2.5x Powermate for Planetary Shots?

[Astro_Bot]

I'd like to increase the resolution I can get for planetary photography. At the moment, I'm limited to 2500mm and f/10 with my Meade LX200-ACF 10". I use a Canon 600d for imaging.

According to what I've read (here and some other advice), my 'scope and camera ought to be able to support an f-number of 21.5 or thereabouts, though some seem to be able to push that on major planets so I figure about f/25 would be a good target (and the 2.5x Powermate is cheaper than the 2x).

Q1. Has anyone had problems with the TeleVue 2.5x Powermate (1.25") (including T-ring adapter) for imaging?

Q2. If I later upgrade the camera to a QHY5II-L or ASI120MM, will the higher pixel density be too much of a stretch with the 2.5x Powermate (since f/19 will then be the "ideal" f-number according to the formula) or is there enough latitude that it'll work OK?

Any other relevant advice will be warmly appreciated.

[Merlin66 (Ken)]

f25 to f30 for planetary is good.
I use the x2.5 PM with the T thread adaptor and a DMK41/51 for solar imaging.
Works very well.

[Amaranthus (Barry)]

It works nicely for me -- the PM x2.5 goes in by default when I use my Neximage 5.

[pdalek (Patrick)]

I have both Powermates and standard barlows.
I find the latter to be far more useful for planetary imaging. The power can be tuned over a good range by adjusting the barlow - camera spacing. The optimum depends on several factors, one being camera pixel size.
The Powermates do not give higher image quality than TeleVue barlows in this application as far as I can measure.

[Rigel003 (Graeme)]

You might like to be aware of a peculiarity of the 2.5x Powermate. With all barlows and most powermates the image scale increases as you increase the distance between it and the sensor. With the 2.5" the image scale actually decreases slightly with distance. There are graphs showing this on the Televue pages.
http://www.televue.com/engine/TV3b_p...p#.Ux4qbueSyrM

Having said that, I've used the 2.5" happily on my 11" SCT.

[Astro_Bot]

Thanks for that advice. Very much appreciated ... can you feel the warmth?*



* Although feeling somebody's warmth could get you locked up in some parts.

[icytailmark (Mark)]

i use 2.5 powermate when the conditions are fair to good, and 5x when the conditions are excellent which is very rare in sydney lol