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Do I even need to align the finderscope if I'm guiding?


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I've seen a few finder scopes that just have a focuser, no rings or anything that you would adjust to star align... However, I don't even do star alignment anymore, It's just a quick polar alignment on sharp cap go to my target plate solve then I'm done. I could just have one guidescope for all 4 of my telescopes right?

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If I am using the asiair, once plate solve succeeds, I polar align, then just got on with it, but, I always ensure the finders are as close as I can get them so they are ready for the night I choose to do visual. I am fortunate in that the telescopes are stored with the finders in place; that leaves the only challenge being me in that I do have a habit of knocking the things when I'm putting it all away.

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No guidescopes have alignment rings. What they have, if they have rings, are misalignment rings which were used in the days of insensitive autoguiders which needed to be pointed this way or that, relative to the imaging scope, to find a workable guide star. Those days are long gone but manufacturers insist on still providing them, leading to the modern myth that guidescopes need to be aligned. Actually I think they are just there because these scopes are based on findersscopes which do need to be aligned. A rigid mounting is much to be preferred.

By the way, I've started using one of these mini finder guiders a couple of years ago and consider it a darned nuisance. It de-focuses itself a couple or three times a year. When I was using locked-up-solid ST80s for guiding I never touched them in ten years, scraping out the worst of the spider webs every three years or so. The worked perfectly. I'd be delighted to see the back of the pretty little anodized pest which replaced them!

Olly

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I use the same finder guider mounted on my ED80 whether l have my Ed72 mounted on the ED80 for a dual rig or whether l have my Samyang set up mounted on the ED80.  
 

For some reason the FOV is slightly different with the Samyang lens.   I tried to adjust it once but it was such a nightmare adjusting it back for the dual rig l vowed never to do it again.   
 

Therefore my finderguider is not aligned with my Samyang rig.  Doesn’t seem to make any difference so l just live with it.  

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As others have said, it makes  no difference for guiding.  It is very useful  though when plate solving the finder-guider image for visual through the main scope.  By comparison I have often found  GoTo with star alignment intensely frustrating when the faint object is seldom anywhere near the centre of view, or visible at all even. Oddly enough though I have found it can be quite difficult to get the finder and main scope co-aligned. 

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5 hours ago, carastro said:

I use the same finder guider mounted on my ED80 whether l have my Ed72 mounted on the ED80 for a dual rig or whether l have my Samyang set up mounted on the ED80.  
 

For some reason the FOV is slightly different with the Samyang lens.   I tried to adjust it once but it was such a nightmare adjusting it back for the dual rig l vowed never to do it again.   
 

Therefore my finderguider is not aligned with my Samyang rig.  Doesn’t seem to make any difference so l just live with it.  

The ED80's finder is useless to me as my camera makes it so that I have to remove the locking ring, making the lens wobble and go constantly out of focus especially when I wrap a dew heater around the thing. I'm trying to look for a solution, if not then mini finder from FLO it is!

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5 hours ago, ollypenrice said:

By the way, I've started using one of these mini finder guiders a couple of years ago and consider it a darned nuisance. It de-focuses itself a couple or three times a year.

That's what I was going to buy because they're the cheapest and smallest, a lot of favourable reviews on FLO, to use for for FMA 180. ST80 would be quite a big guidescope for this, though I am looking to put weight on as i need to counter 5kg.

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10 minutes ago, Quetzalcoatl72 said:

That's what I was going to buy because they're the cheapest and smallest, a lot of favourable reviews on FLO, to use for for FMA 180. ST80 would be quite a big guidescope for this, though I am looking to put weight on as i need to counter 5kg.

My favourable (and very short) review of the ST80 as a guidescope goes like this:

Running an old school, low sensitivity CCD Lodestar in an ST80, I imaged commercially for around ten years, and about 250 nights per year, without dropping a single sub to guiding error. The mount was a Mesu 200.

Olly

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