Info on Barlow lens please.

M54 (Molly) · #1 10-05-2009, 01:33 AM

Good morning all,
I have an Orion 130mm reflector with a 10mm and 25mm eyepiece.
My mum's day pressie was a voucher for the Bintel shop and I've been perusing their website and was wondering if a barlow lens would be a good idea. (I had to do a google search to find out exactly what they're for).
How much difference will it make to viewing planets and dso's, will it make much difference or just a little bit.
I'm eyeing off a book on messier objects as well but I can't afford both, so I want to make the right decision.
I hope this isn't too daft a question.
Thanks in advance,
Molly.

omnivorr · #2 10-05-2009, 04:09 AM

Hi Molly, a 'safe' to assume max mag for your scope would be 200x, in good 'seeing' etc.. and your EP's would not reach that eg, the 10mm would give 90x ( assuming the 900Fl version, or 65x for the 650 Fl version of the 130mm reflectors)
...a barlow of 2x would be quite reasonable at that rate.. but it might depend a bit on how good the EP's that came with the scope are.

perhaps you might borrow one from a kindly soul to see for yourself if you think it's worth the investment?

Gargoyle_Steve (Steve) · #3 10-05-2009, 04:27 AM

I'd personally opt to get the book on Messier objects instead but then I'm not much of a fan of Barlow's, but to be honest many many others think they're a very useful tool.

All I can say perhaps is as suggested previously, see if someone will let you try their Barlow in your scope before you commit yourself to getting one.

Or get the book!

Kevnool (Kev) · #4 10-05-2009, 08:14 AM

I,m with you Steve on this one.

There a good instrument for Astrophotography,But if youve got a few EP's for Obsevational Astonomy why would you bother.

Have a good look Molly before you buy.

M54 (Molly) · #5 10-05-2009, 10:35 AM

Thanks Omnivorr, Steve and Kev.
I'll keep a tight hold of my voucher till I'm satisfied with my decision.
I'm leaning toward the book after what you've said.
I don't know another soul with a telescope but I've just joined the ASV, and am booked in for their New Astronomers Group classes starting in August (it's SO long to wait!) so maybe I'll get to check one out there.
I actually really want the book and I suppose the barlow could wait till another time when I know a little more and have gotten the most out of what I already have.
Thanks again people.
Molly.

Liz · #6 10-05-2009, 12:48 PM

Yes, go for the book Molly.

I also dont use a barlow, though know many do.
Down the track it may be something to consider .... unless you get the 'eyepiece disease' !!

M54 (Molly) · #7 10-05-2009, 07:37 PM

Quote:

Originally Posted by Liz

Yes, go for the book Molly.

I also dont use a barlow, though know many do.
Down the track it may be something to consider .... unless you get the 'eyepiece disease' !!

Thanks Liz,
Have deciced against the barlow, will put some more thought into it.

rmcpb (Rob) · #8 11-05-2009, 09:41 AM

Molly,

I would go for the book. While I have a good barlow I tend not to use it much except to get the really high magnifications on those rare brilliant nights with the moon. Otherwise I just stick to my eyepiece collection.

Cheers