Finder/guidescope help..

[Olsin]

Hello ... I'd like to upgrade my 6x30 finderscope that i got with my C8 to something a bit better that could also be used as a guide scope. Something along the lines of this..

https://www.teleskop-express.de/shop/product_info.php/info/p6383_TS-Optics-Optics-50-mm-DeLuxe-Mini-Guiding-Scope-and-Finderscope.html

The only thing is, i'm unsure as to how i'd attach it to my OTA. The 6x30 finderscope that is on the OTA is only held in place by 2 screws directly into the rear OTA housing. It doesn't sit in any bracket/mount.
Something like what i linked to would need a mount to attach it to my scope. So i'm wondering What would that mount be called and how would i secure it to the housing?

Thanks.

[Ouroboros]

Sorry, I don't the answer BUT .... Does your C8 have a 2m focal length. Something I would want to know before going down this route is whether or not a finder guider is suitable for a scope of that focal length.  Forgive me is this is not relevant to your particular scope. 

[cjdawson]

To go down the finder guider router, you'll probably want to get something like this....

https://www.green-witch.com/altair-60mm-finderguider-with-illuminated-reticle-eyepiece.html

And pair it up with something like this.

https://www.green-witch.com/lodestar-x2.html

 

I personally have a SkyWatcher ST-80 and a Starlight Express SuperStar.     Whilst I've not taken any images with this setup yet, I know that it works great with my Meade LX-90. (Also a 2 meter SCT)

[Olsin]

6 minutes ago, Ouroboros said:

Sorry, I don't the answer BUT .... Does your C8 have a 2m focal length. Something I would want to know before going down this route is whether or not a finder guider is suitable for a scope of that focal length.  Forgive me is this is not relevant to your particular scope. 

Yes it does have a long focal length but i use a 0.63x reducer with it so that brings me down to 1250mm. It also sits on a AVX mount that i'm lead to believe can do sub pixel guiding. The link above mentions sub pixel guiding up to 1500mm so with the reducer i should be covered.

Although to be fair, i'm not really so interested in AP/guiding. I'd just like to be able to use my asi120mm to try out Sharp Cap's polar align feature. I brought it a year ago and haven't really used it. The long focal length makes using that camera very challenging.

[michaelmorris]

With my C9.25 I found that the distance between the screw holes on the OTA were too far apart to use the standard Synta finderscope shoe.

https://www.firstlightoptics.com/finders/finder-mounting-shoe.html

However, the (unfortunately much more expensive) Baader finder shoe works a treat

https://www.firstlightoptics.com/finders/baader-universal-quick-release-finder-base.html

I hope this helps

[Olsin]

3 minutes ago, cjdawson said:

To go down the finder guider router, you'll probably want to get something like this....

https://www.green-witch.com/altair-60mm-finderguider-with-illuminated-reticle-eyepiece.html

And pair it up with something like this.

https://www.green-witch.com/lodestar-x2.html

 

I personally have a SkyWatcher ST-80 and a Starlight Express SuperStar.     Whilst I've not taken any images with this setup yet, I know that it works great with my Meade LX-90. (Also a 2 meter SCT)

Thanks ... As i mentioned, AP and guiding isn't really my main concern atm. I happened on that 50mm finder/guider as i was looking for something that would give me as wide a FOV as possible when used with an asi120...although reading through the reviews on that finder guider page i linked to, i see someone mentions that because of the short focal range, he need to use a barlow with his asi120 ... not really sure what that means!

[Olsin]

2 minutes ago, michaelmorris said:

However, the (unfortunately much more expensive) Baader finder shoe works a treat
 

Thanks Michael..isn't that usually the case

[cjdawson]

1 minute ago, Olsin said:

Thanks ... As i mentioned, AP and guiding isn't really my main concern atm. I happened on that 50mm finder/guider as i was looking for something that would give me as wide a FOV as possible when used with an asi120...although reading through the reviews on that finder guider page i linked to, i see someone mentions that because of the short focal range, he need to use a barlow with his asi120 ... not really sure what that means!

That would because he needed to put in a barlow in order to achieve focus.    This happens when there is not enough inward travel on the focusser to be able to get a camera into the right position.   This happens when the scope is setup for eyepieces and no thought is given to photography.

The scopes that I linked shouldn't have this issue.

[Olsin]

2 minutes ago, cjdawson said:

That would because he needed to put in a barlow in order to achieve focus.    This happens when there is not enough inward travel on the focusser to be able to get a camera into the right position.   This happens when the scope is setup for eyepieces and no thought is given to photography.

The scopes that I linked shouldn't have this issue.

Ok thanks for that. The Altair looks like a fine scope. If i could ignore the mismatch in colour coordination (my mount and OTA is black/orange), what type of finder base would i need to mount that onto my C8........although again looking closer, it appears that some kind of universal base is provided with the scope! I'm not sure it looks very stable though. Do you experience any flexure with yours?

[cjdawson]

Here's another alternative for a FinderGuider

https://www.firstlightoptics.com/zwo-accessories/zwo-finder-and-guider-scope.html

And it's black too.

 

As for the mounting options, I'm not really sure.  All I know is that Celestron are different to meade.  Hopefully @michaelmorris will be back soon with some more sage celestron based advice.

[michaelmorris]

The Baader Universal finder base is as solid as a solid thing!

[newbie alert]

Using it for polar aligning with sharpcap I'd make sure it's aligned with the scope,ie pointing in the same direction...and make sure you have focus with the camera as has been pointed out the lack of inward travel is restricted....

[Olsin]

12 hours ago, newbie alert said:

Using it for polar aligning with sharpcap I'd make sure it's aligned with the scope,ie pointing in the same direction...

I couldn't really imagine it being any other way

Here's the latest offering i've come across..This scope gets good reviews too.

http://www.365astronomy.com/365Astronomy-60mm-Compact-Deluxe-Finder-and-Guidescope-Kit-with-1.25-Non-Rotating-Helical-Focuser.html

But i still don't really know how i'd mount it on my C8. Am i right in thinking that i need another bar similar to the one already mounted onto my OTA, that is fastened both at the front and rear OTA housing ... and then a finder base screwed onto that for mounting the finder/guider?

As in another of these bars..

 

[PeterCPC]

This one should fit link here

Peter

[Olsin]

Thanks Pete .. I've seen those types of finder bases but without ever actually seeing one in the flesh, it's hard to decided how solid and substantial they are. A 60mm finder/guider weighing in at around a kilo would only be supported by 2 screws. To my mind that seems to little and even though i'm not initially guiding with this scope, i may want to try it in the near future. I'd want the finder/guider to be planted solid on the OTA.

 

[michaelmorris]

23 hours ago, Olsin said:

I couldn't really imagine it being any other way

Here's the latest offering i've come across..This scope gets good reviews too.

http://www.365astronomy.com/365Astronomy-60mm-Compact-Deluxe-Finder-and-Guidescope-Kit-with-1.25-Non-Rotating-Helical-Focuser.html

But i still don't really know how i'd mount it on my C8. Am i right in thinking that i need another bar similar to the one already mounted onto my OTA, that is fastened both at the front and rear OTA housing ... and then a finder base screwed onto that for mounting the finder/guider?

As in another of these bars..

 

You can attach the finder shoe by either replacing the existing finderscope or use the other set of screws on the OTA (marked red on pic). The Baader finder shoe is a nice, well-engineered piece of kit with two thumb screws to hold the foot of the finder/guider bracket in place.  I have never had any problem with differential flexure using it.

 

[Olsin]

Thanks a lot Michael, that's what i was hoping to hear