Checking focus Toucam/WO 66mm Petzval

[geppetto]

Using a bad day to play inside and get stuff setup for the next

clear night.

Got the little 66mm to focus with my DSLR using an SCT to 2" extension tube (55mm long)

with little problems.

Today, I found that to get the Toucam to focus needed this extension plus another 35mm which

I got by using a barlow without it's lens.

Shot some AVI's of the castle dome on top of the hill through my very rainy window.

Turned out quite well with a bit of Registaxing, not too much CA and a doddle to focus with the 10:1 reduction knob.

Should be a nice scale for astro stuff.

Another thing that caused me problems the other night was trying to get the 66 to focus my DSLR

with a barlow in line.

Turns out from messing today that the barlow throws the focus point way back on the 66 and even

more extension tube is needed. I reckon at least 6" in total.

With these little 66's, you need a good collection of extension tubes

[jonifive]

Well done Philip

You keep experimenting and I'll reap the rewards of your hard work.

If your are looking at 6" total that seems like quite a lever with the Nikon attached, not so much with a webcam, but still a worry.

Jonathen

[geppetto]

I'll post any findings as I get them JF

Got to play again with the DSLR and barlow but will wait till I

can get outside as the windows are all misted up and covered in rain

Quite right about the leverage, suppose it will cause a problem with balance on the mount.

Using the foot as a dovetail is fine but of course you can't move the scope forward to act

as a counterbalance.

Going to try bolting a medium dovetail bar to the foot and then the longer dovetail bar

should allow the scope to move forward in the saddle, enough to regain balance.

[jonifive]

Phil said:

Going to try bolting a medium dovetail bar to the foot and then the longer dovetail bar

should allow the scope to move forward in the saddle, enough to regain balance

Good idea Phil, I have a spare one from my SW 200, might give it a try.

J5

[barkis]

Using a bad day to play inside and get stuff setup for the next

clear night.

Got the little 66mm to focus with my DSLR using an SCT to 2" extension tube (55mm long)

with little problems.

Today, I found that to get the Toucam to focus needed this extension plus another 35mm which

I got by using a barlow without it's lens.

Shot some AVI's of the castle dome on top of the hill through my very rainy window.

Turned out quite well with a bit of Registaxing, not too much CA and a doddle to focus with the 10:1 reduction knob.

Should be a nice scale for astro stuff.

Another thing that caused me problems the other night was trying to get the 66 to focus my DSLR

with a barlow in line.

Turns out from messing today that the barlow throws the focus point way back on the 66 and even

more extension tube is needed. I reckon at least 6" in total.

With these little 66's, you need a good collection of extension tubes

Are you using a diagonal with the 66 Phil, that would reduce the extension somewhat.

Ron.

[geppetto]

Are you using a diagonal with the 66 Phil

Ron

Yes, your quite right, that does reduce the need for extensions

but I wanted to get by without putting extra glass/mirrors in

the way of the camera if I could get away with it...

A telescopic extension tube would be handy

[jcm]

I had the same problems , Philip.

Did not what to use a diagonal , loss of light etc.

My scope came with a 2" diameter extension tube , but this turned out to be inadequate. Luckily I have a lathe and I made another longer extension tube so that my 2" barlow/DSLR combination could come to focus.

I was surprised how far back the camera had to be to reach focus.

John

[geppetto]

I was surprised how far back the camera had to be to reach focus.

Yes John, it quickly becomes a long scope