Guide a Large Newtonian Scope

[Phoenix2k]

Hi guys,

I recently started astrophotography and bought the following gear:

• Skywatcher Quattro 250p Imaging Newtonian scope (254mm / 1000mm focal length)
• Altair Hypercam 183c color imaging camera
• Skywatcher AZ-EQ6 Pro Go to Mount
• QHY Polemaster polar align camera

In order to focus on deep sky object, now is the time to buy a guiding package. However, at some point I might buy a small APO Refractor to have a smaller kit. So, I was wondering if it makes sense to use an APO 80mm refractor (or higher) as a guiding scope in order to limit my budget. Will a 80mm high quality refractor be that better for guiding compared to a simple 50mm guiding scope at 150$ ?

Many thanks for sharing your views on this...

CLear skies!

[DaveS]

I've not had to guide anything that big (And I don't guide anymore) but my first thought would be OAG.

[wimvb]

Why would you invest in an APO for guiding? An ST80 would do just as well. Long fl reflectors generally need off axis guiders, but otoh, people have successfully used finder guiders with their Quattro. If you want a cheap solution, you could get a 60 mm finder scope with a finder-C adapter and either a qhy5 or asi120 camera. The camera can then be used with any other guiding solution.

Even if you invest in an APO imaging scope, you will still need a guiding solution for that. An APO as guidescope doesn't save you anything.

[alacant]

2 hours ago, Phoenix2k said:

use an APO 80mm refractor

Hi

Yeah, why not? Presumably you'd piggyback them and guide one with the other?

Otherwise as @wimvb suggests, a third telescope to be your guidescope. This one works well

If you want nice stars with your reflector, use an off axis guider.

Cheers

 

Edited August 16, 2019 by alacant

[Whistlin Bob]

Never tried an OAG and I'm sure an 80mm frac would be fine, but I'm using the finder guider option that @wimvb suggests on my 1000mm SW 200p and it works well, although it's only a 9x50 finder. Light, cheap, effective and gives me nice round stars 😊 (except the brighter ones with their diffraction spikes obvs)

Edited August 16, 2019 by Whistlin Bob
Different finder scope.

[ollypenrice]

On 16/08/2019 at 15:38, wimvb said:

Why would you invest in an APO for guiding? An ST80 would do just as well. Long fl reflectors generally need off axis guiders, but otoh, people have successfully used finder guiders with their Quattro. If you want a cheap solution, you could get a 60 mm finder scope with a finder-C adapter and either a qhy5 or asi120 camera. The camera can then be used with any other guiding solution.

Even if you invest in an APO imaging scope, you will still need a guiding solution for that. An APO as guidescope doesn't save you anything.

I guide with ST80s down to 0.9"PP without difficulty but I'm guiding refractors.  Any reflector is, ultimately, best guided by OAG because mirrors cannot be rigidly mounted so their image can shift.

I think it really is time to stop regarding round stars as evidence of good guiding. In reality it is merely evidence of equivalent guiding errors in RA and Dec.

Olly

[spillage]

I can happily guide with my neq6 with a quattro 8" and st80 strapped to the top of it. Normally around .60"pp. I think with very good balancing and no wind at all I could manage the 250, but would probably want to use a smaller guide scope. 

[Phoenix2k]

didn't think of OAG, but it's a good idea. many thanks to all of you!