SkyWatcher SWA 70° Eyepieces: Initial Impressions

[John]

Courtesy of First Light Optics, I've been loaned 3 examples of this relatively new SkyWatcher eyepiece range to try out and report back to the forum on. Thanks FLO 

I choose the 5mm, 13mm and 32mm focal lengths because I think they will be popular and I have eyepieces of similar focal length to compare them with. The 5mm and 13mm are 1.25" eyepieces with a 2" skirt to allow them to be used in 2" drawtubes and the 32mm is a 2" eyepiece. According to the published specifications all offer 70 degree apparent fields of view and 20.6mm of eye relief. All are also described as using 8 optical elements although I have some doubts over the 32mm as it just does not seem heavy enough or large enough to accommodate that amount of glass.

The SkyWatcher SWA 70° Eyepieces are big eyepieces - the 5mm is physically the largest and heaviest of that focal length that I have yet encountered. As with many wide angle ranges, the physical size and weight decrease as the focal length increases. The SWA 70's are well finished eyepieces sporting deep green coatings to the eye lenses and heavily built sculpted rubber bodies. The conical rubber covered top section of the eyepieces twists up and down allowing around 6mm of travel. 

With the 5mm and 13mm eyepieces, the 1.25" barrel is threaded for 1.25" filters but the 2" skirt is not threaded. The 32mm is fully a 2" eyepiece and is threaded for 2" filters. Security set screws are supplied with the 5mm and 13mm eyepieces to allow them to be locked more securely into 1.25" drawtubes. These screws need to be removed and stored safely if the eyepieces will be used in 2" mode, which seems highly sensible given their weight and bulk.

I've not weighed the eyepieces but the 5mm and 13mm are noticeably heavier than the 32mm and all could possibly cause some balance issues with dobsonians when viewing objects at lower altitudes so some adjustment to balance or altitude tension may well be needed.

While the design seems large initially, it does seem to offer secure and comfortable handling, particularly with gloved hands on a cold night I would think. The eye lenses of SWA 70's are large and accommodating and the field stops seem sharply defined. The apparent field of view seems to match the claimed 70 degrees when compared to the 68 degree Pentax XW's.

All in all,  you seem to get a lot of eyepiece for your money in terms of size and build quality but it's the optical performance that really counts of course. Unfortunately I'm clouded out tonight so I've no chance to try these out however I'll do so at the earliest opportunity and report back 

Meanwhile I'll have to ask you to be content with some photos. The SkyWatcher SWA 70's are the center eyepiece in each picture (in case you didn't guess !):

[bingevader]

Thanks John, I'd be keen to hear your opinion.

My goodness, they're big though!

I've been looking at the 8mm to fill a "gap", but it would be with a view to be able to use it with a 2x barlow should I get the chance. I'm not sure I'd want to put one of those on a barlow! Would they even fit with the 2" skirt?

Cheers

[John]

I've been looking at the 8mm to fill a "gap", but it would be with a view to be able to use it with a 2x barlow should I get the chance. I'm not sure I'd want to put one of those on a barlow! Would they even fit with the 2" skirt?

I think I'd prefer to use a 2" barlow with the SWA 70's to be honest although a 1.25" one would fit as long as it's drawtube section is not too thick. The result would look rather like a toffee apple on a stick though ! 

[bingevader]

The result would look rather like a toffee apple on a stick though ! 

And a rather frightening one at that!

Cheers

[michael.h.f.wilkinson]

I understood that the XWs are 70 deg as well.

[John]

I understood that the XWs are 70 deg as well.

Quite right Michael - don't know how I got that wrong as I've owned the XW's for some time now !

Actually the SkyWatcher SWA 5mm looked a tiny bit wider than the 5mm XW so I might re-check that.

[callisto]

I'm thinking about the 32mm, so i'll look forward to first light reports

[RikM]

Quite right Michael - don't know how I got that wrong as I've owned the XW's for some time now !

Actually the SkyWatcher SWA 5mm looked a tiny bit wider than the 5mm XW so I might re-check that.

Could it be that the SWA 5mm is a 5.05mm to a Pentax XW 4.98mm ?

[John]

Could it be that the SWA 5mm is a 5.05mm to a Pentax XW 4.98mm ?

Could be Rik. I'll say that they are 5mm-ish eyepieces offering around 70 degrees