Phenix 150mm F8 with Crayford

[Analogue]

Hi all,

I've just 'bitten the bullet' and upgraded the focuser on my Phenix 150 to a Crayford.

The upgrade included a new rear adapter plate as well as the focuser itself from Alan at 'Sky's The Limit'.

The adapter plate was undersize by about 0.5mm but it was no biggie as I took up the slack with PVC tape. I expect that Phenix may have changed the tube diameter slightly for the more recent models.

The Crayford was pre-assembled to the adapter plate so I has no worries there.

The biggest surprise was that the adapter plate is a big lump of machined aluminium, I was expecting plastic as is the original.

The extra weight of the plate and the focuser meant that I could slide the OTA further forward in the Rings to achieve balance, M13 at 2.30AM and no arguments with the tripod (M13 was near Zenith).

Just to finish up, I have about 13mm more 'in travel' than before which has allowed me to use a troublesome eyepiece (a UO 25mm 2") which would not achieve focus before.

The Photo shows the 'old' in the corner. (I know...I didn't put the counterweights on).

Have fun in the darkness,

Clive.

(click to enlarge)

[John]

Thats an impressive looking instrument Clive

How do you find the EQ5 (or is it a CG5 ?) copes with the tube weight and length ? - I used an EQ5 with tubular steel legs with a 120mm f/8.3 refractor and it was fine but I thought a 6 inch might be too much - I'd be interested in how you have found that pairing.

Is there a finder bracket on that new focusser or will you be mounting the finder on the tube somewhere?.

John

[Analogue]

Hi John,

The mount is the CG5 with the 2" steel legs. The tube rings are just over 1' apart.

It is a surprisingly sturdy setup, of course if I clout the focuser it will wobble but will dampen out in around 7 sec.

I have been experimenting with an Orion Starshoot Camera, equivalent to a 5mm eyepiece, with the old focuser damping was down to 2-3 seconds while focusing. I expect even this will improve now I have the Crayford, particularly now the tube is mounted further forward (less momentum).

Finder: There is room on the new adapter plate to mount a traditional finder. I rarely, if ever, use a finder.

I start out with a 55mm 2" eyepiece and work my way in from there. With increasing magnifications I often see star patterns that would be missed in a finder, these can be helpful guides for next time. Works for me.

One thing I didn't make clear in my original post was when I mentioned the Crayford being "pre-assembled to the adapter plate", what I meant was that Alan had checked that it was a perfect fit, it is in fact attached with 3 grub screws.

If I mucked up the drilling to attach the adapter plate to the telescope I could just rotate it and start again without worrying about the position of the Crayford (I didn't).

Clive.

[iancandler]

I cant wait to see that in the flesh so to speak Clive.. it looks great and from what you said is a vast improvement over the old R&P that was on it.