A lovely night in Norfolk

[F15Rules]

I'm spending the Bank Holiday in south Norfolk with my wife and our Dobermann, Kobi. My sister in law is on holiday in France for the month and kindly invited us to stay at her barn in a rural area while she is away, as long as we feed the chickens..

We've been here since Friday but tonight is the first night we've had a really clear sky, with a lovely sunset and very few clouds. The only downside is the heavy dew, more on that in a bit.

I bought with me my "portable" set up, consisting of my recently acquired Vixen ED103s F7.7 refractor. I have it mounted on a CG4 mount and stainless steel tripod (no motors, just manual slo motions, and with a rough visual alignment to Polaris of the polar axis). The scope itself is secured to the mount with a Takahashi 115mm clamshell (a perfect fit for the Vixen tube which is 115mm diameter), secured to a short dovetail which fits the CG4 head perfectly. It's very solid and damping time is no more than a second or so. I bought with me Tak Hi-LE 3.6mm, LE 7.5mm, Pentax XL 10.5mm, Vixen LVW 13mm and LVW 22mm eyepieces.

My observing list included (not necessarily in this order, but over a 90 minute session):

Moon, Saturn, Double Cluster in Perseus, Vega, M57, M13 and M92 (Hercules), Gamma Arietis, Pleiades, Delta Cygni.

This was my first proper session with the Vixen, which is optically identical to a previous one that I owned until earlier this year. The only difference is that this one has a single speed R&P focuser, not the dual one: the focuser is actually a good bit smoother on this Vixen than my last one, but they can be improved by adjusting the tiny grub screws.

To offset the single speed only R&P, I use a Baader T2 32mm prism with helical fine focuser giving 5mm of travel at approx a 10x reduction, rather like a dual speed in effect: it works really well.

As the evening looked as though it should be clear, I got the scope out early and let it stand for a good couple of hours outside while we watched a movie. We did (my wife joined me) get a quick look at both Luna and Saturn while it was dusk, at around 8.40pm. The moon was very sharp, and quite steady until I upped the power to x220 to show my wife the detail along the terminator: at that point it was a little more shimmering, but very watchable, and I could detect no CA at all. Saturn looked excellent, especially given it's low altitude, and the Cassini Division was very clearly seen at x220 as well, with one band across the main globe also visible. My wife was tickled when I told her that the faint star above Saturn at about 1 o'clock was Titan, a moon larger than our own moon.

When I came out for my main session after the movie, my first view was disappointing, given that the Milky Way was very prominent overhead, with real structure, and with, for instance, the Coal Sack in Cygnus very evident. I soon realised that the objective, which I had left uncovered for the time the scope was outside, was very heavily dewed up. I tried wiping it carefully with a lens cloth, but it only marginally helped: some of the condensation was on the inner side of the lens, so I took the lens cell off and gently inside the barn used a hair dryer to get rid of the condensation. I then replaced it on the tube and thankfully I wasn't bothered too much again.

It was great to see the double cluster again, and the little semi circlet of stars in one of the two cluster cores was very well defined at both low and higher powers. In the LVW 22mm the wider view was just lovely. I turned to the twin globulars in Hercules, the M13 showcase and also M92, which is much underrated in my view: both were resolved at the edges very well, with a smattering of mag 11 or fainter stars right across the field of view.

Next was Gamma Arietis, a lovely twin double star, like a pair of mini headlights. The Pleiades were rising nicely in the east now, and so I had a quick view at low power, just about getting the whole of the main cluster into the view.

I then went over to Lyra and had a wonderful view of Vega, pure scintillating white, no CA at all, and a clear view of it's optical double at 1 o'clock orientation, at magnitude 10 - not easy to see due to the sheer brightness of Vega itself, but very evident nevertheless.

I then went to M57 and found, as ever, that it responds well to high magnification: in particular I was delighted, for the first time for me, to glimpse the nearby mag 13 star at c1 o'clock, and John's earlier map from his session tonight confirmed for me the position of this star. I think the local very good dark conditions made this possible, but for a 4" glass I was well pleased. The Ring itself was very well defined with a clearly darker centre to the doughnut shape.

Finally I couldn't resist Delta Cygni: not always easy for smaller fracs, but tonight at x 220 with the Tak 3.6mm the view was beautiful. The secondary star was right on the first diffraction ring of the primary, and very steady indeed. Lovely!

All in all, I came in feeling so pleased, both with the sky conditions, and with the performance of this great little scope. It really does match my Tak FS128 so well, and I look forward to comparing the two in the coming dark autumn and winter skies back at home in Lincolnshire.

Clear skies to you all 

 

Dave

[John]

Great report Dave

The Vixen 103 sounds like a really, really nice refractor and a worthy companion for the FS 128

 

[Cjg]

Norfolk skies rock, just back from a superb night at Seething Observator, very pleased with tonight.

Chris

[nightfisher]

Nice one Dave, glad the Vixen is a strong performer, Saturday night was clear here and i wanted to luna image but had a housefull so did not set up, also moon was low 

[Stu]

Nicely detailed report Dave, a great night and I'm glad you have been reunited with a Vixen 103S  

[Mark at Beaufort]

Enjoyable report to read Dave. Its these moments when I wish I still had my 4" ED frac.

[MarsG76]

Nice report... I'm just wondering if a hair dryer on optics is a good idea... wouldn't that sort of negate the cooling to ambient routine?

 

[F15Rules]

52 minutes ago, MarsG76 said:

Nice report... I'm just wondering if a hair dryer on optics is a good idea... wouldn't that sort of negate the cooling to ambient routine?

 

It's a fair point..I used the dryer very gently on its lowest warm setting, and I dried both sides of the cell as well as the glass..the dew was very heavy so it was either that or end the session before it started.

My note to self is not to uncover the objective next time until I am ready to start observing.

I did wonder if the lens would simply condense up again but it didn't, maybe as I was only out for about another 75 minutes. But I did take care to use very low heat and make sure the lens cell was also gently heated and therefore dried too.

For the first time with a frac I'm thinking whether I should get a dew heater and/or make a longer dewshield for such nights; but I've never left the lens exposed before a session for that long so maybe that's the main lesson for me.

Dave

[David Levi]

I recently bought a 12V hairdryer for dew control but haven't had cause to use it yet. It draws 18A and so I connect it directly to the battery terminals rather than the cigarette lighter socket. The reviews of the hair dryer were terrible i.e. poor heat for drying hair but perfect for optics. It's like a gentle warm breeze. As you say better than packing up.

By the way - nice painting. Reminded me of Frida Kahlo.

[F15Rules]

1 hour ago, David Levi said:

I recently bought a 12V hairdryer for dew control but haven't had cause to use it yet. It draws 18A and so I connect it directly to the battery terminals rather than the cigarette lighter socket. The reviews of the hair dryer were terrible i.e. poor heat for drying hair but perfect for optics. It's like a gentle warm breeze. As you say better than packing up.

By the way - nice painting. Reminded me of Frida Kahlo.

Hi David,

Thanks. The artist is my sister in law, Nicola Slattery. She was elected to the RBA a few years ago and is quite well regarded with her particular style.

The painting in the picture is almost finished now but I don't know much more than that I'm afraid.

Dave

[John]

When I use my ED120 for outreach sessions the site is more prone to dewing than my back garden. I find a simple extension to the dew shield of around 6-8 inches does the trick. I use a commercial dew shield for this (Astro Engineering) but practically any flexible material could be used.

[MarsG76]

17 hours ago, F15Rules said:

It's a fair point..I used the dryer very gently on its lowest warm setting, and I dried both sides of the cell as well as the glass..the dew was very heavy so it was either that or end the session before it started.

My note to self is not to uncover the objective next time until I am ready to start observing.

I did wonder if the lens would simply condense up again but it didn't, maybe as I was only out for about another 75 minutes. But I did take care to use very low heat and make sure the lens cell was also gently heated and therefore dried too.

For the first time with a frac I'm thinking whether I should get a dew heater and/or make a longer dewshield for such nights; but I've never left the lens exposed before a session for that long so maybe that's the main lesson for me.

Dave

Nice scope... 

I guess with the heater I would opt to do the same rather than end the session.

 

A longer dew shield, in my experience, only slightly extends the time before the objective get covered in dew. Basically dew is still falling and settles on a piece of glass that is pointing up, or nearly up. The only solution that I found to completely solve the dew problem was a veriable dew heater kit. I use AstroZap, and since installing it I have never had a problem with dew again.

[MarsG76]

BTW, nice security for the scope...the Rotty Protection.

[Moon Watcher]

Very nice report mate!  In the US, where I live at the moment (Wisconsin) the skies have just been dreadful.  Did you have to recollimate the lens cell once you removed and then replaced it?  

[Special K]

Great report and I'm impressed with your quick reassembly time and getting back on the task at hand!  Dew can be a killer. My cool down position is to point the lens toward the ground to allow heat in the tube to rise and escape through the diagonal, also pointed away from falling dew.  

[alan potts]

Very nice report, I have only been the once but I really liked Norfolk.

[F15Rules]

8 hours ago, MarsG76 said:

BTW, nice security for the scope...the Rotty Protection.

Thanks..he's a Dobermann actually ??..he's a good old boy.

 

7 hours ago, Moon Watcher said:

Very nice report mate!  In the US, where I live at the moment (Wisconsin) the skies have just been dreadful.  Did you have to recollimate the lens cell once you removed and then replaced it?  

No, the entire cell assembly unscrews from the tube so the elements weren't disturbed at all. The lens cell, as in my FS128, is non collimateable, so it's fixed at the factory.

 

6 hours ago, Special K said:

Great report and I'm impressed with your quick reassembly time and getting back on the task at hand!  Dew can be a killer. My cool down position is to point the lens toward the ground to allow heat in the tube to rise and escape through the diagonal, also pointed away from falling dew.  

That's very kind, thanks!

I normally do all these things, but I think, because the two previous nights had been disappointing, ie looking clear early on, then clouding over, I got the scope outside too early as the forecast for once almost guaranteed it would be clear!?.

6 hours ago, alan potts said:

Very nice report, I have only been the once but I really liked Norfolk.

Thanks Alan. Yes, Norfolk is very nice, especially the North coast and the Waveney Valley in the south-where we were)..?

[MarsG76]

On 29 August 2017 at 21:18, F15Rules said:

Thanks..he's a Dobermann actually ??..he's a good old boy.

Of course, he's not as bulky as a Rotty.... Top dogs...  I miss my Dobys, I had 2 growing up.