John

4 hours ago, Merlin said:

Add a foot long extension to the top of the main tube from, say, lightweight camping mat.This will keep stray light from entering the main tube.

Manufacturers persist in making their main tubes too short at the top, probably to make them look more portable.

Agreed. I use a "half moon" light shield around the top of my tube on the side where pesky local lights have been known to shine and it has improved contrast noticably on DSO's. 

3 hours ago, FLO said:

 

The discussions went well so I can confirm we (with Ian King) will be at the International Astronomy Show 15th – 16th November 🙂 

We will post details in a separate discussion soon. 

Steve 

Good news ! - look forward to meeting up with FLO folks again there

Just now, Stu said:

Too long for carry on unfortunately. Sure it will be another very nice scope but would rather they launched a 125mm, or even a 130mm doublet.

I have the feeling that a 125 doublet might be along sometime. I may be wrong but it would not surprise me in a couple of years if the FC line was a single 100mm (the DZ) and also included a 125mm and maybe even an 80mm ?

14 minutes ago, Highburymark said:

Interesting addition to the range. One of the nice features of the F/7.4 FC-100DC is its shortish tube, which allows it to fit into cabin luggage for trips abroad. However that does require the non sliding dew shield to be unscrewed. Haven't looked at the specs of the DZ yet but if it's airline portable at F/8 that will be a big selling point in my view. 

Apparently, with the dew shield retracted and the diagonal plus extensions removed from the focuser the DZ measures 595mm in total length. It weighs 3.8kg.

Takahashi FC100-DL on Giro Ercole mount observing Jupiter this evening. Lovely views at 180x with the Pentax XW 5mm

It's not OOUK's fault. It's eyepieces / imaging devices / 3rd party focusers / the speed of light that are wrongly configured

Ooops !!!! - I don't know where I got F/8.2 from - the DZ is F/8 "native" focal ratio. Must have misread something !

19 minutes ago, 883 said:

Perhaps it would have been simpler to equip the DC/DF with a sliding dewshield...😐 

That would require a re-design of the objective lens cell which is perhaps not a small matter ?

Looking at the performance charts and spot diagrams and comparing them with those of the FC-100DL I think the important point is not so much that the peformance at F/8.2 looks to be very, very close to that of the F/9 but that when the .66x focal reducer is used, the spot sizes remain very tight even at F/5.3. This seems to me the key feature optically of this doublet - it remains a very high peformer even when focally reduced. Imagers will be attracted by that.

F/8.2 fluorite doublet which fits between the F/7.4 and F/9 of the DL and the DF / DC models. Sliding dew shield, which is a nice touch.

The performance charts look pretty good - they claim that it's as good as the F/9 but with the advantage of the faster focal ratio and faster again for imaging with the .66x reducer in use - just F/5.3.

It's a sort of homage to the original FC series back in the 1980's according to the translated  web page.

Maybe an 125mm version on it's way as well ? (thats just a guess !).

Another desireable Tak !

Maybe the F/9 won't be produced again and the F/7.4 models will be replaced in due course by this single multi-use focal ratio model ?

To be "faulty" in that way the field stop and internal optical elements of thye eyepiece would have to be moved within the body of the eyepiece by a large amount which, as far as I can tell from what I know of the design, is virtually impossible unless someone has dismantled the eyepiece and re-assembled the elements (there are about 7 or 8 of them) completely incorrectly.

It would be very unsual for OO to blame their own scope though

Just now, MSammon said:

It was the Myriad XWA 20mm

Thats odd - when I tested the Myriad 20mm I seem to recall it came to focus in my 12 F/5.3 OO scope at about the same place that the 21mm Ethos does - plus or minus a mm or two

If and when you decide to go for a Moonlite focuser, go for the 10 inch tube fitting kit. The 12 kit fits Skywatcher, GSO, and Orion (USA) tube diameters but Orion Optics tubes are a bit slimmer so the 10 inch kit is a much better fit I found.

Orion Optics tend to position the focal plane of the primary mirror further outside the tube wall than the other manufacturers I've mentioned here (the slimmer tube plays a part in that) which is why you need extension tube(s) or the Moonlite risers to get eyepieces to reach focus.

49 minutes ago, MSammon said:

Are the Moonlites a straight swap John with no drilling? 

I did need to make 2 holes in slightly different positions but the tube is aluminum so this was not a difficult job.

See how you get on with the focuser that is already fitted though - it looks a decent unit.

What 20mm eyepiece are we talking about here by the way ? - most eyepieces have a focal plane that is within 10mm of each other but one or two types vary a lot so will need much more focuser movement than ordinarily necessary.

31 minutes ago, MSammon said:

I think my Orion Optics VX12L is actually lighter than my Synta made Orion XT10 Classic. Certainly easier to carry. 

Those large altitude bearings attached to the tube rings make good carrying handles for the optical tube section.

As above for the finder adjustment. You want the X hairs to match as closely as possible with the centre of the view through the scope, at high power if possible. Precision with this will make finding things more precise. Once aligned, the finder should generally hold it's position but you may need to check it and re-adjust from time to time.

I found that I needed a 50mm extension tube to get my eyepieces to focus. Orion Optics supply one (I see it in your focuser) but the one I had was a bit crude so I swapped to one with a compression ring fitting.

I've now moved to a Moonlite focuser which stands further off the scope tube so no extension tube needed.

The Orion Optics dobs are quite a lot lighter than the Chinese alternatives. The aluminum tube of the Orion Optics saves weight and those MDF Chinese dob mounts weigh a lot !

Excellent scope

My 12 inch dob is the same optical tube assembly but on a dob mount that mirrors the Orion Optics design in baltic ply. Works a treat

From the test sheet, it looks like one of Orion Optics very good primary mirrors

Great result Matthew

Very dependant on the seeing conditions this one and with it so low down, those are highly variable.

I found that the DMB NBP filter (a UHC type) bought out green and red / purple tints in the Orion Nebula when used with my 12 inch scope.

Innovative azimuth axis tensioner !

Where do you keep it Mark ?

This approach does work - I use a 100mm aperture mask with my 12 inch dobsonian from time to time. The result is visual performance virtually identical to my 4 inch refractors. As I have a couple of very nice 4 inch refractors I don't do this often though.

The plastic dust cap apertures do work and give you something around a 50mm aperture I seem to recall. A rather big 2 inch scope !

10 minutes ago, rwilkey said:

Hi John, one of the reasons I got into double stars is because you can see colour, I love looking at Albireo and the Easter-egg double in CAS (Ʃ 60) for example, and I think I am a bit older than you!

I seem to be quite good at detecting relatively small brightness differences but I'm not so good at spotting subtle tints. Maybe I ought to get into variable star observing ?

Very nice report Stephan

I might have a go for some of those with my 12 inch dob tonight.

From Greece, your 130mm newtonian should show the planets somewhat better than we are getting the here in the UK. You will be able to see all 7 planets with that scope when they are in good positions in the sky. With good seeing you should see some detail on Jupiter, Saturn and Mars at opposition. 4 moons at Jupiter, maybe 5 at Saturn on a good night. The phases of Venus and Mercury will be visible and Uranus and Neptune as distinct but very small disks rather than pin points as stars are.

Supernovae have never appeared as more than faint point sources to me even with my 12 inch scope - like a faint star that was not visible before and does not tend to stay visible for long. All the ones we have seen recently have been in other galaxies so far, far away. The last to be observed in our galaxy was in 1604 I believe. I was not around then !

Great early big aperture reports Mark !

The sky last night was excellent even with my little 100mm refractor with the Veil and Owl nebulae being just 2 of my targets. Must have been fun with 5x the aperture to play with !