WTB : Star Analyzer

[dolphy2910]

Im looking for this
http://www.rspec-astro.com/wp-content/u ... 0small.jpg

Any availble store here? Anyone know? would appreciate!

[orly_andico]

I have one. Used it for my spectroscopy coursework. Total exposure time probably 2 hours.

I probably will never use it again.

Cost about 110 UKP shipped. I can sell it to you for a mild depreciation.

[dolphy2910]

Can share me your phone number, I'll call you.

[orly_andico]

If you want to obtain stellar spectra, this is the cheapest way to do it - objective prism:

http://www.lpl.arizona.edu/~rhill/spect/spect.html
http://www.starlink.rl.ac.uk/docs/sc14.htx/node33.html

basically you just need a prism big enough to cover the front of your camera lens. You can buy prisms from Surplus Shed

http://www.surplusshed.com/pages/item/l2001d.html
http://www.surplusshed.com/pages/item/l2004d.html

these are cheap, $9 and $13.50 and yes Surplus Shed will ship overseas. Since these fit in a USPS small international box it would only cost $14 (USD) to ship. So your total cash out would only be about $30 USD, far less than the cost of a Star Analyzer.

the downsides of using an objective prism: -

1) the dispersion is not linear, so the colors won't be spaced out nicely

2) no blazing, so it's not efficient (i.e. you need longer exposures to get stellar spectra). Notice though that with the Star Analyzer I only need 4-second exposures for Mag 2 stars, and 0.5 seconds for Sirius. You literally don't need a tracking mount. With a prism, maybe you'll need 10X the time. No big deal. So long as you orient the camera so that the sidereal drift is perpendicular to the spectral line, the drift actually helps you by smearing out the spectrum vertically.

3) the resolution is low. You can get stellar spectra with this, but you won't be measuring the red-shift of 3C 273 with an objective prism.

That said, it really depends on your goals. Stellar spectra are easy, if that's all you want to do an objective prism is more than good enough and is cheap.

You will also want to use RSpec from Tom Field (not free - get a trial version). Easiest to use software. That guy Valerie Desnoux also has his software VSpec but it's pretty hard to use.

[dolphy2910]

Thanks, appreciate this.

[orly_andico]

this fellow "nytecam" has lots of interesting DIY stuff.. and he discovered a supernova.

anyway here's his prism spectrograph. sometimes it's easier to learn by watching

http://www.youtube.com/watch?v=YJmbFUaH ... ature=plcp

[superiorstream]

Hi,Orly
Actually interested in your grating--is it the 1.25in version or the 48mm version?Actually interested in a 48mm version.How many lines per inch or cm?Thanks.

[orly_andico]

hi chia, it's the 1.25" as my meade DSI has a 1.25" barrel. this is the exact model which i got from paton-hawksley:

http://www.patonhawksley.co.uk/staranalyser.html

i checked my email and it was not 110 gbp shipped, more like 93 ( = 185 sgd). no spacer ring included, it worked fine with my Meade DSI.

[superiorstream]

Hi,Orly
Can pm me the price and your ph.no. for discussion?Thinking of buying it.Thanks.

[astro_chemist]

Have you bought one yet? Are there any shops in Singapore carrying that?