Green laser pointer/finders

[Kokatha man]

Hi all - just a quick question re laser pointers. Use a Telrad on my 10" dob (along with f/scope) and am thinking about a mounted laser for initial "quick-fixing" on the 6" achro: what are people's experiences with these devices and what power is appropriate - 5mW or 10mW?

Would appreciate some experiential feedback as seems they could be an "ergonomic" aid (if effective) for an old fart with a dodgy muscular-skeletal set-up (non-upgradable!)

Regards, Darryl.

[ballaratdragons]

Darryl, I have one permanently mounted on my scope. It is terrific for assisting with Polar aligning, polar pointing at start-up before star aligniment, and letting people see where in the sky an object is that the scope is pointing at.

But beware of any legal issues regarding the laser.

[Ric]

Hi Darryl, I use a 10mw pointer mounted on my scope and find it an invaluable tool.

The best piece of advice I can give is not to use accross any known aircraft flight paths or you may have a few extra guests at your observing session that you didn't plan for.

[Kokatha man]

Thanks for replying Ken - does this mean that as a "rough" targetter it has merit? I realize that it wouldn't have the value of a Telrad (which I find great to get fairly darn close from an eye visual perspective before using my finderscope) - but are they accurate enough to get it into a finderscope's field?

Take your point re legality issues: what power laser do you use - 5mW or 10mW?

regards, Darryl.

[Kokatha man]

Ditto thanks Ric - yes, aircraft would be the major concern re safety: what's your take on accuracy re my last question?

[erick]

I have a 5 mWatt which is plenty, in my opinion. It is fine even in the bright sky of Melbourne suburbs.

Here's a recent thread discussing use of a mounted laser:-

http://www.iceinspace.com.au/forum/showthread.php?t=25313

Search and you'll find more good threads.

Here is a description of how I use mine to point the scope, from a previous thread:-

"I have also perfected the use of my green laser pointer as a finder (after watching Ken use his in this way). A wedge of wood, glued to some fridge magnet pieces, sits between my finder dovetail bracket and the focusser base. I have adjusted the finder bracket to be completely parallel with the focusser base. I can place my pointer neatly between the focuser base and the wood, and the projected beam clears the scope body and “spots” the sky almost in the middle of my 30mm eyepiece (suggesting my optical and mechanical axes are well aligned?). Move the scope until the end of beam is in vicinity of target and check in the eyepiece that I have it. Then pointer goes back into my top pocket to keep it warm and functioning for the next target."


Now, the bad news. Go to your State Government website and search for the list of prohibited weapons. In Victoria, you will find that a "hand-held battery-operated article" that emits a laser beam "greater than 1 mW" is a prohibited weapon and certain licensing requirements exist.


If you get one, I recommend that you, 1) be very aware of the presence of aircraft in the sky, and, 2) don't let a child (or childish person!) get their hands on it regardless of how much they plead with you.

[Ric]

Hi Darryl, I see them as a valuable tool for targeting. Once you have them mounted and aligned with your finderscope. I think you'll find it to be very accurate.

With my style of scope I use my pointer to set up my goto and alignment in conjunction with the finder scope and usually have it completed in a few minutes with a high accuracy for the rest of the night.

I think that with the Dobsonian style of scope you will find even more of a help than even I do.

[erick]

Darryl, in my experience, using a laser to point your scope is the easiest way - no bending the head to look through finderscope or 1x red dot style finders. If you are good at looking at a star chart then looking up at the sky and being able to see exactly where you need to point the scope, it will be very easy for you to use the laser. Just set up so the "end" of the laser beam is visible inside the FOV of a suitable eyepiece - probably in the 25-40mm fl range. My laser is a nice narrow green line with a clear "end" in my 30mm eyepiece.

So I'm forever doing somethng like - OK, I need to be 40% of the way from that bright star to that other bright star, and then a little bit above. Put laser in place, turn laser on, move scope until the end of the laser is there, look in the eyepiece and there it is!

Now, if people are imaging around you, expect something to come flying out of the dark at you, if you are painting the sky with your laser (ouch! :D )! Also, it can draw attention to yourself, if you are trying to hid away behind trees or a building in some public place at night! I believe that someone tens of metres away can still see the beam.

[Kokatha man]

Thanks muchly fellas - and take both your points re safety/legality. I'll check SA regulations; but if it's the same as Vic then it would seem to me (no lawyer!) that if it's mounted on your scope it aint "hand-held." But will investigate further....

Erck, do you still want that Andrews chesire? Only just saw your additional post re Orion tool but in my "Izeegood or Justarsy" thread I also found I couldn't focus the (non-reflected) crosshair view: but it didn't have any impediment to the process - it was still easy to see when it and everything else were super-imposed/aligned.

Regards, Darryl.

[goober]

If you are struggling ergonomically with finders, the laser as a pointer is a great solution. I had one on my dob, mounted with a Lumicon (sp?) bracket. It was very accurate as a 1x finder. No bending, just turn it on and swing the scope to where you want.

I took it off due to all the legal uncertainties, and have since sold the dob.

[Ingo]

5mW is fine. It creates a thin, visible beam bright enough to see in the sky. Other powers will be too bright and annoy you. Well, maybe not up to 20mW, but I personally wouldn't suggest anything more than 5mW.

[ballaratdragons]

I use the 10mw.

Don't underestimate the pinpoint accuracy of a good laser. They are spot on as long as you spend the few minutes to accurately align it. :thumbsup:

Not hard to do. Look through your finderscope and centre the laser. Then look through the scope and centre it even closer.

I see my laser on my monitor and it points exactly centre of the screen. :)

[Kokatha man]

Thanks for all the responses fellas - it's just one of the reason that IIS (and other forums) are so great for us AA's. I sometimes think that our propensity to hover over instruments in the dark - often alone - could be an indicator of introversion in some ways!?! - but these "social outreach" facilities (IIS etc) certainly help ameliorate such!!!???

I just rang the "illegal weapons" hotline here in SA and there are no impediments to their use in these situations at all; so I'll definitely be getting one.

Thanks again for the responses, Darryl.

[erick]

Good news for South Australians!

[thunderchildobs]

Using Green Lasers as pointer could cause you problems if you intend to go some astrocamps. The lasers interfere with those taking pictures. Some large camps ban the use of lasers after dark. Observing by yourself or with small group of friends it is less of problem.

Brendan

[Kokatha man]

Nah....! as I said Brendan; I'm more the introvert type that spends time by myself or just with my partner or a few "guests" (where the extrovert in me gets a turn) - but think that public viewing nights and get-togethers with others to swap stories/ideas/experiences are great group therapy/socialization opportunities: I really must join the local ASSA............

Take your point though, as well as Erick's re annoying others. Incidently, I just purchased Bintel's last Lumicon bracket for aforementioned item: they're not re-stocking due to the hassles/red tape needed to permit them to sell "potentially dangerous" items - particularly from the perspective of Victorian legislation.

On a completely different note, I'll PM you Erick re chesire in the next couple of days: had a long yarn (aren't they allways!!!) with Don at Sydney Bintel this morning; he agrees that the (unreflected) view of the crosshairs in the Orion tool will not appear in focus during collimating - and with all due respect, I have far more faith in his knowledge here than another self-styled authority! (which isn't to cast a blanket aspersion on all of this other persons knowledge and/or experience) regards, Darryl.

[spacemanspiff]

I feel like using my 75mW green laser pointer that I got "relatively" cheap from techlasers (http://www.techlasers.com)is a bit of an overkill after my old 5mW died out. But having a bright clear beam is more awesome as opposed to a faint one.

I was originally just going to buy a 35mW one but it was on sale bundled with safety goggles and other freebies so I picked it up. I got my order in less than a week. :D

[Ric]

75mW, wow you could roast chickens with that much power.

[Zuts]

That site sells 600 mw lasers :scared:

Paul

[Ric]

Now that's a bit of overkill, does it come with its own nuclear backpack :P

[mswhin63]

Also check with Astro clubs, some have limit of power rating as well

[Jen]

:lol::lol: lol Ric :thumbsup: