Converting a Celestron 9x50 finderscope to a guidescope

[souls33k3r]

Hi All,

Has anyone tried to convert a Celestron 9x50 finderscope in to a guidescope?

It's just that i'm getting slightly paranoid about losing stars / decrease in SNR (i'd be lucky if i get 30ish SNR and between 40 & 60 the star is saturated) and in the hunt for getting good guiding.

Is this a good option? How will it stack against some other 50mm guidescopes out there in the market?

Just wanted to find out what parts (sizes) do i need?

I currently have a QHY5L-II mono camera.

I'm not looking to spend £50 on adapters to convert something, any ebay El-cheapo adapters will do or a friend of mine has offered to 3D print the adapter for me.

Thanks in advance

[tooth_dr]

19 minutes ago, souls33k3r said:

Hi All,

Has anyone tried to convert a Celestron 9x50 finderscope in to a guidescope?

It's just that i'm getting slightly paranoid about losing stars / decrease in SNR (i'd be lucky if i get 30ish SNR and between 40 & 60 the star is saturated) and in the hunt for getting good guiding.

Is this a good option? How will it stack against some other 50mm guidescopes out there in the market?

Just wanted to find out what parts (sizes) do i need?

I currently have a QHY5L-II mono camera.

I'm not looking to spend £50 on adapters to convert something, any ebay El-cheapo adapters will do or a friend of mine has offered to 3D print the adapter for me.

Thanks in advance

Is the Celestron finderscope any different to the Skywatcher one?

[souls33k3r]

4 minutes ago, tooth_dr said:

Is the Celestron finderscope any different to the Skywatcher one?

I'm pretty sure it isn't. Looks exactly the same but thought i'd drop that in there in case if it was.

[tooth_dr]

5 minutes ago, souls33k3r said:

I'm pretty sure it isn't. Looks exactly the same but thought i'd drop that in there in case if it was.

It looks the same in the photos.  There is a plethora of info on the use of a 9x50 finder as a guider! Search button is your friend!

On the note of adapters - you wont need to spend £50 but around £28 should get you a nice adapter from Modern Astronomy.  If you want to get good guiding I wouldnt scrimp on the connection of the camera to the finder.

 

I guide my ED80 rig with a finderscope guider, and it seems fine at around 520mm FL.  I plan to guide my 1500mm newt with one was well, but just havent had a chance to try it out yet.  1500mm seems to be quoted as the upper limit for the 185mm FL finderscope.

 

You'll need to change or modify the mounting bracket too, to eliminate flexure.

 

[souls33k3r]

2 minutes ago, tooth_dr said:

It looks the same in the photos.  There is a plethora of info on the use of a 9x50 finder as a guider! Search button is your friend!

On the note of adapters - you wont need to spend £50 but around £28 should get you a nice adapter from Modern Astronomy.  If you want to get good guiding I wouldnt scrimp on the connection of the camera to the finder.

 

I guide my ED80 rig with a finderscope guider, and it seems fine at around 520mm FL.  I plan to guide my 1500mm newt with one was well, but just havent had a chance to try it out yet.  1500mm seems to be quoted as the upper limit for the 185mm FL finderscope.

 

You'll need to change or modify the mounting bracket too, to eliminate flexure.

 

I will have to agree ... i'll use the search (doh! should've done that in the first place).

I remember a friend told me a great Olly's method of bolting everything down ... i can't seem to find a way to do such with this unless i weld it down somehow

[tooth_dr]

1 minute ago, souls33k3r said:

I remember a friend told me a great Olly's method of bolting everything down ... i can't seem to find a way to do such with this unless i weld it down somehow

Mine is held in the finder shoe as normal but I've removed the springy screw and added additional screws.  The cable of the camera is attached to the findscope bracket also to eliminate at snags.  I'm not by any means an expect imager, but I'm getting reasonable results 600s+.

 

Some info here on a thread on mine:

 

[souls33k3r]

Cheers mate, i'll have a read through now

[fozzybear]

I've converted my celestron 9x50 finder model number #51611 and bought the adapter from Bern at modern astronomy

https://www.modernastronomy.com/shop/accessories/adapters/sky-watcher-clones-to-c-mount-adapter-for-straight-through-finders/

[souls33k3r]

25 minutes ago, fozzybear said:

I've converted my celestron 9x50 finder model number #51611 and bought the adapter from Bern at modern astronomy

https://www.modernastronomy.com/shop/accessories/adapters/sky-watcher-clones-to-c-mount-adapter-for-straight-through-finders/

Cheers @fozzybear, how are you mounting your converted guidescope? Is it on the same bracket that it came with or some other method? If you've got an image to share of it being mounted, that would be awesome. Just looking for some ideas.

[fozzybear]

13 minutes ago, souls33k3r said:

Cheers @fozzybear, how are you mounting your converted guidescope? Is it on the same bracket that it came with or some other method? If you've got an image to share of it being mounted, that would be awesome. Just looking for some ideas.

at the moment I am playing around with it using the std finder bracket albeit I have changed the base to a baader one with twin thumbscrews

[souls33k3r]

Just now, fozzybear said:

at the moment I am playing around with it using the std finder bracket albeit I have changed the base to a baader one with twin thumbscrews

No worries, whenever you get a chance to post an image on how you've got it mounted would be helpful. 

Cheers mate

[fozzybear]

Here is a picture of the finder

[souls33k3r]

2 minutes ago, fozzybear said:

Here is a picture of the finder

Cheers mate, that's exactly how i picture it. I wonder where can i find this mounting bracket from. 

[souls33k3r]

Don't worry about it, found it

[fozzybear]

you could try one of these bases

https://www.ebay.fr/itm/Multi-Function-Finderscope-Dovetail-Slot-for-Optical-Telescope-Finderscope-New/172379954816?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

[souls33k3r]

I've already got the shoe but it was the bracket that i needed. Basically the finderscope that came with my Celestron EdgeHD has it's own weird attachment. I will go home and see if i can make use of that some how or do i need the Skywatcher 9x50 bracket.

[fozzybear]

astroboot.co.uk have one for sale £7-90 plus shipping. you will have to check that it comes with the rubber o ring a must

Edited October 5, 2018 by fozzybear
added info

[fozzybear]

or maybe this might help

 

[tooth_dr]

5 minutes ago, fozzybear said:

astroboot.co.uk have one for sale £7-90 plus shipping. you will have to check that it comes with the rubber o ring a must

Actually discarded my o ring (it was perished anyway) and added more bolts instead. 

[Gina]

I've used the SW version.  Would expect there to be any difference but you never know.

[souls33k3r]

Ok I found a sw finderscope bracket. Basically a friend of mine had it and he doesn’t need it so I’m all set for that. Just need to buy the converter now. 

How do these scopes guide any way? Are they on par with the 50mm guidescopes out there?

[Gina]

As I recall mine worked well but I went over to guiding through the main scope - OAG - which was better.

[souls33k3r]

I've got the OAG as well and I'm wondering if I should really invest myself in making that work. 

Issue is, there's nothing out there during the day time that is any more than 200 meters away that I can use to focus both the camera and the guidecam. Not sure if it is at all wise to do that? 

[Gina]

Good focus is not important for guiding, in fact they say it works better if slightly off so that the stars as little circles rather than pinpoints.  OAG is certainly better because there can be virtually no flexibility between imaging and guiding.

[souls33k3r]

I totally get that Gina but my question was with regards to the issue of focusing the oag (guide and main camera) during the day time when the max distance I will be able to see and focus both the main camera and guide cam is about 200m and that’s it. I know the recommendation is something that is a mile away