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Alpy 600 first light!


Gasman

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HI folks

Finally had chance to get my Alpy connected to the scope and the night sky played ball too. Quite a bit of fiddling and tweaking to do and the ccd software put up a fight but got something in the end although I`m sure it will become easier in time.

I`m not sure I`ve got the spectrum the right way round  but haven`t built a Neon lamp for calibrating it yet.

If using a bright object I seem to have a double refection of it on the guide slit but it doesn`t seem to hinder the main ccd. No calibrations were done just raw data!.

Guide slit on Betelgeuse

post-15973-0-37081200-1388278306_thumb.j

Main ccd spectrum of Betelgeuse

post-15973-0-79946700-1388278465_thumb.j

Rspec  processed

post-15973-0-17492700-1388278507_thumb.j

First uncalibrated spectrum of Jupiter (I never could do it with my Star Analyser) some clear absorption lines , unidentified!

post-15973-0-43052400-1388278658_thumb.j

Rspec processed

post-15973-0-41277100-1388278694_thumb.j

So the Alpy shows promise and a lot more resolution than the Star Analyser (when the user knows what he/she is doing . Advice from other Alpy users gratefully accepted :laugh: )

Steve

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Welcome to the world of slit spectroscopy :-)

Yes the spectra are the wrong way round (the band at the left end around 300  is the O2 Telluric line in the IR) easily solved by rotating the camera of course. Otherwise things are looking good. (You are getting plenty of Fraunhofer lines in the reflected sunlight from Jupiter which are difficult to resolve at the typical Star Analyser resolution)  

You can get multiple reflections off the back coated mirror slit  but PHD can lock onto the right one. (Guiding works best when the guiding image is not saturated in any case so if you reduce the guide camera exposure the main image becomes more obvious)

Cheers

Robin

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Thanks for that Robin, glad I seem to be going in the right direction. I did expect to have to take longer exposures through a slit and have been advised that up to 30 secs would be needed for Betegeuse but I found that even 12secs was getting saturated and eventually I settled on 2 secs with adu vales of 40k+. I think it would be near impossible to get the star on the slit without the guide unit

Steve

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Hi Steve,

It was always considered a big jump to slit spectroscopy, that's a great start. You have made it look easy. 

I'd watch out for saturation, take some subs at shorter exposure as a fail safe. (I've been caught out at 40K when conditions change!)

I don't know much about the Alpy, is the slit fixed or variable?  Your spectra are already filling the CCD quite nicely, but I was wondering if the resolution be changed?

The spectra are easily 'flipped' in any processing package. You knew that ;o)

John

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Hi Steve,

 You have made it look easy. 

Hi John

Don`t be fooled by that ! , the laptop and the Alpy nearly went out the observatory window more than once :smiley:  put that down to user error. I wanted everything the right orientation to avoid problems later. I think the Alpy is a brilliant piece of kit but I think the `optional` guide module should reclassed as essential though.

They do another `optional` calibration module but I thought I would try a simple Neon lamp in front of the scope which seems to do the job no probs.

This is the first Neon spectrum calibrated I`m pleased to say it looks a lot like the Neon spectrum on Christan`s site so I think things are falling into place!.

post-15973-0-99587200-1388439240_thumb.j

regards

Steve

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