Sunday, March 17, 2013

Solar Stellarvue 90T

A couple years ago I owned a very nice 90mm triplet refractor from Stellarvue, which I had sold to pay for some other astronomy gear.  Recently, after trying other small aperture scopes, I decided that I wanted to purchase another one of these fine refractors.  At 90mm, the scope is a terrific size to take anywhere, and also has a bit more light gathering than the 80mm telescopes that dominate the small scope market. Additionally I wanted a telescope to use for white light solar observing that would compliment my Lunt 60mm HA without creating balance headaches when used simultaneously.  As it happened, Stellarvue had on their website a used SV 90T, with a carbon fiber tube and a very nice feathertouch focuser.  While one pays a slight premium buying used from Stellarvue as opposed to a private individual, Stellarvue does warranty their used telescopes for two years, just as they do with a new instrument.  To sweeten the deal, they also included a very nice, new soft-sided case with room for much more than just the telescope.  After a few days deliberation, I contacted Stellarvue and ordered the telescope.  It arrived in less than 48 hours, along with wind, dust and scattered clouds...typical with a new telescope, and quite frustrating after a week of clear steady night time skies that define the desert southwest!

While I have not yet had a chance to really shake down the telescope at night (other than point it at a few bright targets like Jupiter and the moon last night) I did have an extensive solar session with it this morning.  All in all, it provides exactly the view of the Sun I was expecting- sharp and detailed when used with my Lunt Solar Systems Herschel Prism.  I am fortunate to have a TEC 140 and compared to that telescope, the SV 90T definitely shows slight color on the limb of the Sun.  There is a very thin blue-green ring along the limb of the Sun, regardless of eyepiece used.  It is not in any way obtrusive and had I not been looking specifically for this color, I may not have noticed it.

Below is a sketch I made of the Sun, completed at 1631 UT 3.17.2013.  Although hard to note in my scan of my sketch, the 90T revealed very fine detail in spot regions, brighter facula surrounding regions near the limb, as well as hinting at granulaton in moments of very steady seeing.

So far, I am quite pleased with this small refractor.  It is light weight and delivers all the detail I expected given the 90mm aperture.  Below you can see my initial attempt at piggybacking my Lunt 60mm HA solar telescope on the SV90T.  It is likely not my final piggyback solution, but it was an exceptional experience being able to go back and forth between images.  Together, these telescopes and required accessories weigh  less than 20 lbs, and likely closer to 15.

No comments:

Post a Comment