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27/09/2021 Circumpolar Sky and Cas, plus other earlier activities...



Three whole weeks since the last proper session due to holidays, offspring and clouds!

Managed to get out sometime a few weeks ago to test this:


It's a 130mm F7 newt built with an SvBony metal focuser, some mirrors from Astroboot, a plastic duct pipe and some 3D printed adapters hot glued in.  I've already got a 130mm F5 newt but I wanted to be able to understand the difference that a smaller primary obstruction and a longer focal length makes to viewing, particularly with regard to planets.  I printed the above very dodgy tube rings and dovetail to take advantage of the last clear day we had a few weeks ago and mounted  it on my AZGTI where it swayed, precariously:


I managed about 15 minutes with it on Jupiter to check it was all OK after collimation and could easily see bands etc and plenty of contrast, approaching what I get with the 10 inch dob even with the mount wobbling about so very promising! I'll build it into a dob mount I think as it's pretty heavy and this is supposed to be a budget project...

I also tried my ST80 on a terrestrial target while on hols and was amazed by how little magnification you can get away with:


In the distance out to sea behind the small human experiencing the beach for the first time is a ship called the Sea Puma:


It was 8.4 Nautical miles away and I could clearly read the name on the bows with 50x magnification, but contrast was very low because of the 15.5Km of soup I was looking  through. - it was looking through fog!

And on to last night!

Got the 10inch dob out about 2200 and let it cool for 30 mins - temperature was around 10 degrees C and it was quite windy - wore the winter coat! 

Started with Polaris to check seeing and collimation - 'scope was fine, sky looked transparent but quite turbulent.  I decided to take advantage of the time before the moon rose above the trees to look at Andromeda as it's the first time it's cleared the trees since I've had the dob!

The core of Andromeda was VERY bright (24mm UFF so 50x) and M32 was also clearly visible (see bad sketch!) but I couldn't find M110. I wasn't sure whether I could see some Andromeda structure or whether it was the moon lighting up the sky around the core (more likely looking at photos after the fact - M32 is very central) .


Next on to the Circumpolar sky :- I tried to spot NGC188 as recommended by Turn Left at Orion but I think the sky was too bright as the moon was looming. I decided to spot some doubles:

Pi1 UMi (HR5829):

Mental note - when planning these jaunts always look up the targets before the session to get them in a format that SkySafari and I understand so I have a chance of finding them... I still find comparing the diagrams in the book in the dark to the view in the finder very hard so the steer from SS is hugely helpful. I have to state that this is me, not the diagrams - once I'm oriented and have found the target they suddenly make sense!

Wide clear vertical white/yellow double - obvious even at 50x

Struve 1694:

Book says white/white but I see more Blue/while horizontal double. Easily found star hopping. I wonder if my red light is messing up my colour perception - it is too bright?

Herschel 2682:

Favourite "double" of the night - a lovely symmetrical slightly squashed triangle - one white, one dimmer blue, one dim blue (looked red to me at first - WHY?)

Apparently they are not gravitationally bound...

On to Cassiopeia - I love this region of the sky - so rich in sights!


Initially sparse but very rewarding roughly triangular open cluster near Ruchbah - very nice at 50x magnification. I'm not normally a particular fan of open clusters but this is very pretty - The brighter half dozen odd stars are of visibly different colours and more dimmer ones pop out the longer you look.

Stock 2 Open Cluster:

This is a HUGE open cluster in Cas. I was packing the wrong telescope really - I could have done with the ST80 or even just binoculars. The views were almost better in the finder!  I need to compile a list of targets for the ST80 for one night...


First view of the season as it cleared the trees. Another ST80 target really.  Last year I was sure I could spot nebulosity in between the stars - not this time but that may have been due to the moon...

Packed up at 0030 as cloud started coming in....

Closing notes:

Swapping between the 24mm UFF and the Seben 24-8mm zoom really shows up the off axis sharpness of the UFF. I really need to replace the Seben (was great terrestrially though!) but with what? A zoom or fixed focal length eyepieces?





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