Fun with 2.5 inches

[RobertI]

On a windy night with surprisingly steady skies, I chose my smallest scope to dart between the gusts. With my Williams Optics Zentithstar 66 mounted on a Giro-WR atop a Horizon tripod I ventured forth for a short session.

Starting with Izar in Bootes, the star showed a lovely but slightly broken diffraction pattern. However no sign of its smaller companion even at the highest mag I could manage of x78, not even an elongation. No matter, perhaps a bit too challenging for this tiny scope and these lowish magnifications, so on to Pi Bootes. This was a lovely double of white stars of slightly unequal magnitude separated by 5.4" - an easy split. Next on to Xi Bootes, another pair separated by a similar distance to Pi, but with a brighter primary and fainter companion. 39 Bootes was much closer at 2.6", and I didn't expect to see anything given my failure with Izar, but surprisingly it was immediately obvious and between gusts I could fleetingly see a gap. Skysafari said the pair had a magnitude difference in brightness but to me they looked almost identical. 

Now my eye was 'in', I thought I'd have another go at Izar. Same result as last time, but this time I noticed a brightening of the diffraction ring in one area. Checking the positional angle it seemed to be in the right position for the companion. So I think definitely more power needed and possibly aperture....and possibly better seeing!

I was getting really cold by this point, so thought I'd finish with some DSOs. M13 rising above the rooftops. I was expecting nothing but a blur with this aperture, but was amazed that, with averted vision, I could make out numerous stars on the periphery and could clearly see it was an object made up of thousands of stars rather than a faint haze.

Finally a scan around the bowl of Virgo with the zoom eyepiece. I found two bright galaxies in the same FOV, I believe they were M59 and M60 but not confirmed. It was intesting to zoom in and out; at lowest power, with the brightest skies, the galaxies disappeared completely in the murk, but zooming in the skies became darker and the galaxies more and more evident. There were a number of other galaxies in the area but I was just too cold to try and identify them by this point. Time to pack away.

I have been looking to get a higher power eyepiece to use with this scope anyway, so Izar will be my first target when I do!

Edited March 22, 2020 by RobertI

[NGC 1502]

Hi Rob, liking your post 👍

My smallest scope is very similar to yours.  It’s a TeleVue Pronto 70mm, on a Mini Giro alt-az with an elderly wooden surveyors theodolite tripod.   It’s a delightful fast to set up combination for short and long sessions.   In the past I’ve intended a short session that turned into a loong one......

The above will easily split Izar but not at 78x.  So my best guess is you’ll have success at much higher power as you’ve mentioned.  As many have found, double stars will usually take higher magnification than other types of object.

Even under a light polluted town sky it’s a whole lot of fun.   For instance, most of the time from my back garden the double cluster cannot be spotted without optical aid, although on the best of nights it’s a faint fuzzy patch. But my Pronto is a huge transformation on that.  Dozens of tiny points of light, just beautiful !

I could go on, but please enjoy your scope 😁

Ed.

 

[RobertI]

Thanks Ed!

[Stu]

Great stuff @RobertI. It was blooming chilly last nights wasn’t it, particularly with that wind so you did well to brave it for a while.

I agree with Ed, your scope will split Izar but just needs more power, perhaps x120 ish will do it. I have had a string of small apo fracs down to 60mm and they will all do it given enough power and reasonable seeing. Often in these scopes the secondary is more like a bulge in the first diffraction ring which can hide it a little without slightly more careful observation, but it is more of a greyish blue vs the primary so you can tell you are seeing it.

I do love pushing these little scopes to their limits, great fun.