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Guest post: David DeLano’s ultimate Galileoscope quest, Part 5 – SCT focuser notes

March 15, 2014

Well, our long journey is at an end (for now!). No new pictures, just some notes on how long the various bits are, should you want to add an SCT focuser to your GS (or just about anything else). For previous posts in this series, go here. Thanks, David!

IMG_1242

Yes, that is a 2-inch focuser on David’s Galileoscope. Why do you ask?

SCT Focuser – 90mm
Low Profile 2″ – 1.25″ adapter – 10mm
Tele Vue Low Profile SCT adapter – 38mm
SCT M-M – 10mm

For F/11 objective, need something close to 75mm + 50mm = 125mm
Above parts are 90mm + 10mm + 38mm + 10mm = 138mm
Need to cut down 23mm, though 20mm might be enough.

Could use a zero clearance 2″ – 1.25″ adapter or negative adapter (ScopeStuff) (negative won’t work, since the diag won’t slide into it).

From Agena

SCT Focuser – 90mm
Low Profile 2″ – 1.25″ adapter – 1mm
TV Low Profile SCT adapter – 40mm (probably a better figure than OPT)
SCT M-M – 1mm

Total – 90mm + 1mm + 40mm + 1mm = 132mm (5-7mm too much)

However……since not using the SV helical, there might be gain on the diag EP end.

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4 comments

  1. […] Guest Post: David DeLano’s Ultimate Galileoscope Quest, Part 5 – SCT Focuser Notes March 16th, 2014 — “Well, our long journey is at an end (for now!). No new pictures, just some notes on how long the various bits are, should you want to add an SCT focuser to your GS (or just about anything else). For previous posts in this series, go here. Thanks, David! SCT Focuser – 90mm Low Profile […]” […]


  2. There were a LOT of intermediate steps that I went through before finding what works. If anyone wants more details about any of the steps, just ask. In fact, if anyone wants help with a conversion, walking you through it that is, just ask. I don’t have the time to actually do the mods (yet).

    Agena Astro is a good place to start for parts. First, the documentation on their web site is mostly complete and accurate. The few parts that didn’t have measurements, Manish and Tom measured for me and updated the web site.

    Scopestuff is another good site, and Tom was helpful in measuring parts AND has the capability to make custom parts – he made me a 2″ – 1.25″ adapter that truly added zero length to the visual train.

    Surplus Shed has some interesting parts that are cheap enough to experiment with. Their 2″ extender barrel has a 48mm thread and will mate to other adapters with that tread (but the part is a bit too long to be useful).

    David


  3. If your looking for cheap telescopes than i recommend http://www.astrobuyandsell.co.uk for used telescopes in the UK



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