Focal Reducers (compressing lens)

[Jandy100]

In a previous thread I explained that I had received some excellent advice from this forum & members of the Milton Keynes Astronomical Society of which I am now a member. I also posted that for my first telescope purchase as a beginner, for ease of maintenance & portability (away from LP) I should look to either a Maksutov cassegrain or Schmidt cassegrain telescope.

Although I would get excellent results for planetary & lunar observing, I would not get the great results for DSO (normally associated with Reflectors) due to high focal ratio & lengths normally asociated with these scopes.

I have researched and identified that Focal Reducers are available which would reduce the focall ratio by a factor of 0.63.

Am I correct in assuming that this would improve results for DSO observing on a SCT or MCT?

Also are these readily available for most of the telescope brands (eg. Meade, Celestron, & Skywatcher etc)?

Any feedback or advice as always is very much appreciated.

Andy

[Merlin66]

Andy,

The x0.63 reducers work better on the SCT than the MCT - yes, they do help with imaging of DSO's. The Celestron/ Meade work on either brand of SCT.

[Macavity]

"Slow" scopes (MCTs) can often give quite a good account of themselves visually on DSOs. Most of the latter will anyway fit into the intrinsically smaller field. And, to some extent, even a 5/6" (somewhat) "apochromatic" scope ain't to be sneezed at...

VISUALLY - Well, let me suggest that BUDGET field reducers may not *extend* the TRUE field of slow (e.g. MCT) scopes, overmuch. <G> As Startrek's Scottie said: "Y'cannae change the laws of physics"?

If you're envisaging basic imaging, using a "Webcam" or Videocam - Especially those with a smaller (1/2" or less) chip, the 1.25" nose-piece focal reducers work quite well. The common ATIK focal reduce (with various extensions!) can yield GOOD results, without expensive (scope attached) flatteners/ reducers.

Not suited for wide-field, full-frame (SLR) coverage, or pin-point star rendition, but it is POSSIBLE to get reasonable (cool anyway!) images at "F5" etc., even with "reduced" F12 MAKs etc.

[Jandy100]

Sounds maybe like an obvious answer to those experienced, but is the Focal Reducer / Corrector used stand alone for astrophotography or is this an dual purpose accessory for enhancing observations of DSO also?

[Merlin66]

90% of the time they are used for astrophotography.

They can be used with suitable adaptors (spacers) for visual observing - but a low power eyepiece works just as well ;-)