 second sub. My attempt at reading that trailing is that the "guiding" started off fairly well, as there are some well defined bright stars, and then as time went on it took a serious drift of the the left with a little vertical oscillation thrown in for good measure! Now I think that like usual I had the camera squared up with the scope, so which axis is that main drift on? I polar aligned like I always do with EQMOD, so I would hope that the DEC would be fairly solid.

Also I've been thinking on a bit of a tangent, and I formulated a cunning plan about adjusting my webcam properties seeing how the AA5 plugin doesn't appear to offer any support in that regard. I knocked up a very quick app that allows me to select a webcam connected to the computer, and then display the default driver properies page. My only concern was that two apps might not be able to access the same camera at the same time, but it's working fine. I think the default exposure is really low, so next time out I'll be able to crank it up and hopefully be able to see some more guide star options.

[ollypenrice]

I guide pretty painlessly in AA5 and in AA4 before that. I think that what you have there is most likely to be dirfit in RA. It's only in one axis so it really isn't likely to be Dec, though I suppose it could be. You can easily find out by driving the scope in one or the other to see which is which while guiding.

I'm sure the problem will be to do with the webcam. I use CCD cameras to guide, two Atiks and a Lodestar. I find it autopcalibrates well but I do sometimes alter the aggressivity by changing the scope speed values. Other things to check might be

-Values for 'Don't guide when error is greater than...'

-Pause after guiding.

Sub exposure duration. How does this work with a webcam?

I don't use EQ Mod. Not what you want to hear (!!!) but this is fairly typical for me now;

Olly

[samtheeagle]

Cheers for the suggestions Olly A few more things for me to try should this cloud ever clear, but it's not looking good for the next week

I also have plans afoot to try and get my DSI back in action for guiding purposes, as I haven't been able to get it to reach focus with my 50mm BigEye finder. I'm going to switch back to my old 50mm finder combined with a variable length t-mount extension tube, which I'm hoping will help to resolve the focusing difficulties that initially pushed me away from using the DSI. It looks like it works like a non rotating helical focuser. My only concern is whether the variable extension will sag under the rather heavy weight of the DSI? I've ordered a few fixed length extenders too, so I don't have to have the variable one out drawn out too far.

[Merlin66]

I use the TS and Baader variable T thread adaptors with cameras (AtiK314L, AtiK16 etc) on the spectroscopes...as long as they are done up tight after adjustment, they work 100%.

[Jessun]

samtheeagle, sorry to hear about your troubles. I have no input but will follow your progress, since I have yet so successfully connect any SX camera to AA...

Doesn't bother me too much to capture and guide in Neb/PHD, but it's extra cash...

Good luck and any advice you get I'm likely to use too!

[samtheeagle]

Well I'm getting acheap and cheerful Astro Engineering device, for the bargain price of £14.50 from the AstroBoot It's like this, although the AstroBoot blurb suggested it extends to 72mm rather than 66mm like the image says. I'm not fussed either way, 66mm is more than enough travel, and I've got the fixed sized extensions too. I'd rather extend it as little as possible, to reduce the sag potential.

Sorry to hear you're not even getting your cameras to connect Jessun. So far I've used the Canon, Webcam and DSI driver plugins, and they've all connected without too much issue, though I have had some stability problems when connecting and disconnecting a lot.

And sorry Olly, I missed your question. I can only assume that with webcams the sub duration is ignored, and the plugin just grabs a frame from the stream when requested. That's why I wrote my helper app so I can adjust the exposure and brightness etc. Ideally I'll get back to using the DSI for guiding, but I'm certainly going to test out the Lifecam to see if I can get it working like it does with PHD.

That is a point actually, putting the appropriate values into CCD calc for my 50mm finder and both the DSI and the HD Lifecam I see that the lifecam has a much smaller Image scale at 3.86 arcsec/px. The DSI comes in at 11.01 arcsec/px. I presume the smaller value is better, but how much of an impact might this have on the guiding quality. Sorry for my lack of knowledge, PHD just makes it too easy! I've been guiding for ages now, but as it just works I've not concerned myself too much with the finer details.

[samtheeagle]

Just a quick update on this one to tidy up... I finally had a good night out last night, and AA5 guided a treat for me. I'm pretty sure that I can tweak the settings to improve the performance, but it all just worked once I figured out that my DSI had a severe dislike of the usb cable I was using.

Happy bunny

[Komet]

..... and AA5 guided a treat for me.

I think AstroArts guiding routine is superb ..... its all I actually use AA5 for now. If only Fabio sold it as a stand alone program .....