Creating Finder Rectangle

[peeb61 (Paul)]

I was wondering if someone could point me in the right direction, I need to create a finder rectangle in CDC and I am a bit unsure to the settings for my QHY8L camera. (Width, Height, Rotation and offset)

Can anyone help me with this??

Thanks in advance.

Paul

[bojan]

You need to calculate the size of the rectangle (in arc minutes), based on size of the sensor and FL of your lens.
Orientation depends on orientation of the chip relative to the celestial coordinates.
If you don't know how, give me those numbers mentioned above (FL, chip size) and I will do it for you.

There is no offset as far as a I know..

[peeb61 (Paul)]

Thanks bojan,
The FL is 1000mm (f/5.2) and chip size is either the total pixel: 3110 x 2030 or Active pixel: 3032 x 2016 and is: 7.8um x 7.8um square.
This is were I go wrong. (I was born without the maths chip in my brain.)

Does this help??

Many thanks
Paul

[bojan]

OK..
so your numbers are 81.3, 54.1 arc minutes.

I also attached excel spreadsheet, so you can do the math for other combinations.. it is pretty straightforward.

[mithrandir (Andrew)]

New Astronomy CCDCalc is the bee's knees.
Feed it all your scopes and cameras and it will give you the answers.

Rotation is to match the camera angle and the outline. Offset is for dual camera setups. eg using an OAG. As people often rotate the camera to frame the target and the OAG to find a guide star these seem to hard to make much use of.

[bojan]

Uh OK, there is offset - but in CdC v3.
I am using v2.76.

[peeb61 (Paul)]

Thanks heaps bojan, that is a great big help!
Andrew, I will also have a look at this CCDCalc.

The spreadsheet will also come in handy as well.

Paul