View Full Version here: : Scope Recommendation for PMX....
29-04-2012, 11:47 AM
I've got a beautiful PMX and a TEC140. Both are such superb instruments!
I've really got a bad case of the "planet photography bug" and as wonderful as the TEC140 is I need/want more aperture. I've been a refractor nut for years and have to say I'm not exactly keen to start to worry about collimation and temperature issues, but perhaps that is the price one pays to join the club. Still, if price were no object, I wonder how a TEC180 or LZOS 203/1420 would perform! I notice that my TEC, while limited in the amount of light it can collect, seems to perform close to a larger aperature SCT (how much larger I'm not sure, but certainly larger), so would a TEC180 show much proportional difference?
Anyway, I digress. A large APO is probably not money well spent even if I could find one. What would be?
29-04-2012, 05:56 PM
A Celestron C-14 is both (comparatively) inexpensive and an excellent planet imager. Combine that with something like the venerable Point Grey Mono Flea3 (FL3-FW-03S1M-C), a good quality barlow, a filter wheel, some AstroDon RGB filters and the latest FireCapture beta software with ASCOM filterwheel support and you have a killer planet imaging system. All the hard work is in the processing.
30-04-2012, 01:40 PM
Thanks for the suggestion! Is there a reason you would be partial to the Celestron over the Meade 14"?
PS I just noticed an "Orange Tube" C-14 for sale on this forum. Would this scope compete optically with a more modern SCT? The price is right....
30-04-2012, 02:39 PM
SCT's rule the planetary imaging game. Have a look at Paul Haese, Damien Peach. Anothony Wesley made his own planetary scope which as I recall is a Newt based scope.
A key point is being able to cool the optics. SCTs have lots of thermal tube currents that prevent you getting that extra bit.
My CDK17 has a fan and temperature control. I know from experience if the mirror temp is more than about 1C different from ambient you will not be at maximum sharpness the scope is capable of.
As far as TEC180 versus TEC140. I have a TEC180FL and an AP140.
For deep sky imaging the difference is AP140 is a wider field scope and TEC180 will show more detail. Otherwise the images of the same object look very very similar.
As far as viewing goes, I have read on the TEC Yahoo Group, 140 to 160 is a bigger jump in visual than 160 to 180.
I think that is for 2 reasons. 1, the percentage increase in surface area is greater in 140 to 160 over 160 to 180. 2ndly, 6 inch APO is kind of a sweet spot for APO refractors.
I love my TEC180 though. Although if I were wanting to do planetary I think I would use my CDK17 or get a 14 inch SCT and fit a cooling solution to it. Also unless Yuri has glass left for 180's I am not sure he is making anymore of these for now until glass supply returns to normal. I don't have current data but last was he had enough glass to do several more TEC180's and once they were made that was it for now until he can get more glass. I read the other day someone commenting he was no longer making them. You'd have to contact Yuri to get the latest update. These APO makers have a hell of a time getting the glass and then when they get it, getting glass good enough to make these lenses. TEC was hitting a 30% rejection rate of glass. This glass is not returnable and is very expensive. So its the glass manufacturers that make their business hell and push them in a certain direction like 140mm or smaller.
Then get a u-beaut planetary cam. There's lots of choice with planetary cameras these days
30-04-2012, 07:44 PM
Go big with what ever choice you make. I prefer an SCT and I have mine peltier cooled. I used Anthony's idea and adapted it to suit my scope, first peltier cooled SCT and I have a how to on my site. It works and means tube currents and heat plumes are not a problem anymore.
Newtonians are very good too and both Anthony and Trevor's images are testimony to that. Although a big (ie 16") Newtonian will most likely be too big for the PMX.
Forget the refractor. As nice as they are for visual and DSO imaging, the aperture is not wide enough for planetary imaging.
Minimum width now is really a 12 inch in newtonian and 11 inch in SCT. Each will be well handled by the PMX.
I would not bother with an orange tube C14. The later models are sharper and contain better features. ie flat field and cooling slots.
Best of luck with your decision.
30-04-2012, 11:03 PM
Thanks guys for all the input! Much to think about. Dare I ask how the Celestron and Meade 14" scopes might compare? I can find a few reviews of the Celestron but have struck out on the Meade.
30-04-2012, 11:29 PM
Both are performers but the celestron has the most runs on the board.
01-05-2012, 01:31 AM
As far as cooling goes, a brand new stock C-14 OTA from Celestron made today has the cooling vents on the back same as the EdgeHD 14 does. So you don't have to purchase an EdgeHD OTA to get them. Deep Space Products sells replacement vents that have little 12VDC fans in them. They also sell a larger fan that fits into the removable secondary holder.
I owned a C-14 OTA years ago and currently own an EdgeHD 14 OTA which I keep on a Paramount ME. Unfortunately I have never owned a Meade 14 or 14 ACF, so I can't comment on them. I did own a Meade 10 in the '90s and it was a POS (both optically and mechanically).
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