Hubble Optics 5-Star Artificial Star

[FLO]

As requested ? 

You can now buy the Hubble Optics 5-Star Artificial Star at FLO. 

Not glamorous (similar to the torches displayed at the end of Supermarket aisles!) but it has five five bright white LEDs behind five precision pinhole artificial stars. Each one is a different size (50/100/150/200/250 microns) so this artificial star can be used with pretty-much any telescope. 

 

[John]

I have one of those. Very simple but it works !

 

[geordie85]

Wish you'd had these a couple weeks ago.

Had to go to another source to get mine, and paid alot more too. Works a treat though 

[LightBucket]

What sort of distance do you have to have them away from the scope...?

[Craney]

35 minutes ago, LightBucket said:

What sort of distance do you have to have them away from the scope...?

That's a good question I'm interested in knowing as well....  with an SCT the 'star' ends up in the next postal code.....

[Ben the Ignorant]

19 minutes ago, LightBucket said:

What sort of distance do you have to have them away from the scope...?

Depends if you want to check collimation or optical quality. When dealing with collimation distance does not matter, I do it at 6 or 7 meters because that's how long my living room is. However optical quality checks demand that the dot not be resolved, especially if it's not perfectly round, so the distance matters.

For a 20 microns artificial star, divide the scope's diameter by 3. So a 200mm scope needs 66 meters. For larger artificial stars the distance has to be proportionately bigger.

With the 50 microns dot the distance would be around 170 meters. Not always practical, better use that dot on smaller telescopes, or switch to a 22 microns or 9 microns artificial star, but who will buy one to assess the quality of his or her few personal telescopes, and then store it in a drawer for ever? It's more sensible to have a club buy it, and let members and visitors use it.

[John]

1 hour ago, LightBucket said:

What sort of distance do you have to have them away from the scope...?

I've used mine at around 15 metres from the scope and it worked fine for collimation checking. I needed to use an extension tube to get some scopes to sharp focus on it though !

 

[LightBucket]

48 minutes ago, Craney said:

That's a good question I'm interested in knowing as well....  with an SCT the 'star' ends up in the next postal code.....

Yes it’s an Celestron 8” SCT that I want to try this on...

[steppenwolf]

I've used mine at 25 metres for checking collimation on several telescopes including a 10" Newtonian and an 8" SCT. It worked very well indeed.