Alpy600+LISA IR Stiched Spectra

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Re: Alpy600+LISA IR Stiched Spectra

Postby James Foster » Sat Jan 11, 2020 4:04 am

To: James,

RE"Is the S/N higher with the Alpy than the LISA-IR?"

That's a little difficult to tell, shooting in the light polluted city. As it is, I cannot shoot the Atik414ex on the Alpy600 in 2x2 bin like I shot the Alpy600 with the Atik460ex.
Also remember that I replaced the CCD cover glass with this to Thorlabs glass improve my UV sensitivity:

WG41010 Ø1" UVFS Broadband Precision Window, Uncoated, t = 1 mm

For 2x2 bin shooting, It seems that the bigger pixels (6.48m vs 4.54m) absorb the heavy background so much its almost impossible for Isis to eliminate on exposures greater than 3 minutes
and object dimmer than 9th magnitude. I'm having much better results shooting at 1x1 bin with the Atik414ex on the Alpy600 and most of the recent "stitched" spectra come from this mode;
after 31Oct19. When I start to use the Alpy600/Atik414 from my dark sky site at Mt. Pinos, CA, I'll try 2x2 bin to see what the s/n is compared to the LISA.
Btw, I tried 1x1 bin on my IR configured LISA and I got inferior s/n results compared to 2x2 bin on objects fainter than 8th magnitude (or otherwise low in IR).

RE:"I liked your spectrum of Mira. If my understanding is correct, photons emitted at the wavelength of H-epsilon,close to the Ca II H line, pump the emission in the calcium triplet. Your spectrum shows both the the absorption and the emission."

Thanks! I've observed this target with both the Alpy600, LISA-IR mode, and LhiresIII and it offers a lot of spectra emission to analyze. Here is a close-up of the CaK region I've previously posted:

James Foster
Lhires III (2400/1800/600 ln/mm Grat) Spectroscope,
LISA IR/Visual Spectroscope (IR Configured Presently)
Alpy 600 with Guide/Calibration modules and Photometric slit
Star Analyzer 200
James Foster
Posts: 371
Joined: Sun Jan 24, 2016 7:14 am


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