SPC880 Magnitude Webcam Sensitivity

[SniffTheGlove]

Hello,

I am asking an experienced SPC880/SPC900 webcam users that can help me with webcam sensitivity.

The reason I am asking is that the other day I tried for the 3rd time to image Betelgeuse but I could not see it on the PC Screen.

In fact with the exposure on the lowest level in Sharpcap (-4) I can see Sirius, the Moon and Jupiter but that is about all. I have tried the gain settings but still only see the most brightest of objects.

What is the limiting magnitude the SPC880 can resolve to on a 10in Scope.

[lukebl]

I can get down to about mag 7 with my unmodded SPC880/SPC900 in my ST80 guidescope. I have used Betelguese to check focus, and it almost burns a hole in the screen!

I can therefore only assume that you haven't got focus right, or it's not on the chip. Remember, it is a very tiny chip and with a relatively long FL can be difficult to locate. Your scope is F/7 and mine are f/5, so not sure if that makes a significant difference, but I wouldn't have thought that it would prevent you seeing Betelguese.

[Ben Ritchie]

Agree with Luke, Betelgeuse is very bright and will saturate easily - so it's either not on the chip or there's something up with the settings

[SniffTheGlove]

I have tried a few times to work this all out but I keep failing.

Look at it from a different angle, if you have an SPC880/900 in your focuser and your focus is spot on (Let me use Sirius here as I have done this) and then allowed your FOV to drift, at anytime do you see any other stars show up on the PC screen.

Or look at it this way, with focus all setup on Sirius and I move the scope to another part of the sky can you see any stars at at all on the PC Screen.

If you can, could you let me know what the settings are so I can input them into Sharpcap.

I would just like to see some stars on the PC Screen with the SPC880 apart from the very bright objects like Sirius,Moon and Jupiter if you know what I mean.

Sharpcap displays the settings as numbers and the scale does not indicate what that number means, like the exposure is -14 to -4 and the Gain is 0 to 63, so if anyone can say here is what I use to see starfields with a SPC880/900 with Sharpcap.

Thanks