Home made artificial star

[N3ptune]

Hello everyone,

I had the idea a few days ago to build my own artificial star after I read the following thread:
 

.. so i did today and here are some the pictures for analyze:

I did the hole with the tip of a needle, the smallest hole I could punch, I barely can see it without looking at it from 10 cm away. But I don't know if it will be usable because the angle has to be perfect to see the star, maybe the light is too far away inside the box...

It's really faint... I can put it at around 140 meters from my house to fine tune my newton telescope. Hope it's going to work really.

What do you think of the device?

The total cost was 6 Canadian dollars.  




This one below, the device was out of collimation, I had to move the light to get it right.

With better collimation below.

[Dave In Vermont]

It looks good-to-go from my perch here. But the real test is when you give it a try, make your adjustments based on what you get - and then try your scope on the real thing. I certainly wish you every success!

I have one of the actual things from Hubble in Hong Kong. If I didn't, I'd surely be tempted to try what you've done. Please keep us updated?

Happy rings,

Dave

[N3ptune]

Thanks for the success wishes they are appreciated. (: My confidence is quite low when it comes to star fine tuning, i have to get experience. 

-->I never saw any clear image of a stars at 200x yet, I don't know if it's normal really. 

 

 

[Dave In Vermont]

4 hours ago, N3ptune said:

Thanks for the success wishes they are appreciated. (: My confidence is quite low when it comes to star fine tuning, i have to get experience. 

-->I never saw any clear image of a stars at 200x yet, I don't know if it's normal really. 

 

 

No need to stress over a star-test. The world won't end if your perceptions differ from someone else's. Just think of a circle - and try to get the rings as close to that as you can. A scope that is slightly off will still give you a view that's fantastic! Everyone is ready to jump out of their shoes the first time they tackle this work. And, believe it or not, you may even end up like me: A nut who actually enjoys the art/science of collimating a telescope!

I admire your being persistant enough to try your hand at making an artifical star for this. Back in my early years of telescopes and observing, not many people actually ever collimated their Newtonian - leave alone a stray Cassegrian (which you didn't even hear about). Artificial stars were rather unheard of - leave alone a laser-collimator! Yet amazing photographs were out there, tempting many to aspire to the ranks of the Astro-Photographer.

The Earth isn't perfectly round (really more pear-shape). Yet it's been spinning around a G2V star without any problem for a long while.

All hail our yellow-dwarf!

Dave

[ollypenrice]

Best of luck with this.

I made an artidicial star today, too, but used a simpler method. Rather than hijack here I'll post an alternative thread. Interesting comparison!

Olly

 

[N3ptune]

Dave

I am releasing the stress now (: it's true, this has to be done.

I didn't tried the star yet but I think your right, it might get fun someday for me too to adjust the optic. Right now, i feel it's an obligation to get good at this, to master the basics, if a good collimation can be reached for this newton, I intend to reach it. (: I will continue to be persistent. (Thanks)

 --> Today I set up the telescope on his tripod inside the house to work on the collimation a little bit more again, I was surprised of what I saw.

Using only a collimation cap, (which I think is a terrific tool for collimation.) I was able to correct my secondary mirror in less then 10 minutes. It was somewhat ok but now it's WAY better in term of overall concentricity. Improved with only small amounts of turns, almost nothing, amazing! (:

The primary was out of center at the beginning, it moved with the car vibration apparently, this exercise was due. But now it's good (I even think it's perfect!?) and the secondary is likely to remain in place for the next time.

--> What a great news!

Finally. the result was double-checked with a Cheshire and everything was correct with both tools, that makes me feel happy (: I can't wait to go out try my new ES 4.7mm on Jupiter. (And the artificial star, in a far second place.)

I didn't had the rush to make it perfect today like you said about the pear-earth spinning around the sun. That state of mind and the objective made a true difference in the outcome just like magic.

(What a great day)
(;

ollypenrice

You can publish the link here for us to see, i am interested in your artificial star concept.

[Dave In Vermont]

You say that a car driving by would vibrate the scope enough to bother the collimation? Aside from locking down the primary with the 3-locking bolts, you might consider some anti-vibration pads under the legs of your tripod. These can be purchased ready-made - Celestron offers them, for instance. Only problem is, over here at least, the prices charged have gotten ridiculous! $70-US.

You can also make your own. Amazon.com offers Sorbothane® Pads - which are commonly used under various vibration-prone machinary - like large freezers and such. What I did was glue 2 of these pads together, Then placed them in a small plastic-bag (the pads are about 2.25" across - or 57mm) to keep them from getting embedded with bits of debris as they're rather sticky. If the scope & mount are heavy, you may wish to add a thin strip of wood or other material on top and under to spead the load across the whole surface-area. Otherwise they could feasibly bottom out from the pointy end of the tripod-leg. And Voila!

I find these will dampen the vibration to under 1 second. Much less ££'s than the commercial offerings. And I find these work better, too.

Keep going! A star is born!

Dave

 

[N3ptune]

Well I guessed the car trips were the cause.. because I don't really know what is the cause of the minor decollimation of the primary mirror.

That's an interesting solution to use the Sorbothane material, they are inexpensive I could build 3 anti-vibration pads, I like that idea. Dave do you suggest the vibration generated from using the telescope simply could be the cause for the primary mirror slight movement?

[Dave In Vermont]

If you move the scope around, it might go out of collimation a bit. But I think I misunderstood you. I had surmised that a PASSING car had caused enough vibration to knock it out of whack. Not being moved about IN a car!

Anytime you move a scope, it can jostle the scope enough to merit attention. Anytime I move my 200mm F/4, I pop my laser in it and adjust as needed. The vibration-pads are great if a passing car or lorry causes vibrations from where you're observing from. I tend to set up on a wooden platform, so I always use my home-brew pads under the legs. Usually being on the ground won't cause vibrations from such. But in some rocky terrain it sure can. So it depends on your location.

As you become more adept at collimation, a laser works wonders. But I always check my laser with my Cheshire eyepiece also once in the light. They always agree, I'm pleased to say. An F/4, as I have, has a tendency to go slightly out of collimation if I so much as look at it. Being a part-time perfectionist, as well as actually enjoying collimating Newts - I always check. If you ever get a laser, make sure it has the 45° bulls-eye on it so you can sit at the back of the scope for collimating the primary mirror and watch your results.

Have fun -

Dave

Typical laser-collimator with 45° bulls-eye.

[ollypenrice]

It might help to find a way of transporting the scope in a vertical position, perhaps?

My artificial star thread is here. 

Olly

[N3ptune]

Dave

I almost bought the exact same laser has your picture 1 week ago, but I decided not to buy it at the last second. Some people like this laser and some  don't, opinions are very much polarized on the subject.

Has for me, the quality of the device was too poor to build motivation to pay 60$ for it, I guess I stand against the device (: ):

(I am at my 3rd attempt to buy one and I just can't yet)

Olly

I think your device is better then mine because there is no need to adjust the angle of it to get the spot of light into the scope so 1 people is enough to use it, which is great.  It's so simple I will build one myself tomorrow. (If I can find a BB)

Actually --> I am going to search for a BB inside my boxes right now, it's a great Saturday night plan ((((:

Thanks for this great idea (:

[N3ptune]

I built another artificial star today based on Olly's concept has seen there:

 

I added a light to it and a bracket option to screw the device on an electric pole at around 340 meters away, total cost was about 20 cents this time for the ball bearing only, lol. (Never even tried the first model yet ) I think this one is way better because the speck can be seen from any angles and it's dimmer.

View from the front

View from the back

Light beam

And a view in the dark with the light on.

Hope it's going to work