SDC-435 Live video behaviour query

[michaelmorris]

I'm confused about the way my SDC-435 is behaving. It is probably normal, but I just want to be sure.

Firstly, is sens-up with a maximum of x 512 basically the same as setting he maunal exposure to x512 (assuming that it is a very dim object and the camera goes for x 512 as the right exposure)?

When I bought the SDC-435 (I suspect wrongly) I assumed that when it was set to x 512 exposure, it added 512 frames together and outputed the result as an image. It then added the next x512 frames and outputted that as a separate image. Looking at a video showing the SCB 4000 in operation, this appears to be exactly what happens. The deep sky objects and star fields come on the screen pretty instantly (with a delay for the integration cycle).

What appears to happen on my SDC-435 is that it outputs one set of frames (x 512 I assume), then adds a further 512 frames, then another 512 frames and so on... This takes many minutes to build up a similarly detailed picture.

Do the two cameras normally behave differently or have I missed something on the camera settings?

[Peter Drew]

I hope you are right in your assumption that the 512x integrations are displayed as separate individual images. My Watec 120n does this for 256x so I bought my SDC 435 on this apparent promise with the advantage of 512x and colour. I've yet to try it out properly yet so can't help with a comparison.

[Psychobilly]

If your using the noise reduction then the image wil continue to change (if the tracking is V good it should improve) over time...

As I understood it (or thought I did) The camera intergrates N frames then displays this frame at the normal video frame rate (25 fps PAL/30 fps NTSC) until the next N frames are integrated...

So you get an updated frame every few seconds (Number of intergrations/video Frame rate) ...

Peter...

[DoctorD]

Hi

I agree with Peter - the effects of AGC and noise reduction (SDNR?) mean that the output can change from frame to frame.

It can take several minutes for the image to stabiles with high levels of noise reduction and integration.

How effective this is will depend upon the accuracy of your mount.

Some of the most impressive images have been achieved with a guided mount (see Steve Wainwrights site - QCUIAG).

Mind you in my opinion this is not where these low cost video cameras fit in - if you are going to invest in a mount capable of being guided you will probably want a dedicated Astro CCD camera or DSLR.

I prefer to use my SDC435 for visually assisted astronomy on a monitor and do not always capture to a PC.

Clear skies

Paul