Astro-Physics 10" Maksutov-Cassegrain

[Hans Tucker]

A rare occurrence, a Astro-Physics 10" Maksutov-Cassegrain is up for sale on Astromart Auction...bids have reached $26K USD.

http://www.astromart.com/auctions/details.asp?auction_id=18243

Whilst viewing the attached images to the For Sale post I noted something pertaining to the secondary. I thought the secondary on these scopes was aluminized on back of corrector like in the following:

http://www.company7.com/astrophy/maks/250f146.html

Looking at the images on the For Sale ad it looks like the secondary is in a cell.

Just an observation.

[Wavytone]

Saw it earlier. Stupid price IMHO. Its still only a 10", and there's nothing magical about a mak that is going to beat the seeing limitations.

The spot aluminised on the secondary is the Gregory Maksutov design. The designs with a secondary whose radius can be different to that of the rear surface of the corrector is the Rumak design, and this provides two more degrees of freedom to correct aberrations. Given the quality of their work I'm not surprised they used the Rumak design on a mak this large.

[glend]

You could have a new Planewave 12.5" CDK for a lot less.

[Steffen]

The pictures at Astromart and Company7 appear to show different kinds of secondary mirrors, it looks like the one for auction could be a Rumak (the only way to go for anything larger than four to five inches, IMO).

[gregbradley]

The AP would still outperform it though.

The AP Mak Cass is a bit of a legend. There are many super hig rez images around using one.

Roland has a prototype for a 12 inch (305mm) one. That would be the one to get if he ever makes them.

I read recently that he says their Mak Cass is not affected by tube currents and is ready to image immediately. There was one shot of M42 resolving the Trap stars better than any other image I have seen of it.
These were taken in Chile under ideal conditions and seeing.

Another is one of M8 and it looks very similar to what I just took with my AP RHA, the Mak Cass one a bit sharper perhaps but I think that is more Chile's seeing than the scope.

Planewave are great but these instruments are in another league in my opinion. Whether its worth that much is another thing. I think in Aussie we need more bang for our buck and 10 inches is a bit smallish even if high quality.

I think it shows the US economy has recovered as well.

Greg.

[Hans Tucker]

Roland purchased the optics for his line of 10" Maksutov-Cassegrain through Aeries Instruments and then apparently did some fine tuning. Aeries Instruments had their own version of the AP 10" Maksutov-Cassegrain, not as aesthetically pleasing as the AP but functionally it's equal.

http://trafyx.com/bao/ariesmk10.html

This scope came up for sale on Astromart 2 years ago (for a fraction of what the current AP Mak-Cass is being sold for) and I enquired about purchasing it but the seller was only targeting a European buyer :sadeyes: