Given he already has a C14, a 15" is too small a jump. To get
1 magnitude more depth, you need roughly 2.5X the mirror
area (assuming equal light reflection losses, and all that stuff),
or roughly 1.6X the diameter, meaning 22" or so. With that size,
portability will need to be carefully considered, and the trailer
idea mentioned in an earlier post sounds wise.
On Nov 28, 2006, at 7:35 AM, Rob Hawley wrote:
> Well of course I am going to endorse a Plettstone also.
>
> Think carefully on whether you want an 18" or not. Before buying
> my 15" I
> did a "bakeoff" of a 15" against several 18" scopes. I could
> really not
> detect a difference in any of the objects I looked at. It was not
> until you
> compare with a 20" that you get a definite difference.
>
> The 15" will be easier to transport which will encourage you to use
> it more.
>
> For full disclosure mine is an f/5 which Michelle indicated she
> could no
> longer get mirrors for. You should check the current status with her.
>
> Rob Hawley
>
>
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-- What TAC Is About. http://www.observers.org/Join.shtml Webcam, DSLR, CCD Imaging use NorCal AI. http://tech.groups.yahoo.com/group/norcal_ai/ Designing and improving TAC's website. http://tech.groups.yahoo.com/group/tac-ops/ Sub-scribe or Unsub-scribe from TAC http://seds.org/mailman/listinfo/sf-bay-tacReceived on Tue Nov 28 19:53:32 2006