dweller25

Snap, except I saw Europa merging with the planet, but my seeing was poor - I could see a stream of air moving across the planet !

Tonight at 7pm….. Europa will start transiting Jupiter and the GRS will be visible.

Hello @Mr Brownstone and welcome to SGL…… What vlaiv said 👍 .

@MalcolmM Took the M180 out of the house at 5:40pm, started the fan running on the front and left it until 6:10pm. Looked at Jupiter at x178 and it was ok but not super sharp, could make out the GRS and several bands but a bit soft. Jupiters moons were trying to show an airy disk but it was not steady. Turned the scope onto Bellatrix and defocussed a little, the outer ring shows small protruding spikes - this could be the hairiness you see ? The scope had clearly not cooled down. But there was no lateral air movement across the out of focus image - so seeing was good. Fan put back on and waited until 6:30pm. Back onto Jupiter at x178, much better views and the moons were showing airy disks. Back onto Bellatrix and that was much better too, the outer ring showing much more stability and slight spikes/hairs. In focus showed perfect collimation then slight mis collimation - scope still not cool. Fan back on until 6:45pm, back onto Bellatrix and it was almost stable at x178, very slight spikes when defocussed and perfect collimation. Fan back on until 7:05pm, back onto Bellatrix at x178 - stable. Turned the scope onto Al Kab at x321, stable, no spikes, perfect airy disk, good seeing. So even with active cooling it took 1 hour and 25mins to cool from the house ! BUT - an obstructed telescope will never quite match a refractor for sharpness 👍 Hope that helps.

From what you say about Polaris and the views of the planets I suspect your collimation is very good and perhaps not worth worrying about too much. I think seeing and that final bit of cooldown where the boundary layer (where residual heat hovers on the primary mirror surface) may be the issues. You should be able to see the airy disk of a star at perfect focus at x300 if your scope is cooled and seeing is decent. I see this regularly in the M180 but I always use a fan. In fact I will get the Mewlon out now and give it a try…

Aah, good idea 👍

Which Mewlon did you have and can I ask In what way was it better ? I’m interested because I tried that but even with filters the secondary got dirty and its harder to clean the secondary than the primary. And the cool rate of the primary was much slower.

Yes Alnitak is too low to assess collimation and it’s a double star - I aim for something at least 70’ high, I aim for Al Kab in Auriga this time of year, which means you are looking through a bit less atmosphere - it all helps ! PS - I have seen a scope that was not fully cooled showing it was out of collimation. Later when it was fully cooled it had perfect collimation 👍

Don’t give your day job up 👍🙂

@MalcolmM I have the same two scopes as you and know how long the Mewlon takes to fully cool down, particularly when compared to the FC100. I aid the Mewlon cooldown by resting a cooling fan with a USB powerbank on the front of the spider blowing air onto the primary and down the primary baffle and OPEN visual back. Even with this active cooling it takes a good hour to fully cool the primary and primary baffle ! The fan solution is not expensive and works well. Once fully cooled, to get the best out of the Mewlon it must be well collimated, I use this method - always making sure the star is perfectly central in the eyepiece before tweaking the collimation screws at x300, step 4 should be done at perfect focus.

The Vixen GP also uses M10 👍🙂

I like both EQ and Alt-Az EQ so I can draw at the eyepiece. Alt-Az lets me get out and observe really quickly with no fuss.

The focus knob does not zoom the image larger as you turn it, it just makes the image come to focus when you go the right way. As others have said, If the view of the object gets bigger when you focus just turn the focus knob in the opposite direction 👍 For the planets you need at least a 10mm eyepiece to give x150 magnification.

For visual I set the latitude scale as accurately as possible, then use a compass to point it to true north - which for my location is about 2’ from magnetic north. Then I level it up and I am ready to go - may need to make small adjustments every 10 minutes. £250 sounds about right.

@quasar117 The Vixen GP has a 60mm snout fitting. I use mine on a UNI28 with the 60mm recess fitting.

Jupiter is getting smaller now but the turbulence in the North equatorial belt is very obvious. I had fairly good seeing tonight and could just make out a projection on the south side of the NEB. Europa was in transit but I could not see it. The Great red spot looks more orange to me nowadays. North is up and the preceding side is to the left. Drawn between 18:00 and 18:10, 25/2/24 TSA120, x175, seeing AII PS - Jupiter was not this big in the eyepiece !

Looking good Mike 👍

Last night (24th Feb) around 7:30pm a meteorite passed directly over me. In a brief few seconds it was bright, then disappeared, then became bright and disappered twice more. So I’m guessing it was bouncing off the atmosphere ? It was a nice sight 🙂👍

Just imagine what you could see in a 12” Mike 😈

Jupiter is slipping into the west now but heres a chance to see the Great red spot, a Europa transit and a Europa shadow transit all between 6:15pm and 7:00pm.

You already own a classic frac 👍🙂

@Sunshine Did you buy it ?

Hello Charles I am also a spectacle wearer and observe with them on as I like to draw at the eyepiece. I look for eyepiece with a long eye relief, typically around 20mm eye relief is good for me. Roughly, roughly Longer focal length eyepieces like your 20,35 and 32mm will have lots of eye relief, the 15mm and below is where you may struggle ? One solution is to take your specs off but I prefer to leave them on and then Barlow the longer focal length eyepieces, so with a x2 Barlow your 20mm eyepiece would become a 10mm but still have long eye relief 🙂 You have a good scope, for the planets you need a magnification of around x180 which is a 4mm eyepiece or an 8mm eyepiece with a x2 Barlow. The eyepiece magnification formula is : magnification = focal length of telescope/focal length of eyepiece. Your scope has a focal length of 750mm, so magnification for a 4mm eyepiece = 750/4, which is x187 Apologies if you know all this 👍

@SwiMatt I see you are using your Skymax 127 on a light weight alt-az setup. Is this because you need to travel to an observing site and need a small light setup ?

Hello @SwiMatt One factor that can drastically effect planetary views is thermal equilibrium of the primary mirror. It can take a long time for the thin boundary layer of residual heat to disappear from the surface of the primary. To overcome this you could try putting a couple of layers of reflectix around the OTA. This will effectively lag the scope preventing the temperature gradient between the optics and the cooler OTA walls. This will allow you to use scope immediately when you take it out and will prevent dew formation on the corrector for much longer.