Can I get some advice on a guide scope please?

[Dbswales]

Hi everyone, I want to take another step in my imaging setup and think I need to start guiding. Is this something that'd be recommended to go with? https://www.firstlightoptics.com/guide-cameras/guide-scope-bundle-suitable-for-piggy-backing.html

I use a 130DPS, HEQ5 with a modified Canon 600D. I'm getting 90 second unguided subs so haven't got any star trail but after reading other peoples setups and guiding I feel it might be worthwhile going down this route.

Is there another setup you might think would be better?

Thanks in advance.

[Cornelius Varley]

The first thing to do is calculate the potential payload on the mount. The 130PDS weighs about 3.66kgs and the ST80 1.5kgs. Add on to this the weight of the DSLR and guide camera plus any extra mounting hardware for the guidescope. If the total is less than the recommended 11kgs  then you should be ok. Another option would be a "finder guider", either a modified 9x90 finder or a smallish refractor ie

[iapa]

Don't think you could go wrong with this - once you figure how to attach to the 130P-DS.

If you haven't got a dove tail atop the rings, you will need to get a longish, I have 11", dovetail to attach to the top of the rings of the 130P-DS.

I pretty much have this bundle - although I bought the Star Traveller 80, clamps and extender separately several months ago, and the Touptek Mono last month.

However, my first trial at guiding was with Orion's 50m guide scope with the Touptek for guiding with PHD2 (under Windoz) - mainly because I couldn't get the ST80 attached nicely to the 200P-DS OTA which I use. Managed to take it up to 300 seconds before trailing (I tried 360, and backed off to 300 'cos is was bad).

I've now got the dovetail to attach to the OTA rings so, watch this space (skies permitting).

 

[Xplode]

An ST80 has a lot of flex in the focuser, not a good thing for a guidescope.

A guiderfinder is a better option, it has less flex and is much lighter.

Something like this would work better: https://www.firstlightoptics.com/zwo-accessories/zwo-finder-and-guider-scope.html

You do of course need a camera too, the camera included in the other package should be ok.

[iapa]

7 hours ago, Xplode said:

An ST80 has a lot of flex in the focuser, not a good thing for a guidescope.

A guiderfinder is a better option, it has less flex and is much lighter.

Something like this would work better: https://www.firstlightoptics.com/zwo-accessories/zwo-finder-and-guider-scope.html

You do of course need a camera too, the camera included in the other package should be ok.

@XplodeNo offence, not disputing the flex in the focuser, however, I have read in several places that a guidescope in such rings demonstrates a lot of flexure - particularly with plastic screws (although these are easily replaced). It will be a matter of scale - having the Orion 50mm guider-scope and the ST80, I will be trying each.

There is still the common issue of requiring a dovetail on the OTA rings whichever option.

Obviously I bow to greater experience - if my back lets me.

Although I do like the , having a helical focuser - a definite bonus.

Please consider I am still a noob - only been at this a couple of years  Give me another couples of decades....... LOL

PS the camera in the other package has given me 300s guided using an Orion guide scope - its nicely sensitive with a QE c70%+ and good sized sensor pixel size. Now that I have had the chance to try PHD2 Im looking forward to improving that 300s..... someone once said I was an optimist (whatever that means - I assume it was an insult :):):)).

 

 

[Marky1973]

Yeah, I don't have any trouble with my ST80 and ZWO guide camera. Still learning, but have had 8 minutes subs out of the set up. No problems with focusing, just get it right and lock it down. As long as everything is bolted on solidly, you shouldn't have trouble BUT, if weight is an issue, then a finder/guider might be a better option.

[Xplode]

I noticed the plastic screws, but assumed since the guiderfinder is so light it wouldn't cause any flex, i could be wrong in my assumption thou.

A helical focuser is great for a guidescope and definitely makes it easier to find the right focus

Another option i can recommend is to buy an old M42 camera lens, they are very stable, but the rings to mount it can be pretty expensive. 

Here's the guiding setup i used before, all adapters are screw type and makes the camera focus at infinity. Focus is locked by the front ring.

200mm f/4.5 lenses can be bought for less than £20, but adapters and guidescope rings are pretty expensive to mount it.

The adapter is M42 to CS.

A cheaper way to mount one can be found here: 

 

 

[Davey-T]

I used to use an ST80 for guiding, the focuser can be fettled (instructions on Astronomyshed) and made very usable.

Dave 

[ollypenrice]

I use two ST80s for guiding and have done for years. There is no problem with the focuser because you don't need to use it as a normal focuser. You just find focus once and then tighten it up very hard with the lock screw. You also need to find an extender to get the camera far enough back to focus. I used a pair of Barlow bodies glued together without lenses. It is also important to make sure the focuser main casting is screwewd tightly into the main tube. You never need to adjust focus. I haven't done so in years. Softish focus is actually recommended for guiding.

Olly