Quote:
Originally Posted by ezio49
Don't worry for your english, mine is worse than your.
I have a Barlow 2x and I could use it. I know that installing the Barlow we change the focus point as it happens with the extender.
It is not clear to me how we can simplify the focus tuning. If you can try to explain me I shall appreciate very much. Teaoretically I should have studied also optical during the phisic couse at university but our professor did not like it and did not include in the program. So I am fully ignorant in optics.
Thanks
Ezio
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Can you disassemly your 2x barlow in 2 parts? One small one with the optic and one larger without the optic? If yes, then use the part without the optics, if not consider to get a part like this:
http://agenaastro.com/blue-fireball-...extension.html
Mine optical knowledge is very limited. So i leave this part out
I just suggested that, if you put some optical element (mirror, ocular, barlow) into your scope, then you have to fasten it with 2 or more screw. Like on this image:
http://www.microglobe.co.uk/images/c...elescope_4.jpg
If you put in your wide field ocular, and then change it to a 10mm or below ocular, then 4 things will happen:
- it will be out of focus
- after focusing you will have a smaller angle of view
- everything will be dimmer
- and because of the 2 or more screws your center of image will move
So after refocusing you have to search again what you want to see.
If your barlow can be disassembled into 2 parts, then the part without optics
can be put into the scope first. If you change your ocular, or put in a 3x barlow befor your ocular, then your center point will be the same. It will come handy for photographing dim object, or using 3x or larger magnification barlows for planetary imaging. (The largest i tried is 5x barlow and the images shows more details as with 3x barlow)