DSLR won't focus

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Joined: Sat Jun 06, 2020 4:00 am

DSLR won't focus

Post by ericr0210 »

I have a small Bushnell 4.5" reflector telescope that worked well with my Pentas *ist, but my Nikons can't get close enough to focus. Really driving me nutso! Any solutions?
David Frydman
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Joined: Mon Jan 18, 2010 9:25 am

Re: DSLR won't focus

Post by David Frydman »


Back focus of Nikons is usually longer.

It might work with a Barlow lens or moving secondary or main mirror along axis. But this may not be easy.

Adapters containing a 1.2x lens may also work, such as Minolta MD to Minolta AF.
SRB Griturn have such adapters.
There may be some Nikon adapters also.

Or just stick with Pentax.

Mirrorless cameras will probably work well.

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Joined: Fri Dec 03, 2004 9:58 pm
Location: Wellingborough

Re: DSLR won't focus

Post by Brian »

Hi and welcome :D

David has covered the options available.

However, it would help us answer your question if we knew:

the model (number) of your 'scope
how you currently attach the Pentax to the focuser
does the 1.25inch eyepiece adapter on your focuser screw off, showing an internal thread (many telescopes do have this and a camera can be attached directly using the correct threaded rings)

52.3N 0.6W
Wellingborough UK.

254mm LX90 on Superwedge, WO ZS66SD, Helios 102mm f5 on EQ1, Hunter 11x80, Pentax 10x50
ASI120MC Toucam Pros 740k/840k/900nc mono, Pentax K110D
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