Observations of IOTA LEO

These are the observations available for IOTA LEO. If you have any of your own that you'd like to submit we'd love to put them on the website.

• A Superb Session!

  Clearing skies from the north meant that by 8.45pm it was totally clear and with the 92% moon rising just after 10pm there was a potential 2 hour window. The skies looked clear and dew free. So the OMC 200 was wheeled out for the session.

  I was looking forward to Iota Leo (STF 1536) because of the difficult challenge to separate the two components, (mag 4 and mag 6.7, sep 2.1). At my last attempt in April 2016 I was unable to split the pair. Also I was keen to check out any hints of colour.

  I synced the scope on Regulus (always a fine sight with its fainter companion) and then headed to Iota, even though it was not dark (8.40pm).

  At x167, Iota was clearly a pale yellow and as it danced in the centre of the fov, it had that feel that it must be a double. There was a repeating hint of elongation to the shimmering, sparkling star. Going to x220, the yellow colour was still obvious and in the moments of steadiness there was the tiny speck of component B sitting on the first diffraction ring. At x320 I confirmed my sighting of B. Using x400 I could see B most of the time.

  Having met the challenge all that was left was to confirm component C, no problem to spot this mag 11 star. I then just enjoyed the view and before I knew it 40 minutes had passed since I first sighted Iota. A delightful way to spend the time under the stars.

  

  More for a laugh rather than with any seriousness I wondered if the Galaxy of the Month (NGC2964) might be visible in the OMC 200, noting that Owen had chosen a pair of brighter galaxies. So I sent the scope to Castor (glorious double) to sync on it and to get the equatorial flip out of the way and then headed over to NGC2964.

  Noting that Owen had chosen a Herschel Galaxy, I thought NGC 2964 should just be doable. As soon as I looked through the e/p (x167), there it was. A definite oval shape and quite large. Then NGC2968 popped into view. I increased the magnification to x200. Both were easily held in view with a steady gaze. In fact as I settled into the view I kept getting hints of brightness within NGC2964 with the brightest part being towards the western end of the oval. NGC2968 was smaller and lacked any hint of a core.

  The reason locating this pair of galaxies so easily was quite simple. The sky was quite transparent for GB skies. There was none of the dreaded clag or dew. Around 9.30pm (BST) I was able to see direct mag 5.6 stars at the Zenith in the 4 minutes of true astro dark.

  With the moon still out of the way I then pondered Owen’s reference In terms of visibility Harrington in his book Cosmic Challenge suggests all three galaxies may be the range of a 20cm (8”) telescope. Two mag 13+ stars were visible near to NGC2964 so I decided to try for NGC2970.

  The obvious mag 11.7 star to the North of NGC2968 was a useful reference point and to my surprise I could see the mag 13.7 to the east of NGC2968 and then also the mag 14+ star came into view. With these 3 stars identified I stared intently, gently moving the scope to maximise my AV. Yep, there was NGC2970 – not exactly screaming at me but every now and then a small, faint fuzz kept appearing in exactly the right place.

  

  Absolutely no way could I have seen it on a typical claggy, mag 5.4 night. Wow, what a privilege to locate it in the OMC. I now wished I had the Dob out and ready.

  With the moon beginning to lighten the SE sky should I go for doubles? I then remembered that there are comets in our sky...

  Mike Wood - 14 April 2017

• Iota Leonis at Haw Wood

  Thought I should mention my observation of this iota Leonis at the Haw Wood star party a couple of weeks ago.

  As usual I’d taken my 24” Dobsonian but also my little 5” Russian Mak-Cass (F10, 34% obstruction) as a back-up. On one night it was very claggy so decided to observe some doubles with the 5” Mak (should add a Vixen Sphinx mount was used so overkill for this scope and very steady.)

  Leo was on the meridian when I thought I’d have a look at iota. From memory I knew it was a tight binary and thought it would be about 2” separation now as I knew it was widening but for some reason I thought both components were fairly equal, I had forgotten there was quite a magnitude difference.

  At x100 nothing so I put the power up to x180 and still nothing (I was of course looking for two fairly equal discs almost touching.) I decided I must somehow be on the wrong star. I was moving my eye away from the eyepiece when I just caught a glimpse of a faint spec and suddenly began to suspect my error. I put the power up to x254 which the little scope took well (it has excellent 1/9th wave optics) and sure enough a faint speck just beyond the edge of the first diffraction ring.

  I crudely estimated the PA to be about 90 degrees. Checking later I gather it’s currently 94 degs PA and 2.15” separation with components of m4, m6.7. So I was quite chuffed at this little scope pulling that one out of the bag. (N.B. I’ve since looked at it with my OMC 200 and it was very easy in that scope.)

  Andrew Robertson - 10 April 2017