Jump to content

Banner.jpg.b89429c566825f6ab32bcafbada449c9.jpg

Doubles at twilight


Nik271

Recommended Posts

I couldn't stay late last night, so decided to try some difficult bright doubles in twilight. I brought out the Skymax 180 from the (now overheated) shed and let it cool for a couple of hours outside. I decided to go all the way to high powers, so used only two EPs, one 15mm giving reasonable 180x and the other at 6mm providing crazy x450. 

Venus was looking great naked eye just after sunset in the north west. Had a quick scan for Mecury with the 10x50s but no luck, it's too dim and too low now.

So back to business at 10pm. It was quite light but Arcturus was easily visible high in the south and from it I jumped to Izar with the finder.

At 180x Izar was an easy split, the diffraction rings well separated into orange /blue circles. Seeing looked good, so jumped straight to Zeta Herculis, didn't even bother with 15mm and went straight to 6mm. Hmmm, a bit of mess, there must be some thermals in the part of the sky, or perhaps 450x is just too much tonight?

I decided to test a different part of the sky and went for an 'easy' one, the Double Double in Lyra. Wow, at 450x the 4 stars just about fit in the field of view. The diffraction rings were perfect this time and there were big gaps of dark space between the close pairs. So... seeing is good, it's just thermals after sunset.

It was time to be reckless so off to Dubhe. This is a very difficult one which I have never seen. The separation is the best in decades, but still only .8'' so not for the fainthearted.

Well, today was not the day, the first diffraction ring was shape-shifting all the time, maybe there was a faint bump to the north for some moments but I'm not sure. To be tried again in the future.

By this time it was 11pm and Zeta Herc was higher so I gave it another try. I have seen it before so knew exactly where to look. This time the seeing was quite a bit better and the little companion resolved itself just east of the first diffraction ring of the primary.  I decided to quit while I'm still winning and packed up. 

A pleasant hour, nice to be observing without hat gloves and jacket :) 

  • Like 7
Link to comment
Share on other sites

Nice report Nik . I often wonder what i can observe between the hour of sunset and the beginning of darkness at this time of year . Venus for me is a 20 minute window which hasn't been that successful so far , mainly due to the seeing conditions at its low(ish) altitude . Of course,  with work priorities observing time seems to be ridiculously short, very frustrating  . Doubles are a great target . 

  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.