ST80 and guiding help

[Carl M]

Hi Guys,

Recently just got myself an ST80 to hopefully start guiding in the near future and I've already hit a brick wall.

First things first how do I actually mount the ST80 on top of my 200P? I know that I need a long dovetail to attach to the top of the already existing tube rings but how do I go about doing that and then mounting the ST80 on it? For the time being I will use my SPC900 for guiding which isn't ideal I know but it should get me going with PHD until I can get a QHY5. Am I right in thinking I need an extension using a barlow lens with the lens detached or using a diagonal to be able to focus the SPC900?

Thanks in advance,

Carl

[malc-c]

Carl,

Hope the attached image helps.

I think that the extension tube is only required for the QHY5 which screws directly to the focusing tube. If you use the web cam it will need to connect via a 1.25" adapter so I guess you wouldn't need it.

[Carl M]

Nice setup malcolm, hope mine will look similar very soon. The picture sure helped, what bolts did you use to attach the dovetail to the rings for the ST80 and the ST80 to the dovetail?

Thanks

[Earl]

Several members of the site use the SPCs for guiding all the time, so its worth a good try before spending on a dedicated guide cam.

[malc-c]

Carl, thanks for the compliment.

I picked mine up secondhand so it had all the bolts, but they seemed to be the same as those used to hold the rings to the dovetail that came with the 200P. I'm sure B&Q probably have something similar. As for the ST80 to the dovetail, these bolts should come with the ST80 I would of though ? Drop Wayne a PM as he has just purchase an ST80 and followed suit

http://stargazerslounge.com/diy-observatories/103639-wetherview-diy-obsy-build-begins-8.html#post2102410

[Carl M]

Several members of the site use the SPCs for guiding all the time, so its worth a good try before spending on a dedicated guide cam.

I had noticed that actually, will see how I get on with the SPC900 for a while and have a rethink.

Carl, thanks for the compliment.

I picked mine up secondhand so it had all the bolts, but they seemed to be the same as those used to hold the rings to the dovetail that came with the 200P. I'm sure B&Q probably have something similar. As for the ST80 to the dovetail, these bolts should come with the ST80 I would of though ? Drop Wayne a PM as he has just purchase an ST80 and followed suit

http://stargazerslounge.com/diy-observatories/103639-wetherview-diy-obsy-build-begins-8.html#post2102410

Thanks, I'll send a PM to Wayne. How well does the 200P work with guiding by the way? Once I get guiding I think an astronomik clip filter for the DSLR will be next on the list, not sure how much LP is going to show up in the subs.

Cheers

[malc-c]

The clip filter is well worth it, and if you set the white balance up on the camera using 18% gray exposure card it takes away the blue tinge that the filter casts.

I'm still learning the dark art of guiding, but Wayne seems to of got PHD nailed by the looks of his PHD graph... when mine was running well I got a test exposure of 20 mins with no problem

[Carl M]

Thanks for the tip, I'll give that a go when I get the filter at some point in the near future. I have a feeling my 1st PHD graph is going to have mountains everywhere, will have to wait and see. 20 minutes is impressive for a large scope like the 200P! I'd be happy with 5 minutes let alone 20! Do you not get many satellite trails, planes or camera noise at such a long exposure? I should be setup for next weekend so will have a test at different exposures and PHD settings.

[pritc]

PM sent Carl

[Stephen]

The clip filter is well worth it, and if you set the white balance up on the camera using 18% gray exposure card it takes away the blue tinge that the filter casts.

You can also do this without the CWB.

jgs001 told me in the stacking options on the lights tab to set it to "RGB background calibration."

Works a treat

[malc-c]

Thanks for the tip, I'll give that a go when I get the filter at some point in the near future. I have a feeling my 1st PHD graph is going to have mountains everywhere, will have to wait and see.

LOL - I've had DEC and RA diverge off the scale !! - Guiding is one of those things where it can all fall into place one night, then without touching anything, go belly up the next !

20 minutes is impressive for a large scope like the 200P! I'd be happy with 5 minutes let alone 20! Do you not get many satellite trails, planes or camera noise at such a long exposure?

No - funny enough there were no trails, and I'm right under the flight path for Luton airport. Here's the result, just re-sized and auto levels applied in photoshop

[malc-c]

You can also do this without the CWB.

jgs001 told me in the stacking options on the lights tab to set it to "RGB background calibration."

Works a treat

LOL - ya mean to say I've wasted £3.83 on a lump of card for no reason :) -

[Carl M]

Uh oh, so in other words I could be extremely lucky and guiding will work first time or it could go horribly wrong and result to me raging in the garden ? That's a lot of nebulosity picked up in only 20 minutes, would be very happy with that!

[pritc]

Hi Guys,

Am I right in thinking I need an extension using a barlow lens with the lens detached or using a diagonal to be able to focus the SPC900?

Thanks in advance,

Carl

It all depends whether you can achieve focus.

Trial and error.........

I had to use a lens less barlow to get focus with my QHY5.

Wayne

[malc-c]

Uh oh, so in other words I could be extremely lucky and guiding will work first time or it could go horribly wrong and result to me raging in the garden ? That's a lot of nebulosity picked up in only 20 minutes, would be very happy with that!

It's not that bad. Its that there are so many settings and variables that come into play, and its a steep learning curve. There are guys on here who have far more serious kit, and its all been working fine and then one day have issues - I guess it's like all modern day equipment PC's, TV's etc they all have their off days

Most of that "nebulosity" is in fact light pollution and over exposure. You get more nebulosity with stacking shorter (3 to 5 mins) exposures

[malc-c]

And as for PHD graphs - this was my worse night

the guiding was stopped each time causing the zig-zag !!

And probably one of my better traces (not as smooth as Waynes)

[Carl M]

Ooer, that first one is very odd, looks like a christmas tree which gets bigger the higher it goes ? Im guessing that the higher the line the more of a correction that it has made to the axis?

Thanks to Wayne I'm now sorted on what I need to do to attach dovetail to tube rings and the st80 to the dovetail. I've rethreaded the tube rings to accept M6 bolts which sorts out the dovetail on the 200P rings, just gotta wait for the dovetail now to drill 2 6mm holes in it using the short dovetail as a template.

[pritc]

Thanks to Wayne I'm now sorted on what I need to do to attach dovetail to tube rings and the st80 to the dovetail. I've rethreaded the tube rings to accept M6 bolts which sorts out the dovetail on the 200P rings, just gotta wait for the dovetail now to drill 2 6mm holes in it using the short dovetail as a template.

Pictures always speak louder than words...

Carl,a couple of photos to show you.

The red arrowed back bolt is the hole you need to drill to get the ST80 ring distance correct.

As I said in the PM, use the supplied small dovetail bar as a template.

The front bolt hole is already pre-drilled into the dovetail bar,but will need opening up to 6mm,to accept the bolt.

Wayne

[Carl M]

Thanks for the pics Wayne, I understand it now. Will pop to B&Q to get some M6 bolts in the week and take the dovetail to my neighbour and then it should be sorted.

Cheers!

[cowasaki]

A useful thread, I'm looking at an ST80 as a guide scope next month

[Carl M]

A useful thread, I'm looking at an ST80 as a guide scope next month

Glad that it's helping someone else also!

Thanks to all that helped me get setup for guiding, I am now ready to get guiding on the next clear night! Tomorrow and friday are looking good

I think it's a great addition to the living room, but my mum thinks otherwise

Once again thank you all!

Onwards and upwards!

[cowasaki]

I think it's a great addition to the living room, but my mum thinks otherwise

Once again thank you all!

Onwards and upwards!

I'm new to this BUT wouldn't you see more stars if you took it outside

[Carl M]

I'm new to this BUT wouldn't you see more stars if you took it outside

I don't understand your comment. It's cloudy and daytime...why would it be outside?

[malc-c]

Carl, I think he was trying to be funny or sarcastic - !

[cowasaki]

Carl, I think he was trying to be funny or sarcastic - !

Yes, I admit it. It was a poor attempt at humour.