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Spectroscopy use

Posted: 14 Jun 2024, 20:18
by Jfisher6626
Phd2 now has a tool for highlighting the slit for star placement in guiding. Astroart seems to work differently.
What would be the setup for slit spectroscopy guiding? How do I highlight the slit in darkness? Any help is appreciated. Thanks john

Guiding with slit

Posted: 15 Jun 2024, 02:19
by Jfisher6626
The manual suggests finding “guiding a star on spectroscope slit” PDF. I haven’t found it. Does any one know where to download this?
Thanks john

Re: Guiding with slit

Posted: 15 Jun 2024, 15:40
by fabdev
Hello, the PDF is attached here:
(372.24 KiB)


more or less is still valid, (nowadays it's also possible to move the star by 0.5 and 0.1 pixels) by the way:

If you don't have the possibility of making a longer exposure (or a illuminated one) to estimate the Y coordinate of the slit, then it must be found in some way, for example pointing the telescope low to the horizon. Once the approximate Y is known, you could always mark it on the image with CTRL+Click (which will add a "star marker" on the image, reading the Y coordinate on the status bar before clicking). Then it will be possible to draw rectangles near that Y, to select the subframe for the fine regulation.

P.S. Once the Y is know, you could also use this script (save it as the default script #1, to launch it with one click).

Code: Select all

ySlit = 372  ' example
x = 0
while x < Image.Width
   x = x + 100
   Image.Points.Add(x, ySlit)
end while
An option to draw this horizontal line automatically is very interesting, it will be added in the next upgrade.

By the way, this line is just a coarse approximation for the first phase of the setup, the fine regulation (with sub-pixel precision) must be done on the actual star, from the Guide Window, as explained in the PDF above.

Clear skies,

Re: Spectroscopy use

Posted: 16 Jun 2024, 00:47
by Jfisher6626
Thanks so much for this. It’s going to make things a lot easier. I just hope the slit mirror reflections
won’t be a problem. John