PE of mounts

[Rocket Pooch]

Hi,

I found the following set of PE measurements for some well known mounts, this before and after are using PemPro from the Maxim guys, I added the EQ6 stats for comparison, look at the RCX Mount!

Mount Manufacture          PE Before    PE After    Reduction    Count(people asked)
Paramount ME Software Bisque       3.8"       0.8"       78%       11
AP 1200 Astro Physics          4.2"       1.3"       70%       8
MI 250 (L4 Gemini) Mountain Instruments 4.2"       1.4"       82%       4
AP 900 Astro Physics          5.8"       1.6"       73%       6
Titan (L4 Gemini) Losmandy       7.5"       1.5"       80%       2
G-11 (L4 Gemini) Losmandy       9.1"       2.3"       75%       4
EQ6 SkyScan            13.2"      N/A
RCX400 Meade             31.5"       6.7"       79%       2
LX200GPS Meade             45.9"       7.5"       84%       9
LX200 Classic Meade          53.3"       12.7"       76%       3

[Rick]

"PE" would be "Periodic Error"?

[Ian]

interesting set of numbers. You could use it as a measurement of the quality of the mount.

Most interesting is the percentage improvement seems largely constant. It looks like you turn a relatively bad mount into a reasonable one, but a good one can become excellent.

I suppose it's the old "you get what you pay for" story again.

I'll have to measure my mount seeing as it's not on the list, see how it compares. I'll add it to the list...

[Rocket Pooch]

Actually one thing it does mean is the HEQ5 & EQ6 SkyScan are very cost effective, the new mead fork mounts are really bad for the price and the older mounts are naff too.

Nut yes for non guided PEC approved mounts this would put the EQ6 to approx 5" peek to peek if PemPro was used which is whats needed for Supernova hunting where limited exposure sets are used, cool eh!

Actually I fancy an AP900, the PE on the new mount is 2" raw!  But there's a 2 year waiting list.