Jump to content

Banner.jpg.b89429c566825f6ab32bcafbada449c9.jpg

Guidescope placement

Vox45

By Vox45
in Discussions - Scopes / Whole setups

Recommended Posts

Vox45

Vox45

Posted
Posted

I used th saddle on the OTA to install my Orion 50mm guidescope and did not bother to buy a telrad or red dot finder as I thought I did not need one anymore.

Saddle and guider

Skywatcher 80ED Black Diamond

First night with that setup, I started the star alignement and was way off ... and since my webcam was all setup and focused in the guide scope, I was left with nothing to point to the star I needed to do the star alignement routine ...

So my questions are:

(1) should I piggy back the guide scope on the OTA (less flexure ? it seems rock solid to me the way it is right now) and use the saddle for a red dot finder ?

(2) if so, what do I need to piggy back ? rails of some kind and would this work with my type of guide scope ?

(3) As I can switch easily from a red dot to a finder scope using the saddle,  can I get away from doing a star alignement when doing astrophotgraphy if I am guiding and plate solving ?

If you have a similar setup do not hesitate to post how you solved this ;)

Link to comment
Share on other sites
  • Replies 26
  • Created
  • Last Reply
Vox45

Vox45

Posted
  • Author
Posted

Why not use astro tortilla to plate solve an image from the webcam and then you can do away with the need for a finder.

Yes :)

This seems nice ! I like the fact that you went for the ASI as a guide cam... I plan to do that also

I use a red dot finder on my ED80 until I have alignment then swap it for my 50mm guidescope and it seemd to work fine.

Peter

Yes makes sens ... I could set up the cam beforehand (focus and everything) and just swap for the alignement process .. or do plate solving as stated above ...

That was an easy one ;) thanks for all your advices

Link to comment
Share on other sites
Zakalwe

Zakalwe

Posted
Posted

Personally, I'd fit a piece of 10mm aluminium bar across the top of the existing rings (or use a spare Vixen dovetail), and then mount the finderguider in something solid. You can buy clamps that riggers use to mount lights and equipment onto trusses that can be adapted. The standard guidescope mount is designed to allow movement- it has a spring loaded plunger and a rubber ring at the front. This is the last thing that you want to mount a guidescope into...it's a recipe for flexure and bloated stars.

You could even use something like this:

http://www.ebay.co.uk/itm/BULLBAR-BRACKET-STAINLESS-40-70mm-FOR-MOBILE-CB-UHF-ANTENNA-AERIAL-SPOT-LIGHTS-/121519619654

It's not pretty, but it'd be rock solid and when it comes to guidesopes I'll take rock-solid over pretty all day long.

Or use something like this:

http://www.ebay.co.uk/itm/2-X-RHINO-MULTI-CLAMP-CLAM10-LED-DJ-DISCO-STAGE-LIGHTING-QUICK-CLAMP-BRACKET-/121736527797

The other thing that I'd suggest is to invest in a plate-solve routine. Some people like Astrotortilla, but personally I found it to be too flaky. My personal favourite is Sequence Generator Pro which comes with a few plate solve options. Then all you do is slew to any part of the sky, take an image and blind synch it. SGP will identify where in the sky you are and issue a synch command to your planetarium program over ASCOM. You can even load in an image from Flickr or a previous night's imaging, have it plate-solve that, slew to the right part of the sky and then centre the image.

Link to comment
Share on other sites
Helite

Helite

Posted
Posted

Personally, I'd fit a piece of 10mm aluminium bar across the top of the existing rings (or use a spare Vixen dovetail), and then mount the finderguider in something solid. You can buy clamps that riggers use to mount lights and equipment onto trusses that can be adapted. The standard guidescope mount is designed to allow movement- it has a spring loaded plunger and a rubber ring at the front. This is the last thing that you want to mount a guidescope into...it's a recipe for flexure and bloated stars.

You could even use something like this:

The Orion guidescope mount has 3 nylon screws, they are not like the standard finder mounts with the plunger. 

Link to comment
Share on other sites
Vox45

Vox45

Posted
  • Author
Posted

Personally, I'd fit a piece of 10mm aluminium bar across the top of the existing rings (or use a spare Vixen dovetail), and then mount the finderguider in something solid. You can buy clamps that riggers use to mount lights and equipment onto trusses that can be adapted. The standard guidescope mount is designed to allow movement- it has a spring loaded plunger and a rubber ring at the front. This is the last thing that you want to mount a guidescope into...it's a recipe for flexure and bloated stars.

You could even use something like this:

I had doubts about my setup regarding flexure but I haven't had any problems with that so far. But now I am more concerned about another issue which is balancing the scope. I guess it is easier when piggybacking than when you have the guide scope sitcking out like in the pictures above. Again, not a problem so far but my setup will get heavier overtime so that may become an issue.

Link to comment
Share on other sites
Zakalwe

Zakalwe

Posted
Posted

The Orion guidescope mount has 3 nylon screws, they are not like the standard finder mounts with the plunger. 

Ahh, fair enough. What holds the finderguider at the front? Do they still use a rubber O-Ring? The bracket itself is held into a sliding-fit bracket with a single clamping screw.  None of that would fill me with any confidence to be honest.

With a minimal cost and a little ingenuity, a much more stable solution can be found. if I've learned anything about this malarkey in the last few years, I've learned that diagnosing problems can be a pain in the posterior.  That's why I like to nail as many variables down as it removes them from the equation.

Link to comment
Share on other sites
Vox45

Vox45

Posted
  • Author
Posted

so there are no commercial solution to piggyback this kind of guide scope to an OTA ?

I saw this at FLO ..not sure if this is the solution ...

Dovetail bar

Dovetail guide

This may be a bit of an overkill for my needs right now ... Just curious to see how people go about on this issue

Link to comment
Share on other sites
Zakalwe

Zakalwe

Posted
Posted

so there are no commercial solution to piggyback this kind of guide scope to an OTA ?

You can buy finderscope rings.

https://www.google.co.uk/search?q=finderscope+rings&cr=countryUK|countryGB&sa=X&biw=1920&bih=947&tbs=ctr:countryUK|countryGB&tbm=isch&tbo=u&source=univ&ved=0CDMQsARqFQoTCIWzxdH07scCFQ8X2wod3K8KgQ

However, they are pricey for what they are. They then to have plastic tipped bolts (or worse still, nylon bolts), which you will never ever use as the FoV of a finderguider is massive, so finding a star is never a problem.  the biggest problem in my eyes is that most just fit into the normal finderscope shoe:

FinderBracket-1-594x300.jpg

In guiding, getting everything clamped down *hard* will save you problems in the long run.

You can get fancy ADM rings:

ADM_mds_guidescope_rings.jpg

but they are about £100.

IMHO, if I have the choice between fancy rings with the potential for flex, and a everything-nailed-down-tight solution with the added benefit of nearly £100 in my back pocket, I will be going for the latter every time.

Link to comment
Share on other sites
Vox45

Vox45

Posted
  • Author
Posted

I see your point !

If you could post a picture of your finderscope and how you made it fit on your OTA I'd appreciate that :) I will try to move in that direction in the future and just fit a simple red dot finder in the OTA finderscope shoe.

For now, I'll just switch between the 2 and/or use plate solving.. should be enough at my level of non-expertise ;)

Link to comment
Share on other sites
Helite

Helite

Posted
Posted

Ahh, fair enough. What holds the finderguider at the front? Do they still use a rubber O-Ring? The bracket itself is held into a sliding-fit bracket with a single clamping screw.  None of that would fill me with any confidence to be honest.

With a minimal cost and a little ingenuity, a much more stable solution can be found. if I've learned anything about this malarkey in the last few years, I've learned that diagnosing problems can be a pain in the posterior.  That's why I like to nail as many variables down as it removes them from the equation.

Yes unfortunately it does still use the rubber O-ring, so could introduce problems there. To be fair I do actually use an ST-80 on a dovetail as well, I don't even have guide rings on it, just have it fixed with standard tube rings, used to use it with the Synguider and it rarely couldn't find a star. I guess it depends on your setup and if you want to keep weight down etc.

Link to comment
Share on other sites
  • 2 weeks later...
Pompey Monkey

Pompey Monkey

Posted
Posted

So, after a spot of light fettling* this morning give me this:

21193130018_630a8b2c4b_z.jpg

21389305301_4668a039a8_z.jpg

I can then swap between the guidescope and Lunt solarscope.

*A fine Northern English word that needs to be used more.

Fettle away, my son! :)

Also, there's not a lot better than having just the right piece of ally bar/plate/tube in the tin just when you need it. ***Scurries off to Ebay***...

Link to comment
Share on other sites
Zakalwe

Zakalwe

Posted
Posted

Fettle away, my son! :)

Also, there's not a lot better than having just the right piece of ally bar/plate/tube in the tin just when you need it. ***Scurries off to Ebay***...

My metal bashing days are long over, so I have to use eBay too. This lot delivered very quickly:

http://www.ebay.co.uk/itm/161064303572?_trksid=p2057872.m2749.l2649&var=460189345198&ssPageName=STRK%3AMEBIDX%3AIT

Link to comment
Share on other sites
Vox45

Vox45

Posted
  • Author
Posted

Hi

I used 76mm pipe clamps to fix my Travel Scope 70 to a dovetail. Very solid though not sure how rust proof they might be. Can always coat them with something and they do a range of sizes, so they could be an option for attaching a finder guider :)

Louise

I do love the rings pointed by Zakalwe in a previous post they look really good at a fair price

I have to say that I am a bit surprised that no one is selling a kit with proper rings (without nylon screws) and dovetail holes that fits ... :)

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.