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First Light: 20" f3.6 Lukehurst Dobsonian

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First light: 20” f3.6 Lukehurst Dobsonian

Date: 2 April 2017. Time: 2130-0200.

Focal length: Native 1814mm, +Paracorr2 (x1.15) 2120mm, +MarkV (x1.7 Newtonian GPC) 3083mm


Finally, got a real first light last night. The conditions were not ideal with a 40% moon and some high level cloud but they were good enough to get everything setup...

I had already tested the Nexus the previous day and after changing a plus(+) to a minus(–) in the Sky Safari encoder settings had got the push-to system tested out using some false alignments.

First job was to set the Baader Skysurfer 5 up using Polaris. It took quite a large adjustment of the finder to get it centred, there was just enough adjustment available for success. Must be the amount of aperture that necessitated the large adjustment needed?

Anyway, once that was done I connected Sky Safari to the Nexus and aligned on Polaris. I slewed over to Algieba in Leo and centred in the red-dot finder. It was in the FOV so nudged it to the centre and hit the Align in the app.

Now as I move the scope, I can see Sky Safari following me around the sky – great!

Nudging note: It isn’t easy! I know that I will pick this up over a few session but most times I moved it the wrong way only to go “Doh!” and move it the other way. It was much easier to get it right when nudging while watching the IPad screen than nudging while peering through the eyepiece.

Collimation note: The defocus star presented a nice set of rings although brighter stars were flaring around the edges (atmospheric conditions I assume). Collimation with the Glatter laser & Tublug is simple!

As the moon was still too high I moved onto some eyepiece focus checks. The point of the test was to be able to get past the focus point of the eyepiece and not worry about the power/image content.

-          3x Ethos & Paracorr2 = check :)

-          MarkV bino & Pan24, Delos 17.3, Delos 10, Delite 7 = check :)

I have about half inch in-focus remaining with the Binos in use and more than an inch of out-focus with the Ethos/Paracorr2, so I am happy with that!

I found the bino was giving a darker background than the Ethos so I stuck with the Pan24 and binos and moved on to view some galaxies (x128 magnification).

Sky Note: As I am short sighted and view without glasses I see the sky out of focus but I could see that the still thin clouds were thicker than before.


Using the Nexus push-to I nudged my way over to M51 and found it on the edge of FOV when the Nexus was showing it as centred. I could see two bright cores and some dusty circles around the main galaxy. Not bad for a milky moon lit sky and more than I expected.

Sky Safari note: I had read up that Sky Safari keeps the last two alignment points from the push-to and that it’s a good idea to align to something in the area that you are observing so I centred M51 and clicking Align in the app. From that point I found several galaxies in the area and they were reasonably centred in Sky Safari at the same time. So, I am happy with that. I was able to identify several galaxies that I came upon using Sky Safari which is what I had hoped for.


I could see the core and one blotchy area to the side. There was a lot of swirly gas that I see with averted vision. Again, not bad for a moony sky!

M97 owl neb

Easy, nice clear circular patch. I didn’t bother with more mag for the “eyes” as the conditions were not worth it.

NGC4631 whale

Easy, nice long streak of grey dust.

NGC4565 needle

Bright core & long streaks to either side. Streaks were longer with averted.

NGC4244 silver needle

Long faint streak observed.

Cocoon Galaxies

Both galaxies seen. One bigger than the other. Smaller one improved with averted.


Nice bright core and circular surrounding dust.


Core with surrounding dust. Less bright that M94.


Easy, nice squarish shaped galaxy.


Core with surrounding dust disk.


Faint core. Faint dust circle. Averted needed.


Faint galaxy, but a good size.

M13 globular

I viewed M13 with the Ethos10mm and was able to resolve some of the stars. It is quite low and I was not getting full aperture due to the shed walls.

Comet C/2015 V2 Johnson

Easily located with the help of Nexus! In the Ethos21 it was easily seen but pretty small.

Comet 41P/Tuttle-Giacobini-Kresak

Bigger that Johnson but more diffuse. Again, the conditions meant that I wasn’t bothering to change magnifications/eyepieces much!

By now the clouds were thicker still. I could see the main stars and the next level too, but even with the moon nearly gone, the images were not improving so I decided to call it a night.

Due to the position of the scope within the shed, I was unable to point at the moon & Jupiter. I have repositioned it this morning (for next time) based on my experiences. David supplied a set of wheelbarrow handles with the scope which are easy to connect and make shuffling the scope around the shed possible.



1. Very happy that I can reach focus will all my eyepieces & binos :)

2. Nexus is simple to get aligned and without it I would not have found very much to observe! Happy with that too :)

3. Surprised that the larger galaxies were visible (and pretty decent) under the moony sky, wasn’t expecting that but I don’t go out usually until the moon has departed :)


Comments welcome,


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Nice report Alan - good start with the big new scope !

I managed to see quite a few galaxies last night as well last night - better than I had expected.


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Sounds like you had a great night. The scope seems quite capable.

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Great report, and good to be seeing details in galaxies despite the moon.

I am trying not to develop aperture envy.


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Brilliant report some great objects there. ( I must not succumb to aperture fever )

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very nice report with the big scope. M13 will only get better once the wall is knocked down. In my slightly smaller scope it is stunning. Often wish I had gone for the 20 inch which I could have at the time.


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      Thoughts of the observer.
      It was nice to get some use from the Pan35 at last. I seem to robotically load up the 55mm Plossl these days. I did prove on several targets that the extra magnification of the 35mm Plossl cannot compensate for the loss of focal ratio provided by the 55mm Plossl. BUT I did also see some benefit on several targets notably the Rosette, Horse Head & Running Man. Looks like I need to use both. The dark lanes in the open clusters M37 & M35 were an unexpected bonus and I think I will be trying the 5nm Ha filter on other non-nebula targets (M45 & M13 for instance) in the near future. I have looked on the internet for some Ha images of the open clusters but nothing was immediately found that showed what I was seeing? Perhaps one of the NV phonetography guys can get a shot of this feature? Its forecast clear again tonight so I packed up early so I could get some sleep in preparation.  
      Hope you are getting some clear skies too?
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