John

Thats a step in the right direction at least

Good "Heads up" Chris. If I get any chance to observe (pretty iffy forecast here as well) I will use a wide angle eyepiece to get both in the field of view together, which should be nice. It's not a bright comet but well worth a look I reckon, especially when it's near something interesting in the sky

Depends on the thickness of the scope tube wall and the profile of the finder mount I guess.

I've seen a sort of metal adhesive tape used for this purpose. This sort of thing: https://www.ebay.co.uk/itm/Silver-Mirror-Tape-Self-Adhesive-Hoop-Tape-Lures-20mm-wide-x-10m-long/292264417158?hash=item440c511786:g:798AAOSw~ZBZw7au

USA made products (which the Rigel is) often use imperial theads. I was not aware that the hole in the Rigel base was threaded though. I don't think the ones on my Rigel are

Great report Mark I'm glad you like the 6mm Ethos - it seems to be gathering quite a fan base as one of the best of the range. I envy you your views of the Helix - my horizon in that direction is so cluttered that it's very difficult to catch sight of it from my garden

I think £700 is a high price for an alt-az mounted 80mm achromat as well. If it offers performance in the Vixen 80MF league then there might be some interest and / or if the link with Takahashi was stronger. But as it is I feel that it is sort of "betwixt and between" as it were

With the exception of the sliding dew shield (which is a nice feature) my interpretation is that the DZ has noticably improved optical characteristics over the original FC range, when used with a focal reducer and, on paper, very slight improvements when used at F/8. At it's native focal length I wonder if there will be any noticable difference in terms of visual performance over the DL ? though. Spotting visual observing differences between the DF/DC and the DL is apparently well nigh impossible in the real world (technically Tak claimed that there were some modest ones) so I'd expect the differences between the DL and the DZ to be very, very hard to spot. I expect that the production run of the DL will stop at the two batches of 100 each that have been produced to date but it will be interesting to see if Takahashi maintain the F/7.4 FC 100 variants as well as the F/8 DZ The FC 100s are all brilliant scopes so it's hardly a chore to own one of the original ones

1. Seeing stuff that I have not seen before. 2. Seeing stuff that I have seen before, better. 3. Showing stuff to others who have not seen it before.

I really hope you get it Gerry and I 100% understand what you mean by the above

I think the point about the dob is that you get the most aperture and therefore the most potential performance per £ / $ spent.

By the way, I hope you don't mind me tagging this evenings observation on to your thread on your Friday night session Marvin ?

Thats the fella ! - nice shot Paul I've packed up now but my last view of the comet tonight showed it just outside the triangle, just to one side of the lowest star in that group of 3 in your image. It is moving fast, this one.

Not yet Dave - Triangulum is not well placed for me until the early hours and the weather has not been good lately. It's on my "to do" list though

I'd agree that the 8-24 zoom would be more comfortable to observe with than the 11mm TV plossl. Zooms work really well for both white light and H-alpha solar viewing I've found.

The TV plossls require around 8-10mm more outwards focuser movement to reach focus than many other eyepiece types. That might be the problem. Pulling the eyepiece a around 1cm out of the focuser drawtube might let you reach focus with it.

Just picked up c2018 w2 Africano with my ED120 refractor. Just now it's in a triangle of mag 7 - 9 stars just above the circlet of Pisces bit wont be there long - it's moving rapidly. Certainly brighter than my last sighting because I found if fairly easily with the 4.7 inch aperture at 43x. The comet stood out from the background better with a bit more magnification though - around 80-90x seems useful. It's currently around 75 million KM away from Earth apparently. Edit: I've been comparing the brightness of the comet with the galaxy M110 in Andromeda and I reckon it's a touch fainter than that. I reckon magnitude 9.5 would be about right ?

The original poster is in Australia so Jupiter will be high in the sky there. Unlike here in the UK I understand that the image was simply used to illustrate the issue - it's not one that the OP actually captured.

Lots of good advice here. I have seen an image just like the one you post very occasionally with my 12 inch scope. What caused that for me was either a fogged eyepiece because it got too cold and fogged as my eye approached it and also, once, a dewed up secondary mirror but I've only had that on a very peculiar night weatherwise. Normally my primary and secondary mirrors stay clear. To stop my eyepieces getting too cold and fogging I keep them just above the outside temperature and that does the trick. A foam lined eyepiece case helps because the foam retains some warmth for some time. An out of collimation scope does not show quite what your image pictures - if the scope is out of collimation the contrast and detail on the planet is reduced / harder to see but the hazy halo effect you show is not collimation-related I feel. It looks like classic fogging / misting of an optic to me.

My cases were quite cheap - I got them in Maplins sale a few years back. About £15 each I think. The contents cost a fair bit more though .......

I agree with this having owned and used both BST's and a couple of the Hyperion zooms. What you gain is the convenience of the instantly variable focal length rather than any notable optical improvement. You would still probably want a low power / wide field eyepiece as well as the zoom though - at 24mm setting of the zoom has a rather narrow field of view (in common with most zooms). To get a step up from the BST's you might need to think about Explore Scientific 68 or 82 degree ranges, Nirvana 82s or even the Tele Vue Delos or Pentax XW's if you really want to push the boat out and let your 14 inch dob really show what it can do.

My society tries to offer public sessions at our observatory a couple of times a month from October through to around June but the reality is that more than 50% of these get scrubbed due to poor conditions. If someone was relying on such sessions for their observing then they might only get a handfull in during a year, at best. As Iain says, a spontaneous approach with your own gear at or close to home will usually deliver much more observing.

You should do some more scope and eyepiece reviews Piero - your eye is clearly very well tuned for spotting these aberrations

I'm motivated to have another try at this one now ! I did try once but found it hard to track down due to how far from the visible core of M31 it is (as Neil says). These observation reports and sketches are very helpful for aspiring Mayall II observers !

I'm surprised to hear that. I've seen other issues such as field curvature with refractors but never coma. https://starizona.com/tutorial/coma/