Merlin66
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Posts posted by Merlin66
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Paul,
I assume(d) the current Jeulin reflective slit plate was a copy of the Custom design plate that OVIO manufactured for me. When viewed from the telescope side, the numbers appear correct, the chrome coating and slits are on the rear face - towards the collimator.
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Louise,
On my Custom OVIO slitplate I had 6mm holes behind the slits (6mm long) to prevent any unwanted light getting through.
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Louise,
A wrap of translucent paper around the bulb then the partial aluminium foil reflector would help.
Bulbs generally need a diffuser to suppress the actual bright filaments.
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Not that I recommend it, but the SCT threads on the FR are the same as the SCT threads on the diagonal, 2" x 24tpi
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Louise,
Thanks for that!
I hope you had a good Hogmanay.
Wishing you a safe and happy New Year.
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I was just reading up on Arp's Atlas of peculiar galaxies, and he said due to the solar minimum he was able to get far deeper images from the 200" Hale telescope than previous!
https://ned.ipac.caltech.edu/level5/..._contents.html
I was wondering if amateurs have noticed the same during the current solar minimum???? -
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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Louise,
long before that.....
It was actually a Shelyak design, hence the “non commercial use”
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“Astronomical Spectroscopy for Amateurs”
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Louise,
No, never met her or her father. Only know they had a Spectra-L200 kit which Piper assembled and used.
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Louise,
p160....
I tried the battery powered neon....batteries didn’t last long!
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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!
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For completeness:
Coronado use the ITF (or Maier equivalent), Lunt went for a Blue Schott BG 38 filter - unfortunately they both can fail....
The Maier replacement has been used by MANY solar observers over the past seven years and I'm not aware of any failures!
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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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The ITF (Induced transmission Filter) is usually the filter element placed before the final narrowband blocking/ sort filter in an Ha set-up.
These are subject to failure.....luckily we found a suitable replacement from Maier Optronics.
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Louise,
I manufactured the Spectra-L200 as a kit which could be easily assembled by amateurs....they sold all over the world.
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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:
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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Lousie,
Now that Paul's on board, you should ask him when he's going to incorporate a reference lamp in the design of the LowSpec
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Louise,
Yes, every time... thermal effects, flexing in the housing etc etc etc can impact on the accuracy of measurements. It's not unusual to take a reference image before and after a long series of target exposures.
Fitting a reference lamp - check the alignment and orientation to the slit gap. Ideally the lamp should be on the optical axis as near the slit gap as possible. On the Spectra-L200 I used a flip mirror to direct the reference lamp to the slit gap.
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Paul,
welcome on board!
good to see you here, as you’ll see there are a few members already building your LowSpec spectrographs.
Keep up the good work.
Ken
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Louise,
I take a reference exposure every time I take a target spectrum of a star....
It quickly becomes second nature.......
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28 minutes ago, Thalestris24 said:
Here is my S10:
CFL:
Both:
The S10 is a bit of a jungle at the red end! Presumably that's mostly neon plus other stuff.
Anyway, I'll give it another go starting from the cfl tomorrow though different people quote slightly different wavelengths for some of the lines...
Louise
Louise,
Use the Buil reference image I supplied for the CFL - it has been used successfully by many.
Need to check back in the messages...but I assume you have the line/ wavelength data for the S10?
ken
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Louise,
Softly softly....
1. Start with the CFL as a "reference image" (place up front as #1 on the list). Us the reference image I posted with the lines identified and mark/ calibrate all the obvious lines you can see.
This will give you a pretty good calibration of your instrument set-up. Once you have done this then.....
2. Import the S10 image (as #2 image on the list). Right click on the image, Properties/ Calibration/ select "use calibration from the first profile" / copy. This will then calibrate the S10 image form the "reference image" of the FCL.
3. If you now want to positively identify any/ all the lines in the S10 spectrum - use the mouse to move over the lines (Crop the X axis if needed) to match lines with the reference that Eric gave. If you want, you can then lable some of the lines - for future reference - Click on the "label" icon, in the pop down screen enter the type of lable you want to use (check the BASS manula for details) When done, save the chart as a .png (Chart/ save chart to file)
Re-reading your message..the S10 data is just that...data which you manually have to select and enter, you can't just superimpose the image.....
.Ken
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The Lowspec spectrometer
in DIY Astronomer
Posted
Paul,
Understood.
I assume your markings on the edge of the slit holder should match the necessary orientation of the slit plate. That would remove ambiguity.
Sorry if I've "muddied the waters" - my only experience is with the Custom designed plates.
Ken