Bonjour à tous Je débute avec le Canon 350 d et première question :Comment fait on un dark ainsi qu'un flat avec le canon 350 d? Et est ce nécessaire avec...
Hi Pierre, I normally take darks with the SA (Just take a set of exposures with the same exposure time as your spectrum, average them and subtract the result...
Hi Robin, if the raw image(s) minus dark(s) is used for calibration, why would anyone ever need to do flats if they placed the item of interest 0th order at...
Hi Richard, If your zero order images and reference star and target spectra land on exactly the same strip of pixels and ar the same width then you could get...
Hello guys ! I keep having the same problem using visual spec . I turn the image to fi. using Photoshop .I follow the instructions in the pdf manual in this...
Hello guys ! I keep having the same problem using visual spec . I turn the image to fi. using Photoshop .I follow the instructions in the pdf manual in this...
Thank you very much :) . By the way ,I use Iris to save the image as a .fit file and not Photoshop . deepinthesky2003 --- Στις ΠαÏ., 23/05/08, ο/η...
Hello, I got the "fit" file from alexander and opened/binned it in visualspec without trouble. Maybe a directory name issue? I am looking at what error 438...
Producing a fits file in a format which is compatible with Visual Spec software can be a problem. (Typical problems include negative values not displaying...
Seen some impressive spectrae in the files and photos section. How large a scope is needed to produce informative spectra of 3rd or 4th mag stars? How about...
Hi Jim, ... 4th mag stars? Well it depends on your camera and somewhat on the dispersion you use (How far you mount the grating from the CCD) but with low...
Hi Jim, it's nice to see you evolving your interest into spectroscopy. It seems to be the "natural" evolution after doing pretty picture astronomy. I think you...
Hi Richard Actually, the interest in spectroscopy is an expansion of my off and on work in photoelectric photometry; eruptive variables. As for the 'pretty...
Most informative, Robin. Thanks. How does seeing conditions; specifically turbulance, affect resolution of spectral lines? Cheers, Jim Livermore CA ... or ......
... Hi Jim, With a slitless setup (The simplest configuration) the resolution is dependent on the size of the star image, so seeing (and guiding if you are...
Hi Jim, what you can see for a given exposure with an Ha filter is typical of the Ha brightness in a spectrum. That should give you some idea of what the...
Hi Richard, I will be most interested in hearing about your experiments with the PIN diode. I too have experimented with them, but have found the amplifier...
Hi Jeff, thanks for the information. I had considered using a photomultiplier, but was concerned with the high voltages, magnetic field effects, and risk of...
... some ... Hi Richard, That depends very much on the distribution of light across the spectrum. To take an extreme example, Wolf Rayet stars have ...
... Well it is definitely OT since we have now even moved away from spectroscopy ;-) I would suggest continuing off list or moving the subject to a more ...
Hi Robin, ok, back to SA spectroscopy, but another harebrain thought? I wonder if it would make any sense to use high transmission RGB filters to increase the...
No, it won't. Why should it ? They just block light in and out of band that could be used for increasing the SNR of the spectra. The only usefull applications...
Hi Richard, Wolfgang, It is rare for me to disagree with Wolfgang ;-) but in fact pre filtering does have a potential advantage with slitless spectroscopy in a...
Hi Robin I thought about light pollution too. But using a filter helps then just if the filter excludes all the major local light pollution emission lines. But...
Hi Robin, thanks for the reply and information. That was my sense for maximizing seeing deep by increasing the S/N and using a more sensitive mono camera than...
Hi Richard, One limitation of imaging RGB filters would be that they do not have sharp cut offs so the sensitivity is dropping away from the centre wavelength....
Hi Robin, as a extension of the increased S/N result by narrowing the bandpass, is there any useful astro LRS spectrometry application to see dimmer object's...
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