9x50 finder guider

[Frank the Troll]

Will be dipping my toe into astrophotography

If I covert the finder, how well will it guide, or would it better to use my newly acquired 80mm F5 scope as a guider

[PeterCPC]

I use a 9x50 to guide either my ED80 or ED120 with no problems.

Peter

[Skipper Billy]

Finder guider will be more than adequate. A converted finder guider is usually OK to guide a scope of up to about 1000mm.

Pop your details into FLO's calculator and see what it gives you - http://astronomy.tools/calculators/guidescope_suitability

I would think your biggest challenge will be avoiding flexure unless you are planning to change the mounting system of your guide scope??

 

 

[Frank the Troll]

Cheers Peter, Billy. will use the 9x50 then, that leaves the 80mm for imaging

Will be mounted on the EQ6

Will also be using an old 6" orion newt, and an old 125mm f8 frac

 

Edited January 26, 2020 by Frank the Troll

[Frank the Troll]

So, which adapter do I go for, the T or C thread ? or are there other adapters?

[JamesF]

I think there's an adapter that gives you a 1.25" holder too.  What you want probably depends on what you intend to use as a guide cam.  Otherwise, T-threads are often convenient because there are so many matching parts available.

James

[Frank the Troll]

41 minutes ago, JamesF said:

I think there's an adapter that gives you a 1.25" holder too. 

James

 

41 minutes ago, JamesF said:

I think there's an adapter that gives you a 1.25" holder too.  What you want probably depends on what you intend to use as a guide cam.  Otherwise, T-threads are often convenient because there are so many matching parts available.

James

That would be easier, as most cams are 1.25

This is the camera im thinking of getting

https://www.harrisontelescopes.co.uk/acatalog/altair-gpcam2-imx224-colour.html#SID=1714

 

Edited January 26, 2020 by Frank the Troll

[JamesF]

I think I'd be tempted to go for the 1.25" adapter as it gives you an easy way to move the camera to find focus, though I guess if you had an adapter with a C-thread that would guarantee to bring the 224 camera sensor to focus that would give you a nice rigid configuration.

James

[ollypenrice]

What you don't really want is the standard spring-loaded guidescope alignment device. While this is handy for visual finders because it can be easily aligned, the spring-loading of guidescopes ranks alongside the constructing of fireguards in chocolate.

Olly

[Skipper Billy]

3 hours ago, Frank the Troll said:

This is the camera im thinking of getting

https://www.harrisontelescopes.co.uk/acatalog/altair-gpcam2-imx224-colour.html#SID=1714

Unless you need a colour camera for something else I would choose a mono camera - much more sensitive.

[Frank the Troll]

9 minutes ago, Skipper Billy said:

Unless you need a colour camera for something else I would choose a mono camera - much more sensitive.

My budget is very limited

[Grierson]

19 minutes ago, Frank the Troll said:

My budget is very limited

How about a ZWO ASI 120 mm. c. £30 less than your preferred option?

[ollypenrice]

While theory favours a mono for guiding, without doubt, I used both mono and OSC versions of the Atik 16ic for many years as guide cameras and found no difference. None whatever. Maybe if guiding with little light, as in an OAG, you'd feel the difference but I was using the same ST80s, FLO's finest, that I use today.

Olly

[TerryMcK]

I have a skywatcher 9x50 Finder scope used in conjunction with a FLO adapter. https://www.firstlightoptics.com/adapters/astro-essentials-sky-watcher-9x50-finder-to-c-adapter.html
This has (I think) an M50 male thread that screws into the finder scope once you remove the existing adapter that carries the eyepiece.

The mono ZWO ASI120MM camera then attaches to the adapter. The focal length of the scope is 180mm and to achieve focus I removed the locking ring. This allows the lens to move a little closer to the camera and I get perfect focus. There is about 4mm of thread left at the lens end.

I used some PTFE plumbers tape around the threads to stop the lens from moving once set and just left it. Everytime I use it is always in focus and never needs adjusting.

 

FLO do a complete guide scope kit based on this method https://www.firstlightoptics.com/guide-scopes/sky-watcher-9x50-finder-adapter-zwo-asi120mm-bundle.html

Your finder scope looks very similar to the Skywatcher one so may indeed be one and the same as I am led to believe they are a generic scope.

Mine guides really well and I get perfectly round stars on 5 minute plus exposures and a great PHD2 graph.

BTW ditch the finder scope spring loaded bracket that it comes with and mount it in a pair of proper 3 screw rings if you can.

Edited January 26, 2020 by TerryMcK

[Frank the Troll]

38 minutes ago, TerryMcK said:

 

Your finder scope looks very similar to the Skywatcher one so may indeed be one and the same as I am led to believe they are a generic scope.

Mine guides really well and I get perfectly round stars on 5 minute plus exposures and a great PHD2 graph.

BTW ditch the finder scope spring loaded bracket that it comes with and mount it in a pair of proper 3 screw rings if you can.

Yes it is the standard skywatcher finder & will get a set of rings for it

[Frank the Troll]

46 minutes ago, TerryMcK said:

I have a skywatcher 9x50 Finder scope used in conjunction with a FLO adapter. https://www.firstlightoptics.com/adapters/astro-essentials-sky-watcher-9x50-finder-to-c-adapter.html

 

FLO do a complete guide scope kit based on this method https://www.firstlightoptics.com/guide-scopes/sky-watcher-9x50-finder-adapter-zwo-asi120mm-bundle.html

 

BTW ditch the finder scope spring loaded bracket that it comes with and mount it in a pair of proper 3 screw rings if you can.

Cheers Terry, that confirms its the c thread I need

[Frank the Troll]

1 hour ago, ollypenrice said:

 but I was using the same ST80s, FLO's finest, that I use today.

Olly

I still have the st80, well for now that is

 

[ollypenrice]

10 hours ago, Frank the Troll said:

I still have the st80, well for now that is

 

I've been using ours for years and am currently guiding an imaging rig working at 0.9"PP.

If you want to economize, any rigid mounting of the guidescope will do the job. You don't really need screw adjusters. They were invented to allow the guidescope to be pointed in various directions in search of a guidestar but modern guide cams find a star in any field. The cheapest way would be to make a pair of vee blocks and strap the guide scope down into them with cable ties and a touch of epoxy resin at the contact points. It should be roughly on-axis but doesn't need to be accurately so.

Olly

[Frank the Troll]

6 hours ago, ollypenrice said:

I've been using ours for years and am currently guiding an imaging rig working at 0.9"PP.

If you want to economize, any rigid mounting of the guidescope will do the job. You don't really need screw adjusters. They were invented to allow the guidescope to be pointed in various directions in search of a guidestar but modern guide cams find a star in any field. The cheapest way would be to make a pair of vee blocks and strap the guide scope down into them with cable ties and a touch of epoxy resin at the contact points. It should be roughly on-axis but doesn't need to be accurately so.

Olly

Thanks for the tips Olly. I have a very tight buget so every bit helps (life rich, cash poor)

Edited January 27, 2020 by Frank the Troll

[ollypenrice]

4 hours ago, Frank the Troll said:

Thanks for the tips Olly. I have a very tight buget so every bit helps (life rich, cash poor)

Same as me!

Olly