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Old 08-10-2015, 10:41 PM
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alpal
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Join Date: Jan 2012
Location: Melbourne
Posts: 3,786
Quote:
Originally Posted by Octane View Post
I'm envious of your DIY skills! I'm a complete gumby when it comes to stuff like this.

H
Thanks Humayun,
I wish I was as skillful as many others on this forums.


To everyone,
I tried the new mirror extensions out last night.
The focus was good.
I used an eyepiece as well & could easily separate Alpha Centauri
with a high power eyepiece.
However - I focused the camera & took some shots of NC 253 & NGC 300
& the FWHM was bad so I returned to Achernar & tested the focus & it had changed by a large amount - out of focus.
I re-focused & went to Tuc 47 but wind gusts were making it hard to guide with PHD2.
The focuser is this one here:
http://www.teleskop-express.de/shop/...oducts_id/6522

with the motor drive here:
http://www.teleskop-express.de/shop/...teeltrack.html

I noticed that when I tightened the friction screw that the focus changed -
a single diffraction spike on one line through Archenar would change
to a double - or out of focus spike.
That screw should not change anything - it's A$638 of motorised focuser.
The first link says:

Quote:
A friction screw adjusts for the resistance.
Additional locking is not necessary, even with heavier payloads
But nevertheless, a knurled locking screw is standard.
Anyway I didn't tighten the friction screw up -
slewed to Tuc 47 & took 2 minutes each of LRGB 1x1 to make a picture.
I didn't take flats & I notice the corners are very dark.
I am wondering if my imaging train here:
https://www.flickr.com/photos/247194...in/photostream
is really suitable for an f4 system?

I have lots to contemplate & more tests to do.
Any advice would be handy.

cheers
Allan


see attached pics - but guiding poor due to severe wind gusts.
Attached Thumbnails
Click for full-size image (Tuc47  LRGB.jpg)
143.4 KB38 views
Click for full-size image (ngc 253  120s L 1x1_c.jpg)
143.7 KB46 views
Click for full-size image (ngc 300  300s L 1x1.fit.jpg)
132.9 KB40 views
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