Setting up autoguiding equipment!

[Kylee]

Hi everyone

I know this is back to basics for the astrophotographers in the society but I just want to ask a question so I buy the right kit. I am looking to get an ST80 and want to know how I piggyback it to my new kit. I have seen the scope OTA for a good price, do I just need to purchase the rings and/or a dovetail bar? Do I need the complete set up with finder scope etc...have got myself a bit confused with it all?

Thankyou

All tips and advice greatly received!!!! 

[Carole]

Hi Kylee.

With an ST80, although it might come with some mounting rings, these will not allow for the ST80 to be slightly adjusted should you need to find a suitable guide star, so you'll need guide rings.  The guide rings will need to be mounted on a dovetail plate which will need to be mounted onto the rings of your imaging scope.

An alternative is to use the rings supplied with the ST80 (assuming it comes with some) and using one of these and a dovetail plate, this gadget allows you to move the guidescope left and right and up and down - I believe Jim has one:



You might also like to watch this video:
http://www.youtube.com/watch?v=EROhpDr_dXw


You don't necessarily need a finderscope with an ST80.

Depending on what guide camera you are using, you might need a short extension tube to get focus with the ST80.

Carole

[JonH]

I use an ST80 for guiding but it is firmly attached to my Equinox with no means of adjusting it. Am yet to have any problems finding a guide star...

[RobertM]

Kylee,

Although in theory it's nice to be able to aim the guidescope in practice you will not find that necessary.  One thing you will need is an extension on the end of the drawer tube otherwise the guide camera will not reach focus.  You could use a very cheep 1.25 barlow with the lenses removed or some other contraption if you prefer.  One thing you will notice about the ST80 is that the drawer tube is very wobbly so that may need to be clamped down in some way.

Hope that helps
Robert

[Rocket Pooch]

Kylee,

Although in theory it's nice to be able to aim the guidescope in practice you will not find that necessary.  One thing you will need is an extension on the end of the drawer tube otherwise the guide camera will not reach focus.  You could use a very cheep 1.25 barlow with the lenses removed or some other contraption if you prefer.  One thing you will notice about the ST80 is that the drawer tube is very wobbly so that may need to be clamped down in some way.

Hope that helps
Robert

If you do up the two small allen keys it should not be wobbly.

[JonH]

If you do up the two small allen keys it should not be wobbly.

I tried this and all it did was make it stiff, but still moves all over the place when changing focus direction or tigheninh the locking screw.

[Carole]

I find tightening the locking screw stops it wobbling.

Carole

[MarkS]

I use an ST80 for guiding but it is firmly attached to my Equinox with no means of adjusting it. Am yet to have any problems finding a guide star...

Contrary to Robert and Jon's experience, I have often needed to adjust my guidescope to find a decent guidestar (using a QHY5 at 1 sec exposure).

[RobertM]

Chris, maybe I had a particularly bad example of an ST80 as it wasn't stable enough to guide properly without having the drawer tube clamped in place.

I use an ST80 for guiding but it is firmly attached to my Equinox with no means of adjusting it. Am yet to have any problems finding a guide star...

Contrary to Robert and Jon's experience, I have often needed to adjust my guidescope to find a decent guidestar (using a QHY5 at 1 sec exposure).

I suppose that's a testament to the QHY5's poor signal to noise.  A second hand Atik 16ic would make a great guide camera if it's supported by PHD and also double as a proper cooled astro cam.  It would also be money better spent than on guide scope aiming device such as the one Carole mentioned plus a QHY5.

I would suggest the converted finder but by the time all the bits are bought it might end up costing more than an ST80 (which also doubles as a fair rich field travel scope).  The 50mm finder guider would be good for guiding just beyond 1000mm f/l (depending on flexure), much beyond that and a off axis guider is probably the way to go.

Robert
 

[Carole]

Contrary to Robert and Jon's experience, I have often needed to adjust my guidescope to find a decent guidestar (using a QHY5 at 1 sec exposure).

I have the same experience though I would change the word "often" to occasionally.  

Guess it all depends on what camera you are using as your guide camera.  When I was using the SC3 modified webcam as a guide camera I was always hunting around for a guide star, so in comparison the QHY5 is a huge improvement.

Carole

[Kylee]

Thanks everybody...I will let you know how I get on. I will go ahead with the st80 as it seems an affordable and popular choice with many people....hopefully I will get it nice and stable...we will see. As for the camera I will have to wait a little while longer until the funds are boosted again. Would I be able to use my webcam in the mean time?? Even if it's not the best way at the moment, is it possible?

Kylee   

[Carole]

Depends what webcam you have Kylee.  I think you have an SPC900, which sees stars.  You might be able to get away with it, have you downloaded PHD yet, and does it recognise the SPC900?
You probably need something more sensitive, but just might do as a temporary measure.

Carole

[Kylee]

Thanks...I'll have a look!

[The Thing]

I can always find a guide star with my QHY5 and finderscope setup. Flocking the finderscope improved the contrast and made all the difference.

[Mike]

Kylee, if you are using a webcam, also give MetaGuide a go. Version 5 was brought out recently and its free.

[Kylee]

Thanks chaps 

[Kylee]

Hey Mike

Just been looking at Metaguide...it says it doesn't support modified webcams! I've got the Phillips that has been pre-flashed, do you think it includes that?

[Kylee]

I can always find a guide star with my QHY5 and finderscope setup. Flocking the finderscope improved the contrast and made all the difference.

What is flocking the finderscope?

[Ian]

hmm, might need to tune the profanity filter.

That should read "What Is fl*cking the finderscope?" Apologies to anyone offended by Kylee's use of that word.

[Mike]

Kylee, modded means the webcam has been modified for long exposures. Yours hasn't so should be fine.

[The Thing]

I can always find a guide star with my QHY5 and finderscope setup. Flocking the finderscope improved the contrast and made all the difference.

What is flocking the finderscope?

Practically it means lining the inside of the OTA tube with something blacker than than the paint the manufacturer used, which often isn't as light absorbing as one would. It improves the contrast by cutting out more light which would have been reflected down the tube making the background light level higher than it should be on the CCD. I used some black material that was part of some CD filing sleeves I had to line the inside of my finderscope. Often done to main scopes as well.

Notice the shine of the CCD on the left hand picture below.