QHY8 First light

[Ford Prefect]

Hi TJ

Ive been having similar field flatness issues with my QHY8 and WO72 and WOFFIII, I have found a spacer of 26 mm between the QHY8 and FF gives a flat field of around 8%.

Cheers Jon

[LostNSpace]

Their not bad 1st light images TJ.....It always takes a while to get used to a new imaging equipment when you have been used to doing DSLR imaging for so long....

Mark

[Tim]

Hi TJ

Ive been having similar field flatness issues with my QHY8 and WO72 and WOFFIII, I have found a spacer of 26 mm between the QHY8 and FF gives a flat field of around 8%.

Cheers Jon

That sounds better! I'll give that a try. So its 26mm between the nosepiece and the FF ?

Thanks Jon

[Ford Prefect]

Yes, 26 mm is correct, since we almost have the same setup Ill be intrested to see how you get on.

Cheers Jon

[Tim]

Quick question for qhy8 owners.

Following Craig Starks advice, I have just tested optimum gain and offset levels.

With an exposure length of 0.01 secs, it takes an offset of 30 to get an ADU of around 500.

Then Mr Stark recommends taking a picture of a bright object or just unscrew the lens and expose the chip to the light. BUT, what exposure length should this pic be taken at? The same 0.01secs?

I found that using 0.1secs instead showing the histogram flat across the length, about halfway up, but with a little bunch at the right hand side. I increased the gain to just slightly nudge that bunching a little further to the right, to avoid the problem with peaking too early (ahem).

Of course, having longer exposures gave many more pixels at max adu. SO any idea what exposure length is best to test with??????

I am very surprised at the offset figure, as this is way below what I've read for most other qhy8s?