Is there a great finderscope??

[Gem (Grant)]

Originally Posted by bartman

Not sure if this is for you Grant, but Bintel are selling this.
Maybe with a reducer you could use a laptop to view the field on a larger scale?????
And use it as an autoguider to boot!
Anyway ...just a thought
Bartman
mmmm the link doesn't want to go to the page I want.
It's the Orion mini 50mm Guide scope - with or without the ccd- under the 'imaging and accessories' section page 5.

Interesting thought! Might be a bit complicated though... without the laptop I'd still need a reticle eyepiece to use it as a normal finder.

Now the question is... who can spare a 32mm or 40mm reticle eyepiece for the 80mm refractor?

[Gem (Grant)]

Originally Posted by rider

The Stellarvue 80 is about f3.75 so you get a bigger aperture without loss of any field of view, - like you would by using a small refactor as a finderscope.

Nice! The Stellarvue sounds impressive...
Time for some serious thinking (a.k.a. look at the budget!)...

[Jules76 (Julian)]

Another vote for the Stellavue (see my sig). Great little finderscope which I've found to be perfect as a grab and go as well.

[dannat (Daniel)]

Kokusai k in japan have a good one, also there is an illum finder on the 127ed which I really like - explore scientific use on a few of there scopes. Intes micro had an excellent one - the optics were razor sharp

[stringscope (Ian)]

Hello Grant,

Certainly a 50mm will show you a lot more than a 30mm. Once you get above 60mm, finders can become quite bulky and depending on the size of the primary telescope, can cause balance issues.

Finderscopes and reticle eyepieces are not that hard to build if you have access to a small home workshop. Attached images show a home made 80mm F5 finder (SurplusShed objective) and home made 32mm plossel X hair eyepiece. Finder is covered in insulation with integral objective and eyepiece heaters so it looks a little bulky. It is mounted in 100mm WO guidescope rings. I have various other finders here if you want to come around, have a look and get some ideas.

Cheers,

[Gem (Grant)]

Interested in how you made the cross hairs... maybe I will have to come to a CAS meeting soon!

[Logieberra (Logan)]

Grant, if you can convince Ian to help us... I have 2 x 50mm used binoculaur objectives sitting at home. They are in a threaded / standard binocular housing (kind of of like a refractor primary cell with a small lens hood)... I was not sure how to make the focuser end so I held off on the project

Ian, nice work there. Where did you get the machining / CNC done? I know there are people in the club that do it... but the waiting list is about 2 years...

[Gem (Grant)]

Originally Posted by Logieberra

Grant, if you can convince Ian to help us... I have 2 x 50mm used binoculaur objectives sitting at home. They are in a threaded / standard binocular housing (kind of of like a refractor primary cell with a small lens hood)... I was not sure how to make the focuser end so I held off on the project

Logan,
I have a 40mm Bintel Plossl that can be used for the job (and then added onto the 80mm refractor). A crosshaired 40mm on an 80mm f/5 should produce a 10x80 finderscope. The eyepiece could also help with doing the two star goto aligment procedure. Either way, we have a project ahead!!

[stringscope (Ian)]

G'day Logan, for the 80mm F5 finder, no machining:

• 100mm WO Guidescope rings.
• Objective lens and cell from SurplusShed
• Telescope body and dew shield are standard plumbing fittings plus a 50mm drawtube from a GSO Crayford forcuser, hose clamp and 1.25" reducer.
• 1.25" UO RACI 90 degree diagonal
• 32mm

Celestron Plossel circa mid 1990's with added cross hairs.

Grant, at F5, not much point in using a 40mm eyepiece due exit pupil size, suggest 32mm or shorter.

[binofied]

I must have missed this but what telescope are you putting this finder on? The weight of the bigger finders matters more on small scopes (12" or smaller I mean) Also no-one has asked why do you want or need a finder now days? When I built my 16" Binocular telescope I realized there was no sensible place to put a finder. So I only have a telrad, it only ever gets used twice to help me get the two alignment stars in the eyepiece so i can align my ArgoNavis digital setting circles. I then spend the evening actually looking for long periods at objects rather than wasting observing time star hopping.

Finders are irrelevant forget them :-)

[Gem (Grant)]

The scope might have goto, but nothing beats the thrill of finding something yourself! I've lived without goto for 27 or so years of astronomy afterall...

Actually, I must have had some dud finder optics in the past since the Celestron 6x30 finder on the CGEM 925 has surpassed my expectations. I wasn't expecting much based off past experiences with finders. Still want something better though...

Thanks everyone for your inputs... much food for thought!