John

Good list of "Moon-proof" targets there If a planet is close to the moon in the sky I think that is often an advantage. I've noticed that planetary colour tints look more saturated when they are bathed in a bit of moonlight. Maybe the same for coloured double stars ?

I think Sirius has been a bit steadier than previous winters when I've observed it. Betelgeuse seems to be more or less like it's old self. I have found the Pup star a bit easier than previous years but I guess I've had more practice and the separation is more or less the max it will get now.

The Baader zoom comes with 2 barrels - a 1.25 inch one and a 2 inch one. It is a 1.25" eyepiece and the barrel you use does not change that but some people prefer to put it into the 2 inch adapter because it is quite a large eyepiece. Full 2 inch eyepieces are pretty weighty bulky things but they can show about 60% more sky than a 1.25 in the same focal length:

Are you prepared to go to the 2 inch format ? If you stick with 1.25 inch you can get a little more true field than the 25mm BST gives, but not a lot more.

I sometimes find a 6x30 finder easier than a 9x50 for that reason. For more detailed and precise "hopping" the additional aperture and scale can be useful though. As the seasons go by I do still need to remind myself of where seasonal targets are if I have not observed them for a few months. The first "hops" on a seasonal target can be a bit embarrassing

Last night I was observing Sirius A and B again using my 12 inch dobsonian. The gap between the pair is currently about 11 arc seconds so about as wide as it gets during their 50 year orbit. The actual distance between Sirius A and B varies between 8.2 and 31.5 AU so at their furthest apart a distance similar to that between the Sun and Neptune lies between them. At their closest approach the distance is a bit closer than the Sun - Saturn gap. So the above gives a little idea of the scale of what we are observing over the 8.6 light years between us and the Sirius system. With Sirius A being about twice the physical size of the Sun but 25x more luminous and Sirius B about the physical size of Venus, the system would make a fascinating spectacle from, say, .5 of a light year distance I would think

Great sketch !. If not a 100% split, it is very close indeed. I think the challenge is that our eye and brain tend to "join things up" if we sense they might be there from the other evidence, ie: the heavy notch between what are virtually touching airy disks. IMHO the "cleaner" star images presented by a refractor make it a bit easier to determine whether that black gap is really present in full or not although the larger aperture presents a smaller airy disk so the split will be there if a little masked by diffraction effects. It's a strangely compelling business, isn't it ?

Great report, I enjoyed reading it I sympathize re: your LP issues - I have the Bristol glow to the NE and the Newport / Cardiff glow to the SW so those horizons are not productive unless targets are well above them. I find that using a bit more magnification does increase the contrast between the darker and brighter parts of the Orion Nebula as well. Last night 200x was wonderful for examining that central area (fishes mouth etc) with my 12 inch dobsonian.

I've just been doing some experiments with my Vixen ED102SS (focal length 663mm), the Baader 2.25x barlow and the Baader T2 prism and zoom eyepiece at 21.5mm. Target was the top of a conifier about 200 metres away. Interesting results: - No barlow = focuser drawtube 55mm extended at focus. - Barlow in the diagonal (so 2.25x amplification) = focuser drawtube 49mm extended at focus so a manageable amount of inward focuser travel. - Barlow before the diagonal (much higher amplification - maybe 4x-5x ?) = ran out of OUTWARD travel of focuser. With focuser drawtube at max extension and holding the barlow / diagonal / eyepiece unit at sharp focus I reckoned the extension would be around 115mm so much, much further out. Matches @GazOC's prediction but more so than I expected. How relevant to your situation this is Mr Jones, I don't know and the proximity of the target might have made a difference as well but it did demonstrate that the difference in focus point, depending on where you place the barlow, can be very significant. I expect the optical element of the Baader 2.25x has a shorter focal length than that of the Tak 2x barlow. Kept me busy on a boring Sunday morning anyway

I've owned a couple of the Baader 8-24 zooms, a Mk II and a couple of Mk III's. I thought they were pretty good eyepieces although I found the AFov restrictive at the 24mm end so really treated them as 8-20 zooms. The field stop edges get mushy as well at the longer end which I'm not keen on. I found the light transmission when observing galaxies and nebula suffered a bit with the zooms compared with a good fixed focal length eyepiece. Not massively but noticeable when I changed eyepieces from zoom to fixed FL when observing Messier 82, for example. I would not have a zoom as my only eyepiece but I find the couple that I currently have (not Baaders as it happens) useful tools to have in the eyepiece case.

The only barlow that I use with my FC100-DL is the Baader 2.25x Q-Turret which is used after the diagonal and, while eating up a bit of inward travel, comes to focus OK. If I put that before the diagonal it gives more amplification (3.5x I'd guess) but also needs a lot more inwards travel so a similar situation. The Baader has the optical elements within the 1.25 inch barrel though so the risk of it impacting the prism is much lower. The Baader is probably not as good optically as the Tak of course. I'm fortunate to have a good range of short / very short focal length eyepieces so I tend to opt for those more often than using a barlow. It seems to be quite complex to assess the impact that a barlow will have on the focal point when used in different configurations. I guess someone with optical design expertise could work it out if the focal length of the barlow is known Is the focal length of the Tak 2x barlow given anywhere ?

Is this the barlow ?: https://www.rothervalleyoptics.co.uk/takahashi-2x-barlow-lens-125.html It does say that the amplification if used after the diagonal will be diminished. It seems an odd design to me - a "shorty" body and 1.25 inch barrel but a rather long optical element section with the potential, as you say, to impact a diagonal prism / mirror surface There is a very recent thread on another forum where folks discuss similar issues that they have had with this barlow: https://www.cloudynights.com/topic/749134-takahashi-2x-barlow-vs-others/

As Jeremy says, probably one of the very best 4 inch refractors made, or possibly ever made. Congratulations Out of production as well now

The Nexstar 6SE optical tube will fit onto the mount and be carried very well by it. You might need to check where the finder mount will end up if you switch from the SE alt-azimuth mount to the EQ5. The 200mm F/6 optical tube of the Zhumell Z8 will be just about OK on the EQ5 for visual observing but the mount is not capable of handling that tube for imaging.

Great report Rob The Hippalus Rilles were showing wonderfully well tonight !

Thanks, but it's not my image (I rarely take any) That one was from the Lunar Orbiter IV I think. I should have given a credit for it.

Excellent stuff ! You did well on those fainter face on galaxies (M33 and M101) they can be hard even without the moon around. We are getting some great reports on the forum with these clear skies (at last) And you did manage to find some words ......

Super report - nice to read your enthusiasm ! I've just bought my 12 inch dob in after a nice session. Thin cloud is creeping across the sky so no point in hanging around out there. Finished on high notes of Sirius B followed by the Eskimo Nebula. The planetary nebulae such as the Eskimo hold up quite well even with a bright moon in the sky. The moon was really lovely as well wasn't it ? Glad you are having fun - that's what it's all about

Very crisp moon here. 454x with the 12 inch dob. Alpine Valley rille and 6/7 Plato craterlets, possibly more. Hadley Rille really well defined. Highlight at the moment are the Rimae Hippalus. Three concentric rilles and a faint 4th one, running for around 190 km:

Sounds like a possible plot for a thriller novel / movie: "The Masuyama Conspiracy"

If Zaphod Beeblebrox has a solar setup, that would be it !

I have the 12 inch dob out but according to "Clear Outside" I've got until around 10:00 pm until clouds arrive. Between now and then I can pretend to be an Apollo astronaut nearing the moon using my new 4.7mm Ethos eyepiece

This thread is about the Rowan AZ100 alt-azimuth mount. Have you posted this in the wrong place perhaps ?

That's the challenge. You might actually be best to stick with the 25mm Tele Vue plossl as your low power for now. They are well corrected eyepieces and the exit pupil generated (eyepiece focal length divided by focal ratio of scope) is 5.3mm which is useful. You can get eyepieces that show more sky but to get such eyepieces that show well corrected wide fields in an F/4.7 scope, has quite a price tag associated with it.

If the mount is perfectly polar aligned the declination drive is not needed, in theory. You could make any declination adjustments using the manual slow motion. You can get single axis drive systems but, with the hand controller and battery pack, they seem to cost a good chunk of a dual drive system. I only ever used such drives for tracking when observing so where imaging is concerned, my knowledge runs out real fast !