Anyone used the Samsung 2.8-10mm under the stars?

[Ben Ritchie]

Not much to add to the title really, but i'm wondering about using the SCB-2000P as a widefield 'finder' - one option is to pick up a C mount to M42 lens adapter and then search ebay for a cheap M42 lens, but I was wondering about how the 2.8-10mm Samsung lens might do. Would be looking for reasonably distortion-free stars across the FOV, although don't expect miracles for the price.

Anyone tried it?

[Psychobilly]

Hi Ben,

How wide a FOV do you want...? Even a 50mm 1/3" format CCTV lens gives a reasonable FOV... I have the Genie 5-50 and the Samsung 2.8-10

I can point mine skywards if ever the clouds clear...

Peter...

[great_bear]

I got a 10-40mm for my (1/2" ccd) SCB-4000 specifically for astronomy use, and found it was the right range for my tastes...

[Ben Ritchie]

Which 10-40mm did you get?

I'm looking something that'll show constellation-sized widefields, the idea was that I could piggyback it and then put some kind of marking on the screen to show the telescope FOV. Picked the Samsung one just because it was listed on buythis in conjunction with the -2000P.

[Psychobilly]

You will shortly have a PM...

[great_bear]

I got this one <click> but bear in mind it's for a camera with 1/2" CCD (SCB-4000) and the SBC-2000 has a 1/3" CCD,

[Ben Ritchie]

Thanks to Peter kindly lending me one, I can say that ... it appears remarkably good.

Conditions aren't great for a detailed test, being not fully dark and with cloud now blowing through, but I set the Samsung up on a camera tripod for a play anyway. Fully zoomed in looks like stars may suffer a bit, i'm not sure yet, but when dialled out slightly it gave a sharp field of view from Delphinus to the 'bowl' asterism between lambda Aql and beta Scu which stellarium estimates at about 30 degrees. So, not for picking out faint fuzzies and tiny planetary nebulae, but with stacking set to 128x it gave a very nice sharp starfield down to around 8th magnitude which is brilliant for pointing out constellations - things like Sagitta that are easy naked-eye asterisms once you know where too look but rather hard to point out to a beginner really stand out well on the screen. Another bonus is that 128x and 256x modes are great at making satellites stand out, as they slowly blur across the screen in front of a sharp starfield.

So initial impressions are very positive, and a useful and interesting tool too.

[Psychobilly]

Glad you have had a chance to try it .. have you tried the Genie 5-100?

[Ben Ritchie]

have you tried the Genie 5-100?

Not yet, started to clag up while I was still tweaking the Samsung lens.

[Psychobilly]

be interested in what you find...

The back focus needs to be adjusted on the camera if you want them to be parafocal across the zoom range... the lens mount can be adjusted...