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Green Laser pointer as a Finder !

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#1 clusterbuster

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Posted 16 July 2019 - 09:11 PM

The Green Laser is a great Finder. I have a very good knowledge of the sky, (40+ years of Star Hopping), and and with this pointer, I have never found objects so fast.

For instance; Mesarthim (Gamma Aries) nice double star, I see it in the sky, I put the laser on it, takes 2 seconds or less to aim it right on the Star, and BOOM, IN THE EYEPIECE at 167X..

I just started using one last week, VERY IMPRESSED, I am not a fan of the Telrad (don't Hate me), basically because you have to look through it like a STRAIGHT THROUGH finder, so I have been a RACI FINDER person.

The laser will not be shut down by DEW either. I aquired the Green Laser Pointer in a TRADE and I love this thing !

Mark


Edited by clusterbuster, 16 July 2019 - 09:11 PM.

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#2 ggalilei

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Posted 16 July 2019 - 09:23 PM

It is great, as long as the target is visible to the naked eye, or easy to locate. For most DSOs I still prefer a 50mm (or 60) finder scope.



#3 Jon Isaacs

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Posted 16 July 2019 - 10:35 PM

I just started using one last week, VERY IMPRESSED, I am not a fan of the Telrad (don't Hate me), basically because you have to look through it like a STRAIGHT THROUGH finder, so I have been a RACI FINDER person.

The laser will not be shut down by DEW either. I aquired the Green Laser Pointer in a TRADE and I love this thing !

 

Lasers are shut down by temperature, airports and dead batteries.  Telrads are effective and have calibrated reticules which makes aiming at unseen objects easier.  

 

I am a user a Telrad combined with an RACI.  Pointing a bright star that's visible is no biggie.  Pointing at an unseen object relative to a star field is what it's all about... 

 

Jon


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#4 rockethead26

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Posted 16 July 2019 - 11:13 PM

Lasers are shut down by temperature, airports and dead batteries.  Telrads are effective and have calibrated reticules which makes aiming at unseen objects easier.  

 

I am a user a Telrad combined with an RACI.  Pointing a bright star that's visible is no biggie.  Pointing at an unseen object relative to a star field is what it's all about... 

 

Jon

Well, last time I looked, my Telrad used a battery, too. I've been out at least once without a spare battery and a dead Telrad, so it happens. I don't live near an airport and have a green laser pointer that operates at low temps. They work really well for me with my 100mm BT, even down to 15-20°F. I don't use it often, but it does come in handy when I get tired of bending over to sight thru a one power finder. My Telrad lives on my 14" dob and I love it. I also have smaller red dots on my refractors. Right tool for the right job.


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#5 markb

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Posted 16 July 2019 - 11:13 PM

Agree 100% on the green laser. I use mine on short and long tube refractors, SCTs and 45 degree binos.

 

It is a great star hopping aid, and is great for getting right on objects visible to the eye. Mine, combined with the 'modern planisphere'. SkySafari on a tablet, are helping me learn the sky. Horrific light pollution and lack of time and pattern memory always held me back.

 

Most come with Weaver (no groove needed) or Picatinny style (anti-recoil groove accommodation needed) trapezoidal 'dovetail' bases, adapters to Vixen/Synta finder mount shoes are easy to find on EB, for as little as $6. My last ones came with a Vixen/Synta finder shoe female for $11. All my 50mm RA finders will go to the classifieds soon. My Telrads will go with scopes I sell. 

 

My GLs have restored most of my lost time in observing sessions, and the microadjustable ones are a snap to readjust if you are moving one from scope to scope; I have one for each scope now.

 

The last one bought was a 25mm diameter one for an ETX finder ring. I searched using 'AA' within the search term and got one that runs on a single AA cell. No more issues with dead batteries.

 

Be careful to only buy intermittent switched GLs. Most of the firearms GLs come with a pressure switch, but note that I have have to resolder all but one, so US sellers are preferred if it needs to be returned.

 

For those folks with battery issues on green lasers I can offer my experience so far. My firearms type green lasers have used CR123 cells, and even Amazon sourced cells were spotty until I tried the Surefire ones. Apparently they are a high quality flashlight maker, and their cells are the best I have bought. Apparently they are not name brand enough to counterfeit. I just tried two that were sold with rechargeable cells (not CR123a compatible) and was surprised that the rechargeables gave excellent battery life. I do hate keeping track of the chargers though.


Edited by markb, 16 July 2019 - 11:14 PM.

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#6 Jon Isaacs

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Posted 16 July 2019 - 11:20 PM

Well, last time I looked, my Telrad used a battery, too. I've been out at least once without a spare battery and a dead Telrad, so it happens. I don't live near an airport and have a green laser pointer that operates at low temps. They work really well for me with my 100mm BT, even down to 15-20°F. I don't use it often, but it does come in handy when I get tired of bending over to sight thru a one power finder. My Telrad lives on my 14" dob and I love it. I also have smaller red dots on my refractors. Right tool for the right job.

 

Obviously one can run the batteries dead on a Telrad if one tries hard enough.  Some years ago I measured the current flow in a Telrad at a reasonable brightness for an urban setting.  I calculated that it would run a pair of AA batteries dead in about 2.5 months.  I do carry extra batteries just in case.  

 

No lasers for me..  they mess up the night sky.. If it's OK for me to mess with the night sky because it's convenient, it's OK for the next guy or gal.. 

 

Jon


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#7 NorthernlatAK

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Posted 16 July 2019 - 11:21 PM

Is there a bracket that will allow the laser to come off and be accurate when put back on quickly? I observe down to -10°F and sometimes colder so I want to be able to keep it in a pocket on me. Does anyone have experience with these lasers at these low temps? I've read about people using them at temps in the teens but not lower.

#8 pierce

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Posted 16 July 2019 - 11:47 PM

first, get a true green laser, *NOT* a frequency doubling green laser triggered by an IR laser   the true ones are typically 515 or 520 nm instead of 532nm.   they have far better battery life, and typically are powered by 2 x CR123 batteries rather than 2 x AAA or 1 x 18650, and more importantly they don't bleed massive quantities of invisible 1064 or 808 nm IR laser, which is far higher power than the green output, and often not properly filtered on cheaper lasers

 

2nd, make sure the business end of your telescope is well above the head level of anyone in the vicinity.  most of these cheap lasers have a lot of green scatter from their exit lens.

 

for very cold operation, you'll need an external power supply thats in a temperature protected environment, either 6V for the native green laser, or 3V for the IR doublers.

 

finally, don't use this at any astronomy event where there may be imagers anywhere in the vicinity, you'll ruin their exposures.


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#9 markb

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Posted 17 July 2019 - 05:53 AM

Pierce's tips have been around for a while, and it was great to have them in one place.

 

When recommending the GLs, I also strongly suggest not using them, or taking extra precations when young kids are around. Too enticing for the young scientist types to avoid being tempted to do something potentially dangerous. Also, this is another reason not to use them, or limit use, at gatherings. I am keeping a 50mm RA finder and a Rigel for these times, and the Rigel does dead battery duty as well . I also have a setup with both a GL and scope but have not had to use it.

 

For cold weather, tamper-proofing, and stepping away from the scope, most have batteries that are easily removed. And I suspect some cold weather issues are related to the laser and not the batterries, so being able to remove and reinstall the entire GL assembly is a plus, and also reduces unauthorized use by the curious.

 

Even with the simple Vixen/Synta shoe, GLs appear to realign acceptably, but I have not stringently tested this yet as I just stopped swapping them to different scopes this month, and my use has been overy a limited time span so far. . Also, my spare time has been been used for preparing for an upcoming move, and updating scopes that I am selling before moving. Others can better address this. An alternative to removing the adapter stalk is to keep it fixed and remove the GL itself.

 

I carry a stubby hex head screwdriver to let me rapidly retune alignment of the firearms microadjusters. It goes quickly, even with the cheap and sloppy chinese GL adjuster bodies (future project, lube the adjuster bodies internally). I also loosened and shifted/shimmed my screwmounted V/S shoes to roughly match alignment of my cast-in focuser body shoes, to minimize realignment if I have to swap GLs between scopes.

 

The Weaver/Picatinny mount can give repeatable alignment on reinstallation but gun fans and perhaps red dot users on the forum can answer authoritatively. The same for users regularly removing and reinstalling V/S shoe finders. Before finding the GLs I always had to tweak finder alignment with my RA finders, but that was mostly due to the finder ring design. I am not a fan of the rubber oring design.


Edited by markb, 17 July 2019 - 05:58 AM.


#10 Eddgie

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Posted 17 July 2019 - 08:08 AM

Well, I use a red laser rather than green for my finder, but yes, I really love using a laser pointer as a finder.

 

Mine is just one of the regular "military" style lasers with the push/hold button and this means that it runs for many sessions on a single rechargeable Lithium battery. (Since I use red, no issues with temps).  While I don't dismiss the safety issues at star parties, for solo observing (99% of what I do), I have never felt safety was a concern, and since I am watching the beam in the sky, if there is a plane nearby, I simply let go of the button!  I don't know why anyone would leave it on.

 

On my Skywatcher 130 PDS, it makes it a cinch to locate objects and get them into the field.  My field is only about 1.8 degrees, but usually I am able to get most targets into the field using just the LP. 

 

And the battery objection???? Pleeeease.  I have come out many nights and found the batteries in my Telrad were dead because I accidently left it on, but since my laser is only on when I press the button and hold it, it is impossible to leave it on accidently.  I always have spare batteries for my LED flashlight though, and I change the battery in the laser regularly anyway because it is best to not let lithium ion batteries fall below voltage.   But that is just good lithium ion battery management practice, and since I use this kind of rechargeable in just about everything, I am very good about maintaining and rotating my batteries. 

 

And I hate it when I leave the Telrad on because it kills Li-ion batteries to let them fully discharge.  That means I have to use disposable batteries in the Telrad, which I really hate to do, but I have accidently killed a couple of sets of Li-ions.   Never have this problem with the laser. 


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#11 howardcano

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Posted 17 July 2019 - 08:22 AM

Is there a bracket that will allow the laser to come off and be accurate when put back on quickly? I observe down to -10°F and sometimes colder so I want to be able to keep it in a pocket on me. Does anyone have experience with these lasers at these low temps? I've read about people using them at temps in the teens but not lower.

To each of my telescopes I have added a finder bracket with an empty tube in it (the tubes are from old 0.965" Barlows I got on Ebay).  The tube ID fits just right around my laser pointer.  The laser pointer stays in my pocket, cozy and warm, until needed.  Then I slip it into the tube on the scope of choice, turn it on, and have at it.  A few seconds later the laser is off and again in my pocket.

 

As a safety feature, I've also inserted a long-focal-length negative element at the front of the laser pointer to spread the energy at long distances.  At a mile out, the intensity is reduced by several orders of magnitude.  But I still check for airplanes before use!

 

These are for not for use in groups!


Edited by howardcano, 17 July 2019 - 08:23 AM.

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#12 markb

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Posted 17 July 2019 - 09:21 AM

Eddgie, good to hear a red laser will work. Here 15 miles from NYC it is impossible to tell if it would work in a dark or moderately dark location. Here only a green laser is visible.

Given the intermittent switch it is trivial to check for planes first. After all, we are already looking up. My area has limited Kennedy traffic, but we do get tons of flight levels transits, never a problem.

As to aiming, I was amazed to find planets in the field of a short 82 degree ep on even the C11. If not, I pop in a longer eyepiece, center the target and reinstall the short ep, and never have a problem. I really did not expect this aiming accuracy (looking right over the beam). I use an refractor or binos on a zero friction alt az much of the time so accurate aiming is a frustration ending godsend. Moving from an optical or headsup finder to the ep often jostles the scope a bit, and Telrads just cannot carry that accuracy.
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#13 REC

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Posted 17 July 2019 - 11:32 AM

The Green Laser is a great Finder. I have a very good knowledge of the sky, (40+ years of Star Hopping), and and with this pointer, I have never found objects so fast.

For instance; Mesarthim (Gamma Aries) nice double star, I see it in the sky, I put the laser on it, takes 2 seconds or less to aim it right on the Star, and BOOM, IN THE EYEPIECE at 167X..

I just started using one last week, VERY IMPRESSED, I am not a fan of the Telrad (don't Hate me), basically because you have to look through it like a STRAIGHT THROUGH finder, so I have been a RACI FINDER person.

The laser will not be shut down by DEW either. I aquired the Green Laser Pointer in a TRADE and I love this thing !

Mark

That's all I use on my dob. Point and SEE!


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#14 clearwaterdave

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Posted 17 July 2019 - 01:04 PM

I use the rifle lasers made by Pinty.,They work down to 0*F.,maybe more.,That's "my" limit.,.

  I use them for three things.,pointing at a naked eye star to start a hop.,or to point the scope at an object who's location I know.,or am guessing at by aligning with visible stars,.the later being a point n search kinda deal..

  I have neck and back trouble so using a laser has made my observing much more comfy.,and I have tested to see if it effected my night vision and to the best of my ability I could not see any effect.,ymmv.,


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#15 SteveG

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Posted 17 July 2019 - 01:16 PM

I use a green or blue laser 95% of the time. These are fantastic:

https://www.custom-l...s.com/astronomy


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#16 Eddgie

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Posted 17 July 2019 - 02:39 PM

Eddgie, good to hear a red laser will work. Here 15 miles from NYC it is impossible to tell if it would work in a dark or moderately dark location. Here only a green laser is visible.

Given the intermittent switch it is trivial to check for planes first. After all, we are already looking up. My area has limited Kennedy traffic, but we do get tons of flight levels transits, never a problem.

As to aiming, I was amazed to find planets in the field of a short 82 degree ep on even the C11. If not, I pop in a longer eyepiece, center the target and reinstall the short ep, and never have a problem. I really did not expect this aiming accuracy (looking right over the beam). I use an refractor or binos on a zero friction alt az much of the time so accurate aiming is a frustration ending godsend. Moving from an optical or headsup finder to the ep often jostles the scope a bit, and Telrads just cannot carry that accuracy.

I use red because I use an image intensifier when I observe.    I have one image intensifier that is always at 1x, and with this, I can see the red beam easily, and I have another one that is mounted in the scope.

 

I love using a laser pointer though, but for visual, red does not really work that well.  To the OPs point though, I vastly prefer using the laser to the ergonomics of using a Telrad or red dot. 


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#17 KLWalsh

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Posted 17 July 2019 - 03:23 PM

Green laser pointers work for astronomy due to back-scattered light from the laser. The back-scatter is caused by water vapor, dust, and pollen particles in the air.

So in the Winter - when it's cold - there is less water vapor, very little pollen, and typically less dust.

 

Thus, the reason the laser is not as bright when it's cold outside is only partly due to the lasing element and/or batteries being cold.

It has as much, if not more, to do with there simply being less 'stuff' in the air to cause back-scatter.

 

Even if you keep your green laser pointer inside your jacket, so it is kept warm by your body heat, it still won't look very bright in the Winter due to the lack of back-scatter particles.

 

Incidentally, this is why even high power red laser pointers don't work very well. The back-scatter is wavelength dependent, with shorter wavelengths having greater back-scatter. Blue light scatter the best, but the human eye has poor blue response. Green light scatters very well, and the eye has its highest response to green light. Red light has the longest wavelengths, scatters the least, and the eye has poor response to red light. Thus red laser pointers are almost useless as astronomy pointers.


Edited by KLWalsh, 17 July 2019 - 03:24 PM.

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#18 Chesterguy1

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Posted 17 July 2019 - 09:04 PM

Like Steve I use a green laser with all my scopes because of neck issues. I use them solo, am far from any airport and only use it for two star alignments, then typically use DSCs. As Jon mentions, mine all lose efficacy when temps drop to 40 or below, which can be challenging to the hands and body anyway and I prefer warmer nights to stargaze. I have been interested in the low temp blue (or green) lasers that Steve provided the link to. I have used my Telrad when it gets cold and used to always use one when I starhopped (and my neck was more cooperative). You can also use a Telrad at dusk, but lasers don’t work well as pointers until it gets dark, which is why I always use a RACI finderscope as well.

GLs can be used sensibly and effectively.

Chesterguy

Edited by Chesterguy1, 17 July 2019 - 09:08 PM.

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#19 telesonic

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Posted 17 July 2019 - 09:33 PM

I also recently picked up a green laser for this use..... the same Pinty brand that Clearwaterdave has mentioned. While I haven't worked out how I'm going to mount this little guy to work with my assorted scopes yet. (awaiting for my cheap pack of Picatinny rails from Amazon to arrive) I have taken it out a few times. Pretty neat!!

 

I can see it's benefits as being a really handy device to have IMHO. I've used it a few times to point out things to my girlfriend, and yes - it's much better that saying "three stars this direction" and getting a confused reply or look. Since I only observe solo, I thought I'd give one of these a try. We'll see how it pans out in the long run I 'spose.

 

If I find I don't like it, off it will go. Honestly it didn't cost much more than a large pizza, and can be re-sold easier too. grin.gif

T


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#20 pierce

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Posted 17 July 2019 - 10:05 PM

again, avoid *all* 532nm green lasers, they have massive infrared output, and way too many of them lack adequate IR filtration.

 

the 515 or 520 nm 'true green laser diode' ones have *no* IR output, and are much more power efficient.  they cost 2-3X more than the cheap 532nm ones.  maybe even 10X more than the cheapest chinese imports.



#21 telesonic

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Posted 17 July 2019 - 10:22 PM

Hrmm.... just checked my Amazon Pinty and it clearly is marked as being 532nm.... I didn't even bother to look at that when it arrived.

It does appear to have some kind of optical window in the end..... which I'm supposing is "acting" as an IR cut filter.

 

 

So, maybe not the best choice of 'em then. Live and learn.

I Still have a Telrad, I use and a recently acquired ST Correct Image finder.

 

T


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#22 Napp

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Posted 17 July 2019 - 11:51 PM

I do most of my observing with groups at remote dark sky sites.  Usually there are folks doing imaging so lasers as finders are not appropriate.  I usually use a Telrad with my scopes.  My neck will not allow me to use a Telrad mounted close to the tube of either of my DOBs.  However, a 4 inch riser base for the Telrad has solved that problem.  No more neck pain!



#23 kksmith

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Posted 18 July 2019 - 05:24 AM

Hrmm.... just checked my Amazon Pinty and it clearly is marked as being 532nm.... I didn't even bother to look at that when it arrived.

It does appear to have some kind of optical window in the end..... which I'm supposing is "acting" as an IR cut filter.

 

 

So, maybe not the best choice of 'em then. Live and learn.

I Still have a Telrad, I use and a recently acquired ST Correct Image finder.

 

T

I have this Pinty too. Works just fine. I use it with the remote paddle. Gets me in the ball park very quickly. Mounted a Picatinney rail on my C8 and one on the mounting rings of my 102 refractor. I also bought a pair of 1" quick mount scope rings. Turn of a finger knob and I can quickly transfer the laser between both scopes. Or...if I have both scopes out and set up, I can follow the activated beam in the finder of the other scope to the object of interest. If I find it in the binos, I can activate the laser and move the scope till the beam terminates at the object in the binos. Then move to the scope. Nine times out of ten, the object is in the eyepiece field of view. The rifle scope type adjustment knobs make it very easy and quick to align with the scope.

 

Ken


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#24 rustynpp

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Posted 18 July 2019 - 05:28 AM

Love using green lasers - can't imagine ever going back to a red dot, unless I'm ever at a star party or something. I've been a purely solo observer, save some friends or family, so I usually don't need to worry about etiquette. 

 

I have a cheapo laser from Orion as well as a very nice 515mm cold-temp laser from Z-Bolt. The Z-Bolt is the better product in every way - it shines brighter, the battery lasts way longer (very important), and it has much better build quality. It's a no-brainer.


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#25 clearwaterdave

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Posted 18 July 2019 - 05:34 AM

T.,Your microwave is probably more dangerous than your laser.,I have been using 532nm lasers for years and I still haven't grown a second head yet.,

  35yrs. ago I had Lukemia.,got "full body radiation".,they laid lead sheets over my lungs and wished me well.,

  I don't listen to all the hyped up reports of the dangers of leaking radiation.,Don't point it in your eye.,it hurts.,so does a  bright flashlight.,

Burgers cooked on a grill are supposed to be carcinogenic.,I'm not giving those up either.,


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