Tweedledee Posted November 23, 2012 Share Posted November 23, 2012 One night at Belper I tried to use my green laser pointer as a finder. I have the proper small adjustable laser mounting bracket fixed to the scope. This method works absolutely brilliantly on a clear night when you can locate the object or a nearby star with the naked eye. According to the blurb it projects the beam up to 13000 feet into the sky (effectively to infinity as far as the naked eye is concerned) therefore you don't need to get into awkward positions, as with a normal finder, and can simply point the beam to the object without even sighting down it or even having your head near the scope, and the object will be in the eyepiece if well aligned. I was very disappointed to find that in cold temperatures the laser only worked for a few seconds and its brightness rapidly reduced until after 30 seconds or so the beam could no longer be seen. After removing it from the bracket and warming it for several minutes in my hand, it would then work again for about 30 seconds and become invisible. This obviously made the laser unusable for use as a finder. I tried new alkaline batteries on another night and found the same problem. Searching the internet I found other people having the same problems and coming up with solutions such as using a dew heater strip around the laser to ensure it stays warm. Some other reports concluded that some laser pointers just will not work in cold temperatures but found in general that the more expensive lasers usually £50 to £120 did work in the cold. My laser was about £20 from a company called GY3 Lasers. Since I didn't want to spend a load more money on another laser, I dug a bit deeper into the subject on the internet. Somewhere I found a suggestion that Lithium batteries had solved the problem for one user. I needed 2 AAA Lithium batteries, and realising they were substantially more expensive than the alkalines I was currently using, I searched ebay and bought the cheapest lithiums I could find. Usual price is about £8 for 4 but I found 4 for £3.99 so got them. I since found that I could have gone to my local Maplins and got their special £3.99 for 4 deal, but anyway I just had to wait 4 days. Received the batteries this afternoon, put them straight in the laser and at least noticed that it seemed a bit brighter. Looking at the details on the packet, they apparantly work at full power down to minus 40 degrees C!!! It wasn't dark yet so I decided to put the laser with the batteries in the freezer, as you do. Forgot all about it and eventually got it out of the freezer after 3 hours, and it was sticking to my fingers. Dark outside so I tried it. Didn't work, except for the dimmest green light, no beam. So I'd overdone it a bit. Within a couple of minutes it was working again at full brilliance with a fantastic beam. I then put the laser in the fridge for 2 hours at probably +3 or +4 degrees C, as cold as Belper recently. Took it outside and the beam was brilliant, better than it had been with the alkalines. I immediately put the clip on the on button and left it outside on a garden chair switched on in an ambient temperature of about +5 degrees with the beam brightly spanning the garden to the fence. I kept checking on it every few minutes and the beam was still brilliant. After 30 minutes switched on outside the beam was still as brilliant as it was initially, so I switched it off. I reasoned that in use as a finder, I would only switch it on for a few seconds at a time whilst finding an object and then switch off until the next object and would probably not even use it for 20 minutes total on an average night. So I'm very pleased. RESULT = COLD LASERS WORK WITH LITHIUM BATTERIES. Go on - tell me you could have told me that . Link to comment Share on other sites More sharing options...
catman161 Posted November 23, 2012 Share Posted November 23, 2012 That's cool Pete. I use my green laser pointer only when showing other people stuff really. Have not heard of a finder bracket to hold the pointer. Have you got a link or a photo for the bracket/holder? Link to comment Share on other sites More sharing options...
Tweedledee Posted November 23, 2012 Author Share Posted November 23, 2012 This is the standard bracket I bought.../>http://www.365astronomy.com/laser-pointer-bracket-with-william-optics-dovetail-finder-base-p-1691.html But then I turned it into this.../>https://dl.dropbox.com/u/104047272/650.jpg Link to comment Share on other sites More sharing options...
catman161 Posted November 23, 2012 Share Posted November 23, 2012 (edited) Thanks Pete nice work there. How did you attach it to the tube rings like that? Are the lithium batteries you went or rechargeable or single use? Edited November 23, 2012 by catman161 Link to comment Share on other sites More sharing options...
Tweedledee Posted November 23, 2012 Author Share Posted November 23, 2012 Just 2no. 4mm holes. The big rings are for my 12 x 80 RACI finder. RDF on there as well. Like to keep my options open . Link to comment Share on other sites More sharing options...
Tweedledee Posted November 23, 2012 Author Share Posted November 23, 2012 The batteries are disposable. The rechargeable ones are probably a lot more expensive. Link to comment Share on other sites More sharing options...
catman161 Posted November 23, 2012 Share Posted November 23, 2012 Cover all bases, I like that. 12x80 what a beast of a finder! I use a RACI 9x50 by Orion. Didn't know you could get a 12x80. Cheers for the info. Will pick up some lithium batteries for my pointer and maybe even the bracket Link to comment Share on other sites More sharing options...
Perkil8r Posted November 23, 2012 Share Posted November 23, 2012 A laser finder for the red dot finder for the finder..... belt and braces there Pete all you need now is a Telrad Link to comment Share on other sites More sharing options...
Tweedledee Posted November 23, 2012 Author Share Posted November 23, 2012 Felix, there are other brackets available to fit different bases, in case you don't have the Williams Optics base. Some have sticky fixers for fitting on the OTA. Have a search. Link to comment Share on other sites More sharing options...
Tweedledee Posted November 23, 2012 Author Share Posted November 23, 2012 I'm planning to replace the RDF with a Telrad, but they are on a boat in the Atlantic at the mo. Don't want too much hanging off the scope . I also have an 8 x 50 straight through seperately on the same OTA . This is just an alternative to goto . Link to comment Share on other sites More sharing options...
catman161 Posted November 23, 2012 Share Posted November 23, 2012 Yeah I'll have a good hunt around. Thanks Pete Link to comment Share on other sites More sharing options...
Tweedledee Posted November 23, 2012 Author Share Posted November 23, 2012 Felix, here's another.../>http://www.scopesnskies.com/prod/binocular/laser-finder/laser-tripod-bracket.html Link to comment Share on other sites More sharing options...
Tweedledee Posted November 23, 2012 Author Share Posted November 23, 2012 And this.../>http://www.ebay.co.uk/itm/Laser-Pointer-Bracket-telescope-dovetail-fitting-/380482023357#vi-content Looks like a SkyWatcher shoe fitting. Link to comment Share on other sites More sharing options...
catman161 Posted November 23, 2012 Share Posted November 23, 2012 Nice one. Thanks for links Pete Link to comment Share on other sites More sharing options...
Cazz Posted November 26, 2012 Share Posted November 26, 2012 Interesting Pete, I look forward to seeing that at some point. This thread has raised a big question, Why do GoTo's have a finder? It's a bit like a shop that's open 24 hours a day having locks on the door. ;-) Link to comment Share on other sites More sharing options...
Daz Type-R Posted November 26, 2012 Share Posted November 26, 2012 (edited) Interesting Pete, I look forward to seeing that at some point. This thread has raised a big question, Why do GoTo's have a finder? It's a bit like a shop that's open 24 hours a day having locks on the door. ;-) Helps when you have to do your 2,3 star alignment. You cant just plug a GOTO in and away you go, you have to tell it where it is (co-ordinates) (unless it has GPS, some do) then once you have told it that, tell it the time and date and then you have to star align. The above applies to a ALT/AZ mount, with a EQ mount you also have to polar align. Without a finder - it will be difficult but not impossible. Edited November 26, 2012 by Daz Type-R Link to comment Share on other sites More sharing options...
Daz Type-R Posted November 26, 2012 Share Posted November 26, 2012 Also with regards to lasers, I have been told by a few people off here that the more you pay, the better they work in the cold - Santa is bringing me one of these bad boys........ />http://www.sp3plus.co.uk/visible-lasers/green-laser-pointer/green-laser-pointer-1.html I have asked Santa very, very nicely for the SP32!!! Link to comment Share on other sites More sharing options...
Cazz Posted November 26, 2012 Share Posted November 26, 2012 Helps when you have to do your 2,3 star alignment. You cant just plug a GOTO in and away you go, you have to tell it where it is (co-ordinates) (unless it has GPS, some do) then once you have told it that, tell it the time and date and then you have to star align. The above applies to a ALT/AZ mount, with a EQ mount you also have to polar align. Without a finder - it will be difficult but not impossible. Cheers Daz, so goto's aren't as clever as they think they are lol. ;-) Link to comment Share on other sites More sharing options...
catman161 Posted November 26, 2012 Share Posted November 26, 2012 They're still a marvellous piece of engineering IMO Link to comment Share on other sites More sharing options...
Cazz Posted November 27, 2012 Share Posted November 27, 2012 I agree :-) I must wait for a long dark night to get my head round ours and put it through it's paces. :-) Link to comment Share on other sites More sharing options...
Daz Type-R Posted November 27, 2012 Share Posted November 27, 2012 I agree :-) I must wait for a long dark night to get my head round ours and put it through it's paces. :-) You could all ways pop round if want, all though it is a bit far to travel, if you can wait until the new dark site meet on the 15th I can give you a run through if you want to bring it, it really is quite simple when you know how? Is it a SkyWatcher ALT/AZ GOTO mount? Link to comment Share on other sites More sharing options...
Cazz Posted November 27, 2012 Share Posted November 27, 2012 Cheers Daz, it is possibly or very similar if not. The Dec meet will be perfect. :-) It'll take a while to view the 42,000 objects lol. Shame the 130 won't actually see most of them :-S Link to comment Share on other sites More sharing options...
Daz Type-R Posted November 27, 2012 Share Posted November 27, 2012 Yeah the object amount in the database is nothing more than a sales ploy and can not be taken seriously. Link to comment Share on other sites More sharing options...
Cazz Posted November 27, 2012 Share Posted November 27, 2012 Yeah the object amount in the database is nothing more than a sales ploy and can not be taken seriously. To true, to true. Link to comment Share on other sites More sharing options...
BAZ Posted November 27, 2012 Share Posted November 27, 2012 According to the ETX 80 data base, there were two black holes and a Quasar. None of them remotely possible. 3C273 is a visible Quasar, but is mag 12.9. Link to comment Share on other sites More sharing options...
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