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The easiest way to get the Orion StarShoot Autoguider into Focus


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Dear all,

After tinkering around several nights, i finally got around getting the Orion starshoot Autoguider (also called SSAG) into focus using a small 50mm guidescope.

I want to share the info as i have received a ton of great advice from SGL users, and maybe there's a noob like me out there with the same problem?

The biggest problem for me was that i expected the combination of the 50mm guidescope and the SSAG to be balanced to each other... but they are not.

In other words, if you completey insert the SSAG into the guidescope, you will not be able to achieve focus.

The distance between the foremost frontend of the guidscope to the back end of the SSAG should be around 21.8 cm.

If you take a look at the photo below, you can see that the SSAG is not completely inserted into the guidescope; in my case, there is a space of 1.25 cm between the SSAG and the inmost position and about the frontend of the scope is about 0.3cm screwed out.

These positions should get you very close to the optimal focus position.

Getting the driver and installing PHD2 is straight forward. I suggest setting camera gain to 95, and exposure to auto. For final focusing, fire up PHD2 and select a star- PHD2 will show you the SNR (signal to noise ratio- the higher it is, the better). The do quarter turns of the scope's front lens, always checking the SNR after each turn, repeating the process until you reach the point of maximum SNR.

Congratulations- you are on focus! To make all this more repeatable, you could get T2 adapters and adjustment rings so that you need no guessing around where the focus point is. That is left as an exercise to the reader ;)

 

Bildschirmfoto 2016-05-28 um 20.24.50.png

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  • 11 months later...
On 5/28/2016 at 11:47, uhb1966 said:

Dear all,

After tinkering around several nights, i finally got around getting the Orion starshoot Autoguider (also called SSAG) into focus using a small 50mm guidescope.

I want to share the info as i have received a ton of great advice from SGL users, and maybe there's a noob like me out there with the same problem?

The biggest problem for me was that i expected the combination of the 50mm guidescope and the SSAG to be balanced to each other... but they are not.

In other words, if you completey insert the SSAG into the guidescope, you will not be able to achieve focus.

The distance between the foremost frontend of the guidscope to the back end of the SSAG should be around 21.8 cm.

If you take a look at the photo below, you can see that the SSAG is not completely inserted into the guidescope; in my case, there is a space of 1.25 cm between the SSAG and the inmost position and about the frontend of the scope is about 0.3cm screwed out.

These positions should get you very close to the optimal focus position.

Getting the driver and installing PHD2 is straight forward. I suggest setting camera gain to 95, and exposure to auto. For final focusing, fire up PHD2 and select a star- PHD2 will show you the SNR (signal to noise ratio- the higher it is, the better). The do quarter turns of the scope's front lens, always checking the SNR after each turn, repeating the process until you reach the point of maximum SNR.

Congratulations- you are on focus! To make all this more repeatable, you could get T2 adapters and adjustment rings so that you need no guessing around where the focus point is. That is left as an exercise to the reader ;)

 

Bildschirmfoto 2016-05-28 um 20.24.50.png

Thanks much. I just sent magnificent guide camera back to orion for a new one. I could not reach focus, and stars were 3-lobed blobs. Also, the "camera settings" in phd2 ( just to the right of the brain), were unavailable and I had no gain control. I hope it was just the sensor. When i get replacement I'll det it up as you advise. Great share!

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Through a comedy of my own doing, I finally arrived at Orion's MMAG in a round about way. I had bought the SSAG camera, so when I came to my sense's about OAAG, I got the 50 MM guide scope but with the Helical Focuser for my own sanity.

I've been real happy with mine. In fact, it has been one thing that has been entirely trouble free.

I will be looking into the SNR by adjusting the front lens. Thanks for that.

I have the picture fairly sharp in PHD2 as it is. But if a little tweaking can improve the SNR, I'll give it a try.

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Craig Stark, who wrote PHD, does not recommend perfect focus for autoguiding. The software calculates a notional centroid for the chosen star, this point being far smaller than a single pixel, so you can guide to sub pixel accuracy. Apparently the centroid calculation works best on a slightly soft star. I wouldn't over-do it though.

Olly

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  • 1 year later...
On 21/05/2017 at 08:57, ollypenrice said:

Craig Stark, who wrote PHD, does not recommend perfect focus for autoguiding. The software calculates a notional centroid for the chosen star, this point being far smaller than a single pixel, so you can guide to sub pixel accuracy. Apparently the centroid calculation works best on a slightly soft star. I wouldn't over-do it though.

Olly

I went for close enough but not spot on.

The Lacerta guider does allow to get near spot on but it's no problem if it's not.

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  • 2 weeks later...

Whoo-hoo! I'm glad I browsed far enough into the Forum to stumble on this gem, as I've had no luck finding a guide star let alone focus on my identical Orion 50mm guidescope and StarShoot autoguider. Granted, I've only had my new gear up and running for testing for a short period of time, but the few clear nights I've had have left me wondering what 'on Earth' is going on, especially after testing in daylight with 5% gain with no trouble. Thank you, uhb 1966!

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