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Night vision globulars


Highburymark
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After last week’s report on night vision in the dark skies of Norfolk with a small refractor, tonight I had the chance to see what a 120mm frac could deliver from a particularly orange corner of London, with patchy cloud to round things off. Scope: TSA-120, night vision device: PVS-14 with Photonis 4G tube, eyepieces: 18.2mm Delite, 32mm and 55/67mm TeleVue Plossls with Baader IR pass 685nm and Chroma 3nm Ha filters. All from my kitchen - may be the last time this year I can observe from indoors due to temperature differences inside and out. Just a very quick 15 min session.
Started with M92. 32mm plossl gave a nice view, though at this power it was a little small. Outer stars were resolved, but the core of the globular was fuzzy. 18.2mm Delite opened up more stars, but the cluster was too dim to justify more attention.
After M92 I wasn’t expecting too much from M13, but it was beautiful. Resolved to the core with the 32mm plossl, I really felt the benefit of the scope’s 120mm aperture here. Definitely the best globular result I’ve ever had with night vision from London. 
I moved over to M56, which was disappointing, though cloud was beginning to gather by this time. I swapped filters to enjoy a surprisingly prominent Dumbbell - this is an object that night vision brings out very well, though of course it’s best from a dark site with no gizmos to help. Cygnus was just too high to try for any of its nebulae.  So I packed up. Love this scope! Further proof you don’t need fast astrographs to enjoy pleasing NV views from the city.

 

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Hi Mark,

I thought of you last night as I viewed the Milky Way just after midnight - a poor night I could only see visually down to mag 5!!!!! and there is you viewing from your kitchen. Good to know that you enjoyed M13 and there was me viewing mag 18 galaxies using the 15/ultrastar...............

Mike

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43 minutes ago, JeremyS said:

Enjoyed that report Mark 👍🏻

Thanks Jeremy. One compromise you have to make with night vision is even the best image intensifier tubes produce haloes around the brightest stars. You can see it on virtually all NV images. At the eyepiece it’s less obvious, particularly with apo refractors - and this seems to help increase definition on objects like globular clusters. So the TSA works very well on star targets - extra aperture and star sharpness. Doesn’t mean that well figured achromats can’t also do a good job though.
 

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