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The Lowspec spectrometer

Thalestris24

By Thalestris24
in DIY Astronomer

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Thalestris24
Thalestris24

In case anyone is interested here's some images of spectra and the Lowspec from Paul Gehrlach's posts on the German forum: Daylight line spectrum in near IR The corresponding spectrum:

drjolo
drjolo

Hi again! Yesterday evening I assembled LowSpec device - I still miss focusing bolt, so I need to focus manually moving the camera. And also spectroscope collimation is rough, for testing purpose

drjolo
drjolo

Ken, thank you for your suggestions. I will review guider path and check guiding mirror and lens once more. I have 25um artificial star that should help to figure this problem out. Despite such p

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Thalestris24

Thalestris24

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6 minutes ago, Paul Gerlach said:

Well, the ALPY calibration unit obviously has a an inverter build into it as it uses 12 volt and a Relco.
In the book 'Spectroscopy for Amateur Astronomers' from Marc F.M. Trypsteen and Richard Walker there is in appendix D a circuit depicted that converts 12 Volt DC into 230 Volt AC.
So in order to avoid messing with a soldering iron the 'Chinese circuit' should do the same.

Yes, it's quite easy to build an inverter but it's a question of whether you want to mess about getting all the individual components together etc. or just buy one from China!

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Thalestris24

Thalestris24

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The 40W one I linked to above should do also and is only 4.5cm square. Richard Walker's looks very small and is all you need really but it's not something you're likely to be able to buy ready made. The Alpy circuit is probably the same! Easy enough to build if you can get the transformer - couldn't see it on the link he gives.

Anyway, the 40W I ordered is on its way :) Still a bit overkill but for a few pounds/Euros, I'm not bothered.

Louise

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Merlin66

Merlin66

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A spectrograph definitely needs a reference lamp.

As a minimum a Neon, this provides calibration around Ha which is an important wavelength for astronomers. The RELCO is also good and give a wider coverage.

When I started with the Spectra-L200 "IKEA" kit, I had the same reference lamp issues.....

I found at the time that the hand held fluoro "inspection" lamps had a small 12V to 110/220V inverter built in, so I used to raid the hardware shops and buy them up, and strip them for the inverter and the 12V plug.

The inverter looked very similar to this one:

https://www.banggood.com/150W-Inverter-Boost-Module-150W-DC12V-Step-Up-Board-Frequency-Square-Wave-p-1278570.html?rmmds=detail-left-hotproducts__3&cur_warehouse=CN

This initially powered a neon lamp. I used about 100 of them (!!) with no failures, no issues, in fact I'm still using one of the early build inverter/ neon set-ups today, almost ten years later.

This is shown in "Astronomical Spectroscopy for Amateurs" p160 and p202. There's also a "non commercial"  circuit diagram for a suitable inverter.

 

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Thalestris24

Thalestris24

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2 minutes ago, Merlin66 said:

A spectrograph definitely needs a reference lamp.

As a minimum a Neon, this provides calibration around Ha which is an important wavelength for astronomers. The RELCO is also good and give a wider coverage.

When I started with the Spectra-L200 "IKEA" kit, I had the same reference lamp issues.....

I found at the time that the hand held fluoro "inspection" lamps had a small 12V to 110/220V inverter built is, so I used to raid the hardware shops and buy them up, and strip them for the inverter and the 12V plug.

The inverter looked very similar to this one:

https://www.banggood.com/150W-Inverter-Boost-Module-150W-DC12V-Step-Up-Board-Frequency-Square-Wave-p-1278570.html?rmmds=detail-left-hotproducts__3&cur_warehouse=CN

This initially powered a neon lamp. I used about 100 of them (!!) with no failures, no issues, in fact I'm still using one of the early build inverter/ neon set-ups today, almost ten years later.

This is shown in "Astronomical Spectroscopy for Amateurs" p160 and p202. There's also a "non commercial"  circuit diagram for a suitable inverter.

 

Yeah, I think that's the same as the one Paul's ordered, just on a long, thin pcb.  How did you get through a hundred of them??

I'm wondering whether to buy some other starters now that Philips has stopped making the S10. I think one of the Osram deos starters has a bulb which emits blue light - might be worth looking into.

Louise

 

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Thalestris24

Thalestris24

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1 minute ago, Gasman said:

I actually had some success using a disposable camera circuit from Asda using the info from a site like this one

http://www.marcellocucchi.altervista.org/html/neonlamp.html

Can't seem to find the English version!

That's really a high voltage flash lamp circuit. The circuit from Richard Walker that Paul posted above is probably the simplest and smallest.

Louise

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Thalestris24

Thalestris24

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21 minutes ago, Merlin66 said:

Louise,

I manufactured the Spectra-L200 as a kit which could be easily  assembled by amateurs....they sold all over the world.

Piper S&T.pdf 297.84 kB · 0 downloads

Of course, yes, that would explain it! I'm not sure the 150W psu you linked to would be the same - I think it's maybe too big? (10x3x2cm) or maybe not! Might it have been more like this one?

Louise

ps did/do you know Piper Reid?

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Merlin66

Merlin66

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Louise,

No, definitely more like the Chinese one....

I mounted it in a small project box, with 12V socket and on/off switch. This sat on the outside of the housing and powered the Neon lamp fitted in a perspex block which flipped down onto the slit gap.

 

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Paul Gerlach

Paul Gerlach

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8 minutes ago, Thalestris24 said:

Of course, yes, that would explain it! I'm not sure the 150W psu you linked to would be the same - I think it's maybe too big? (10x3x2cm) or maybe not! Might it have been more like this one?

Louise

I think that one needs 12 Volt AC to work or am I wrong?
It's only to be sold in .... the Netherlands 😉

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Thalestris24

Thalestris24

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2 minutes ago, Merlin66 said:

Louise,

No, definitely more like the Chinese one....

I mounted it in a small project box, with 12V socket and on/off switch. This sat on the outside of the housing and powered the Neon lamp fitted in a perspex block which flipped down onto the slit gap.

 

Oh ok. Neons are easy to power - only need 70-90v and now problem with swithching themselves off! I might get some Sylvania brand FS-11 starters - I think they may glow blue (Argon rich?).

Louise

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Paul Gerlach

Paul Gerlach

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16 minutes ago, Merlin66 said:

Paul,

IMHO go for one of the Chinese options....recommend a 12V 5.5/ 2.1 mm socket and a on/off switch - if this could be automated it would be a bonus!

 

Yes, that's the whole idea. A solution build out of off-the-shelf components. So it's easy for everyone, not just me.

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Thalestris24

Thalestris24

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11 hours ago, Paul Gerlach said:

I'm also struggling with designing a calibration unit for the LOWSPEC that is easy to build for someone like me who has no experience in building electronic circuits.
I've recently ordered a 12 Volt DC to 220 Volt AC converter board form our friends in China. Maybe this can bring me up to speed.

Hi again

I think, on reflection, that converter should be ok (though still overkill!). I think I'd use the 110V output with a suitable resistor plus fuse, switch etc and a small box with suitable connectors. I'm on the lookout for something very small that could run from a small battery like the Richard Walker one but ready made. I'll keep looking!

Louise

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Thalestris24

Thalestris24

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Just now, Merlin66 said:

“Astronomical Spectroscopy for Amateurs”

Oh - Richard Walker's circuit? Obviously depends on the battery... I have some small 12V battery which will power an eq3 for hours. Also have a 5V power bank which would power something for quite a while :)

Louise

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Thalestris24

Thalestris24

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3 minutes ago, Merlin66 said:

Louise,

long before that.....

It was actually a Shelyak design, hence the “non commercial use”

 

Oh, that one - sorry, I was thinking of the simple circuit that Paul posted from Richard Walker's book:

https://www.ursusmajor.ch/downloads/inverter-12v-dc-_-230v-ac-3.0-englisch.pdf

Simple, small, easy to build - if you want to spend the time and trouble!

Louise 

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Merlin66

Merlin66

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Paul,

I’d like to think all the amateurs who build a LowSpec, and any other spectrograph will put them to regular use. We need as many active spectroscopists as possible.

There are more challenges and opportunities in spectroscopy than there are observers.

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