John

1 minute ago, Nigella Bryant said:

There is a barge on the NEB, imaged on 24th November

Excellent, thanks. Nice image 🙂

Last view tonight before coming in - there seems to be an elongated dark feature on the N side of the NEB, currently around the central meridian. It looks a little barge-like. I've not seen a barge for a while on Jupiter.

Sky & Telescope guide to jovian features:

30 minutes ago, John said:

Europa's shadow is crossing the jovian disk with Europa itself ahead of it. I can't see the moon itself currently - maybe I'll get a glimpse as it nears the planets limb......

 

Yep - Europa itself is now showing as a small bright disk close to Jupiter's limb. It's shadow is nearing the central meridian of the planet. Nice to get the two showing against the disk at the same time with the relatively small aperture 🙂

Just like this:

Saturn then Jupiter with the 100mm refractor so far tonight. It's cold so I'm popping in and out. The sky is quite clear now so I will have a look at the moon shortly.

Europa's shadow is crossing the jovian disk with Europa itself ahead of it. I can't see the moon itself currently - maybe I'll get a glimpse as it nears the planets limb. The shadow is nicely defined though. 180x seems an optimum observing magnification this evening.

Stellarium image of the event:

35 minutes ago, tico said:

maybe, can be a good zoom for the SW ED 80/600 ? 

It would give you magnifications from 75x to 200x with that scope. The whole of the mid to highest magnification range covered with one eyepiece.

I'm using mine right now to observe Saturn with my Tak FC100. Gorgeous views at 225x 😁

3 hours ago, JeremyS said:

... I generally try to avoid astro stuff from China (especially with a daft name), but this EP appears to be unique. 
 

 

Those were my thoughts when I bought mine Jeremy. I will be interested to know what you think of yours.

51 minutes ago, johnturley said:

Do you think that there is much difference in quality between the T2 Zeiss prism diagonal, and the non- Zeiss version apart from the different size. As mentioned, I was thinking of getting the latter with a built in 1.25in helical focuser, as an alternative to fitting a MEF3 Micro Edge Focuser.... 

 

I have not compared them myself. I have read that a few folks have noticed slightly less light scatter with the Zeiss version but only on the nights of best seeing and when observing certain targets. Most reports are that they perform the same.

When I'm using 2 inch eyepieces with my FC100-DL (which is infrequently) I use an AP Maxbright 2 inch diagonal or a TV Everbright 2 inch. 

59 minutes ago, johnturley said:

Agree, presumably you also need to get a T2 to 2in eyepiece holder, and that this doesn't cause any vignetting with the 30mm UFF (which I also have), and which I think has a field stop of about 36mm. 

According to Baader the T2 Zeiss prism diagonal has a clear aperture of 35mm.

The non-Zeiss Baader T2 prism diagonal has a clear aperture of around 32mm I think.

I'm ambivalent about the need for 2-focusers. 4 of my scopes have them, 2 don't. I find the focal ratio of the scope makes a difference to how easily things "pop" into or out of focus though. As I understand it, steeper light cones (faster scopes) have a narrower zone of apparent sharp focus than slower scopes do. 

1 hour ago, Mr Spock said:

Has anyone compared this to a Nagler 3-6 yet? At £75 v £424 it looks tempting!

I've compared it with the Nagler 2-4, Pentax XW's, Ethos 8, 6 and 4.7 and Astro Hutech HD orthos so far.

Not lengthy comparisons examining each minute detail of multiple aspects of the image being seen (I've not owned the Svbony for long enough !) but comparisons enough for me to realise that the Svbony 3-8 is a very decent performer. Last night I actually felt that the Svbony zoom at 5mm was showing Jupiter slightly better than the mighty Pentax XW 5mm. 

I'm not about to sell off the XW's or the Ethos on the basis of what I've seen so far but I have let the Astro Hutech HD orthos go to a new home. The Svbony zoom showed Saturn, Jupiter and the Moon as well as they did but with the additional comfort of 10mm of eye relief, a larger eye lens and 16 degrees additional AFoV. 

1 hour ago, phantomgod_06 said:

Yeah that is exactly what I am seeing. Would it be the same for planets or not? When I try to observe Venus I come across the same problem

The same applies to planets as well. Adjust the focus so that the planet looks as small and sharp as possible in the eyepiece. You might be surprised at how small planets look in the eyepiece, even the giants such as Jupiter and Saturn.

33 minutes ago, AndyM001 said:

Thanks for the replies, forgot to mention I live in Bortle 5, not sure if that makes a difference.

I've seen a couple of second hand Dobs for sale at reasonable prices, so if I purchased one of them I could potentially upgrade the focuser if needed.

My skies are Bortle 5 as well. The Skyliner 200P that I have recently acquired performs very well now that I've made a couple of minor tweaks to it. Optically it's very good indeed. I owned one about 10 years ago and have forgotten how good they are.

The focuser seems to have been a weak link in quite a few brands / models that I can think of over the years 🙄

1 minute ago, Franklin said:

Well I don't know for sure because I haven't succumbed to that but I would guess that the outer grubscrews are flat-headed for applying pressure to the Teflon strip and the central grubscrew is pointed and actually screws into the Teflon strip to prevent it from slipping out of place.

That sounds quite logical 👍

33 minutes ago, Franklin said:

Have you figured out why it says NOT to touch the middle grubscrew?

Nope. You know what happens when there is a screw, bolt or knob labelled "do NOT touch" though 😈

1 hour ago, Franklin said:

One thing that I've noticed with regard to these "add-on" fine focusers that attach to the original pinion shaft, is that they are fitted to the scope via a plate which in turn is fixed using the screws that adjust tension on the original R&P mechanism. This can cause problems and make the action "lumpy" and "gritty", for example if the pinion shaft is not perfectly true, which can happen if it's taken a knock, then this slight bend would be unnoticeable with the original focuser knobs which would just turn but with the "add-on" the fine focuser side is now fixed to the plate and any bend in the shaft will cause undue pressure and drag, again causing issues. Not the best design imo really.

This is true. The instructions for the Feathertouch micro pinion unit mention this and describe testing the pinion shaft to check it is straight. There are some useful photos in on the first page of this which show how the Tak FC pinion is held in place. Might be useful even if not fitting an FT:

Microsoft Word - MPA-TAK Instructions.doc (starlightinstruments.com)

9 minutes ago, Franklin said:

This is pretty much the same advice that I've seen on adjusting the Vixen R&P which is a similar design to the Takahashi. The idea is to allow the drawtube to run freely on the two lower rails, just being held there by the upper grubscrews and Teflon strip, rather than the pinion gear pressing up against the rack.

Yes it is very similar. I use this guide for my Vixen focuser:

Vixen Focuser Adjustments (miltonhill.us)

This guidance was posted by @mikeDnight on the CN forum. It refers to the FC100-DC that he had at that time:

The stiff focuser problem is easily resolvable! I noticed in a side by side comparison with a FL102 that my DC focuser was really quite stiff, so after giving it some consideration, I eventually plucked up the courage to try and rectify the problem. Now the focuser is buttery smooth and easy to move.

First remove the pinion by unscrewing the top cover and then the two screws on the brass plate underneath. It's a simple process and you can do no harm.

Next, remove the locking nut on top of the focuser. Now there are three small grub screws also on top of the focuser. The holes for these grub screws may be filled with glue to prevent tampering. The glue however is quite soft and a fine Allen key can be pushed through it. Unwind each of the three grub screws equally until the drawtube slides freely by hand. Then gently retighten each grubscrew evenly and a fraction at a time, until the drawtube feels firm but still easily moveable. Uneven tightening will result in image shift! Trial and error may be necessary to get it just how you want it.

Next, reattach the pinion by screwing the two screws holding the brass plate back on focuser. Don't overtighten these screws! Then reattach the pinion cover.

Mike

I found the same with the Skywatcher focuser, all though not as extreme as in the above photo. I now use a shorter eyepiece extension tube - 35mm whereas the original 1.25 and 2 inch adapters are around 50mm. This change means that the focuser is racked out a little further to get eyepieces to focus so the end of it does not intrude into the light path, or at least not as much. I can't say that I've noticed a difference in the views though, to be honest. 

It is also worth bearing in mind that not all eyepieces come to focus at the same point. There can be as much as 15mm difference depending on the brand / model of eyepiece. So that can affect the degree to which the focuser extends into the light path as well.

The focuser on my FC100-DL was rather stuff when it was new. I found that I could adjust the focuser to make it good to use. The process is documented somewhere online - I'll see if I can find a link. I then found the DL focuser fine to use for a few years but I came across a Feathertouch micro pinion upgrade at a reasonable cost so added that and now the focuser feels just the same as the full FT on my TMB/LZOS 130mm. I've not tried either the Tak or the Moreblue upgrades.

10 hours ago, Ags said:

What did you make of the AVX mount? Just a dressed-up EQ5, or something more than that?

It's closer to the HEQ5 than the EQ5 I thought. Of the ones I mentioned above it actually did the best job with the 130mm F/9.2 triplet. I didn't use the GOTO system so I can't comment on that.

My 130mm F/9.2 triplet has similar mounting needs to a 150mm F/8 doublet in terms of weight and length. In the end I ditched EQ mounts and found a superb T-Rex alt-azimuth mount, which did the job far, far better than any of the EQ mounts.

Another thing very noticeable tonight is the apparent size difference in the eyepiece between Ganymede and Europa. These two are on the same side of Jupiter tonight and not too far apart. The physical size difference between them (illustrated below) is clear from the eyepiece view. Their apparent diameters (according to Stellarium) are 1.78 arc seconds for Ganymede and 1.06 arc seconds for Europa. 

I've just popped out with my 100mm refractor because I noticed that a patch of clearer sky had appeared with Jupiter and the moon in the middle of it. I got some very nice views of Jupiter with the GRS just past mid-transit. The NEB is showing lots of interesting details currently. In particular there is what looks to be a noticeable pale "bay" on the southern edge of the NEB to the NW of the GRS's position. Both the NEB and the SEB seem to have twists or knots in them and variations in the darker colouration. Far from the plain bands that sometimes show. The GRS seems a stronger salmon-pink tone that last time I saw it as well. 150x - 180x seems to be delivering the strongest contrast variations in the jovian features this evening.

Glad I bothered to get out 🙂  

26 minutes ago, bosun21 said:

My Starfield 102 has 8 or 9 baffles in the focuser tube as well as the main tube being baffled. I kept going cross eyed trying to count them 

 

Baffled by baffles 😁

My Vixen has quite few in the focuser drawtube as well plus 4 in the main tube.