Binoviewers & Skyliner 250px

[Stargazer_00]

Hi,

I have a Skyliner 250px and am about to buy a pair of binoviewers for it.

I am reading across many sites that sell these that Newtonian telescopes can struggle to come to focus, however not all.

Does anyone have the same scope as me and have experience with the focus of binoviewers in it or know how I can find out if these will work ok?

Also I am planning on upgrading the focuser to a 10:1 shortly, same question as above.

Any advice on the various models of binoviewers would be appreciated, clearly there are some low end price and higher end price, however the lower end seems to simply not come with supplied eyepieces and barlow all of which I already own (unless specific EP/barlows are required for usage)

I currently have a range of BST explorer/starguiders eyepieces which I intend to double up on. I assume the eyepieces will be ok.

Most sites suggest using a barlow to increase the focus travel, however this clearly comes at the expense of magnification. I would like to look at open clusters and DSOs using a pair of 25mm or 18mm eyepieces.

For reference:

Scope http://www.firstligh...-dobsonian.html

Various Binoviewers

http://www.firstligh...binoviewer.html

http://www.harrisont...inoviewers.html

Thanks

[BinocularSky]

I currently have a range of BST explorer/starguiders eyepieces which I intend to double up on. I assume the eyepieces will be ok.

I wouldn't. The BST explorer eyecup has a maximum diameter of a touch under 5cm. You'd be advised to check that the bridge of your nose will fit between two of them when they are at the correct inter-pupillary distance.

[Mark at Beaufort]

I have the Skywatcher 10" flextube and the focuser is a Moonlite low profile. I have some binoviewers similar to these from Telescope House - http://www.telescope...wer___Case.html

I had to purchase a 1.6x barlow to gain focus but the quality of the view is incredible. Although I own Televue Ethos and Nagler EPs the ones I use on the binoviewers are quite cheap. I have Antares 25mm plossls, Skywatcher wide angle 15mm and 9mm although the later gives too much magnification with the barlow on the 10" Dob.

I also have a Skywatcher 150P-DS with its original focuser which is similar to the one on your scope. If I remove the extension from the focuser I am able to focus with the binoviewers.

Hope this helps.

Mark

PS - I have just read Steve's comment above and he makes a very good point about the size of individual EPs and basically getting your nose close enough to view the image. This is why I bought less expensive plossls - these are the Skywatcher EPs that I bought - http://www.green-witch.com/acatalog/Ultra_Wide_Range.html

[Stargazer_00]

Thanks for the replies, so the WO BVs from FLO that come with the 1.6x barlow and EPs is probably the best bet?

I'll wait on EPs until I have the BVs

[Mark at Beaufort]

I have used WO binoviewers on my 4" APO frac when I attended a SGL star party. The quality is very good and they come with EPs and a 1.6x barlow. The reason I bought a different pair was that I obtained mine second hand from eBay, otherwise I would have bought the WO.

[Eastridge]

If I may butt in with a related question? : the 250PX being a fast f4.7 scope it normally needs better quality EP's to avoid edge issues.

Does the same apply to when using binoviewers or does the arrangement of the optics mitigate that edge distortion in some way?

Thanks,

[Stargazer_00]

A secondary question, does the singular part of the binoviewer (the part that is essentially the barrel that fits into the focuser) have a thread for filters or do they require a filter per EP?

[Mark at Beaufort]

One of the surprises that I had using binoviewers was the lack of any distortion especially considering the cost of the EPs that I was using. I wondered whether the prism within the binoviewers was correcting something. I must admit that I do not use the binoviewers for DSOs because it slightly dims the view. As previously stated I have Ethos and Nagler EPs so they are used for DSOs. So my binoviewers are used in the Dob and 6" Newt for Lunar and Planetary viewing. I also use the BV for solar viewing with the frac.

The second question yes my BV have a thread for filters - I usually screw a Moon filter into this part. I assume the WO has the same arrangement.

Mark

[Eastridge]

Thanks Mark, helps my mulling this over.

[Stargazer_00]

So I bought the WO binoviewers. Got an hour break in the cloud today and omg are they good on the moon and jupiter! Best buy ever!!

I had to remove the 2 inch to 1.25 eye piece tube that comes standard on the crayford and replace it with the reducer on my 2inch ed 2x barlow which reduced the focal length enough to get focus with the supplied 1.6x barlow. Also found focus with the 2inch 2x barlow and the binoviewers only. Moon was simply amazing. Speechless. And jupiter.wow. can see cloud detail. Lovely moon shadow on the face. Best ever.

Does anyone know how I can use them on the scope without a barlow? I assume I need to change the focuser but any advice welcome. Want to use them on dso at as low magnification as possible. Having to use a barlow really effects getting low mag views. Not sure why a barlow has to be used, can anyone explain that to me too? Thanks

Typed on my mobile. Excuse typos

[Eastridge]

Thanks for that info. It's getting tempting!