yet more secondary questions
Posted 18 June 2013 - 12:46 PM
The only suppliers I'm aware of are Antares and Protostar. Does that about cover it?
Posted 18 June 2013 - 01:07 PM
I purchased a 4.5" secondary to replace the 4" secondary I had. I bought an Astrosystems holder for the new secondary and made sure that the existing secondary holder (which either was an Astrosystems holder, or was very similar to theirs) and the new one both utilized the same diameter mounting bolt that slips into the spider.
The only problem I ran up against was that with my UTA and the spider mounted in it, I cannot move the new 4.5" mirror far enough away from the primary to square the focuser. I could remount the spider with, what I consider, a severe amount of effort, but I have instead decided to just move the secondary away as far as possible sans remounting the spider. (I did have to drill new holes in my Astrosystems holder to help facilitate this or else it would have been so far off center it would not have worked well I don't believe)
I hope this helps.
Posted 18 June 2013 - 01:14 PM
Posted 18 June 2013 - 01:32 PM
Both can be ordered from Astro Systems, whose website can be accessed at the link below.
Posted 18 June 2013 - 01:59 PM
The shrouds used in the Astrosystems holders eat up a fair amount of area around the edge of the secondary. In one of mine I ended up scrapping the shroud and using a glued wooden dowel to support the secondary. This only becomes an issue if your secondary is near the minimum size for the OTA configuration.
Posted 18 June 2013 - 03:13 PM
Posted 20 June 2013 - 07:45 AM
Posted 20 June 2013 - 08:19 AM
you could get a stalk from 1800destiny, you'll have to glue it to the back of the mirror cause they don't make them with the typical shrouds.
Posted 20 June 2013 - 08:26 AM
Posted 20 June 2013 - 08:59 AM
It will take me from 17.3% CO to 20.6%. Not significant, IMO. The existing secondary is almost 10 years old, so a new one might bring other benefits as well.
Ideally, yes, I'd go with the protostar integrated system. However, it will take longer (wait times), cost more (more than double) and involve surgery on the UTA. If the existing spider can't take the 3.1, I can just go back to the 2.6 with longer poles or buy the protostar at that point.
Mostly, I was just wondering who sold these items and the astrosystem secondary holder looks to be an exact match for the spider I currently own.
Posted 20 June 2013 - 09:00 AM