Lodestar Problem

[MikeP]

In preparation for SGL7, I thought I'd check out my imaging set up and I have run into a problem with my guide camera - a SX Lodestar.

I have a SX filter wheel with an SX OAG attached to it with an Atik 16HR and SX Lodestar attached to the OAG. Last time I used it (the whole assembly) I spent some time getting the two cameras parfocal. The assembly was removed as single unit and carefully packed away.

Tonight, I replaced the assemby into my ED80, pointed at M81 and did a rough focus with the Atik - no problem. When I switched over to the Lodestar, I got a grainy image with lots of short horizontal lines with a few small blobs that look like they could be slightly out of focus stars. The blobs go away when I cover the end of the scope but the horizontal lines don't.

I've tried altering the focus and exposure times but the lines remain.

The only thing I can think of that has changed is that I upgraded Maxim from version 5.x to 5.18 where x was 1 or 2 or 3 - can't remember.

So can anyone help please? I'm probably doing something stupid.

Mike

[RobH]

Have you tried changing the USB cable Mike....it sounds like a problem I had when a cable decided to expire.

Rob

[MikeP]

Thanks for the suggestion Rob but on this occasion it seems to be software.

I found references to settings: "Show Progress during Readout" and "Apply Venetian Blind Correction", that sounded like they'd do the trick - they didn't. However, there was a throwaway remark in the reference to 2x2 binning, so I tried that and normal service was resumed.

I'm sure that wasn't a problem with my old Maxim (5.07) but 2x2 is acceptable for my purposes.

Never a dull moment with imaging is there.

Mike

[RobH]

Aaah...now you mention it Mike, I did hear some talk a while ago of folk having issues at full binning with lodestars, but I have 2 and have never had a problem with them except for cabling.

Yes, never a dull moment......I'm currently working up the new RC from Ian King.....all my stars were doubles last night!!...except they shouldn't have been ......It seems that collimation is critical in RC's......I'm learning a lot

Cheers

rob

[steppenwolf]

Those horizontal lines are normally a sign of a slow USB port or, as Rob has said, a duff USB cable. The 2 x 2 binning reduces the image size so the horizontal artefacts don't appear in the image because it is a smaller more manageable file to download so there are less readout issues.

[ollypenrice]

The cable attachments into the Lodestar are poor, so poor that Telescope Service do a dedicated aftermarket cable guide device to screw onto the top, presumably because lots of people have had trouble. We had issues with Yves' Lodestar as well. It is very sensitive to how well the cables are inserted. On mine I loop the cables over and have them taped to the camera body.

The use of what are really indoor cables in astrophotgraphy is an issue in my view and something better is called for. I'm often given old fashioned looks by visiting imagers because I don't have all my cables neatly funneled though cable shrouds but that is because I know how often you have to change them when they decide to give up the ghost!

As you say, never a dull moment.

Olly

[blinky]

I'm thinking about getting one of these and from the reading up I have been doing it seems to be that it's suggested you use 2x2 Binning - cant quite remember the reason mind......

[MikeP]

Thanks for all the replies.

I'd assumed that because I'd upgraded Maxim, I'd introduced a bug. From what has been said, it sounds like the problem really is attributable to cabling.

I'll check everything later but it is hard to see what can have happened because I keep all my electrics permanently connected in a Tupperware box. The leads that emerge from the box just connect to the mount, cameras etc and I'm good to go. The box connects to an 85aH leisure battery and via USB to my laptop. The USB hub inside the box is a powered one.

Presumably, if I go back to 1x1 binning and wiggle the cable to the Lodestar, I might see some effect? Anything else I could try (I don't think I have another USB cable like the one the Lodestar uses).

Mike

PS Hi blinky - it works for me but I if a buy a camera and associated bits, I don't expect to be obliged to use 2x2 binning.

[RobH]

I've had cables that are part of my permanent setup fail for no apparent reason at all Mike.

Craig.......you definately don't need to use 2x2 binning with lodestars....in fact, if you use PHD, you don't have that option available to you.

Rob

[daz]

I have had issues where the lodestar cable was too long and suffered voltage drop - I think I was running on a 3m cable... so now keep it down to the 1.5m with a powered hub velcroed to the mount

I have always had problems with 1x1 binning with my lodestar, so just resigned myself to using 2x2. Never bothered me though...

[daz]

I have had issues where the lodestar cable was too long and suffered voltage drop - I think I was running on a 3m cable... so now keep it down to the 1.5m with a powered hub velcroed to the mount

I have always had problems with 1x1 binning with my lodestar, so just resigned myself to using 2x2. Never bothered me though...

I ought to do a set of calibration frames for it - job for a cloudy night!

[Starflyer]

I'm thinking about getting one of these and from the reading up I have been doing it seems to be that it's suggested you use 2x2 Binning - cant quite remember the reason mind......

I've read that too Craig... PHD doesn't (and probably won't) support 2x2 binning with the lodestar, so be aware that you'll need to use another guiding package if you want binning.

That said, I've never had a problem with mine and always have a choice of stars with the OAG at f/4.8, if I take darks and use noise reduction it can double the amount of stars I get.

You'd probably want the extra sensitivity if using an OAG at high focal ratios, it's very sensitive without binning and from my experience you won't need it for fairly fast scopes.

Cheers,

Ian

[psjshep]

By binning the lodestar x2 you get an apparent increase in sensitivity, and the download time is reduced. I did an astrometric reading on a star shortly after obtaining the lodestar, & I reckon it was mag. 7! I am sure I have surpassed this over the time.

If you have an AO unit, then a fast download means more corrections per second. For pulse guiding, you can get the pulse corrections much closer together BUT you may end up chasing the seeing.

Maxim has no problems calculating the centroid of a binned star UNLESS that star has saturated the pixels (too bright). In that case, a reduction in the exposure.

I cannot remember the last time I needed an exposure of > 0.5 seconds.

Just my experience.

Phil