Five Doubles In Aquarius

[cloudsweeper]

Saturday, 4.40pm, 8SE ready. Jupiter low, west of south – Galilean moons nicely lined up on the same side.  Aligned on him, and GoTo put me very close for all targets.

I wanted to try for some 1.3” doubles, and went for D20 Aql, but going up to x254 didn’t crack it, and the star images were getting very fuzzy.  This seems to be an issue with the SCT.  The Dob is better (managed a 1” split last month), but fracs certainly win in this regard.

So – on to some wider-spaced doubles in Aquarius.

Σ2913 – 8.6” – close match, secondary at 11 o’clock, close but clear split at x56.

Σ2944 – 1.9” – another close match, separated at x185, secondary at 2 o’clock, although the images were getting a bit blurry by then.

Σ2862 – 2.5” - yet another close match – raising the mag in stages (as usual) to x135 I got the split – very close in the EP, secondary at 9 o’clock.

Σ2936 – 4.2” – mismatched pair – going from x56 to x102 gave the split, with the fainter companion at 2 o’clock.  At x116, the pair were clearer, still sharp, and made a most pleasing and close apparition.  The nicest view of the session.

55Aqr – triple, visual double - 2.3” - a bright and very closely matched pair – got the split at x185, just separating the stars from each other’s glare in moments of good seeing, one beneath the other in the EP.

A good session, lasting 1.5hours, and using 11 EPs.  (I like using small steps to improve the view, and keep below fuzziness.)

Doug.

[chiltonstar]

Good to see someone has seen the night sky recently.......... nowt but permacloud here.

Chris

[Mr Spock]

A nice session. I'm hoping to explore the Aquarius/Pisces/Pegasus region when my mount arrives. There are lots of interesting doubles in that area and it's a lot less crowded with stars than Cygnus.

[chiltonstar]

15 minutes ago, cloudsweeper said:

Saturday, 4.40pm, 8SE ready. Jupiter low, west of south – Galilean moons nicely lined up on the same side.  Aligned on him, and GoTo put me very close for all targets.

I wanted to try for some 1.3” doubles, and went for D20 Aql, but going up to x254 didn’t crack it, and the star images were getting very fuzzy.  This seems to be an issue with the SCT.  The Dob is better (managed a 1” split last month), but fracs certainly win in this regard.

 

Doug.

Collimation? The 8SE should surely manage 1.3 arcsec.

Chris

[cloudsweeper]

2 minutes ago, chiltonstar said:

Collimation? The 8SE should surely manage 1.3 arcsec.

Chris

Yes Chris - in principle, the 8SE should manage something in the region of say 0.8" under good conditions, but although I checked the collimation not long ago, it has always given "softer" star images as mag increases.  I shall check it again, to make sure!

Doug.

[RobertI]

Nice haul and nice report. My experience of using my SCT for doubles has been similar to yours, I generally go to my refractors or newts for splitting really tight doubles. The C8 is a great DSO and planetary scope though. Well done on getting out under some clear skies. 👍

[Nik271]

10 minutes ago, cloudsweeper said:

Yes Chris - in principle, the 8SE should manage something in the region of say 0.8" under good conditions, but although I checked the collimation not long ago, it has always given "softer" star images as mag increases.  I shall check it again, to make sure!

Doug.

Most likely it was the seeing that was the limiting factor. For doubles below 2-3'' of separation the atmosphere is a major player. I had a brief window of partially clear sky yesterday and I looked at Mars but the seeing was moderate to poor, so didn't bother with high powers. The stars were twinkling a lot. I think I've had only a couple of clear spells in the past 2 months and even then the seeing was poor

At least I had a good view of Uranus in binoculars as a bonus, so happy considering the conditions.

 

Nikolay

 

Edited December 6, 2020 by Nik271
grammar!

[Mr Spock]

The main factor is seeing conditions - not much you can do about that. But SCTs are critical where collimation is concerned. Even slightly out will cause fuzzy images. On good nights my C925 would split 0.7" with room to spare. Tweak until perfect is the only way to get them performing.

[wookie1965]

Brilliant Doug I'm going to write those down for next time when Aquarius is better placed for me. 

Great Hall of some fine doubles a great read.