Telescope Focuser

Hi

Tried the focuser out again today, this time I left the 1.25" adapter in place, inserted the 8mm Hyperion and it focused, what a relief.

It seems that when I use the Hyperions in 2" mode they won't focus, in 1.25" mode they focus.

As I never break the EPs into the 2" mode only I'm set to go.

Now, what can be done about the weather?

I had the same experience with my Hyperions Paul. I was mightily confused when I measured available out-travel and thought I had more than enough to account for the apparent 3/4 cm thickness of the 1.25" adapter. SUrely I would have no problem removing the adapter and using the Hyperions in 2" mode. I was really scratching my head when it now seemed that I hadn't anywhere near enough out-travel to bring the HyP's to focus. What I hadn't realised was that the 2" stop on the hyp's is about half way up the Eyepiece. So without the 1.25" adapter they didn't just sit 3/4 of a cm lower in the drawtube, they sat about an inch lower!!

Just on your last point though about 'never breaking them into 2" mode'.

Maybe I am reading wrong but you know that you don't remove the lower 1.25" barrel in 2" mode. The 1.25" barrel contains the built in barlow. Removing this changes the focal length of the EP and induces massive aberations to the image. 2" mode h the Hyperions means it fits both sizes of drawtube without altering the EP at all. SO removing the 1.25" barrel is a non goer on most of the hyperion range. The one exception is the 21mm. Usually most people leave this one out of their collection because for some reason its AFOV is less than the standard 68 degrees across the rest of the range. It has the same FOV as the 17mm but with less magnification so its a bit pointless really. I ordered it however to use as a finder EP. You see, with the 1.25" barrel removed it becomes a servicable 32mm. There is a lot of coma(or is it astigmatism ) around the outer 1/4 but the centre of the FOV is decent enough. Its the only EP in the range that with the barrel removed provides a semi decent view. All others with the barrel removed are useless.

What I was doing Keith was removing the 1.25" adpater on my diagonal and popping the Hyperions in, it meant that I didn't have to keep putting the adapter in and removing it for the Moonfish.

I've never removed the lower half of the EP.

Funny storry, when I first recieved my Hyperions I tried to remove the lower half, in my wisdom I believed that they snapped off :roll: , dumb huh? Before coming to the brilliant revelation that they might actually screw off.

I wonder what would have happened if I managed to snap it in two?

Ahh!! Same reason I was trying them in 2" mode then. In my case it was to use the 1.25" 21mm in 2" 32 mode. Save me popping in and out the 1.25" adapter like you. Turns out the 21mm in 2" mode was the only EP that came to focus without the adapter in place.

I just wondered did the "breaking them into 2" mode" mean you were removing the 1.25" barrel with integrated barlow.

My GSO 1:10 low profile focuser arrived yesterday and I tried installing it last night. I knew I would have to do a small bit of hole extending (couple of mm), but I ran into a bigger problem.

SCREWs (hold on a minute mods I ain't cussin').

The existing screws in the C8N-GT are too short by about 3mm for this new focuser. No screws were delivered with the new focuser. Anybody know where I can get suitable screws?? (with proper countersink rebate etc.) AAAggghhhh......... :x

Hi John,

The original screws may be to an American Standard (which are awkward to get) rather than metric. If you're drilling new holes then that doesn't matter your best bet is to go down to Woodies and choose something suitable. If you need to match threads then the first thing you need is a set of thread guages to figure out what they are (UNC, UNF, etc.). If you don't know anyone who has them look up www.radionics.ie .

yea, dealing with american AWG is a right pain, when I got a new central bolt for the base of the LX200, I had to go to a machine shop to get it made up, could not get it anywhere else.