Need Help with 15mw astronomy laser

hey!

So i'm about to order a 15mw laboratory laser to mount on my telescope as a AF focus for my Camera. I've run into big problems with getting a perfect manual focus on my compact SLR camera and my friends 5mw laser was rather good at using as a AF assist lamp (just holding them side by side) so I'm thinking a considerably larger laser will easily function as my Galactic AF lamp for my newtonian reflector ^_^

Hes an example of my problem from last week out west of the city.

It's just...absolutely impossible to focus on something you can't see, not through a finder, and certainly not through a 3" LCD screen.

I can use a bright star like this and dial it in manual focus, But anywhere by itself i'm stuck practically guessing what the focus point should be =|

It goes great on the moon, But farther out objects are very hard, and nebula are absolutely out of the question, especially long exposures where focus is extremely important.


Anyways my whole problem, is i need some ideas for the power supply, and ideally i'd like to use a resistor in tandem with a higher voltage battery pack so i could leave it on for longer periods of time. but... Ohm's laws kinda escape me as math has never been a good subject of mine. =p


Anyways I hope you guys can help me, You've always came up with kick ass ideas in the past ^_^

(lol taken at 4am in the morning @ a extremely high iso)

HS physics guy, right here.


Just give me the battery pack voltage, the rating of the device (volts/amps), and I can help you out.

Get in touch with CJ (oneslowz28) too. He's been doing some killer astronomy stuff lately.

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Originally Posted by AmEv

HS physics guy, right here.


Just give me the battery pack voltage, the rating of the device (volts/amps), and I can help you out.

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2.800 to 3.00v operating input voltage

<280mw operating amperage

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Now i'm not quite sure but i might go ahead and get a 40mw laser instead.

Where are you getting the laser? Online? Have a link?

Any bright star you focus on will be more than sufficient focus for any object you can see with that scope. My buddies and I image with several different scopes and we always focus on a near by bright star. That is as close to infinity focus as any focuser you are able to buy will get. The laser idea is a good one but you are only focusing on that laser within a mile or two inside our atmosphere. You are not actually seeing it anywhere near close to your target.

That is a nice dob btw! Here is my baby and one of my latest images.

10" Meade LDX-55 Schmidt Newtonian on a Meade LDX-55 Goto GEM

Taken with a 14" Meade LX200 with a 100mm William Optics Triplet acting as a guide scope.

Whelp, I have a new, expensive hobby. Thanks Oneslowz28!

How far outside of urban areas do you have to go to get such pics? The night sky is usually a dim yellow here. I've always wanted to take a trip to MI's UP to witness the Milky Way with my own eyes.

You could not have been more correct when you said expensive.

You will need to be in a fairly dark sky. We wont even image if the milkyway is faint. It needs to be very visible before we will roll the roof of the observatory back for imaging.

To get started you will need a telescope with a computerized mount. To get a shot like the one I posted you will need a minimum apeture of 8" for a Newtonian or 90mm for a refractor. The mount needs to be able to hold about 60% more weight than what your optical tube weighs also. This is because you will need to mount a second telescope onto it to use as a guide scope and you will also need to mount a dedicated Astrophotography CCD camera or at the very minimum a Astrophotography modified Canon DSLR.

The Cameras. You will need a Canon DSLR. Nikon wont cut it here as they do not modify well nor do they play nice with any of the image capture software that is out there. Anything 1000d and higher will do. You will need to have that camera's sensor modified. I recommend Hap Griffin for the mod. This will run between $300 and $600 on top of what the camera cost. You will also need some sort of camera you can use for guiding. We use a Meade DSI II. This guiding camera will need to be mounted on a guide scope that is piggy backed onto the main imaging scope.

You will need software to run the scope, automate the camera's imaging process and something to stack, stretch and post process all of the images you take as well. We use a combination of programs to control the scope, I like Registax for stacking, and Photoshop for stretching and processing.

The image I posted above was a combination of 2 hours of exposure with 90 second subs . That means I took a 90 second exposure, waiting 90 seconds for the camera to cool down and took another one. There are also about 30 dark frames @90 sec each, 30 bias, and 30 flat frames stacked in there. All in all it took about 14 hours to produce that image and about $35k in equipment.

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Originally Posted by Oneslowz28

...$35k in equipment.

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I think I've done all I can with this hobby. Next!

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Originally Posted by Oneslowz28

...roll the roof of the observatory back for imaging.

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:eek: You work in an observatory now?!? Do you have more pics online anywhere?

Also, does your equipment auto-track or are you sitting nearby, with beer in hand, making adjustments all night?

I don't work in an observatory. A friend of mine owns a 14" Meade LX200 that is inside a backyard roll off roof observatory. We guide everything with guide scopes and cameras and PCs. Here is our facebook page http://www.facebook.com/pleasantpoin...vatory?fref=ts

This DSLR mod you speak of ... is it just removing/replacing the internal IR-filter, or is it something more involved?

I've removed plenty of those IR-blocking plastics, it's a good way to turn half-obsolete digital cameras into surprisingly effective nightvision gear. It's also a trivial piece of camera surgery for a modder, hope you didn't pay a lot to have it done.

Infrared lasers might not be attenuated as much by atmosphere, plus a modified camera is very sensitive of IR light. I agree it's not an optimal solution, but it is a helluva lot less costly and apparently works pretty well. A few years ago it was cheaper to mod a green laser (lol, again, by removing an IR-filtering part) than it was to buy an official IR laser, but that may have changed.

I imagine CCD is preferred over CMOS because it has greater Lux sensitivity?

Damn that hobby's expensive! Probably cheaper to launch a satellite.

IT involves removing the ir cut filter and installing a special one, but making sure everything is aligned properly so the DSLR still functions correctly. I will be modding my old 30D soon myself but the 40D we use at the observatory was modified by Hap Griffin as that is what its owner wanted.

Hey dude thanks for the input (nice freggin newt)

I definantly dont want to crack my DSLR open though, cause i use it for standard photography as well.

I've been chatting with the guy at Steve's Telescopes and bowling (our only astronomy store in the state) and he suggested the same thing as you, focusing on a near by star and then going back to whatever i want to take a picture of

He's also willing to sell me a motorized mount for my huge dob for around 585$ (omg its beautiful)

I usually try and get out to the Cheddar ranch observatory here in oklahoma =)

Takes like five people, But the whole roof slides off on rollers =)

Oh and i was typo'ing this whole time.

I mean 15 WATT laser not 15mw.

he said its probably illegal to use such a powerful laser in the sky lol!