Sunday 17th Session

[Nightspore]

The BBC Weather app reckoned it would be crystal clear from around 21:00 to 03:00 GMT. I was highly apprehensive of this claim, but the radar map seemed to substantiate that there would be no cloud even after 20:00. I had the ED80 set up on the AZ5 mount well before 9pm but there was hardly anything to see because of a thick blanket of cloud. However, there was a bit of wind coming from the south west and seemed to be breaking up the cloud layer. So I waited.

 

 

Nearly an hour later and the bright Moon made an appearance. I could see it fleetingly earlier but now there was more of a chance. With a modified William Optics Amici prism diagonal, a Baader Single Polarising filter, and a 7.5mm Plossl I got an 80x magnification. To my surprise the image was pretty sharp and clear. I think the seeing was near a good Antoniadi ‘I’ but the transparency was below average. The occasional breeze did slightly move the OTA but this and the transparency didn’t affect lunar viewing that much though. Eventually I was able to raise the magnifications to 100x, 120x and even 160x for a while. 

About the same time exactly a month ago (on my birthday) I went out with the ED72 to have a look at the Moon (I knew the terminator was nicely placed near Schroter’s Valley) as it was unseasonably warm. I can’t remember going outside with a telescope on my birthday before as it’s usually too cold or snowing or something. Oddly, it was cooler yesterday than in February! This time the terminator was virtually running right through Schroter’s Valley and the bottom of Aristarchus was too dark to really see anything. The Montes Harbinger were quite dramatically realised by their shadows and the ghost crater of Prinz was easily seen. Herschel and the Bay of Rainbows were very nicely illuminated. Other highlights were Gassendi and the Sea of Moisture.

At about 23:00 the clouds had abated enough to try some rich field observing. I could see Cassiopeia and Ursa Major fairly clearly, but Virgo, Leo, Cancer and Gemini were hazy, the Moon being in Cancer didn’t exactly help. After observing Taurus and the Pleiades I moved to Cassiopeia. Carolines’s Rose, the Owl Cluster, NGC 663, M103, and other clusters were good at about 19x with a Baader 31mm Hyperion Aspheric in a 2” Sky-Watcher dielectric diagonal. Mel 20, St 2 and the Perseus Double Cluster were also very nice. 

I decided to test my 32mm GSO Kellner for a while. These Kellners are not particularly expensive and don’t have a very good reputation in fast scopes. The eyepiece itself is quite light though and I wanted to see how it fared in an f/7.5 refractor. It produces a fair amount of off-axis astigmatism in my ED72 and is virtually unusable. The GSO (possibly a modified or reversed Kellner) has an FOV of 56º and I make the field stop to be 35mm. I’ve also swapped the drawtube, which originally featured an undercut, with a smooth tube from a GSO Barlow. The first thing I noticed viewing the Perseus Double Cluster sequentially with both eyepieces was how much brighter the Baader was. This surprised me to be honest as I believe both eyepieces only have three lenses in two groups. The larger FOV of the Baader was also apparent of course. I didn’t have enough time to really put the GSO through its paces but from what I can see at least 45º of the FOV is relatively undistorted. I’ll have to experiment more at a later date. I doubt it will replace the Aspheric any time soon!

 

As the clouds were starting to reappear I switched back to the 1.25” diagonal and a 15mm Celestron Luminos for 40x and a 2mm exit pupil. Finally, spending the last quarter of an hour on the Moon with a 10mm Vixen NPL and a 2x Barlow for 120x.

[newtyng5]

Nice session you had there Nightspore. And an interesting write up. Let's hope for more clear skies (after the full moon)

[BAZ]

You had a productive session there, and a great report too, many thanks.

[Doc]

A very pleasent read Nightspore, I was also out, had an hour looking at the moon.

[+Streetbob]

I enjoyed your report.  Thanks

[Nightspore]

9 hours ago, newtyng5 said:

Nice session you had there Nightspore. And an interesting write up. Let's hope for more clear skies (after the full moon)

Thanks. I'm sure there will be clear skies soon. It's spring lol. Time for the ST102 in a Moonless sky.

 

[Nightspore]

6 hours ago, BAZ said:

You had a productive session there, and a great report too, many thanks.

Thanks and you're welcome. There were slightly more clouds than I needed lol.

[Nightspore]

2 hours ago, Doc said:

A very pleasent read Nightspore, I was also out, had an hour looking at the moon.

I'm glad you enjoyed it. I like the ED80 for the Moon as I don't have to worry about CA. I normally just use a single polarising filter, sometimes an ND.

 

[Nightspore]

20 minutes ago, Streetbob said:

I enjoyed your report.  Thanks

Thanks, and you're welcome.