Quote:
Originally Posted by multiweb
I'd say it would be close to a miracle to get a flat field on an SCT reduced to F3 at prime. Why not use an hyperstar which has better correction if you want to go that fast?
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Cheers Marc, interesting none the less, guess its something one needs to experiment with, if plausible, & tho am preferring near the 1mt F/L at moment as well, it may be another option
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Quote:
Originally Posted by Atmos
Not sure what the correction is like on that F/3.3 reducer BUT I know the imaging circle is tiny, thinking about the same size as a guide camera chip!
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Thanx Colin, wow, I didnt enter the idea of considering the Image circle, , never have actually !
Sounds like it has a rather intense effect in this situation
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Quote:
Originally Posted by redbeard
Hi Bob,
First of all I only know a little about this but here goes:
The 3.3 has been around for a while and when it first came out, and for a while later, the CCD sensors on cameras were very small. Worked well back then, but I think that you would get a lot of vignetting with today's size sensors.
I have the GPS LX200 10" and almost always use the 6.3 reducer which is also meant to flatten a little as well and that works well. In the Meade 3.3/6.3 manual, it states that they both do some flattening so you may not want that with your ACF.
It's always nicer for a faster image though, and I can recommend the AstroPhysics - CCD Telecompressor(CCDT67). Same as focal reducer.
No flattening.
From their website
http://www.astro-physics.com/product...&%2027TVPH.pdf
But hey, if you have a 3.3 or can borrow one, then give it a go. Then you will know exactly how it works with your gear. I did that...once.
Cheers,
Damien. |
Hi Damien, & I much appreciate your feedback here, all very worthy of mentioning
I should atleast try giving my 6.3 a go with imaging, and see what it produces.. Then take it from there
Good Stuff