Planets, doubles and the ISS

[RobertI]

I went to the local park last night last for a brief session with my grab and go set up (Megrez 72mm on a Horizon photo tripod). I took along two eyepieces; a 5mm BST giving mag of x86 and a Seben zoom giving a range from x54 to x18. Conditions were slightly hazy with fairly good seeing but a brightish sky due to the time of year.

First up was Mars. At a mag of x54, around three dark surface features were visible. Although it was low on the horizon the view was pretty steady and I wish I had bought the C8 but I really did not have the time to let it cool down (or warm up in the current heatwave!) before venturing out. Increasing the magnification did not reveal any more detail so I tried a blue filter; this turned Mars pale white and I felt helped the surface features stand out a bit more. A surprisingly good result.

I also had a quick look at Saturn which was very low. The cassini division could be glimpsed in the rings during moments of steadiness but no definite surface detail was visible. Always a beautiful sight though.

On to some doubles. 

I started with Izar but was disappointed to find I was unable to resolve the 3" gap with any of the eyepieces. To check what the scope was capable of on the night I tried the 'double double' of Epsilon 1 and Epsilon 2 Lyrae, at 2.3" and 2.4" separation respectively. To my surprise I found I could (eventually) resolve Epsilon 2 at higher mags, with a tiny but discernible gap, but not Epsilon 1 for some reason. So in theory the 3" gap of Izar should have been resolvable, and I failed for some other reason, possibly because the relatively large difference in brightness between Izar and its companion meant that much higher magnification is required (I can feel a barlow coming on). Any thoughts on this welcome. The zoom was a new experience and it was fun too zoom out and see when the split was no longer discernable.

Some other doubles seen:

• Mu Bootes was a very wide double with a distinct colour difference, the primary seeming yellow and the fainter secondary seeming bluer.
• Zeta Corona Borelias was a pretty double which was easy to split at the lowest powers. Comprising two stars of similar magnitude the brighter of the two was clearly bluer and and the pair made a nice contrast.
• Cor Caroli was an easy pair comprising a bluey white primary and a redder secondary.
• Alberio was a beautiful sight as always with an orange primary and green (to my eyes) secondary. The colours were less marked at lower power but became more obvious as the magnification was increased and the background sky darkened.

I found star colours quite difficult to determine in many cases unless it was orange or red. Quite clearly there was a colour difference when seeing two companions side by side, but was it blue or green? Or grey?! Defocusing helped a bit.

Halfway through the session, the ISS flew across from West to East. On the spur of the moment I thought I would train the scope on it and try and see if I could discern a shape. To my amazement I homed straight in and managed to track it, and although  somewhat jiggly on the FOV, I could very clearly make out its shape. I tracked it across much of the sky which probably amounted to around 45 seconds. An unforgettable experience!

I thought I would finish off the session with with some deep sky objects. 

M13 was a welcome return to the skies for me. I found that at x54 the outer edges were just resolved but there was no improvement with higher power.

M51 was clearly visible as two smudges of different size. The zoom clearly demonstrated how changing the magnification affects the contrast between the sky and the object. At lowest zoom the sky was too bright to really see M51 but zooming in the sky became darker and the object started to appear. Somewhere around x40 the galaxy was at its brightest before fading again as it increased in size. 

Surprisingly M101, which is an an object I have struggled to find even on the darkest winter nights, was clearly visible at low power.

A very enjoyable, eventful and educational night's observing. And I was very impressed with the performance of the Seben zoom give its price. 

 

 

[mapstar]

Nice report. Some craking objects and nice details.

 The ISS in a scope is difficult to do but a great challenge

[Piero]

Very nice report Robert. Saturn is really beautiful in these days

[laudropb]

Very nice report.

[chiltonstar]

Nice! Saturn always amazes, and double are a good target in Summer with the rather short nights.

Chris

[cotterless45]

Nice report, I often use the double double as a tester of seeing and collimation. Last night I got down to a 1.3" split in Ophuichus, some nights I can get 1.1", but with a 150 frac. It's very dependant on seeing, which due to the jet stream hasn't been great.

Nick.

[RobertI]

Thanks Nick. Is it normal to be able to split one but not the other, as they are so similar in brightness and separation?

[Stu]

16 minutes ago, RobertI said:

Thanks Nick. Is it normal to be able to split one but not the other, as they are so similar in brightness and separation?

One of the pairs is slightly tighter and the secondary is a little dimmer at mag 6 so yes, there is a difference between the two pairs.

[RobertI]

13 minutes ago, Stu said:

One of the pairs is slightly tighter and the secondary is a little dimmer at mag 6 so yes, there is a difference between the two pairs.

Thanks Stu.

[alan potts]

A very nice report on some lovely targets, well done Rob.

Alan

[RobertI]

Puzzled by the fact that I was only able to split one of double double pairs with my 72mm frac (see original post above), I tried agian last night. Conditions were moonlit and Lrya was close to the rooftops, and i was observing from a light polluted drive, so in theory conditions were worse. But with a 5mm ep giving approx x85 mag, both pairs were easy to split, with beautiful little diffraction rings and a discernable gap between both pairs. I also tried with my 66mm frac, which gave even more perfect diffraction ringsand pinpoint stars, but the split was noticably more difficult - surprising what a difference 6mm decrease in aperture and a slighly lower magnification can make. So I am assuming last night had better seeing conditions and that was the key?