Lodestar Bad Pixels and Columns on Purchase

[badgers]

I received a Lodestar for guiding from FLO today.

I just gave it a quick test out of the box. It appears to have numerous bad pixels and column defects.

Images taken with cap on for 2.0secs

A dark frame deals with most of this.

Do I need to be concerned ?

The dark frame tackles most of the issues, but it did seem like a lot of defects for a Grade 1 CCD ?

Any one got any experience of a Lodestar out of the box ?

Badgers

[Stephen]

A frame shot with the cap on is a dark frame, so you've just subtracted the garbage from the garbage which you would expect to result in little to no defects in the output

How warm was it when you were taking the shots? IIRC the Lodestar is "air cooled" so might perform differently out at night if you shot during the day in the house?

The lines I don't know enough about to comment, the number of hot spots may well just be a temperature issue.

Have you sent the image to FLO and asked their input?

[Jessun]

I have a few hot pixels on my Lodestar, but no funny colums. My M25 has what looks like a bad column but is not actually that in tech lingo but rather some readout anomaly - meaning that it fulfills the specs. I wonder if your Lodestar would be classed as the same.

The darks work for you, and for me on both cameras so I wouldn't be concerned. Send the SX chaps an image and see what they class it as just to make sure.

[badgers]

A frame shot with the cap on is a dark frame, so you've just subtracted the garbage from the garbage

How warm was it when you were taking the shots? IIRC the Lodestar is "air cooled" so might perform differently out at night?

Yes, true enough..... And it's very warm in the office here.

Point taken, I'll check it outside hooked up to the finder-guider as soon as the clouds clear - i.e. never

[steppenwolf]

By subtracting a Dark frame, you have also subtracted a Bias frame and I suspect that it is the Bias frame that has removed the bad column issue. I have a 'bad column' on my SX SXVF-M25C and a Bias subtraction resolves this nicely for me.

[badgers]

A bit of research online shows people having a couple of dead pixels and maybe one column issue with out of the box lodestars.

The Starlight express website says:

"CCD quality: Grade 1 or better - No bad columns, no dead pixels, no more than 6 'hot' pixels (saturated in <10 seconds)."

I'll test it tonight on the 9x50 guider at the appropriate temperature, but if it still looks like the first image above I may look at exchanging it.

Even if dark frames will mostly cure the issue, i don't see the point of paying for Grade 1 and getting Grade 4.

[rfdesigner]

A bit of research online shows people having a couple of dead pixels and maybe one column issue with out of the box lodestars.

The Starlight express website says:

"CCD quality: Grade 1 or better - No bad columns, no dead pixels, no more than 6 'hot' pixels (saturated in <10 seconds)."

I'll test it tonight on the 9x50 guider at the appropriate temperature, but if it still looks like the first image above I may look at exchanging it.

Even if dark frames will mostly cure the issue, i don't see the point of paying for Grade 1 and getting Grade 4.

I have to say yours does look less than good.

I have one cool column, and 4 noticable pixels, although I'd call them 'slightly naughty' not really bad.. That is at +10C. Dark current doubles with each 6~8C rise in temp, hot pixels and columns can be flatter or steeper than this.

Derek

[badgers]

Naughtly Pixels lol!

There are many of those on the internet

[steppenwolf]

Have to agree that your columns do look particularly 'naughty' and the Lodestar is supposed to be a high end device. With all those columns, yours does seem to fall short of that.

[badgers]

I've run it now attached to the finderscope fridge cooled to below 10C with the cap on.

I've also replaced the cable and tried both Windows and Macintosh version of PHD.

This was run at 10 seconds as per SXV instructions.

Same story, this should fail for one column defect, it has at least 6

A lot of 'warm' pixels and 2 or 3 properly hot pixels.

And 2 seconds here (about 5 degrees C)

I'll email FLO and see what happens, clearly this is below the standards described for a Grade 1 CCD.

Thanks for the help

[badgers]

Hats off to Martin and everyone at First Light Optics.

They agreed it looked pretty woeful for an out of the box Lodestar and will issue a replacement.

I know this is an expensive hobby (or can be), but it is really reassuring to see this kind of customer service.

[badgers]

New lodestar is just fine, thank you FLO!

[Stephen]

Result

[ollypenrice]

The joys of using a good dealer...

Olly

[mhard26339]

I must admit that I have just purchased a Lodestar and have a problem with Hot pixels, no photo available at this location but 7 or 8 large hotspots to auto guide on!!. I went another route and contacted Starlight Xpress direct, they were very helpful, have given me a couple of potential fixes ie use dark slides in PHD but it has not helped. Further contact and they have agreed, without hassle, to take the item back and change the chip for "one with less defects". Not sure what this means but from your results a. I know that my class 1 ccd is not good enough and b. I will await the results of the new chip with "less defects", if the result is the same as your "fixed" image it will be a great improvement and I will be happy.

I must agree with the comment that this hobby can be expensive and when you buy quality equipment I expect it to work given correct operating parameters. will keep you informed.

[mhard26339]

Further to my last, as you can see I am a new member and also new to this game. the advice on this forum is invaluable although sometimes the more I read the more confused i become???

Regards

Mike

[Cath]

I have to say yours does look less than good.

+1

Image sensors age with time as well. I'd be wanting to start with a good one rather than one with several columns myself.

Well done FLO for replacing it.

[Gina]

I have one on order from FLO and these defects just go to confirm that I did the right thing - I know that whatever happens I shall end up with a perfect or very near perfect guide camera That would not be the case buying second hand - that's pure luck!

[mhard26339]

I can only agree with you Gina. An update on my saga with Starlight Xpress; I live in Spain but I am returning for 1 week over the May bank holiday, Terry Platt has sent me his home address and will work on my lodestar over the weekend in order to get it back to me whilst I am still in UK - that is what I call Customer Service - hope the end result is as good as above.

Mike