Are GSO 2" Barlows any good?

[stevemac]

Hi All, this is a really informative website, and has greatly helped our family with developing our amateur astronomy addiction!

We now have a 12" GoTo collapsible Dob, and whole bunch of 1.25" EP's which we still use with our 130mm SW (when we are are travelling), however we now have also added a couple of 2" EP's (38mm SWA & 26mm SWA with allegedly 70deg FOV) either way the FOV is great.

Question: We have seen positive comments about the GSO 2" ED Barlow's and we are considering purchasing one, however how will that impact on the FOV for our 2" SWA EP's?

We have also seen comments about the GSO 2" ED Barlows having a removable section which actually screws onto the EP to provide 1.5X? is this correct? and if so, how would that impact the FOV?

Many thanks for any thoughts,

Steve

ps: Andrews seems to have the GSO 2" ED barlows?

[multiweb (Marc)]

I have one (still got it) and let's say it's very good for the price. Good entry price barlow. Yes you can separate the barlow cell and add it to another spacer or even a separate imaging train. You will get some coma with large CCD though.

[stevemac]

The feedback is greatly appreciated, thanks Marc. Thats also along the line that I was thinking. eg: for the price it seems to be good value?
cheers
Steve

[multiweb (Marc)]

Yes it is. Another good thing about the cell is that if you stick with 2" GSO extension tubes it will thread in any of them. Even the 2" Baader filters will so it comes really handy when you want to place the barlow or a filter in your light path.

[stevemac]

More great advice, thanks Marc. I'm definitely going to order one.
I'm still unsure about how the GSO 2" Barlow will affect the wide field of view on the 2" EP's we are using, and I've sent as note to the distributor asking that question also.
Cheers Steve

[casstony]

Your AFOV (apparent field of view) will be similar but the real field will be less due to the increased magnification. Some eyepieces can suffer reduced AFOV (vignetting) when used with a barlow but I doubt you'll have that problem with the eyepieces you're using.

You will probably notice increased eye relief with the barlow; this can make it harder to hold your eye in the right spot with eyepieces that already have long eye relief, but is a bonus with eyepieces that have shorter eye relief.

[ballaratdragons (Ken)]

I really like my GSO 2" 2x Barlow for 2 reasons:

1. It gets rid of the seagulls in my GSO 2" 30mm Superview EP,

2. It make a great 2" extension tube by removing the Barlow lens.

It's 'across the field' quality as a Barlow is questionable with other EP's apart from the 2" 30mm Superview, but for it's price it does a pretty good job

Worth it

[stevemac]

Many thanks again for the comments, they are all very useful.

Ken - thanks also for your link to another website on another part of the forum. The link has some really interesting challenges for the family..
Cheers
Steve

http://outreach.atnf.csiro.au/educat...nsitivity.html

[Kevnool (Kev)]

I had one of these but i gave it away as i found out out it was useless, Not in the Barlow as it was quite good the GSO ED but as you soon learn for visual astronomy if you have a 28 or 30 mm EP why would you put more glass into the view to get a view down to say 14mm.
I just buy the EP,S then the barlow becomes obsolete as most people will find .Me personally i rekon there a astrophotography tool.

Cheers Kev.

[Suzy]

I love my GSO 2" ED barlow (thanks again Kev!)

I agree with Kev though- I prefer not to add more glass to my eyepieces (it's also more mucking around in the dark, adding and taking off barlows when changing eyepieces). Therefore, I now keep the barlow for times when I can use very high magnifications when the seeing permits to boost up the mag. on my eyepieces of 10, 7 and 5 mm. Those times I will jump at the chance to use my barlow. They don't happen very often though . But still, I think it's handy to have a barlow in the kit for that reason.
I have to add though, for a beginner starting out, or for someone on a budget, it's a great way to double your eye pieces.

[stevemac]

Thanks again for the guidance Kev and Suzy, it seems as if we are travelling the same journey.

That's exactly what happened with the 1.25" EP's. The collection stared a couple and a Barlow, and then gradually expanded to the stage where the 1.25" barlow is no longer used .. and now it seems as if we are travelling the same journey again with a bigger scope and now 2" wide angle EP's !!

We suspect that the journey is not finished ..

[Kevnool (Kev)]

Originally Posted by Suzy

I love my GSO 2" ED barlow (thanks again Kev!)

.

Your most welcome Suzy.

I have not purchased any more equipment or EP,s for a while and i seriously think my EP pelican case is siezed up as its been a while since i have been observing(But thats another story).


To steve it doesnt happen much but its good to see we are all thinking along the same wave length.

Cheers Kev.