How to remove dust from the optical slit of spectroscope?

Wah · Post by **Wah** » Thu Dec 26, 2013 8:35 pm

There is so much tiny dust on the slit of my spectroscope, how can I clean it without adding more dust on it?
I've tried using a tooth pick to clean it, but usually don't success...

Post by **Merlin66** » Fri Dec 27, 2013 4:07 am

Wah,
On my Surplus Shed adjustable slits I find a blast of compressed air generally works. Then I use a wooden toothpick in a wide slit gap to "wipe" the edges, generally works very well.
(The new multi-slit reflective plates we now use are a dream...no gaps to collect dust and the actual slit is protected behind glass.)

Wah · Post by **Wah** » Fri Dec 27, 2013 4:30 am

Where can I find a multi-slit reflective plate? Are they much more expensive than the Surplus shed one?

Post by **Merlin66** » Fri Dec 27, 2013 4:41 am

Wah,
The multi slit plate (9 slits 20-100micron and 3 pinholes 20-100micron) I designed it for the new Spectra-L200 spectroscope. There's details over on the astronomical spectroscopy group.
I have a few left, $65 delivered...drop me an email.

Wah · Post by **Wah** » Fri Dec 27, 2013 9:07 am

I finally have found the topic:
http://groups.yahoo.com/neo/groups/astr ... opics/6703

It seems the slits are quite short, it requires to scan the sun twice for a full disk if the telescope has focal length longer than 600mm, right?

Does a glass slit become very hot after the focused solar image shining on it?

BTW, it there any topic about how wide should a slit be?

Post by **Merlin66** » Fri Dec 27, 2013 9:58 am

Wah,
Yes....
It was designed for spectroscopy not specifically for a spectrohelioscope...
I've used in in my MG80 spectroscope for solar spectrum recording with no effects...it reflects 99% of the light and heat.
You can calculate the optimum slit gap from the spreadsheet SimSpecV4 (in the astronomical spectroscopy group files area)- this looks at your focal length, grating and camera pixel size...the smallest projected slit (on the CCD) would be between 2 and 3 times the pixel size (Nyquist sampling) i.e. a 5 micron pixel = 10-15micron projected slit. If you have a 500 mm collimator and a 200mm imaging lens then the actual slit gap could be 500/200 * 10 = 25micron.

Wah · Post by **Wah** » Wed Jan 08, 2014 6:48 am

Dear Merlin,

Can this product be used on a SHS?
http://catalogue.ovio-optics.com/index. ... &Itemid=10

It seems to be longer...

Wah!

Post by **Merlin66** » Wed Jan 08, 2014 6:52 am

Wah!,
Yes. I used these before custom designing the multi-slit plate for the spectroscope.
Limited line widths....

Wah · Post by **Wah** » Wed Jan 08, 2014 7:22 am

Dear Merlin, is the one I quoted exactly what you used before? Or you were using another model? Are they expensive or cheap?

Post by **Merlin66** » Wed Jan 08, 2014 7:32 am

That's exactly the one I started with...infact I may still have one.
Drop me an email and I'll check my "box" for you...
They are not cheap.

Wah · Post by **Wah** » Thu Jan 23, 2014 9:31 am

Dear Ken,

I received the slit plate today, thank you!

Wah!

How to remove dust from the optical slit of spectroscope?

How to remove dust from the optical slit of spectroscope?

Re: How to remove dust from the optical slit of spectroscope?

Re: How to remove dust from the optical slit of spectroscope?

Re: How to remove dust from the optical slit of spectroscope?

Re: How to remove dust from the optical slit of spectroscope?

Re: How to remove dust from the optical slit of spectroscope?

Re: How to remove dust from the optical slit of spectroscope?

Re: How to remove dust from the optical slit of spectroscope?

Re: How to remove dust from the optical slit of spectroscope?

Re: How to remove dust from the optical slit of spectroscope?

Re: How to remove dust from the optical slit of spectroscope?