Green laser pointer use with DSLR

[langman78]

Hi all.

A couple of yrs back I purchased a decent quality green laser pointer to mount on my (hopefully soon to be sold) 8se to take the place of the finder scope. Never got around to doing so I pondered on the thought of using with my 70d.
I posted a thread on cloudy nights sometime ago asking if it was safe flash through the view finder to make targeting easier when selecting object for widefield AP with my iOptron skytracker? Never really got a definitive answer. As couple of ppl suggest it was fine and a great tactic for the mentioned purpose but live view MUST be deactivated to be 100% safe. Others said bad idea don't do it know of others who damaged sensors etc.
Anyone here use the method or know it to be a safe/practical method?
Cheers for reading,
Ben

[fsr]

I have seen videos of camera sensors damaged by "disco" lasers when recording video. DSLRs when NOT taking pictures have a closed physical shutter over the image sensor, and a half-mirror on top of that. I've never tried, but i don't see how the light would reach the sensor at all in that conditions.

[RB]

Ben please be aware of the dangers to your eye sight first.
I have experience with lasers and I can tell you that those pointers are dangerous.
Even so called 'low power' ones can actually be over spec which means they may claim 1mW or 5mW but could actually be much higher.
Anything above 5mW can cause instant eye damage, before your eye has time to blink or react.
Also if they're a 'cheap' Chinese green pointer, ie: 532nm then you need to make sure it has a built in IR filter since it's pumped with an IR source to produce 532nm.
Decent ones usually have IR filters but you can't be sure unless you check or test them.

A lot of cheep pointers don't have this filter so it leaves you exposed to dangerous levels of invisible IR.

Also, the only way to know for sure about the power level is to use a proper Laser Pointer Meter.
Brightness is no indicator of true power levels.
And as we all know various states have different max legal levels, between 1mW and 5mW, nothing over and for good reason.

This all adds up to the point I want to make.
If by chance you get any type of unfortunate reflection via the camera viewfinder or other surface, even for a brief moment, you could be damaging your eyes without knowing it.

If this happens, your camera sensor is the least of your worries.

Just wanted to share, hope it helps.
Safer to just mount the pointer on a bracket and take all precautions.

Another unrelated matter, those 532nm pointers don't take kindly to the cold and may fail until they're warmed up.

Not saying don't use it but be aware or the power levels, IR dangers and the legalities.
Make sure there's no aircraft in the sky, very important.
You don't want a knock on your door from the authorities.

RB

[sil]

Just buy a "hot shoe red dot finder". Its the tool for the job, lasers for home astrophotography are not needed ever and people like yourself misunderstand the point of them at all in astronomy. Its just not the right tool.

[DarkKnight]

I've looked into this and found that the green pointer throws a beam, whereas the red one doesn't, and I think it would be really difficult to see a red dot on a star sixteen zillion miles away.

My intention is to mount it on my cameras hot shoe, align it, and use it to get me into the ballpark with finding what I intend to image, without looking through the viewfinder or using live-view. Be aware of not using it if aircraft are in the vicinity, gaol is not a good place to be from what I've heard.

As I'm sure you are aware, looking through a DSLR's viewfinder at a night sky can be pretty underwhelming, particularly trying to find that one speck of light.

[raymo]

I presume that you are aware that it is illegal to use any laser pointer
unless you are a member of an astronomical organisation. Big fines.
Stick a red dot finder on your hot shoe; would do the same job with no possibility of danger,
or the green beam showing up in someone else's photograph[if there is anyone nearby ].
raymo

[DarkKnight]

Yes raymo, I'm aware of the legal requirements re using a laser pointer. And I am a member of an astro society.

I have both, have tried them both outside, after dark, and I can see SFA with the red dot finder when pointed at the sky, whereas the green pointer throws a visible beam which is a useful assist in where to point your DSLR.

[sil]

A red dot finder is NOT a laser it does NOT throw a beam ever. I dont think you understand the difference you're talking about. A laser advertises itself to everyone for miles around so expect police cars to show up, and I'll repeat a laser is the wrong tool for the job, its a red dot finder or telrad you need. Hard to imagine your astro society so poorly educates its members (plus being a member is NOT a licence to use lasers, so you are clearly also NOT aware of the legal requirements.

[DarkKnight]

EDIT: It seems Sil and myself are on two different wavelengths here with me talking about red lasers and Sil about red dot finders.

All lasers throw a beam, full stop, it's just that some colour wavelengths are more visible to the human eye, with green, followed by blue, being the most visible. To see the beam of a red laser you would need to be in a heavily dust polluted or smoke filled environment, not the best of settings for viewing the night sky.

For any laser beam to be visible it must have something to reflect off and in normal conditions there is enough reflecting particulate matter in the air to see a green beam, the one with the wavelength most perceptible to our eyes.

I assume that is why the military use red laser sights for target acquisition, because it doesn't throw a tell-tale warning beam but merely pinpoints the target itself.

That is great for finding a target that is only a hundred metres or so away but not so useful when the target is light years off in the distance.

I am well aware of the dangers that improper use of lasers can pose and when using one would take whatever steps necessary to mitigate the risk of danger, or inconvenience, to others.

As for the legal requirements for owning and using lasers I will post a quote from the NSW Police Departments website. I'm sure the requirements vary in other states.

It is my belief that a green laser pointer, used thoughtfully and responsibly in an appropriate environment, should offer no risk to others.

And Sil, in the future please try get your facts right before you decide to waffle on about things you seem to know little about

[bojan]

This is very much correct... and sometimes on ebay RDF's are incorrectly advertised as "laser" devices.. .




This is also correct, at least in VIC.

Green lasers are not welcome at gatherings, where someone may be imaging at that moment and the (even brief) laser firing at the wrong part of the sky could ruin the frame.

This (https://stargazerslounge.com/uploads/monthly_07_2013/post-1029-0-38244100-1373806839.jpg) is what you really need...

My 2 cents...

[DarkKnight]

Bojan, it would seem that Sil and myself were not referring to the same thing and got our wires crossed.

I'll have a look at red dot finders as an alternative to the green laser.

PS; What brand is the finder in your link.

[bojan]

It could be one of those (http://www.ebay.com.au/itm/Holographic-Laser-Sight-33mm-Scope-Reflex-4-Red-Green-Dot-Reticle-Picatinny-Rail/171007011997?ssPageName=STRK%3AMEBI DX%3AIT&_trksid=p2060353.m1438.l2649).
You will also need a shoe adapter... one of those (https://www.thingiverse.com/search/page:1?sort=relevant&q=red+dot+adapter&type=things&subjects=&grades=&standards=&license=&category_id=&dwh=8059e431c8cd89f)?
Or this (https://www.thingiverse.com/thing:1652883)...

[sil]

I couldn't agree more, Ken. ?This is Ben's thread, his question. I'm trying to give him precise facts without you muddying up the waters on this subject even further. Deal with it. Yes green lasers are more visible than red lasers to the naked eye. Its why sensors are bayered with two greens to one red and one blue for each pixel and it ALL comes back to the properties of our eyes.

Either way the right tool for BOTH of your going of your descriptions of what you want to do is a Red Dot Finder or Telrad (if you're going to whinge about not seeing a red dot on a star. Sound like you're arguing to justify you wanting to play with lasers which is an irresponsible attitude especially on a family friendly forum.

Lasers are handy for educators pointing out stars on location for a group of students, and observatories use them to create an artificial star by ionising the atmosphere to take calibration data for the adaptive optics system its NOT required for amateur astrophotography.

Feel free to start a new topic instead of hijacking and wasting others with irrelevance.

[SkyWatch]

Just a comment about the use of laser pointers as a member of an Astronomical Society. It is my understanding that each State has different rules- so you need to check what is legal in your State; and if you are from another State but using a laser pointer (say at a Star Party), then you need to abide by the rules of the State you are in: not your home State.

Further, in SA at least, we (the ASSA) are required to hold a register of members who have laser pointers. This is updated regularly, and the members are issued with an identification card, including details of their pointer/s, that they may be required to show the Police. Just being a member of the ASSA is not enough, you must register your laser with the secretary. This is a condition that was included in the legislation when we negotiated directly with the SA Attorney General at the time (we even had him come to our observatory at Stockport and have a play with a laser pointer!). The alternative was that they could be banned outright in SA even for amateur astronomers.

So, bottom line: be very careful with their usage, and check the laws in your State.

All the best,

Dean

[doppler]

I did notice that NSW laws all refer to use/ possession in a public place, I guess that means it's ok at home? BTW, Lasers are only visible side on for a very short distance so the only ones coming to police attention are miss behaving by pointing them directly at something they shouldn't be. We use them at school astronomy nights and the group has to stand close and behind the beam or it is not very visible, so no one will know you have one unless you misbehave.