Lodestar autoguider

[gregbradley]

Is anyone using a Lodestar autoguider?

I have one.

When I first got it it showed a white line near the top of the image. An artifact. It would disrupt the autoguiding function in CCDsoft as the software would sometimes confuse the white line with the guide star. Not so much in autoguiding but it became almost impossible to callibrate it.
If you used subframes the white line would simply appear in the smaller image.

I sent it back as later on the USB socket broke off and fell inside the camera.

Terry Platt of Starlight Express sent it back after the repair (free).

I used it again last week. It only has a small artifact in the top horizontal part of the image which is acceptable and does not confuse the software.

But now it has a bright and quite wide white line on the left side edge of the image. Straight line and the outer edge of the image.

This really affects autoguiding. I was able to callibrate it several times (sometimes it fought). But what happens now is occassionally the autoguider software (CCDSoft) picks this white line and I get a massive correction ordered. It then sticks on this correction and occassionally it unsticks itself and goes back to normal.

So I get quite a few images with nice round stars and then some that are wrecked. Once it goes it sometimes does not fix up.

I emailed Terry about it and he emailed back that he replaced the camera - its a different one. Oh.

So 2 in a row not working properly at least in CCDsoft.

I would prefer to use CCDSoft as I can use direct guiding with my Paramount Mount which per Software Bisque is better than the relay method.

Anyone else had this trouble with a Lodestar?

I am going to try it at some point with PHD guiding to see if that helps.

Greg.

[leinad]

This is present on mine as well. Its a white vertical band line on the left side. Using full calibration with darks frames in MaximDL guiding removes it .

Cant help with CCDSoft though, as I dont use it.

Got a screengrab you can post?

[gregbradley]

Thanks Leinad.

I use auto dark in CCDsoft and that helps but does not fully get rid of it.
I think the autodark in CCDsoft is a bit flawed or at least the display of it is as it seems to get rid of the stars as well or make them very small.

That white line is not present in every other CCD I have used including a Starfish which also used a CMOS chip.

My ST402 does not do that.

I think I'll have to check out these new SBIG Sti guiding cameras. They seem similar but it uses a Kodak KAI0341 chip.

Greg.

[gbeal]

I have one, and as far as I can recall, mine is without defect. Try it in PHD first. On the bright side, selling it will be simple, they are well sought after, very.
Gary

[bert]

Greg,

I would have to ask why you would use the lodestar over your st402. The lodestar is not as sensitive, and from what you have written, problematic. What is the attraction of the lodestar?

Brett

[leinad]

Maybe Terry can explain what the cause is. I recall it mentioned somewhere but cant remember now what the explanation was.

I have a dark library for the lodestar of .01 secs though to 2sec, and 2secs shots.

Which ever sec iteration I use in Maxim for AO guiding it uses that library dark frames.


Im not sure if hes using a different firmware or electronics, but it mine seems to have less noise present to an older version.

My Lodestar is plenty sensitve at 0.1sec frames. Then again it is OAG on the 1800mm f/9 scope.

[RickS]

I've never noticed any white lines on mine and it has guided flawlessly with Maxim so far...

Cheers,
Rick.

[leinad]

Here Greg,

Heres a single dark 1x1 500ms; and calibrated dark(10frames), just auto scaled, saved and cropped with CCDStack and PS.

I've also just emailed Terry for his insight.

[gregbradley]

It is lighter and it connects instantly and works off the USB hub of the Proline whereas the ST402 does sometimes and not others. The ST402 is very good though and it is my standard guider.

I also need a 2nd guider as I am about to use a 2nd setup at the same time.

I guided with the Lodestar recently and it does work but this white line does cause the occassional difficulty. Perhaps the dark library is the way to go.
The St402 is a bit more sensitive and less noisy with its cooling but it does require a power lead and a separate USB cable. Minor I know.



That's good advice.



That's good to know.

Cheers,

Greg.

[gregbradley]

Do you use CCDSoft for guiding?

Greg.

[leinad]

Hey Greg,

Heres a reply from Terry. :)

"It will be a firmware difference, rather than a hardware one. The light edge will be caused by a minor transient voltage change as the line readout begins.

I can't be sure which version didn't show this, but I might be able to locate it. However, it is a very low level effect and is completely removed if you subtract a bias frame."

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Nah I use MaximDL's AO Guider feature. I've been thinking about trying CCDSoft, but havnt got around to trying it out yet.

Looks like Reduction Groups is CCDSofts option?

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*added Bias frame to the above images.

[gregbradley]

Does he mean there is an updated firmware that corrects this? Or does he mean if you get the white line you must do a bias subtract?

CCDSoft does an autodark which only half works. But there is an option for full reduction or bias only etc. I have never used it and it is not completely clear how it works. I think you probably have to save the bias image somewhere in the folder group specified?? Anyone know?

Greg.

[leinad]

It can be removed with Bias subtract.

Most likely similar to Maxim. Go to Redcution groups; put your autioguider cal file in the appropraite autoguider folders, then possibly under camera control settings, enable it.
Every light frame taken (even autoguiding) should then by bias/dark subtracted; either pre or post frame.

I had a quick glance at the manual; seems to be all in there. Pg 60-80ish

[gregbradley]

Oh yes I see. Under image/image reduction then there are empty files where you can put your bias, dark and flat.

That's great. I'll do that for both the Lodestar and the ST402 and see how that goes.

Cheers,

Greg.