Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

stargazine_ep29_banner.thumb.jpg.da7f3b163f7bd35187cb558b0346baf6.jpg

Recommended Posts

I have to use my 2x Barlow to attain focus with my SW-130P and D70.

Now, I've noticed this 1.6x barlow for sale and I'm wondering if it will give me a wider (and brighter) field.

The reason I'm not so sure - I can actually unscrew the end of my existing 2x barlow and fix it much closer to the camera, doesn't this effectively do the same thing as reducing magnification of the barlow? I've already done this and the field didn't look wider to me, but maybe I'm wrong (as I wasn't looking for it).

Share this post


Link to post
Share on other sites

Yes unscrewing your barlow element from your current barlow will do the same as that AE 1.6x. It should work as a 1.5x barlow when screwed directly into an eyepiece barrel. I presume it gives the same when screwed into the 1.25" nosepiece on your DSLR.

Share this post


Link to post
Share on other sites

Yes you can do this, but you might lose optimal correction of the barlow. Barlows are always a compromise, and using them in a configuration they were not designed for could present problems. The only way to find out is to try of course, it may save money.

Share this post


Link to post
Share on other sites

I'm using the barlow along with the "nosepiece" unscrewed from the end of this adapter:

Antares 1.25in to T thread adaptorTelescope Accessories | Rother Valley Optics

...It seems to be reasonable distance from the CCD, but I don't know?

Here's two frames, the first taken using the whole barlow, the second with the barlow+nosepiece. Both frames are in the M45 region, but I can't quite work out the orientation and therefore the difference in FOV I'm getting. Can anyone help?

before:

frame-before.jpg

after:

frame-after.jpg

Share this post


Link to post
Share on other sites

perhaps shooting a mundane subject like a brick wall (at a fair distance) will help. Just measuring the size of the bricks in the two images should give you a good estimate. Any other easily recognizable object could do.

The optical performance does not seem to suffer, so that is a plus.

Michael

Share this post


Link to post
Share on other sites

I've realised that in the second image, that's Alcyone at the bottom, with Atlas and Pleione to the left. In the first image, I'm looking at the 4 stars on the other side of the cluster, Taygeta, Caleano, Maia and Electra. I've worked it out and the FOV is around 10-15% wider with the newer configuration, which is a good thing. I'll have to experiment moving the barlow around a bit, perhaps even moving it further away for planetary imaging...

I have another question: How can I use a filter with this setup? I don't think the end of the barlow is threaded, so where & how can I attach one?? I've been looking at getting a light pollution / nebula filter.

Edited by Shibby

Share this post


Link to post
Share on other sites

I have another question: How can I use a filter with this setup? I don't think the end of the barlow is threaded, so where & how can I attach one?? I've been looking at getting a light pollution / nebula filter.

Filters are often threaded both ends so they can be stacked. That also means you should be able to place them before the barlow lens and whatever you screw onto the barlow gets screwed onto the other end of the filter instead

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.