Generic battery-powered green 5mW from Meritline

[Xaromir]

I've promised i post once it's here, so here i am.

I've ordered he described item at 12th of November, and it took about 3 weeks to arrive in Germany from China, which i find reasonable. I uploaded a few pictures for you guys.

Ir arrived in this little neat gift box, which is very nice considering that it was dirt cheap. It did come with 2AAA batteries, which i've already inserted into the device at the time i've taken that picture.

It's supposed to be 5mW, some argued that it may be less considering it was so cheap, but it produces a very nice beam during the night and will be just great for pointing at the stars, though i can not see the beam during daytime or in a brightly lit room, in a slightly dim room it's slightly visible already. I noticed some minor (but noticeable) fluctuations in brightness on the dot, but it's not really noticeable when looking at the beam. It feels a little cheap but fore the price it fulfills it's intended purpose and i'm rather satisfied.

 

[InfinitusEquitas]

Most likely the laser is very overspec (usually 20mW+) so be mindful of reflections, or having the beam hit you, or others.

 

[Xaromir]

Interesting. Well, i'm always careful, that thing lights up my small room pretty good. 99% of the time it will be pointing at the stars anyways.

 

[svdr]

if it is really much more than 5mW, you will find it is too bright for stargazing

 

[ApexProxy]

if it is really much more than 5mW, you will find it is too bright for stargazing

Not true... my 300mW 532nm(green) is perfect for stargazing. You are pointing it into the sky not at the ground so its not bright enough to mess with your night vision. My 1.1W 635nm also works great for stargazing but I would have to say that my 2.7W 445nm messes with vision a little but the wow factor is high enough that it is worth it lol.

 

[svdr]

You cannot see the faint stars at the end of the beam, which you need for directing your telescope. Astronomers aren't looking for wow factor beams, we are looking for faint and dim galaxies and nebulae, and if the laser is to bright, you simply overshine your target. Any green laser of more than 5mW is FAR too bright for astronomy use. Trust me, I'm into astronomy for over 30years (and working with lasers for over 15 years).

 

[svdr]

>>My 1.1W 635nm also works great for stargazing but I would have to say that my 2.7W 445nm messes with vision a little but the wow factor is high enough that it is worth it lol<<

It occurs to me that you are rather into beamgazing instead of stargazing. No problem with that lol, but keep in mind that some of us do use lasers for real life purposes, not just for shining a bright bundle of fancy coloured light into the sky

 

[Xaromir]

It's fine actually, i mainly mean to point out constellations and "landmark" objects like (for example) the Orion Nebula and the Pleiades, to educate my girlfriend. It's perfectly fine for what it's supposed to do, and while looking at the dot would most likely mess up your adjustment to the dark, the beam is perfectly fine, though i'm puzzled for what else you would need a laser in amateur astronomy, for anything dimmer than that i have my telescope.

 

[ApexProxy]

>>My 1.1W 635nm also works great for stargazing but I would have to say that my 2.7W 445nm messes with vision a little but the wow factor is high enough that it is worth it lol<<

It occurs to me that you are rather into beamgazing instead of stargazing. No problem with that lol, but keep in mind that some of us do use lasers for real life purposes, not just for shining a bright bundle of fancy coloured light into the sky

My definition of stargazing is using your eyes. This would be the root of our differences in desired outputs and why I think your laser is massively underpowered any why you think mine is massively overpowered.

 

[svdr]

>> though i'm puzzled for what else you would need a laser in amateur astronomy, for anything dimmer than that i have my telescope.<<

My laser is mounted on my dobsonian telescope, and in exact alignment with the scope's field of view. That way you can use it as a finder in combination with a pair of binoculars : put laser on, move telescope with one hand while keeping the target area in the eye with the binoc's. Many deepsky objects are allreadily visible as small grey dots with 10x50 binoc's, or have faint stars nearby that you can direct your laser to. Put laser off when desired target is in the eyepiece. Only practical for the larger dobsonians.

 

[Xaromir]

This is not that common, and you should know that. Most people use a finder-scope or a red-dot thingy (or both) for finding their objects. Personally i don't see why you would use the laser that way, i find it somewhat silly.

Well, i find it hardly sporting to talk down to people like that, especially considering that they don't seem to be that much into astronomy, and you are the one with the exotic practices. For what they do, and for what i intend my laser to be used it it's perfectly fine to have a few mW more. Besides that: These people been nice enough to offer their help, and i think that should also be respected. And consider that this is a laser forum.

 

[svdr]

I know,my friend. The information I gave was just as an aside. Please do not take offence.

>>This is not that common, and you should know that<<
In fact, it is a very common practice, and certainly not silly ;-) Maybe you should see it demonstrated, or check forums like Cloudy Nights or astrotreff.de.

>>especially considering that they don't seem to be that much into astronomy<<
BTW, I'm over 30 years into astronomy, and over 15 into lasers!

Fully agree that this is a laser forum, just know that many astronomers are also laser enthousiasts. Can't blame us appearing here, too. Since we use lasers, it is quit logically that we can discuss the way we use them on this forum. After all, you're the one that wrote :

>>it produces a very nice beam during the night and will be just great for pointing at the stars<<

If someone finds a different way to make use of an existing item, then does it make him an idiot just because others are not yet aware of the advantages of the new finding? Most people on this planet would call this progress.

>>i find it hardly sporting to talk down to people like that<<

You are right. It is not sporting. It is unpolite.


>>Besides that: These people been nice enough to offer their help, and i think that should also be respected<<
I'm not disrespectecting anyone over here. In fact, I may be buying a 1W+ 445nm from someone over here.

And now to an end with this. Hope you fully enjoy your laser for what you bought it for!

 

[Xaromir]

Within 10 years it's the second time that i've heard about that, i'd call that fairly un-common, but maybe it's a local thing, and i don't really have much to do with Dobsonians either. Well, i still don't see the big up-side, but i guess it's fine if it works for you. I'll stick with my finder-scope though.

 

[StardustSprinkles]

Maybe I'm way way way off, but I've seen photos of ground based observatories shining their targeting lasers into the night sky and they looked to be 589nm-593.5nm and multiple watts in power. Could've been a really perfectly exposed picture though..

EDIT: Yes! The Keck Observatory. Here's the basic info on the laser guide star system and how it works at the Keck, I found it to be an interesting read: http://www2.keck.hawaii.edu/optics/lgsao/lgsbasics.html

..but when we're talking about a 10-14W pulsed 589nm laser I'm happy regardless.

 

[ApexProxy]

The first image would be a very very long exposure since the star movement is very long. The second image is likely taken as a longer exposure but not as long as the first. Based on the link you posted, the lasers are pulsed and doing so would mean that the beam would only be visible for super short lengths of time and the beams in the images are likely several pulses.

 

[svdr]

Yup, these lasers are used for guiding and optical correction for atmospheric turbulence, not for targeting. These lasers are part of a system what is called adaptive optics.