[Andy Wilson]

Hi Peter,

Interesting project.

At a guess I would say that you have a light leak as a neon bulb should only generate discrete emission lines, no continuum. It is possible that there is a problem with the neon bulb, but I think a light leak is more likely.

You could try taking 2 exposures of the same length, one with the neon bulb turned on, and the other with it turned off.

The other effects that can cause an offset are dark current and bias offset, but they should be roughly uniform, not showing the hump you seen in your spectrum.

Cheers,

Andy

[Andy Wilson]

Hi Andrew,

I will contact you by email about changing your username.

Best wishes,

Andy

[Andy Wilson]

Hi Jack,

You can measure the resolution using BASS, as per section 9a of the BASS tutorial I wrote (I think you have already done this):

You can also create a .png, .jpg or .bmp of your spectrum graph at any time by selecting:

Chart -> Save Chart to file

These will be small compared to the original fits file.

Best wishes,

Andy

[Andy Wilson]

There are a couple of other factors which will change how the chart looks.

First it will depend on which filter, filters or unfiltered were used when acquiring the image. I suspect the AAVSO chart is showing magnitudes for a V filter, so you would expect similar results when using a V filter on your camera. However, unfiltered or RGB would cause the stars to appear at different relative brightness. For example very red stars will typically appear much brighter in an unfiltered image.

The other factor is variable stars. You will occasionally come across other stars in your field which vary in magnitude by a sufficient degree to look different. Indeed great care has to be taken when producing charts for variable star measurement, to ensure that non of the comparison stars are themselves variable.

Nice image by the way 🙂

Best wishes,

Andy

[Andy Wilson]

Thanks for the links Marc. I’ve added both books to my wish list 🙂

Andy

[Andy Wilson]

Congratulations on the new magazine Ernst. Great to have another spectroscopy publication!

Eric, you can try translating it with Google Translate. Type ‘Translate’ into Google. Follow the link and upload the document. Then select German to English. You’ll find you need to switch back and forth between the Google translation and the pdf as the table and figures are missing from the translation.

Best wishes,

Andy

[Andy Wilson]

Hi Matt,

First of all welcome to the BAA 🙂

Robin has already given you some excellent advice on spectral typing so I won’t bother adding any more.

I own an Lhires III and I find it an excellent spectrograph. It took me several months of practice to get to know it well and tweak its performance, but I was able to get good spectra of bright stars very quickly. While a star analyser is great to start off with, as well as always being a good tool for fainter targets, there are some things that will be easier with the Lhires III. For example wavelength calibration, flat fielding and simply having a slit removes the potential problem of nearby stars contaminating a slitless spectrum. Though of course you do need a good mount to be able to position the star onto the slit and to hold it there accurately.

Best wishes,

Andy

[Andy Wilson]

I am completely with you there Gary! 🙂

I think it is an interesting enigma but the evidence does not support any kind of intelligence. It could be an opportunity to help solve the puzzle using science, putting a stop to the unfounded speculation which has dominated some of the press.

Cheers,

Andy

[Andy Wilson]

Hi Paul,

That is a very useful webpage, thanks for sharing.

Though I usually do spectroscopy, this is not the right kind of target for my setup. So I’m hoping to take a look at it though my Dobsonian instead.

Cheers,

Andy

[Andy Wilson]

Hi Ernst,

An interesting paper and a good demonstration of what can be achieved with the high resolution spectrographs that are now available to the amateur community.

Best wishes,

Andy

[Andy Wilson]

Hi Michael,

That is a very thorough analysis! Hopefully Bill or someone with knowledge of meteor spectroscopy will comment on your spectrum. It certainly looks good but I cannot comment on the line identification.

Cheers,

Andy

[Andy Wilson]

Congratulations Bill! A fantastic achievement!

Andy

[Andy Wilson]

Hi Bill,

Those are great spectra of the Lyrids! There is a whole wealth of spectral lines. Is it difficult to identify them all or do you have resources that allow you to identify all or the majority of the lines?

Cheers,

Andy

[Andy Wilson]

Robin,

That is a good point about ensuring that amateur software should be able to read the files.

Andrew,

Glad to hear you are making progress. Python with astropy are fantastic for programming with fits files. So far I’ve only been using them on a Mac, but I must get around to trying them out on Windows.

Cheers,

Andy

[Andy Wilson]

Give me a shout if you get stuck. It would be nice to have a single fits file format for the multiple orders in Echelle spectra, but I suspect agreeing that amongst the community would be no small task.

Andy

[Andy Wilson]

Hi Andrew,

You are correct in your assumption that the BAA Spectroscopy Database does not support IRAF multispec format at this time. However, it is possible to build in support. The big question is how long it would take me to build, noting I already have some outstanding development work for the VSS Database.

It may take until the second half of May or June to take a proper look at the file format. Then I can assess whether a ‘quick’ change is possible.

Note of course that the other header fields would need to be BeSS compliant. If this is going to be a problem then it won’t be worth going down the route of building IRAF multispec compatibility.

Best wishes,

Andy, BAA Spectroscopy Database Manager

[Andy Wilson]

Hi Marc,

It is great to see how spectroscopy has grown at the BAA over the past couple of years. The subject being one of the main areas of discussion on the forum, with advice being given to help members get started, as well as some fantastic results being shared.

We also have a spectroscopy database where members can upload their 1D fits format files. Noting a separate login is needed as it runs on different software to the main BAA webpages.

https://britastro.org/specdb/

I think Ernst’s proposal for a VV Cep campaign is great. Though I am aware that Ernst has a long running campaign on VV Cep and so I am not sure if it is appropriate to think of it as a BAA campaign. There is a separate thread that Ernst has started on the campaign so probably best to post any questions there so that there is a single place to access the information.

Sadly for me a bank holiday weekend when I actually have time to do some spectroscopy and the forecast is for wall to wall cloud! Oh well, as a UK based amateur astronomer I learned along time ago that large reserves of patience are essential 😉

Best wishes,

Andy

[Andy Wilson]

Hi Ernst,

Thanks for the information which is useful to know. I’ll try to get an observing session in soon on VV Cep. If that doesn’t work out then I may use my limited observing time on Be stars which are well suited to an occasional spectrum when time allows.

Best wishes,

Andy

[Andy Wilson]

Welcome to the BAA Marc and great to have another spectroscopist! As you have no doubt seen, the spectroscopy forum has been very active.

Andy

[Andy Wilson]

That is an interesting campaign Ernst.

I’d like to get involved if I can, though my own observing has been significantly curtailed this year due to other commitments. If things settle down over the Spring/Summer then I’ll add it to my target list so that I can contribute.

Best wishes,

Andy

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