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Star Analyser lens options


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I’m looking some help regarding setup. I’ve quite a bit of kit not being used, so I’ve decided to try and use it!

I have a star analyser 100 that I want to get occasional use from.

Here are my options:

1) put it into the last spare filter wheel slot, used in conjunction with an Atik 383L+ and ED80 (at 522mm).

2) I have a spare mono camera - a Lumenera LU070 mono CCD with 7.4um pixels.  I spent an hour earlier using adapters to get it to work with a Canon lens.  I have a few lenses that I can use from the standard 18-55mm to a 55-200mm lens and a nice 105mm F2.8 lens.  I was planning on putting the SA100 within the adapter so it will be close to the camera sensor.

3) open to other suggestions ...


Thanks!

Adam

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Edited by tooth_dr
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Check out also our website:

http://www.astronomicalspectroscopy.com/How_to.html

The TransSpec spreadsheet, by entering your parameters will give a good indication of performance. It handles both "in the converging beam" and as "objective gratings"

Your option 1 will work, needs around 50mm grating spacing in front of the sensor

Option 2 I think may be problematic due to the limited spacing, but an objective grating set-up would work.

Hope this helps,

Ken

 

TransSpecV3.5.xls

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18 hours ago, tooth_dr said:

Here are my options:

1) put it into the last spare filter wheel slot, used in conjunction with an Atik 383L+ and ED80 (at 522mm).

2) I have a spare mono camera - a Lumenera LU070 mono CCD with 7.4um pixels.  I spent an hour earlier using adapters to get it to work with a Canon lens.  I have a few lenses that I can use from the standard 18-55mm to a 55-200mm lens and a nice 105mm F2.8 lens.  I was planning on putting the SA100 within the adapter so it will be close to the camera sensor.

3) open to other suggestions ...

Hi Adam,

I am the Robin that Andrew referred to. I am also the person who developed the Star Analyser.

Option 2 with the grating between the lens and camera sensor will not work as the focal ratio is too low (I recommend using the calculator on the RSpec website which is based on my recommendations to the Star Analyser manufacturer, Paton Hawkley Education Ltd.

https://www.rspec-astro.com/calculator/

If you use the calculator you will see  that the minimum recommended focal ratio for the SA100 is f4 and for the SA200 f4.5 and the calculator gives a warning for lower focal ratios)

You could use the grating with the lens in an objective grating configuration though with the grating on the front of the lens. here are some examples of this on my website

http://www.threehillsobservatory.co.uk/astro/spectroscopy_11.htm

http://www.threehillsobservatory.co.uk/astro/spectroscopy_17.htm

Use the same calculator to calculate the focal length range which will allow the spectrum to fit in the field by putting the focal length of the lens in place of the grating to sensor distance (Ignore the other warnings as they apply to telescope applications)

Option 1 might work ok but it depends on the distance between  the grating and the camera sensor. Use the RSpec calculator to test this. It will tell you if there are problems

(The SA200 is more commonly used in filter wheel applications as it can be used closer to the sensor and has a lower profile so fits in most filter wheels)

If you need more information you are welcome to contact me direct via the email address on my website

Cheers

Robin

Edited by robin_astro
correction to minimum focal ratio
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On 30/10/2020 at 14:16, robin_astro said:

Hi Adam,

I am the Robin that Andrew referred to. I am also the person who developed the Star Analyser.

Option 2 with the grating between the lens and camera sensor will not work as the focal ratio is too low (I recommend using the calculator on the RSpec website which is based on my recommendations to the Star Analyser manufacturer, Paton Hawkley Education Ltd.

https://www.rspec-astro.com/calculator/

If you use the calculator you will see  that the minimum recommended focal ratio for the SA100 is f4 and for the SA200 f4.5 and the calculator gives a warning for lower focal ratios)

You could use the grating with the lens in an objective grating configuration though with the grating on the front of the lens. here are some examples of this on my website

http://www.threehillsobservatory.co.uk/astro/spectroscopy_11.htm

http://www.threehillsobservatory.co.uk/astro/spectroscopy_17.htm

Use the same calculator to calculate the focal length range which will allow the spectrum to fit in the field by putting the focal length of the lens in place of the grating to sensor distance (Ignore the other warnings as they apply to telescope applications)

Option 1 might work ok but it depends on the distance between  the grating and the camera sensor. Use the RSpec calculator to test this. It will tell you if there are problems

(The SA200 is more commonly used in filter wheel applications as it can be used closer to the sensor and has a lower profile so fits in most filter wheels)

If you need more information you are welcome to contact me direct via the email address on my website

Cheers

Robin

Thanks Robin.  I’ve it fitted to the EFW, and will check measurements later. I ran it through the calculator and looks to be approx ok. 

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