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Hubble Artificial Star......its the bong !!!

Astro_Baby

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Astro_Baby

Astro_Baby

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1000 blessings on AndyH's head for putting me on to one of these little treasures...

http://www.hubbleoptics.com/artificial-stars.html

Its a budget artificial star for collimatimg with. OK its not the last word in clever or fancy, and in truth its a little bit plasticky BUT it does the job of helping you collimate when there are no stars around and for $24 delivered to my door ai am not complaining.

I was suffering a super bad dose of telescope hypochondria. The TAL has never delivered anything but the best but I decided to mess with it and see if it couldnt be improved. Unfortunatly the cheshire used was duff and gave some strange results. In the end despairing of ever getting a star to test it with I put my hand in my pocket and paid out for one of these dinky artificial stars after it was mentioned by AndyH and hola, problems fixed.

I'd say a good bit of kit for us collimation freaks and for $24 I am well happy. One of the best investments for not much cash.

10000 thanks to AndyH for the heads up.

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Astro_Baby

Astro_Baby

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John,

Testing tonite was for the TAL which can reach focus down to about 20' as it has a very long focuser tube. I tested at around 36' which is not ideal bit its good enough to make sure that the collimation is ok. Its not good enough to check whether there are errors in the lens figuring with a super fine airy disk sufficient to show stuff like zonal errors.

The tool might well be good enough for that over a bigger distance. Unfortunately I cant get further than about 36' away from anything in my flat so for more comprehensive testing I would need to test down at my sisters place where her back gardEn is about 80'long and by using the side of the house I could probably get out to maybe 200' if need be.

I think even if this tool was unable to give a full test for the money it costs it would be useful as a collimation check at least.

I will put it through its paces a bit more but right now, its saved me pulling my hair out trying to align a diagonal and check the TAL out for collimation hiccups (which in fact werent there anyway in all liklihood but having a reasonable star test was a useful thing to be able to do)

The tool may be less useful for a newt, they tend to have short focus tubes and need distance but at the weekend Ihope to test this tool out with my 180 Mak and see what that shows. Never tested howw close the Mak can focus.

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kirkster501

kirkster501

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I recently bought one. Highly recommended. To the collimation purists, it is probably true that a star is slightly better but the artificial star at least gets you within 1% of collimation perfection and allows you to practice collimation of your scope at leisure; you can do this anytime and do not feel compelled to rush when [at last] you can get out under the stars in the UK. Our increasingly rare, clear nights should be for observing, not collimation duties!!!

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kirkster501

kirkster501

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Nice to have some feedback on this - I've wondered about these devices for some time :smiley:

What sort of distance did you place the artificial star at for your scopes ?

In the case of my CPC 1100 11" SCT about 40 meters - other end of garden on a dry night.

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Psychobilly

Psychobilly

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I got one when they first came out... the very early ones had a habit of overheating and melting the reflector but they soon sorted it out and sent out free replacements...

I used mine for my CPC800 with a DMK21AU04 and a laptop running Metaguide connected to the scope through gpusb which would recentre the "star" image as you tweaked the secondary...

Peter

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AndyH

AndyH

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Totally agreed. Great simple little device.

My refractors come to focus no problem when I have the hubble in one room, scope in the other. Approx 15 - 20ft? I found I need an extension tube if I want to use the scope straight through. No problem with a diagonal.

My 2 small newts(65 + 80mm !!) come to focus, Tal 1 needs a bit of extension tubing. Tal2(6"F8) needs more. I have some T thread extensions tubes, that I screw together and put on the focuser, for that scope to focus.

I've still to try the Hubble on my 200K as even in my garden, I'll need about a metre of extension hanging off the back, before it'll be near getting focus!!! A downside of a fixed mirror Cassegrain. I shall persevere and do it one day soon.

You can vary the brightness and also choose 1 of 5 possible sized 'stars'. Mix n match to find what gives the nicest airy disc for your particular scope.

A great fun way to pass a cloudy evening, even in your house !

:grin:

Andy.

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Moonshane

Moonshane

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I think I may have sold this to Andy? I did so as I could not get anywhere near the distances required in my garden and also I don't like collimating with the tube completely horizontal which is just a quirk of mine I suppose. I'm glad it works for others and I agree it's excellent value for money if you can get the distance required.

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Astro_Baby

Astro_Baby

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Bong as in.....

Wicked

Kris

The Mutts Nuts

All that and a bag of chips

Crucial

Bodacious

Jesus Made

Far out

Amazeballs

Lush

Massive

Off the heezie fo sheezie

Righteous

Kicking

Coolio

Bizniz

Bees Knees

Advantages or otherwise of having a son into rap music :)

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  • 3 years later...
Coastliner

Coastliner

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I've just ordered one of the Hubbles from ebay.

To get the extra distance (I'm leaving myself wide open to getting a "stupid" label here!) would it not be possible to mount the Hubble next to the scope and reflect the star off a mirror on an opposite wall, thereby doubling the distance? Or would the scope see the star as though it were stuck on the surface of the mirror?

(Hides under a blanket).

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The Admiral

The Admiral

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Hi Coastliner, funny that you should resurrect this old thread, as I made one a couple of days ago. In answer to your question, if you search on the web for star testing you'll find at least one contributor who does just that. Mind you, you'd need to be sure that the mirror itself doesn't introduce spurious aberrations; you don't want to broaden point of light. I think an optical flat is called for. If you focus on the light source then that is what you'd see, not the mirror surface.

Here's my device.

post-40604-0-37710200-1453203234_thumb.j

It's a high power LED torch, and to the front I've attached a piece of foil that has a small pinprick in it. Although the hole in the photo looks quite large, because it was made with just the point of a needle, the aperture is in actual fact quite small. Your arrangement will need to produce a pinpoint light source, the size of which is less than the resolution of the 'scope, so a bigger 'scope will need a smaller hole, further away. To check out my 102mm OTA I put my artificial star at end of the garden, about 50 feet away from the 'scope. It seemed to work well, giving me fringes from one side of focus, through focus itself, and out the other side. At that distance I was just able to focus on it, using the extra length a diagonal gave me, but I wasn't able to focus in the straight through arrangement. I'd need a draw tube extension for that (or move the star further away, which I guess is what you're doing)

Ian

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kirkster501

kirkster501

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Since my post three years ago I have revised my opinion on these downwards, regrettably.  The hole which shines the light through and performs the role of the "star" is too big and gives inconsistant results I have found when using it to collimate 8" and above reflectors.  This was even when the scope was 40m away.

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RT65CB-SWL

RT65CB-SWL

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I ordered mine direct from Hubble Optics, ($24.95USD*, inc. worldwide P&P), during mid-2015 for star-testing my ETX105 & C6. It arrived within fourteen days of ordering. The white LED's are bright. (I presume for outside use when a type G2/magnitude -27.5 star is visible from GB/UK skies). I keep the small magnetic metal plate, (I don't think these are available as spare parts), in a 35mm plastic film canister, along with some spare nylon thumbscrews.

* 'cheap as chips' - 'bong' not included!

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