spectro-aras.com

Hello.

I have been searching in the documentation and i have not been able to find information on this topic.
I did not find any specification on the lenses used between the slit and the guider both in LISA and Lhires III.

Does anybody know what is the field of view in the field seen by the guider?
I guess it depends on the guider's chip's width and the telescope but i would like to know a formula to calculate it.

In my case i will be using a 300 mm SCT telescope with 3040 mm of focal length. I will probably add to it a field reducer.
I do not know yet which camera i will use. Probably an Atik Titan as reccommended.

Thanks.

David Cejudo.
Observatorio El gallinero.
El berrueco, Madrid.

To David,

Here is an image of my Titan guide star FOV superimposed/aligned on an AASVO chart of V0838 Mon using my LISA spectroscope:

Using the long side of the guider FOV (up & down) with the scale given on the AASVO chart (7.5')
I calculated that the long side of the Titan guider FOV is 5.69' wide. The focal length of my CDK17 at F/6.8
is a just under 3000mm (2940mm to be exact), so this should be a good approximation to your set-up.

James

Hi David,

I have a Shelyak LISA. I use a Starlight Xpress LodestarX2 as a guide camera on the LISA. The CCD chip is 752x580 pixels. I have determined the FOV in two ways. First I used a calculator on the internet https://starizona.com/tutorial/pixel-re ... alculator/ When I choose the Starlight Xpress LodestarX2 camera and enter my focal length of my telescope at 2562mm, It calculates an FOV for the guider of 8.6’ x 6.4’. I also checked this by plate solving a guider image of a star field using PinPoint. The guider image was binned 2x2 and it came up with a scale of 1.37”/pixel. Divide this in half for Pixel binning 1 x1 and multiply it by the number of pixels in each axis. Which gives me:

X axis: (1.37”/2) x 752) = 515” Divide by 60 to get arc-min = 8.6’

Y axis (1.37”/2) x 580 = 397” Divide by 60 to get arc-min = 6.6’

These plate solved values for FOV are very close to those obtained with the calculator.

So it would appear to me that you could use the internet calculator to give you a good idea of what your FOV would be with the guide camera you are thinking about using.

Also I use the Atik414ex monochrome camera as the science camera with the LISA.

Cheers!
Woody Sims