Project Star Precision Spectrometer, Spectra Observation Instrument with Built in Chart, 31 x 18 cm

It's meant for school experiments. It's plastic. It feels like a toy. But it's vastly better than all the other under $100 spectrometers on the market.The original 1991 version had an adjustable scale so you could calibrate out any scale error. This one still mentions that on a sticker, but the scale is NOT adjustable.Mine reads low by about 1.5 nanometers. You have to squint to use it; it's awkward.But if you're careful you can read lines to the nearest 1 or 2 nanometers.The EICO and all the other ones I've seen (I think I bought all of them) are worse. This one is not great, but it's by far the best for less than $100. Nothing else is even close.Update 2024-11: Google on the "little garden spectrometer". It's a electronic gadget, doesn't cost much more than this, and is vastly more capable. With that one you read the spectrum on a computer screen.

The instructions are very poor and if you do not have prior knowledge of how to use it you may struggle to figure it out. Point the instrument at a light source and rotate the grating until the refracted light illuminates the scale in the instrument.

I intended to use this spectrometer to have my grandson learn about the spectrum of light.To use it you aimed the slit side at the light source and then looked away to the left to see the spectrum. This was awkward with the hand held spectrometer as I would lose the aim to the light source. It seemed impossible to ever keep a small light source aligned. I would not want my grandson to try to use it and get fustrated.There was no focusing that I found so I had to look through the close up part of my tri-focals to try and focus on the spectrum. The lines did not look too sharp. ??Hard to use and I quit after 30 minutes of trying to optimize its use. Minimal instructions for using the spectrometer.

Since Science First took over the construction of these spectrometers, their accuracy has dropped considerably.Using the mercury 546 nm line and a mercury light source (not just a random fluorescent light), I've received some spectrometers that are within 2 nm, but several that are off by 5 nm or more. This can make the spectrometers virtually unusable, if you are trying to determine whether that green spectral line is in fact from mercury or a different element.The instructions suggest calibrating the spectrometer by sliding the scale one way or another. I have found that this simply cannot be done ( in contrast to the early, original Project Star spectrometers, which could be calibrated just fine). The scale simply would not slide. I tested using a spectrometer that was more than 10 nm off true, carefully and gradually increasing the force applied to the scale. Eventually, the scale ripped a bit, but it never slid over.Arbor Scientific has been willing to exchange a couple of the spectrometers for me, but really only promise to do so if the spectrometers are off by more than 5%. That's more than 25 nm. Given that the original spectrometers were supposed to be 1-2 nm, I think that spec must be a typo, and should be 0.5%. I can't imagine that anyone who spends fifty dollars on a quantitative spectrometer is doing a lab where it doesn't matter if a green line appears gold.

These spectroscopes are not good. I am an astronomy teacher and have been doing spectroscopy for years. The projected spectra are barely visible and pretty useless for any type of real speceral analysis. It is awkward to use. Not worth the money. The cereal box spectroscopes we made years ago are still way better than this product. I wouyld not recommend buying this

Like any instrument, it should be calibrated. I use table salt and an alcohol flame. I read the value of the sodium line from the scale and subtract 590 nm from it. The difference is the correction for the spectrometer. Thereafter, just add the correction to the scale reading to get an accurate result.