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Autumn Sessions

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In 2020 I achieved one hundred and three observing sessions in total. Twenty five were with my Sky-Watcher 72ED DS Pro Evostar. I purchased the Evostar three Septembers ago ostensibly to replace my modified 80mm StarTravel grab and go scope. The 72ED is well balanced, compact, lightweight, and a very easy scope to set-up with my physical disability. Especially combined with a light alt-az mount and tripod. As a consequence it gets out a lot. Although it has an eight millimetre smaller aperture than the ST80 it contains an ED element making it a better and more versatile all-rounder. I now tend to use it predominantly with 1.25” accessories as it is then very well balanced on a Sky-Watcher AZ5 Deluxe mount/tripod.




On the twentieth of September 2021 I carefully cleaned the 72ED objective with some Baader Wonder Fluid and a microfibre cloth and prepared to take it out for its thirty seventh session this year. Coincidentally this would also be the hundredth session in total for 2021. I was set-up by 20:00 specifically to evade a 99.7% illuminated ‘Harvest Moon’ rising rapidly in Aquarius. Seeing was about an Antoniadi II with slightly below average transparency. I decided to use an Orion 7-21mm zoom paired with a Baader 2.25x Hyperion Zoom Barlow as the combination is compact, lightweight, and the element threads perfectly into the Orion EP giving a range between 45x and 135x. This is basically around a 1.6mm to an 0.5mm exit pupil. Realistically, as the FOV is quite narrow at the lowest setting, it gave me a useful range between about 70x to 135x.




I was out earlier than usual and pleasantly surprised to see Arcturus setting in the west. This enabled me to split one of my favourites, the nearby ε Boo (Izar), at 135x. The transparency wasn’t improving and I failed to properly split the ‘BC’ pair of Mu Bootis (Alkalurops). Cor Caroli and Mizar were easier. I managed M57 in Lyra at about 70x and split the Double Double and several other Summer Triangle doubles at various magnifications. Later I used a 19mm Tele Vue Panoptic to see M27 and as many open clusters as I could before the Moon became too high. I switched back to the zoom/Barlow combo to view the start of an Io transit and then observe the tiny blue disc of Neptune. I knew the rough location of Neptune in relation to the now quite apparent Harvest Moon which made it easier to find.




I got another session on the twenty first and was set-up around 20:30. This time I managed to split the BC pair of Alkalurops at 135x with the Orion zoom. I could just about make out the individual stars in the pair so I decided to up the magnification to 175x with a 2x Barlow and a 4.8mm orthoscopic. Unfortunately by the time I’d swapped eyepieces conditions had deteriorated and I couldn’t re-acquire the target. However, I did get a very nice view of Iota Cassiopeiae at both 175x and 135x. The Harvest Moon was now in full swing at 99% illumination and I decided to turn back to Jupiter to witness a Europa occultation.




On the evening of the Autumnal Equinox I set-up a bit later at around 21:00. I managed to split Izar again but the transparency was degenerating and I couldn't even find Mu Bootis. The seeing seemed better than the previous couple of nights enabling me to get a sharp 135x on both Saturn and Jupiter. I was so impressed by the drier and less humid conditions that I even tried several filters including a Lumicon Wratten #82A, a Baader Contrast Booster, and a Baader Light Blue 470nm. I’ve always found that light blue filters help reveal detail on Jupiter with smaller aperture refractors.




I switched from the Orion zoom to a Takahashi 6mm orthoscopic in a Tele Vue 2x Barlow believing I might get even better surface detail definition. The biggest surprise was that as far as I could tell there was no discernible difference in surface detail between the Takahasi ortho’ and the Orion zoom. I’ve sung the praises of the Orion 7-21mm zoom before, but it really is that good considering it’s not what most people would consider a ‘high end’ zoom eyepiece. It's a distinct possibility that it contains one or more ED elements. Eventually it clouded over and I packed up my equipment and prepared to carry it back indoors. As I stood there, carrying both the tripod case and the bag containing the 72ED, the clouds suddenly parted and the effulgent Moon was resplendently revealed in the east.




I had originally wanted to observe the Petavius rille and had taken an ‘Omegon’ (Long Perng XP-H) Amici diagonal out with me specifically for this. The Omegon is lighter than the Baader Zeiss specification prism I usually use for dedicated lunar viewing. It may not be quite as good as the Baader but it’s perfectly fine for occasional lunar viewing.




There is often only a small window every month that enables the terminator to be in the right place to properly reveal the rille. I hastily set-up and used the Amici prism instead of the dielectric diagonal. Mission accomplished, I packed up again.




I got the little Evostar out for two more nights in a row. Making Friday night the 104th session and so exceeding the total amount of sessions for the previous year. To date the 72ED has now been out for sixteen more sessions than in 2020. I think that’s pretty good value for a telescope that cost less than some of the eyepieces that I own.


Astronomical images by courtesy of Photoshop Elements 2021, SkySafari 6 Pro and Moon Atlas

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