Barlow's

[Fay]

I am wondering if I should buy another Barlow for forthcoming moon & planetary images.
I have a x2. I see Mark used 2.....x2 Barlows. Should I buy a x3 or another x2?

Thanks

[JohnP]

I have a X3 if you want to give it a go.... John

[Fay]

Thanks John, that would be good to see the difference between the two. Can you use them with a Canon?

[JohnP]

The one I have is only 1 1/4 inch so I would say you would have Vignetting issues if you tried to use it with Canon...?

John

[Fay]

Yes, I never thought of that

[Fay]

Mark, have you used a 2x Barlow with your, can't remember, Nikon or Canon?

[MarkS]

Fay,

For high magnification planetary work I generally use a webcam.  I either use a Barlow or use eyepiece projection - it doesn't seem to make much difference either way.

For general use with the DSLR (I have both Nikon & Canon) I use an adapter (roughly 2" wide) to connect it directly to the visual back of the SCT, normally including a  focal reducer.  A Barlow can't be placed in this optical chain, so for high magnification work with the DSLR I use eyepiece projection.

Where would you put the Barlow?  Do you already use a 1 1/4" T-adapter that would take a Barlow?  If so, just try it in daylight and see if the vignetting is unbearable - use a lightbox or LCD screen to create a flat and find out! 

What do you intend to image with this setup?  If you are photographing a planet then all that matters is the centre of the image so vignetting is a non-issue.  If you are doing the moon and trying to fill the whole frame then it is more of a problem.  But if it's not too severe, the flat will compensate.

Mark

[Rocket Pooch]

Fay,

The 3x barlow John an I use the Tal one is brilliant, I also have a 4x Televuew 2" barlow as well, you can;t however borrow it because I'm in love with it, and I dare say I would have to end my life if anything happened to her err it.  After all we met on a business trip to the usa when I met the grand daughter of the person who discovered Pluto..........



Chris

[Fay]

Mark, that's a good idea to try my 1 1/4 2" barlow on the Canon first. As you say I think the vignetting will be too bad. I would like to get some close ups of the Moon in colour with the Canon, is what I was thinking, but a 2" is probably what I would  need.

May purchase a x3 for the DMK, John thought my image of Saturn looked a bit small.

[Tony G]

Fay,

I have a 2" barlow which suits the Canon. I haven't used it yet, but you are welcome to try it and if its OK I can tell you where to purchase one.
Just let me know.
By the way it a X2 barlow.

Tony G

[Mac]

I have a 4x 2" barlow if you want to borrow it,

Telescope is resigned to the cupboard at the moment, untill my questions are finished.

Mac.

[Fay]

Thanks Tony, I would like that.
That would be interesting Mac. I will have to put names on them so I know whose is whose!!!

[Tony G]

Fay,

Don't worry about putting names on the barlows, mine has my initials scratched onto the lens.

Tony G